# AttestPage

> Signed evidence about web pages for AI agents, paid per call with x402. Check whether a quote appears on a page or check all the citations in an answer at once, fetch a page with a verdict on what came back, check links, check that package names exist on npm, PyPI or crates.io, or timestamp a hash. Every answer carries an Ed25519-signed receipt you can check offline. A receipt records what our fetcher saw at a given time; it does not show that a statement is correct.

Prices are per call in US dollars, paid in USDC with x402 v2 on Base Sepolia (a test network). A request with a body that fails validation is refused before payment and never charged; a POST with an empty body gets the 402 offer, so the price can be read. Every page below is also served as HTML at the same URL without `.md`.

To pay after a 402, read the offer from the `PAYMENT-REQUIRED` header, sign it with your wallet, and send the same request again with the signed payment in the `PAYMENT-SIGNATURE` header; the paid answer carries `PAYMENT-RESPONSE`.

Which route: you have a URL and a quote, use verify/quote; you already hold the text, use verify/text-quote; several quotes from one page, use verify/quotes.

The live offer is `eip155:84532`, Base Sepolia (a test network): payments use free test USDC from a faucet, and no real money moves.

Install the client first: `npm install @x402/fetch @x402/evm viem`.

Get test USDC first (test mode only: Base Sepolia, `eip155:84532`, free; skip it on the live offer, which is real money):

1. Make a wallet key: 0x followed by 64 hex characters (a 32-byte private key). In Node: `import { generatePrivateKey } from 'viem/accounts'; console.log(generatePrivateKey())`. Put it in `ATTESTPAGE_X402_KEY`.
2. Get its address with `privateKeyToAccount(key).address` (the example below prints it).
3. Ask the Base Sepolia faucet: POST `{"address": "<your wallet address>"}` as JSON to `https://api.run402.com/faucet/v1`; one drip per wallet and IP every 24 hours, no key or account needed. If it answers 429, wait for the limit to reset (about 24 hours) or fund the wallet address with Base Sepolia test USDC from another source (for example the Circle faucet at faucet.circle.com, or ask your operator). One drip is 0.25 USDC, enough for 25 calls at 0.01 USDC (US$0.01) each.
4. Then pay with the example below. No ETH is needed; the facilitator pays the gas.

Example with an x402 v2 client (installed above; save as an `.mjs` file for top-level await), paying one check on Base Sepolia (a test network):

```js
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';

// ATTESTPAGE_X402_KEY: 0x + 64 hex characters, funded with USDC (steps 1-3) before this runs
const account = privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY);
console.log('wallet address', account.address);
const client = new x402Client();
registerExactEvmScheme(client, { signer: account });
const payingFetch = wrapFetchWithPayment(fetch, client);
const res = await payingFetch('https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ url: 'https://www.iana.org/help/example-domains', quote: 'These domains may be used as illustrative examples in documents' }),
});
console.log(res.status, res.headers.get('PAYMENT-RESPONSE'));
const body = await res.json();
if (res.status === 200) {
  console.log(body.result ?? body);
} else {
  // not a payment problem when the status is not 402: 400 is a bad request (never charged), 429 slow down, 5xx try again later
  console.error('not paid or refused', res.status, body);
}
```

There is no free trial at the moment; use the free samples instead.

## Paid endpoints

- [POST /v1/verify/quote](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-quote.md): Body fields: `url` (required), `quote` (required), `match`, `case_sensitive`, `threshold`. US$0.01. Use when you are about to quote or cite a web page as the source of a claim: send the URL and the quote word for word, and get back exact, fuzzy or none, offsets, context, page verdict, an additive `evidence` field (the matched passage and a one-line reason) and a signed receipt, so a misquote is caught before a user sees it. A fact check of the claim against its source. For a paraphrased claim, the 3 passages that share most of its words are evidence to judge, not a verdict. For 3 or more quotes on one page, verify/quotes costs less. PDFs are read too, on the full service (edge: 501 not_on_edge, uncharged), with pdf_page and pdf_page_end.
- [POST /v1/verify/quotes](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-quotes.md): Body fields: `url` (required), `quotes` (required; max 20 items), `match`, `case_sensitive`, `threshold`. US$0.02 per batch of up to 20 quotes on one page. Use when you are about to quote one page several times. The verify/quote verdict for each quote, the page fetched once, under one receipt; one price for 1 to 20 quotes, so from 3 quotes up it costs less than one verify/quote call each. A call where every quote fails answers 422, not charged, under the same per-IP limit as verify/citations.
- [POST /v1/verify/text-quote](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-text-quote.md): Body fields: `text` (required), `quote` (required), `start`, `end`, `match`, `case_sensitive`, `threshold`. US$0.005. Use when you already hold the source text (a file you read, a tool result) and are about to quote it. Send the text and the quote, get exact, fuzzy or none and a signed receipt; nothing is fetched. Declared offsets (start and end) check one slice of the text; declared offsets are raw, result offsets are into the normalised text. The receipt attests the hash and the match, not where the text came from.
- [POST /v1/verify/text-quote/preview](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-text-quote.md): free, 30 a day per IP address. Send the same body as POST /v1/verify/text-quote and get back exact, fuzzy or none, the score and the number of matches. Use when you want the label before paying. Not signed: no offsets, no receipt.
- [POST /v1/verify/citations](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-citations.md): Body fields: `citations` (required; max 10 items), `match`, `case_sensitive`, `threshold`. US$0.10 per batch of up to 10 quote and URL pairs. Use before giving an answer that cites web pages. A fact check of each cited claim against its source: the verify/quote verdict for each citation and the verdict on each page, each page fetched once, under one receipt. For 1 to 9 pairs, one verify/quote call per pair costs less. A batch where every citation fails answers 422, not charged; each IP address gets 6 of those a minute, then 429 `rate_limited` (`details.reason` `uncharged_failures`) with `Retry-After`.
- [POST /v1/verify/document](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-document.md): Body fields: `document` (required), `format`, `match`, `case_sensitive`, `threshold`, `min_words`, `part_size`, `part`. US$0.10 per part of up to 10 quote and link pairs. Use before sending a finished answer or report that quotes web pages. Send it as written; its quotes and their links are found and checked on the live pages, with offsets in your document and on each page. For a part of 1 to 9 pairs, one verify/quote call per pair costs less. Free preview at POST /v1/verify/document/preview (pairs, doc_spans/doc_spans_truncated for repeats, skipped with skipped_truncated and skipped_counts by reason, parts, price). The check response lists skipped the same way; too_short means a quote with fewer words than min_words, which is skipped and not checked.
- [POST /v1/fetch](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/fetch.md): Body fields: `url`, `urls` (max 10 items), `return_text`. US$0.002 per URL. Use when you need a web page as clean text, or to notarize one. Send a URL and get `page.content_kind` (real, bot_wall, js_shell, paywall, http_error and others), `page.http_status`, `page.final_url`, `page.title`, hashes, optional clean text and `injection_flags` (prompt-injection patterns found in the text), with a signed receipt as provenance: evidence of what the page said at that time. `page.content_kind` is our verdict on what the server sent: real (readable text), bot_wall (a named challenge page), js_shell (no text until scripts run), paywall, or an error kind. A soft block served with status 200 is caught only by known wording, so it can read as real. content_sha256 covers the full text: keep the receipt, and a changed hash on a later call means the page changed. The receipt is signed; check it free at /v1/receipt/verify. A URL whose host name does not resolve gets 422 `host_not_found` before payment, not charged. Example response, one line: `{"page":{"final_url":"https://www.iana.org/help/example-domains","http_status":200,"content_kind":"real","title":"Example Domains","content_sha256":"…"},"receipt":"eyJ…"}`. Send `urls` for up to 10 pages in one call, priced per URL, each with its own receipt. PDFs too, on the full service (edge: 501, uncharged): page.pdf with page_count, pages_read and truncated.
- [POST /v1/recheck](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/recheck.md): Body fields: `receipt`, `url`, `content_sha256`, `return_text`, `history` (max 10 items), `quote`, `quotes` (max 20 items). US$0.003. Use when you rely on a web page you read earlier and need change detection: send an earlier receipt or URL with its content_sha256, and get back unchanged, changed, gone or unreadable with the fields that differ, and a signed receipt naming both hashes. With `quote` (the quote of a verify/quote receipt, sent word for word), `quote.verdict` says still_exact, now_exact, now_fuzzy, now_missing or unchecked. Nothing is stored and nothing calls you back: re-check as often as you like (daily for 30 days is about US$0.09).
- [POST /v1/check/links](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-links.md): Body fields: `urls` (required; max 10 items). US$0.005 per batch of up to 10 URLs. Use when you are about to give a user links or citations: send up to 10 URLs, and get back the status, redirect chain, final URL, title and hash of each, so a dead, moved or blocked link is caught first. Each URL gets a link verdict: ok, broken, moved or unknown. An optional expected_text per URL is matched on the page and reported; it does not change the verdict.
- [POST /v1/check/packages](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-packages.md): Body fields: `packages` (required; max 10 items). US$0.005 per batch of up to 10 package names on npm, PyPI or crates.io. Use when you are about to install or recommend a package an LLM suggested: send each name with its ecosystem (npm, pypi or crates), and get back whether each is listed, its latest version, licence and known OSV.dev advisories (vulnerabilities, malware) under one signed receipt, so a made-up or known-bad package is caught before install. No advisory listed does not mean no flaws: not a security verdict.
- [POST /v1/attest](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/attest.md): Body fields: `sha256` (required), `note`, `idempotency_key`. US$0.002. Use when you need to show later that a file, answer or record existed unchanged. Signed, timestamped receipt over a SHA-256 you supply: provenance, evidence that the content existed at that time.

## Free

- [POST /v1/receipt/verify](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/receipt-verify.md): check a receipt against our published keys, free. Receipts are signed by iss https://still-rapids-9yt7.here.now (JWKS at /.well-known/jwks.json), not the origin; this is the free check. A paid answer's body has `receipt_id` and the receipt names the settled `payment.tx`.
- [GET /v1/sample/{quote,citations,document,fetch,links,packages,attest,quotes,recheck,textquote}](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/samples.md): each paid route run on fixed demo data, signed with the example key. Try these first; `/v1/sample/quote?match=passages` shows match "passages" on a paraphrased claim. In openapi.json each paid operation names its sample in `x-402.sample`.
- [Receipt demo](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/receipt-demo.md): a signed receipt end to end with free calls: sample, verify, a changed receipt failing, offline check.
- [Demo: one paid call and its signed receipt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/demo.md): one `POST /v1/verify/quote` call recorded in full: the request, the 402 offer, the paid retry with x402, the answer and its receipt, and how to check the receipt signature with Node.js.
- [Verify a receipt offline](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline.md): a single-file Node.js checker and the JWKS.
- [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp.md): `quoteproof-mcp`, a stdio MCP server with one tool per route. It pays with x402 from your own key. Install it from [the download list](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json).
- Remote MCP endpoint: `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp` (streamable HTTP, JSON answers, no session). The same tools; pay per call by putting an x402 payment payload in `_meta["x402/payment"]`, otherwise paid tools return the payment requirements. Server card: [/mcp/server-card](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp/server-card). See [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp.md).
- [Agent Skill](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/skill.md): `attestpage-check-sources`, a SKILL.md that tells an agent when to check a source and how to read the verdict. Index with digests: [/.well-known/agent-skills/index.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/agent-skills/index.json).
- [POST /v1/verify/document/preview](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-document.md): free. Send the same body as POST /v1/verify/document and get back the quote and link pairs it would check, what was skipped and why, the number of parts and the exact price. Nothing is fetched, signed or charged; call it before paying.

## How to use it

- [Docs index](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/index.md): all pages.
- [Paid routes at a glance](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/demo.md#paid-routes-at-a-glance): a curl example for every paid route.
- [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments.md): the 402 flow, headers, network and when you are charged. A charge without a delivered result (result_lost) is refunded by hand in USDC, no time limit.
- [Quickstart](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/quickstart.md): from discovery to your first paid call, step by step, with prices from pricing.json.
- [Worked examples](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/worked-examples.md): one paid call per route, from the request and the 402 offer to the signed receipt, with prices from pricing.json.
- [Example recipes](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/recipes.md): LangChain, LlamaIndex, OpenAI Agents SDK and Claude Agent SDK agents that check a source before citing it, paying with x402.
- [More examples](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/index.md): runnable recipes with a route and price table: [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/langchain.md), [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/openai-agents-sdk.md), [LlamaIndex.TS](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/llamaindex.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/vercel-ai-sdk.md), [Claude Agent SDK with the stdio MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/claude-agent-sdk.md), [one x402 payment step by step with plain `fetch`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/fetch-x402.md) and [one x402 payment step by step in Python](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/python-x402.md). Their clients ask for the price once the day's trial is used up.
- Checking several quotes on one page with `POST /v1/verify/quotes` (US$0.02 per call): [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md) and [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), through the MCP server or over HTTP with x402, and [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md) and [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md) in Python over HTTP with x402, [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md) in JavaScript over HTTP with x402, [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md) and [Pydantic AI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/pydantic-ai.md) in Python over HTTP with x402, and [Mastra](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/mastra.md) in JavaScript over HTTP with x402.
- Quickstarts for any client: [curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/curl.md) (one x402 payment) and [an MCP client](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/mcp.md) (the `quoteproof-mcp` server, one tool per route).
- [How it works](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/how-it-works.md): what the fetcher does, content_kind values and receipt fields (including the site's IP, TLS certificate and key headers).
- [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits.md): size caps, timeouts, rate limits and what the fetcher does not do.
- [Errors](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/errors.md): every error code and whether it was charged.
- [Status](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/status.md): current state of each route and uptime for 24 hours, 7 days and 30 days. JSON: [/status.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/status.json).

## Answers

- [Guides](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides.md): every step-by-step guide in one list, with what each one checks, its price and how to use it.
- [How to verify a quote an LLM cites](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-a-quote-an-llm-cites.md): fetch the cited page and match the quote, allowing for small differences, with a page verdict and a signed receipt.
- [How to check a quote an LLM cites, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/verify-llm-quote.md): the free sample, the 402 offer, one check with x402, how to read the answer, how to check the receipt and the same call as an MCP tool.
- [How to check every quote in a draft before publishing, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/verify-document-before-publishing.md): the free preview, the 402 offer, one part paid with x402, how to read the summary and each result, and how to check the receipt.
- [How to check the quotes in a draft one source at a time before publishing, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-quotes-before-publishing.md): the recipe for grouping quotes by URL, the price from the 402 offer, one quote or one page of up to 20 quotes with x402, how to read the verdict and page kind, and how to keep the receipt.
- [How to check every quote in a Markdown document from a CI job before merge, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-documents-in-ci.md): the free preview, the 402 offer, one part per paid call, the rule that fails a build on a quote missing from a readable page, a shell script for the CI step, and the same call as an MCP tool.
- [How to get a signed receipt of a web page](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/signed-receipt-of-a-web-page.md): what a receipt records about one fetch and how to check it offline.
- [How to get a signed receipt of a web page, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/signed-page-receipt.md): the free sample, the 402 offer, one receipt with x402, how to check it and match the page text to its hash, and the same call as an MCP tool.
- [How to check links before citing them](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-links-before-citing.md): dead, moved, unreadable and invented links, checked 10 at a time.
- [How to check links before citing them, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-links-before-citing.md): the free sample, the 402 offer, one batch with x402, how to read each result, how to check the cited words, how to check the receipt and the same call as an MCP tool.
- [How to check packages before installing them, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-packages-before-installing.md): the free sample, the 402 offer, one batch of up to 10 names, how to read exists, the latest version and advisories, how to check the receipt and the same call as an MCP tool.
- [How to check a package's licence before installing it, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-package-licences-before-installing.md): the free sample, the 402 offer, what the license field holds for npm, PyPI and crates.io, how to sort names by an allow list, how to treat a null licence, and the same call as an MCP tool.
- [How to check whether a web page has changed since you read it, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/recheck-page-for-changes.md): the free sample, the 402 offer, one recheck from a receipt or a URL and hash, how to read unchanged, changed, gone and unreadable, how to chain receipts and the same call as an MCP tool.
- [How to check a signed receipt before you rely on it, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-a-receipt-before-relying-on-it.md): free; get a sample receipt, check it, see what an altered one returns, read the payload and the same call as an MCP tool.
- [How to check the citations at the end of an answer before you send it, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/verify-citations-before-answering.md): the free sample, the 402 offer, one batch of up to 10 quote and URL pairs, how to read exact, fuzzy and none beside content_kind, and the same call over MCP.
- [How to check many quotes against one page in a single call, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-many-quotes-on-one-page.md): the free sample, the 402 offer, up to 20 quotes on one URL at one price, how to read exact, fuzzy and none, and the same call over MCP.
- [How to check a quote against text you already hold, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/use-attestpage-text-quote.md): the free sample, the 402 offer, one check of a quote against text you send with no fetch, how to read exact, fuzzy and none, declared offsets, how to check the receipt and the same call as an MCP tool.
- [How to turn a web page into clean text for an agent, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/read-web-page-as-clean-text.md): the free sample, the 402 offer, one page as clean text with x402, how to read content_kind and injection_flags, how to check the receipt and the same call as an MCP tool.
- [How to fetch a web page as clean text from code, with an x402 client](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/fetch-a-page-with-an-x402-client.md): the free sample, the 402 offer, a Node script that pays one page with x402 and checks the offer first, how to read content_kind and injection_flags, the receipt and the same call as an MCP tool.
- [How to get a signed timestamp that shows a file did not change, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/attest-a-file-hash.md): the free sample, the 402 offer, one attestation of a SHA-256, how to read the answer, a retry with idempotency_key, checking the file later and the same call as an MCP tool.
- [How to use AttestPage tools from an MCP client, step by step with curl](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/use-attestpage-tools-in-mcp.md): the tool names and prices, the remote endpoint, listing the tools, the 402 offer for a tool call and where the x402 payment goes.
- [How to check a package name an LLM suggested before installing it](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-package-names-before-install.md): invented package names on npm, PyPI and crates.io, caught before install, 10 at a time.
- [How to tell a bot wall from the real page](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/tell-a-bot-wall-from-the-real-page.md): bot challenges, JavaScript shells, paywalls and redirects that return 200 but are not the page.

## Machine-readable

- [OpenAPI 3.1](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/openapi.json)
- [Prices](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json)
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## About

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---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-quote.md

# Verify a quote

Last updated: 2026-10-10

`POST /v1/verify/quote` fetches a page and reports whether a quote appears on it: `exact`, `fuzzy` or `none`, with offsets, surrounding context, the page verdict and a signed receipt. For a paraphrased claim, `"match": "passages"` returns instead the passages that share most of its words (below). Price: US$0.01 per call.

It checks your exact words, not a reworded version, against the page and returns offsets and page hashes in a signed receipt, all in one US$0.01 call.

Use it before citing a page, to check that the words you attribute to it are on it, and that the page you got is real content rather than a bot wall or an error page.

For 3 or more quotes on one page, [verify/quotes](/docs/verify-quotes) costs less: one call checks up to 20.

## Request

```json
{
  "url": "https://www.iana.org/help/example-domains",
  "quote": "These domains may be used as illustrative examples in documents",
  "match": "fuzzy",
  "case_sensitive": false,
  "threshold": 0.9
}
```

| Field | Required | Meaning |
|---|---|---|
| `url` | yes | http or https URL, at most 2,048 characters |
| `quote` | yes | text to look for, or with `passages` the claim to find support for; at most 1,000 characters after normalisation |
| `match` | no | `fuzzy` (default) also accepts small differences; `exact` needs the same text after normalisation; `passages` finds the passages that best share a paraphrased claim's words |
| `case_sensitive` | no | default `false`; must be `false` with `passages` |
| `threshold` | no | fuzzy similarity needed, 0.5 to 1, default 0.9 |

Before matching, both the page text and the quote are normalised: Unicode NFKC, curly quotes and dashes become plain ones, invisible characters are dropped, and all whitespace becomes one space.

## Response

From the free sample (`GET /v1/sample/quote`), shortened:

```json
{
  "result": {
    "match": "fuzzy",
    "score": 0.963,
    "start": 211,
    "end": 238,
    "context": "...the agency said that emissions fell 12 % in 2025, after two years of slow growth...",
    "occurrences": 1,
    "normalised_sha256": "086a29af…"
  },
  "page": {
    "requested_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "http_status": 200,
    "content_kind": "real",
    "signals": ["status_200"],
    "title": "Regional climate report 2025 (demo page)",
    "content_sha256": "0e429607…",
    "retrieved_at": "2026-10-09T14:19:34.903Z"
  },
  "injection_flags": [],
  "advice": "The page loaded and looks like real content.",
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid",
  "rail": "x402",
  "network": "eip155:8453"
}
```

- `match` is `exact`, `fuzzy` or `none`. `score` is the similarity from 0 to 1.
- `start` and `end` are code-point offsets into the normalised page text. `normalised_sha256` is the SHA-256 of that text, so anyone holding the page text can check the offsets.
- `occurrences` counts exact matches.
- `evidence` (added, nothing else changed) holds `passage` (`start`, `end` and `text`: the matched text with 200 characters either side, or `null` with no match), `verdict_reason` (one line, such as `exact at offset 115` or `fuzzy 0.93, differs in 1 word`), `content_kind` and `fetched_at`. The receipt signs only the passage offsets and the reason.
- Read `page.content_kind` before relying on `match`. A `none` on a `bot_wall` or `js_shell` page means we could not read the page, not that the quote is absent from it. See [How it works](/docs/how-it-works).

## Passages: a paraphrased claim

An agent rarely quotes word for word. With `"match": "passages"`, `quote` is a claim (for example "The agency reported a 12 percent drop in emissions during 2025") and the answer is the 3 passages of the page that share most of its words:

On the demo page ([`https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page)), shortened; try it free with [`GET /v1/sample/quote?match=passages`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote?match=passages):

```json
{
  "result": {
    "match": "passages",
    "score": 0.583,
    "start": 115,
    "end": 271,
    "occurrences": 3,
    "passages": [
      { "start": 115, "end": 271, "score": 0.583, "text": "It is not a real report and its numbers are made up. In its annual summary the agency said that emissions fell 12 % in 2025, after two years of slow growth.", "missing": ["drop"], "flags": ["negation_mismatch"] },
      { "start": 357, "end": 513, "score": 0.217, "text": "The agency also noted that the share of renewable power rose to 41 percent, and that the next report will cover water use and air quality across the region.", "missing": ["12", "drop", "emissions", "2025"], "flags": ["number_mismatch"] },
      { "start": 0, "end": 114, "score": 0.136, "text": "Regional climate report 2025 This is a demo page served by AttestPage so that agents can try every route for free.", "missing": ["agency", "12", "percent", "drop", "emissions"], "flags": [] }
    ],
    "scorer": "lexical-v2",
    "note": "Passages ranked by how many of the claim's words (weighted by rarity on the page) and word pairs they share. This is evidence for you to judge, not a verdict: ..."
  }
}
```

Here "reported" counted as found because the passage has "report". The best passage does support the claim, but only a reader can tell that "fell 12 %" means a 12 percent drop. It is flagged `negation_mismatch` only because its first sentence says "not a real report": a flag tells you where to look, not that the passage contradicts the claim.

- **This is evidence, not a verdict.** A score measures shared words, not meaning. "Emissions did not fall" shares as many words as "emissions fell". Read each passage, and check negation, numbers, dates and the words in `missing`.
- **Passages.** A passage is a sentence, or two neighbouring ones; text with no sentence ends is cut every 40 words. A sentence ends at `.`, `!` or `?` before a space, or at `。`, `！` or `？`, but not after a short abbreviation such as "e.g.", "i.e.", "Dr.", "Mr." or an initial ("J. Smith"); "etc." ends one only before a capital. Passages do not overlap and are sorted by `score`, highest first. The top-level `score`, `start`, `end` and `context` are those of the best passage, and `occurrences` counts the passages.
- **Score.** From 0 to 1: 0.75 × the share of the claim's words the passage holds, each weighted by how rare it is on the page, plus 0.25 × the share of the claim's neighbouring word pairs it holds.
- **How words are compared.** Without case, with light English stemming ("emissions" meets "emission"), and ignoring common English words such as "the" and "was". `%` counts as "percent". In Chinese and Japanese, each character counts as a word.
- **Offsets and text.** `start` and `end` are code-point offsets into the normalised page text, as above. `text` is cut to 800 characters with `...` when the passage is longer.
- **missing.** Lists the claim's words that the passage lacks, at most 20.
- **flags.** Marks a passage worth a closer read; it never changes the score or the order. `negation_mismatch`: the claim or the passage has an English negation ("not", "no", "never", "n't", "without" and similar) and the other has none. `number_mismatch`: the claim has a number the passage lacks and the passage has one the claim lacks, such as 12 against 15 (`12 %`, `12 percent` and `12.0` count as the same number, and so do `1,000` and `1000`). An empty list does not mean the passage agrees with the claim.
- **No match.** `match` is `none` with an empty `passages` list when no passage shares a word.
- **Errors.** A claim made only of common words or punctuation gets 400.
- **Same answer every time.** No language model is used, so the same page and claim give the same answer. `scorer` names the method (now `lexical-v2`) and changes whenever the same page and claim could give different passages, scores or flags.
- **Cost.** The cost is linear in the page size, so passages never gets `match_too_costly`.
- **Receipt.** The receipt signs `mode`, `scorer` and each passage's `start`, `end` and `score`. The text can be recovered from the page at those offsets, and `missing` and `flags` from that text, the claim and the `scorer`.
- **Price.** The same as any other `verify/quote` call.

## PDF

A PDF page is matched like any other page. Its text layer is read as described in [Fetch: PDF](/docs/fetch), with no OCR.

- A match on a PDF also has `pdf_page` and `pdf_page_end`: the 1-based pages where it starts and ends. Each passage has them too.
- `start` and `end` are still offsets into the whole normalised text. In that text, each page break is one space.
- Only text inside each page's box is read, as a reader sees it. A quote from text drawn outside the page is not found.
- The receipt signs `pdf_page` and `pdf_page_end` next to the offsets.

Only the full service reads PDFs: an edge server answers 501 `not_on_edge` (`details.reason` `pdf`) for one, not charged. Limits are in [Limits](/docs/limits).

## Charging

The quote and options are checked before payment: a bad request gets 400 and is not charged. A quote too costly to match fuzzily gets 422 `match_too_costly`, not charged; use `"match": "exact"` or a shorter quote. A URL whose host name does not resolve gets 422 `host_not_found`, not charged. Results about the page itself, including 404s, bot walls and timeouts, are charged. See [Payments](/docs/payments).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-quotes.md

# Verify quotes on one page

Last updated: 2026-10-10

`POST /v1/verify/quotes` checks 1 to 20 quotes against one web page in one call. The page is fetched once, and each quote gets the same answer as [Verify a quote](/docs/verify-quote) (`exact`, `fuzzy` or `none`, score, offsets, context), all under one signed receipt. Price: US$0.02 per call, whether it carries 1 quote or 20, so from 3 quotes up it costs less than one `verify/quote` call per quote.

Use it when an answer quotes the same source several times: every quote is checked against the same copy of the page in one paid call.

## Request

```json
{
  "url": "https://www.iana.org/help/example-domains",
  "quotes": [
    "These domains may be used as illustrative examples in documents",
    "without prior coordination with us"
  ],
  "match": "fuzzy"
}
```

| Field | Required | Meaning |
|---|---|---|
| `url` | yes | the page, http or https, at most 2,048 characters |
| `quotes` | yes | 1 to 20 strings, each at most 1,000 characters after normalisation |
| `match` | no | for every quote: `fuzzy` (default) also accepts small differences; `exact` needs the same text after normalisation; `passages` treats each quote as a paraphrased claim (below) |
| `case_sensitive` | no | default `false`; must be `false` with `passages` |
| `threshold` | no | fuzzy similarity needed, 0.5 to 1, default 0.9 |

The URL and every quote are checked before payment. If the URL is malformed, blocked or disallowed by robots.txt, or any quote is empty, too long or not a string (or, with `passages`, has no word to compare), the whole request is refused with 400 or 403 and not charged. The error's `details.field` names the quote, for example `quotes[2]`. Other fields are refused too.

## Response

From the free sample (`GET /v1/sample/quotes`), shortened:

```json
{
  "results": [
    {
      "match": "exact",
      "score": 1,
      "start": 384,
      "end": 431,
      "context": "... The agency also noted that the share of renewable power rose to 41 percent, and that the next report will cover...",
      "occurrences": 1,
      "normalised_sha256": "086a29af…"
    },
    {
      "match": "fuzzy",
      "score": 0.963,
      "start": 211,
      "end": 238,
      "context": "...In its annual summary the agency said that emissions fell 12 % in 2025, after two years of slow growth...",
      "occurrences": 1,
      "normalised_sha256": "086a29af…"
    },
    {
      "match": "none",
      "score": null,
      "start": null,
      "end": null,
      "context": null,
      "occurrences": 0,
      "normalised_sha256": "086a29af…"
    }
  ],
  "page": {
    "requested_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "http_status": 200,
    "content_kind": "real",
    "title": "Regional climate report 2025 (demo page)",
    "content_sha256": "0e429607…"
  },
  "injection_flags": [],
  "advice": "The page loaded and looks like real content.",
  "summary": { "exact": 1, "fuzzy": 1, "none": 1, "failed": 0 },
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid"
}
```

- `results` has one entry per quote, in request order. Each is the `result` of [Verify a quote](/docs/verify-quote): `match`, `score`, `start`, `end`, `context`, `occurrences` and `normalised_sha256` mean the same, and give the same values a `verify/quote` call on that page would.
- `page` is the page verdict, hashes and network evidence, once for all the quotes.
- Read `content_kind` before relying on `match`. A `none` on a page that is not `real` (a 404, bot wall or JavaScript shell) means we could not read the page, not that the quote is absent from it.
- Each result has the additive `evidence` field, the same as in [Verify a quote](/docs/verify-quote): the matched passage with 200 characters either side and a one-line `verdict_reason`.
- `summary` counts the verdicts; `failed` counts quotes that carry an `error` instead of a verdict (below).
- The receipt signs the page's URL, status, `content_kind`, hashes and evidence, and per quote the SHA-256 of the quote and the verdict. It does not contain the quote text. Check it with [`POST /v1/receipt/verify`](/docs/receipt-verify).

## Passages: paraphrased claims

With `"match": "passages"`, each quote is a claim. Each result is then the one described in [Verify a quote: passages](/docs/verify-quote): up to 3 passages from the page that share most of the claim's words, each with `start`, `end`, `score`, `text`, `missing` and `flags`, plus `scorer` and `note`. These are evidence for you to judge, not a verdict.

- `match` is `passages` or `none`, and `summary` adds a `passages` count.
- The receipt signs each claim's passages (`start`, `end`, `score`) and the `scorer`.
- The work is linear in page size, so passages never fail with `match_too_costly`.

The price is the same.

## PDF

A PDF page is read and matched as in [Verify a quote: PDF](/docs/verify-quote). Each match and passage on it has `pdf_page` and `pdf_page_end`, and the receipt signs them. If the PDF cannot be queued for reading, the call gets 503 `over_capacity` (`details.reason` `pdf_queue_full`) and is not charged.

## Partial failures

A quote that would cost too much to match fuzzily gets `"error": { "code": "match_too_costly", ... }` and null match fields; the other quotes are still checked and the call is charged. The fuzzy searches of one call also share a work limit (twice what one `verify/quote` call may use), spent in request order: a quote reached after it is used up gets the same error with a message saying so. If every quote fails this way, the call gets 422 `match_too_costly`, not charged, and `details.failed` lists only which quotes failed. Use `"match": "exact"` or shorter quotes.

This route shares the per-address count of uncharged failed batches and the match queue with [Verify citations](/docs/verify-citations): over the count it answers 429 `rate_limited` with `details.reason` `uncharged_failures`, and when the queue is full 503 `over_capacity` with `details.reason` `match_queue_full`, both with a `Retry-After` header and not charged. See [Limits](/docs/limits).

## Edge servers

Only the full service runs this route: an edge server answers 501 `not_on_edge`, not charged.

## Charging

A URL whose host name does not resolve gets 422 `host_not_found`, not charged. If the page turns out to be disallowed by robots.txt or rate limited after payment (for example after a redirect), the call answers with an error and is not charged. Results about the page itself, including 404s, bot walls and timeouts, are charged. See [Payments](/docs/payments).

A free-trial call covers at most 5 quotes. A larger one is not run as a trial: it gets the normal 402 offer, with `details.reason` `trial_too_large`, and is not charged.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-text-quote.md

# Verify a quote against text you hold

Last updated: 2026-10-13

`POST /v1/verify/text-quote` checks a quote against text the caller already has: a file it read, a tool result, a document. Nothing is fetched, so there are no robots, DNS or bot-wall failures. The answer is `exact`, `fuzzy` or `none`, with a score, offsets and context, under a signed receipt. Price: US$0.005 per call.

Use it when the source is already in hand. To check a quote against a live web page, use [Verify a quote](/docs/verify-quote), which fetches the page.

## Free preview

`POST /v1/verify/text-quote/preview` takes the same body and returns `result` (`match`, `score`, `occurrences`), `signed: false`, `advice` and `paid_route`. It is free, 30 a day per IP address; `start` and `end` are ignored. The answer has no offsets, hashes or receipt, so nobody can verify it later. Past 30, it answers 429 with `reason: "preview_cap"`. For the signed receipt, call the paid route.

## Request

```json
{
  "text": "Refunds are paid within 14 days of purchase, to the card that was used.",
  "quote": "refunds are paid within 14 days",
  "match": "fuzzy",
  "case_sensitive": false
}
```

| Field | Required | Meaning |
|---|---|---|
| `text` | yes | the source text, as sent: a non-empty string of at most 50,000 characters (code points) and 64 KB of UTF-8 |
| `quote` | yes | the quote, at most 1,000 characters after normalisation |
| `start`, `end` | no | both or neither: a slice of `text` to check, in characters (code points), 0-based, `end` exclusive, at most 1,000 characters |
| `match` | no | `fuzzy` (default) also accepts small differences; `exact` needs the same text after normalisation; `passages` treats the quote as a paraphrased claim and returns the passages of the text that share its words (not with `start` and `end`) |
| `case_sensitive` | no | default `false`; must be `false` with `passages` |
| `threshold` | no | fuzzy similarity needed, 0.5 to 1, default 0.9 |

`url` is refused: this route never fetches. Every field is checked before payment, so a bad request is answered with 400 and not charged.

## Offsets

Two coordinate systems, named differently:

- `start` and `end` in the request are **raw** code-point offsets into `text` as sent. With them, only that slice is matched, so the answer is whether the text at those offsets says the quote. `result.declared` echoes them with `slice_sha256` (the hash of the raw slice) and `slice_matches`.
- `result.start` and `result.end` in a search (no offsets sent) are **normalised**: offsets into the text after normalising (curly quotes, spaces and case folding for matching, as on `verify/quote`). `normalised_sha256` is the hash of that normalised text.
- `result.located` appears only when the declared slice does not say the quote but the whole text does: it gives the quote's position in the whole text (`match`, `score`, `start`, `end`, `occurrences`), with offsets normalised (`offsets: "normalised"`), not raw.

## Response

```json
{
  "result": {
    "match": "fuzzy", "score": 0.972, "start": 0, "end": 34,
    "context": "Refunds are paid within 14 days of purchase",
    "occurrences": 1, "normalised_sha256": "…",
    "source": { "kind": "supplied", "text_sha256": "…", "code_points": 79 }
  },
  "injection_flags": [],
  "advice": "The supplied text contains a close match to this quote, with small differences. This says nothing about where the text came from.",
  "receipt": "eyJ…",
  "tier": "paid"
}
```

- `injection_flags` lists instruction-like text found in the supplied text. Agents paste untrusted output, so read them.
- The receipt is the caller's claim: it attests the hash of the text (`source.text_sha256`) and the match, not that the text came from any particular site.

## Errors

A 400 with `invalid_request` covers: an unknown field (including `url`), a missing or empty `text` or `quote`, `start` or `end` alone, a non-integer or negative offset, `start` not below `end` or `end` past the text (`reason` `offset_out_of_range`), a slice over 1,000 characters, text over 50,000 characters, a lone surrogate in `text` or `quote`, and offsets with `match` `passages`. A body over 64 KB gets 413. A fuzzy match too costly for the matcher gets 422 `match_too_costly`, not charged.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-citations.md

# Verify citations

Last updated: 2026-10-10

`POST /v1/verify/citations` checks 1 to 10 citations, each a quote and the URL it is attributed to, in one call. For each one you get the same answer as [Verify a quote](/docs/verify-quote) (`exact`, `fuzzy` or `none`, score, offsets, context) plus the verdict on its page, all under one signed receipt. Price: US$0.10 per batch.

Use it on the sources at the end of an answer before the user sees it: a made-up quote, a misquote, or a link to a dead or blocked page is caught in one paid call.

For 1 to 9 pairs, one [verify/quote](/docs/verify-quote) call per pair costs less, without the Crossref data.

## Request

```json
{
  "citations": [
    { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" },
    { "url": "https://www.iana.org/domains/reserved", "quote": "IANA-managed Reserved Domains" }
  ],
  "match": "fuzzy"
}
```

| Field | Required | Meaning |
|---|---|---|
| `citations` | yes | 1 to 10 objects `{ "url", "quote" }`. `url` is http or https, at most 2,048 characters; `quote` is at most 1,000 characters after normalisation |
| `match` | no | for every citation: `fuzzy` (default) also accepts small differences; `exact` needs the same text after normalisation; `passages` treats each quote as a paraphrased claim (below) |
| `case_sensitive` | no | default `false`; must be `false` with `passages` |
| `threshold` | no | fuzzy similarity needed, 0.5 to 1, default 0.9 |

Several citations may share a URL: each distinct URL is fetched once and every quote on it is matched against the same copy. Every URL is checked before payment; if one is malformed, blocked or disallowed by robots.txt, or any quote is empty or too long (or, with `passages`, has no word to compare), the whole request is refused with 400 or 403 and not charged. The error's `details.field` names the citation, for example `citations[2].quote`.

## Response

From the free sample (`GET /v1/sample/citations`), shortened:

```json
{
  "results": [
    {
      "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
      "page": 0,
      "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
      "http_status": 200,
      "content_kind": "real",
      "match": "fuzzy",
      "score": 0.963,
      "start": 211,
      "end": 238,
      "context": "...the agency said that emissions fell 12 % in 2025, after two years of slow growth...",
      "occurrences": 1,
      "advice": "The page loaded and looks like real content."
    },
    {
      "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/missing",
      "page": 1,
      "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/missing",
      "http_status": 404,
      "content_kind": "http_error",
      "match": "none",
      "score": null,
      "start": null,
      "end": null,
      "context": null,
      "occurrences": 0
    }
  ],
  "pages": [
    {
      "requested_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
      "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
      "http_status": 200,
      "content_kind": "real",
      "title": "Regional climate report 2025 (demo page)",
      "content_sha256": "0e429607…",
      "normalised_sha256": "086a29af…",
      "injection_flags": []
    }
  ],
  "summary": { "exact": 0, "fuzzy": 1, "none": 2, "failed": 0, "retracted": 0, "doi_unchecked": 0 },
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid"
}
```

- `results` has one entry per citation, in request order. `page` is its index in `pages`, which has one entry per distinct URL with the page verdict, hashes and network evidence.
- `match`, `score`, `start`, `end`, `context` and `occurrences` mean what they mean in [Verify a quote](/docs/verify-quote). Offsets are into the normalised text of that citation's page; `normalised_sha256` on the page lets anyone holding the text check them.
- Read `content_kind` before relying on `match`. A `none` on a page that is not `real` (a 404, bot wall or JavaScript shell) means we could not read the page, not that the quote is absent from it.
- Each result has the additive `evidence` field, the same as in [Verify a quote](/docs/verify-quote): the matched passage with 200 characters either side and a one-line `verdict_reason`.
- `summary` counts the verdicts; `failed` counts citations that carry an `error` instead of a verdict (below). `retracted` counts citations on a paper Crossref marks retracted, and `doi_unchecked` citations whose page's DOI lookup was skipped, so their retraction status is unknown (see Retracted papers; both absent when DOI lookups are off).
- The receipt signs, per page, the URL, status, `content_kind`, hashes and evidence, and per citation its page index, the SHA-256 of the quote and the verdict. It does not contain the quote text. Check it with [`POST /v1/receipt/verify`](/docs/receipt-verify).

## Passages: paraphrased claims

With `"match": "passages"`, each citation's `quote` is a claim. Each result is then the one described in [Verify a quote: passages](/docs/verify-quote): up to 3 passages from the page that share most of the claim's words, each with `start`, `end`, `score`, `text`, `missing` and `flags`, plus `scorer`.

- `match` is `passages` or `none`, and `summary` adds a `passages` count.
- The response has a top-level `note`: the passages are evidence for you to judge, not a verdict.
- The receipt signs each citation's passages (`start`, `end`, `score`) and the `scorer`.
- The work is linear in page size, so passages share no work limit and never fail with `match_too_costly`.

The price is the same.

## PDF

A cited PDF is read and matched as in [Verify a quote: PDF](/docs/verify-quote). Each match and passage on it has `pdf_page` and `pdf_page_end`, and the receipt signs them. Its entry in `pages` has `pdf` (`page_count`, `pages_read`, `truncated`). If one PDF in the batch cannot be queued for reading, the whole batch gets 503 `over_capacity` (`details.reason` `pdf_queue_full`) and is not charged.

## Retracted papers (DOI)

A cited page with a DOI gets `crossref` in its `pages` entry: the work's `title`, `authors` (up to 10, with `authors_total`), `year`, `container_title` (the journal) and `type` from Crossref's public metadata, and `retracted`: `true` when Crossref lists a retraction, withdrawal or removal notice for it (Crossref carries the Retraction Watch database). `updates` lists every notice that updates the work (`type` such as `retraction`, `correction` or `expression_of_concern`, notice `doi`, `source`, `date`), and `update_to` is filled when the cited DOI is itself such a notice. `summary.retracted` counts the citations on retracted works. A citation that matches its quote on a retracted paper still needs a warning before you use it.

The DOI is taken from a `doi.org` link, else the page's own `citation_doi` (or similar) meta tag, else a DOI in the URL path; `doi_source` says which (`url` or `page`). `status` is `found`, `not_found` (not a Crossref DOI; DataCite and other agencies are not checked) or `skipped` with a `reason` (`rate_limited`, `busy`, `timeout` or `unavailable`) when Crossref is slow or we are at our share of its public limits. A skipped lookup never fails the call or changes the charge; `summary.doi_unchecked` counts the citations whose page's DOI lookup was skipped, so `retracted`: 0 with `doi_unchecked` above 0 means not every DOI was checked. Lookups are made one at a time across all callers (at most 120 a minute for paid calls; free trial calls have their own budget of 6 a minute, so they never use the paid one) and answers are cached for a day. The receipt signs each page's `doi`, `status` and `retracted`.

## Partial failures

A quote that would cost too much to match fuzzily on its page gets `"error": { "code": "match_too_costly", ... }` and null match fields; the rest of the batch is still checked and the batch is charged. The fuzzy searches of one batch also share a work limit (twice what one `verify/quote` call may use), spent in page order: a citation reached after it is used up gets the same error with a message saying so, while an exact match is still found. If every citation in the batch fails this way, the call gets 422 `match_too_costly`, not charged, and `details.failed` lists only which citations failed. Use `"match": "exact"` or shorter quotes.

Each caller IP address gets 6 uncharged failed batches a minute (a bucket that refills one every 10 seconds). A batch holds a place in that bucket while it runs and gives it back unless every citation failed, so a caller with 6 batches still running also waits. Over the limit, `verify/citations` answers 429 `rate_limited` with `details.reason` `uncharged_failures` and a `Retry-After` header, before any page is fetched, and nothing is charged. This normally comes before the 402; if your own parallel batches take the last place meanwhile, it comes after your payment is verified and before it is settled. Charged batches never use the bucket up.

A few batches are matched at once across all callers and a short queue waits behind them. When that queue is full, `verify/citations` answers 503 `over_capacity` with `details.reason` `match_queue_full` and a `Retry-After` header (a few seconds), and nothing is charged: before the 402 if the queue is already full, or after your payment is verified and before it is settled if it filled while your pages were fetched. Retry the same request after `Retry-After`.

## Dead domains

A URL whose host name does not resolve is reported as a result: `content_kind` `http_error`, `http_status` null, `match` `none`, and the batch is charged. If no URL in the batch resolves, the call gets 422 `host_not_found` and is not charged.

## Charging

If a page turns out to be disallowed by robots.txt or rate limited after payment (for example after a redirect), the whole batch answers with an error and is not charged. Results about the pages themselves, including 404s, bot walls and timeouts, are charged. See [Payments](/docs/payments).

A free-trial call covers at most 5 citations. A larger batch is not run as a trial: it gets the normal 402 offer, with `details.reason` `trial_too_large`, and is not charged.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-document.md

# Verify a document

Last updated: 2026-10-10

`POST /v1/verify/document` takes an answer or report as written, finds every quote in it with its link by fixed rules, and checks each pair on the live page, as [Verify citations](/docs/verify-citations) does: `exact`, `fuzzy` or `none`, score, offsets in your document and on the page, and the verdict on each page, under one signed receipt. Price: US$0.10 per part of up to 10 pairs.

Use it before sending a finished answer or report that quotes web pages. Call the free preview first: it lists the pairs, what was skipped and why, the number of parts and the exact price.

For a part of 1 to 9 pairs, one [verify/quote](/docs/verify-quote) call per pair costs less; the free preview lists each pair and its part.

## Request

```json
{
  "document": "WHO says \"Air pollution kills an estimated seven million people every year\" ([WHO](https://www.who.int/health-topics/air-pollution)).",
  "format": "markdown",
  "match": "fuzzy",
  "part": 0
}
```

| Field | Required | Meaning |
|---|---|---|
| `document` | yes | The answer or report as text, 1 character to 60,000 bytes UTF-8 |
| `format` | no | `markdown` (default), `text` (only bare URLs and `[n]` references are links) or `html` (`<a href>` links, `<blockquote>` and `<q>` quotes; other tags are dropped) |
| `match` | no | `fuzzy` (default), `exact` or `passages`, as verify/citations; it also chooses what is found (below) |
| `case_sensitive` | no | default `false`; must be `false` with `passages` |
| `threshold` | no | 0.5 to 1, default 0.9 (fuzzy only) |
| `min_words` | no | 1 to 20, default 4: a quoted span with fewer words is skipped as `too_short` |
| `part_size` | no | 1 to 10, default 10: pairs per part. A free trial call takes at most the size in `extensions.trial.info.max_batch_items` of the 402 offer |
| `part` | no | 0-based part to check, default 0. Ignored by the preview |

Unknown fields are refused with 400. Every URL in the part is checked before payment, as on verify/citations: a blocked or robots-disallowed URL refuses the call with 400 or 403, `details.field` naming the pair (for example `pairs[3].url`), and nothing is charged.

## Preview

`POST /v1/verify/document/preview` is free. Send the same body; nothing is fetched or charged.

```json
{
  "document_sha256": "9f2c…",
  "extractor": "doc-v1",
  "pairs_total": 1,
  "part_size": 10,
  "parts": 1,
  "price": { "usd_per_part": "0.10", "sats_per_part": 100, "usd_total": "0.10", "sats_total": 100 },
  "pairs": [
    { "pair": 0, "part": 0, "quote": "Air pollution kills an estimated seven million people every year", "url": "https://www.who.int/health-topics/air-pollution", "doc_start": 10, "doc_end": 74, "source": "inline_link" }
  ],
  "skipped": [],
  "skipped_truncated": 0,
  "skipped_counts": {},
  "limit_reached": false
}
```

- `doc_start`/`doc_end`: code-point offsets of the quoted words in `document` as sent. A pair found more than once (same quote, same URL) is one pair with `doc_spans`, checked and charged once. `doc_spans` holds the first 20 places; `doc_spans_truncated` counts the rest.
- `source`: `inline_link`, `reference`, `footnote`, `numbered`, `bare_url`, `blockquote` or `sentence` (passages).
- `skipped[]`: `{ doc_start, doc_end, reason, text }`; reasons `too_short`, `too_long`, `no_url`, `bad_url`, `beyond_limit`. It lists the first 100; `skipped_truncated` counts the rest and `skipped_counts` gives every skip by reason.
- The preview contacts no URL, so a dead or blocked URL shows up only on the paid call.

The preview takes from the same per-address limit as the paid routes and works on the edge server too.

## Response

The verify/citations response for this part, plus the document fields:

```json
{
  "document_sha256": "9f2c…",
  "extractor": "doc-v1",
  "part": 0, "parts": 1, "pairs_total": 1,
  "results": [
    { "pair": 0, "quote": "Air pollution kills…", "url": "https://www.who.int/health-topics/air-pollution", "doc_start": 10, "doc_end": 74, "page": 0, "final_url": "…", "http_status": 200, "content_kind": "real", "match": "fuzzy", "score": 0.96, "start": 412, "end": 478, "context": "…", "occurrences": 1 }
  ],
  "pages": [ "as verify/citations" ],
  "summary": { "exact": 0, "fuzzy": 1, "none": 0, "failed": 0 },
  "receipt": "eyJ…",
  "tier": "paid"
}
```

- `doc_start`/`doc_end` are offsets in your document; `start`/`end` are offsets on the page, as in [Verify a quote](/docs/verify-quote). Read `content_kind` before relying on `match`.
- The receipt (kind `document`) signs `document_sha256`, the extractor, the options, the part and, per pair, its page, the SHA-256 of the quote, its document offsets (with `doc_spans` and `doc_spans_truncated` for a repeated pair) and its verdict. It does not contain the quote text. Whoever holds the document can tie every part's receipt to it. Check it with [`POST /v1/receipt/verify`](/docs/receipt-verify).

## How pairs are found

The rules are fixed and named by `extractor` (`doc-v1`) in every answer and receipt; a change gets a new name.

- Code blocks and inline code are ignored. With `format` `markdown`, links are inline links, reference links, footnotes, `[n]` references with a numbered list and bare URLs; with `text`, only bare URLs and `[n]` references; with `html`, `<a href>` links, `<blockquote>` (its `<footer>` is the attribution) and `<q>` quotes, and `<script>`, `<style>` and `<head>` are skipped. Offsets (`doc_start`, `doc_end`) count characters in the HTML as sent.
- A quote is text between paired `"…"`, `“…”`, `«…»` or `„…“` inside one paragraph, or a blockquote (its last line starting with `—`, `--`, `-` or `Source:` is the attribution and its link the source). Single quotes are not used.
- A quote must be in quote marks. A sentence with a link but no quote marks, such as `Water boils at 100 C ([NIST](https://www.nist.gov/)).`, finds no pair (`pairs_total` 0), so the preview answers 200 with nothing to check. Put the claim in quote marks: `"Water boils at 100 C" ([NIST](https://www.nist.gov/)).`
- A quote's link is the first link after it before the next quote or the paragraph end; else the last link before it in the same paragraph; else the blockquote's attribution; else it is skipped as `no_url`.
- With `match` `passages`, every sentence that carries a link is a claim and gets its best-matching passages as evidence, as in verify/citations.
- Then `bad_url`, `too_short` (`min_words`, not for passages), `too_long` (over 1,000 characters), duplicates and the 100-pair limit (`beyond_limit`) are applied, and pairs are numbered in document order. Part `p` holds pairs `p × part_size` to `p × part_size + part_size − 1`.

### Fixes to doc-v1

- 2026-10-10: in an indented code block (4 spaces or a tab, after a blank line or heading), every line is now code. Before, only its first line was skipped, so a quote and link on a later line of the block could be taken as a pair. Nothing else changed.

## Parts and price

Each paid call checks one part of up to 10 pairs, at US$0.10: the same price as a verify/citations batch.

| Document | Calls |
|---|---|
| 4 quotes | 1 |
| 10 quotes | 1 |
| 23 quotes | 3 |

## Limits

| Limit | Value |
|---|---|
| `document` | 60,000 bytes UTF-8 (400 over it) |
| Pairs per document | 100 (10 parts of 10); the rest are skipped as `beyond_limit` |
| Pairs per part | `part_size`, at most 10 |
| Places listed per repeated pair | 20 in `doc_spans`; the rest counted in `doc_spans_truncated` |
| Skipped items listed | 100 in `skipped`; the rest counted in `skipped_truncated` |
| Quote or claim | 1,000 characters |
| Free-trial part | Up to `extensions.trial.info.max_batch_items` pairs (in the 402 offer); a larger part gets the normal 402 offer (`details.reason` `trial_too_large`) |

Matching shares its slots, queue and failure limit with verify/citations: 6 uncharged failed calls a minute per IP address across both routes, then 429 `rate_limited` (`details.reason` `uncharged_failures`); a full match queue gives 503 `over_capacity` with `Retry-After`. See [Limits](/docs/limits).

## Charging

A part is charged when it is checked, including pages that are 404s, bot walls or timeouts, and a pair whose fuzzy work ran out (it carries an `error`). Never charged: any 400, 422 `no_pairs` (no quote with a link was found), 422 `host_not_found` (no URL in the part resolves), 422 `match_too_costly` (every pair in the part failed), 429, 503, and the edge server's 501 `not_on_edge`. See [Payments](/docs/payments).

## Errors

See [Errors](/docs/errors). `part` past the last part gets 400 with `details.parts`.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/fetch.md

# Fetch a page

Last updated: 2026-10-12

`POST /v1/fetch` fetches one URL (or up to 10 with `urls`) and tells you what came back: a `page.content_kind` verdict, HTTP status, final URL after redirects, title, hashes, injection flags and, if you ask, up to 20,000 characters of clean text. Price: US$0.002 per URL: one `url` is US$0.002, and `urls` costs US$0.002 times the number of URLs.

Use it when you need to know whether a URL gave you real content, a bot challenge, a JavaScript shell, a paywall or an error, with a receipt that records it. It is also how you notarize a web page: the signed receipt records what the page said and when.

## Request

```json
{ "url": "https://www.iana.org/help/example-domains", "return_text": true }
```

| Field | Required | Meaning |
|---|---|---|
| `url` | `url` or `urls` | http or https URL, at most 2,048 characters |
| `urls` | `url` or `urls` | instead of `url`: a list of 1 to 10 distinct URLs, each priced as one fetch; see [Several pages in one call](#several-pages-in-one-call) |
| `return_text` | no | also return up to 20,000 characters of clean text (per page); default `false` |

## Response

From the free sample (`GET /v1/sample/fetch`), shortened:

```json
{
  "page": {
    "requested_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "http_status": 200,
    "content_type": "text/html",
    "content_kind": "real",
    "signals": ["status_200"],
    "title": "Regional climate report 2025 (demo page)",
    "redirects": [],
    "content_sha256": "0e429607…",
    "raw_sha256": "179b9ac4…",
    "retrieved_at": "2026-10-09T14:19:34.909Z",
    "bytes": 847,
    "truncated": false
  },
  "text": "Regional climate report 2025\n\nThis is a demo page…",
  "text_chars": 636,
  "text_truncated": false,
  "injection_flags": [],
  "advice": "The page loaded and looks like real content.",
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid",
  "rail": "x402",
  "network": "eip155:8453"
}
```

- Receipts are signed by `iss` https://still-rapids-9yt7.here.now (keys at /.well-known/jwks.json), not by the origin you called. Check one free with `POST /v1/receipt/verify` ([docs](/docs/receipt-verify)).
- `page.content_kind` and `page.signals` are explained in [How it works](/docs/how-it-works). `advice` is one plain sentence about the verdict.
- `content_sha256` hashes the full extracted text, not the 20,000-character copy. `raw_sha256` hashes the bytes as received. `content_sha256` is null when no body was read.
- `injection_flags` lists prompt-injection patterns found in the text, such as `instruction_override` or `hidden_instructions`. They are flags, not a verdict: an empty list means none of our patterns matched.
- `text` is null unless you set `return_text`.

## Several pages in one call

Send `urls` instead of `url` to fetch up to 10 pages in one paid call:

```json
{ "urls": ["https://www.iana.org/help/example-domains", "https://www.iana.org/domains/reserved"], "return_text": true }
```

- The price is US$0.002 times the number of URLs, on every rail: the 402 offer (x402 `PAYMENT-REQUIRED`, the L402 invoice) is made for that body, so send the same body when you pay. A credit key is charged the sats price times the count.
- The answer is `{ "results": [...], "tier", "rail", "network" }`. `results` has one entry per URL, in the order sent: `{ "url", "page", "text", "text_chars", "text_truncated", "injection_flags", "advice", "receipt" }`, each as for one `url`.
- Each page has its own receipt, the same size as a one-page receipt, so [Recheck](/docs/recheck) and `POST /v1/receipt/verify` take each one alone. Each also signs `result.batch: { "index", "count" }` (its place in the call) and the `request_sha256` of the whole request.
- Each URL may appear once; a repeat is refused with 400 before payment. Send `url` or `urls`, not both.
- As for one page, a bad URL, a blocked address or a host name that does not resolve is refused before payment (with `details.field` such as `urls[2]`). If any page turns out to be disallowed by robots.txt or rate limited after payment, the whole call answers with that error and is not charged.
- A free trial call covers at most 5 URLs; a larger one gets the normal 402 offer, `details.reason` `trial_too_large`.

## PDF

An `application/pdf` page is read too, within the same 2 MB and 10-second limits. Only its text layer is read, with no OCR, so a scanned PDF comes back as `empty` with the signal `pdf_no_text_layer`.

- `signals` includes `pdf`. `title` is the PDF's own title, if it has one.
- `text` has the pages in order, separated by a form feed (`\f`).
- Only text inside each page's box is read, as a reader sees it. Text drawn outside the page is not in `text`.
- `page.pdf` gives `page_count`, `pages_read` and `truncated`. Very long PDFs stop at a page or character cap, with the signal `pdf_truncated`. The receipt signs these as well.
- A PDF we could not read is `unsupported_type` with a signal saying why: `pdf_encrypted`, `pdf_invalid`, `pdf_over_budget`, `pdf_timeout` or `pdf_out_of_memory`. It is charged like any other page we cannot read.
- When too many PDFs are waiting to be read, the call gets 503 `over_capacity` (`details.reason` `pdf_queue_full`) with `Retry-After`. It is not charged.

Only the full service reads PDFs: an edge server answers 501 `not_on_edge` (`details.reason` `pdf`) for one, not charged. Limits are in [Limits](/docs/limits).

## Later: has it changed?

Keep the receipt. [Recheck](/docs/recheck) (`POST /v1/recheck`, US$0.003) takes it later, fetches the page again and says `unchanged`, `changed`, `gone` or `unreadable`, with a signed receipt naming both hashes.

## Charging

A bad URL, a blocked address or a host name that does not resolve is refused before payment and not charged. Results about the page itself, including 404s and bot walls, are charged: that is the answer you paid for. A fetch that read no page (a timeout, a failed connection, an undecodable body, too many redirects, or a redirect we refuse) answers 502 `upstream_unreachable` with `details.reason`, and is not charged. In a batch the call is charged once, when at least one URL read a page; if none did, it is 502 and not charged. See [Payments](/docs/payments).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/recheck.md

# Re-check a page against an earlier receipt

Last updated: 2026-10-15

`POST /v1/recheck` fetches the page named in an earlier receipt again and tells you whether its text changed: `unchanged`, `changed`, `gone` or `unreadable`, the fields that differ, and a signed receipt naming both the old and the new hashes. Price: US$0.003 per call.

## When to use it

- For page change detection without storing anything: keep the receipt, recheck when you need to know.
- Before reusing a quote or a citation you checked days ago.
- To keep a dated chain of evidence that a page stayed the same (each receipt names the one before).

## Request

Send exactly one of the two baseline forms. The receipt from an earlier call:

```json
{ "receipt": "eyJhbGciOiJFZERTQSIs…", "return_text": false }
```

Or a URL and the `content_sha256` from our own fetch of it:

```json
{ "url": "https://www.iana.org/help/example-domains", "content_sha256": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "return_text": false }
```

| Field | Required | Meaning |
|---|---|---|
| `receipt` | one of the two forms | compact JWS receipt from an earlier `/v1/fetch`, `/v1/verify/quote`, `/v1/verify/quotes` or `/v1/recheck` call of this service, paid or trial (not a sample), at most 160 KB |
| `url` | one of the two forms | only without `receipt`: http or https URL, at most 2,048 characters |
| `content_sha256` | with `url` | the `page.content_sha256` from our own fetch, 64 hex characters; other tools hash other text, so their hashes will not match |
| `return_text` | no | also return up to 20,000 characters of the new clean text; default `false` |
| `quote` | no | only with `receipt` from a verify/quote call in exact or fuzzy mode: the quote exactly as sent to verify/quote. Any other value is a 400 before payment |
| `quotes` | no | only with `receipt` from a verify/quotes call in exact or fuzzy mode: every quote of that call, exactly as sent, in the same order, 1 to 20. Not with `quote`. Any other value is a 400 before payment; on the edge it is a 501 `not_on_edge`, uncharged |
| `history` | no | 1 to 10 earlier receipts of this service for the same URL, oldest first (fetch, quote, quotes or recheck; paid or trial); adds a `timeline`. Not stored: send it again each time |

The page fetched is the baseline's `url` (the URL first asked for, not the final URL), so redirects are followed again. The body may be up to 168 KB, so a long receipt fits.

## History (timeline)

Send your own earlier receipts for the same URL in `history` and the answer gains a `timeline`: each receipt in order, then this check. `changed` on each entry compares its clean-text hash with the entry before it (`null` for the first, or when a hash is missing). A receipt that does not verify, names another URL or is out of order is a `400 baseline_invalid` before payment, with its `index`. The timeline is also in the signed recheck receipt. Requests without `history` are unchanged.

## Answer

From the free sample (`GET /v1/sample/recheck`), shortened:

```json
{
  "change": "unchanged",
  "changed": false,
  "differences": [],
  "baseline": {
    "source": "caller",
    "receipt_sha256": null,
    "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "content_sha256": "0e429607…"
  },
  "elapsed_seconds": null,
  "page": {
    "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "http_status": 200,
    "content_kind": "real",
    "content_sha256": "0e429607…",
    "raw_sha256": "179b9ac4…"
  },
  "text": null,
  "injection_flags": [],
  "advice": "The page's text is the same as in the baseline (byte for byte on the clean text). Markup or other bytes may still have moved; see differences.",
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid",
  "rail": "x402",
  "network": "eip155:8453"
}
```

| `change` | `changed` | Meaning |
|---|---|---|
| `unchanged` | `false` | The page's text is the same as in the baseline. A page already gone in the baseline and still gone is unchanged too. |
| `changed` | `true` | The page's text differs from the baseline. Fetch it again or check your quote before you rely on it. |
| `gone` | `true` | The page no longer exists (404 or 410, or the site's name no longer resolves). |
| `unreadable` | `null` | We could not read the page this time (`page.content_kind` says why), so we cannot say whether it changed. Try again later. |

- Receipts are signed by `iss` https://still-rapids-9yt7.here.now (keys at /.well-known/jwks.json), not by the origin you called. Check one free with `POST /v1/receipt/verify` ([docs](/docs/receipt-verify)).
- `differences` lists every compared field that differs, whatever the verdict: `content_sha256`, `raw_sha256`, `http_status`, `final_url`, `content_kind`, and with a receipt baseline also `server_ip` and `tls.cert_sha256` when both sides have them.
- `baseline` is what was compared against. With the `url` form, `source` is `caller` and the fields only a receipt carries are null.
- `elapsed_seconds` is the time since the baseline was fetched (null with the `url` form).
- `page`, `text` and `injection_flags` are the new fetch, as [`/v1/fetch`](/docs/fetch) gives them.

## What "changed" means

The comparison is byte for byte on the clean text we extract (`content_sha256`). Markup-only changes are not changes: `raw_sha256` may differ while the answer is `unchanged`. A page with a date, a counter or rotating text reads as changed on every visit. A `content_sha256` from another tool will not match ours: use the hash from our own fetch.

## Quote

With `quote`, the quote is matched on the live page again and the answer adds `quote`, with a `verdict`:

| `quote.verdict` | Meaning |
|---|---|
| `still_exact` | The quote was exact in the receipt and is exact now. |
| `now_exact` | The quote was fuzzy or not found in the receipt and is exact now. |
| `now_fuzzy` | The quote matches now only with small differences. |
| `now_missing` | The quote is not on the page now, and the page is real (`page.content_kind`). |
| `unchecked` | The quote is not found on a page that is not real, so this says nothing about the quote. |

With `quotes` (a verify/quotes receipt), each quote gets its own verdict in `quotes`, in the order sent: `index`, `quote_sha256`, `verdict` (the same values as above), `was`, `now`, `score`, `start`, `end`, `occurrences`, and `error` when that quote was too costly to match now (its verdict is then `unchecked`). If every quote is too costly, the call is a 422 `match_too_costly`, not charged.

## Chaining

The recheck receipt is itself a valid baseline: send it to the next call. Its `result.baseline.receipt_sha256` is the SHA-256 of the receipt you sent, so a chain can be checked offline with [verify-receipt.mjs](/docs/receipt-verify).

## Charges and errors

The call is charged like `/v1/fetch` whenever it answers, `gone` and `unreadable` included: the fetch was done and the receipt is evidence of it. If we read no page at all (a timeout, a connect error, a bad decode, too many redirects or a redirect we refuse), the call answers 502 `upstream_unreachable` with `details.reason` set, and is not charged. Every baseline problem is a 400 before payment, never charged:

- `bad_request`: neither or both baseline forms, or `content_sha256` without `url`.
- `baseline_invalid`: the receipt does not verify against this service's keys, is not a fetch, verify/quote, verify/quotes or recheck receipt, is a sample, or names no URL; `details.reason` says which.

The other errors are those of `/v1/fetch`; see [Errors](/docs/errors). On the edge, a PDF page answers 501 `not_on_edge`, uncharged.

## Compared with a hosted watch

No schedule, no webhook, nothing stored: you call when you want to know, and pay US$0.003 per check.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-links.md

# Check links

Last updated: 2026-10-10

`POST /v1/check/links` checks 1 to 10 URLs in one call: status, redirect chain, final URL, `content_kind`, title and content hash for each, under one signed receipt. Price: US$0.005 per batch.

Use it to check the sources in a draft before you publish or hand it on.

## Request

```json
{ "urls": ["https://www.iana.org/help/example-domains", "https://www.iana.org/domains/reserved"] }
```

`urls` is a list of 1 to 10 items. Each item is an http or https URL string, or an object `{ "url": "...", "expected_text": "..." }` (see [expected_text](#expected-text)). Each URL is at most 2,048 characters. Every URL is checked before payment; if any one is malformed, blocked or disallowed by robots.txt, the whole request is refused and not charged.

## Response

From the free sample (`GET /v1/sample/links`), shortened:

```json
{
  "results": [
    {
      "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
      "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
      "http_status": 200,
      "redirects": [],
      "content_kind": "real",
      "verdict": "ok",
      "title": "Regional climate report 2025 (demo page)",
      "content_sha256": "0e429607…"
    },
    {
      "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/missing",
      "final_url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/missing",
      "http_status": 404,
      "redirects": [],
      "content_kind": "http_error",
      "verdict": "broken",
      "title": null,
      "content_sha256": "cb699046…"
    }
  ],
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid"
}
```

## Link verdict

Each result has a `verdict` for the link itself, one of:

| verdict | meaning |
| --- | --- |
| `ok` | The URL resolves and stays on the same address; the page was read, or is a PDF. |
| `broken` | The URL fails: `content_kind` is `http_error` (4xx, 5xx, DNS, connection or redirect-loop failure), or it redirects to another site that answers 4xx or 5xx (`off_site_error`). |
| `moved` | The URL redirects to a different address, and the page was read, or is a PDF, or it is off-site. |
| `unknown` | The page was not read or was blocked (bot wall, JavaScript-only page, paywall, empty, too large, timeout, unsupported type, or disallowed by robots.txt). The link is not claimed to be ok or dead. |

The verdict is per URL and is signed into the receipt. It is not the page verdict: `content_kind` still says what the page was. A 403 from a bot wall is `unknown`, not `broken`.

## expected_text

An item may carry `expected_text`: a words or sentence the page should contain. It is matched on the page text, fuzzy and case-folded, the same match as verify/quote. Each result then has `expected_text`: `null` when none was sent or the page was not read, otherwise `{ match, score, start, end, context, quote_sha256, evidence }`, where `match` is `exact`, `fuzzy` or `none`.

`expected_text` never changes the `verdict`. A link can be `ok` while its `expected_text.match` is `none`: the link works but the content is not what you expected. It is 1,000 characters at most, and an empty value is refused with 400.

```json
{ "urls": [{ "url": "https://www.iana.org/help/example-domains", "expected_text": "reserved for use in documentation" }] }
```

## Dead domains

A URL whose host name does not resolve is reported as a result: `content_kind` `http_error`, `http_status` null, and the batch is charged. If no URL in the batch resolves, the call gets 422 `host_not_found` and is not charged.

## PDF links

A live PDF link (status 2xx, content type `application/pdf`, on the same site as the URL) is reported with `content_kind` `pdf`. check/links does not read PDFs, so its `title` and `content_sha256` are null. To read a PDF's text or check a quote in it, use [fetch](/docs/fetch) or [verify/quote](/docs/verify-quote) on the full service.

## Links that are not read

check/links reads HTML, text and JSON only. Any other link (a PDF, an image, a download) with a 4xx or 5xx status is `http_error`, so a dead PDF reads as dead. Any link that redirects to another site is `off_site`, whatever its type, as for an HTML page. If the other site answers with a 4xx or 5xx status, the result also has `"off_site_error": true`, so a link that moved to a dead page is not missed; otherwise the field is left out. Where archive snapshots are on, a paid call also looks such a link up (the URL you sent) and adds `wayback`, as for a failed URL. A live link of another type on the same site is `unsupported_type`.

## Charging

If a URL turns out to be disallowed by robots.txt or rate limited after payment (for example after a redirect), the whole batch answers with an error and is not charged. See [Payments](/docs/payments).

A free-trial call covers at most 5 URLs. A larger batch is not run as a trial: it gets the normal 402 offer, with `details.reason` `trial_too_large`, and is not charged.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-packages.md

# Check packages

Last updated: 2026-10-12

`POST /v1/check/packages` looks up 1 to 10 package names on npm, PyPI or crates.io in one call and says, for each, whether the registry lists that name, with its latest version, description, licence, links, a few flags and the known OSV.dev advisories for that version, under one signed receipt. Price: US$0.005 per batch.

Use it before you install a package an agent or a model suggested: a name that does not exist may be a hallucination, and a squatter can register it later.

**It answers "exists in registry" and "OSV.dev lists these advisories", nothing more. It is not a security verdict.** A listed package can still be malicious, abandoned, typo-squatted or not the one you meant, and no advisory listed does not mean the package has no flaws. Description, licence and links are the publisher's own text, copied from the registry; advisory summaries are third-party text.

## Request

```json
{ "packages": [
  { "ecosystem": "npm", "name": "left-pad" },
  { "ecosystem": "pypi", "name": "requests" },
  { "ecosystem": "crates", "name": "serde" },
  { "ecosystem": "npm", "name": "lodash", "version": "4.17.20" }
] }
```

`packages` is a list of 1 to 10 objects, each with these fields:

- `ecosystem`: `npm`, `pypi` or `crates` (crates.io)
- `name`: the package name as you would install it. npm names may be scoped (`@scope/name`).
- `version` (optional): the exact version you will install, up to 64 characters, starting with a digit (then letters, digits and `. + ! _ ~ -`; not a range such as `^1.0.0` or a tag such as `latest`). Advisories are then listed for this version instead of the latest.

Every name is checked against its registry's naming rules before payment; if any one is invalid, the whole request is refused with 400 and not charged. No lookup happens before payment.



## Response

From the free sample (`GET /v1/sample/packages`), shortened:

```json
{
  "results": [
    {
      "ecosystem": "npm",
      "name": "left-pad",
      "exists": true,
      "status": "found",
      "registry_name": "left-pad",
      "latest_version": "1.3.0",
      "description": "String left pad (demo copy of registry data)",
      "license": "WTFPL",
      "homepage": "https://github.com/stevemao/left-pad#readme",
      "repository": "git+ssh://git@github.com/stevemao/left-pad.git",
      "created_at": "2014-03-14T09:09:20.762Z",
      "deprecated": "use String.prototype.padStart()",
      "yanked": null,
      "signals": ["deprecated"],
      "vulnerabilities": { "status": "checked", "reason": null, "version": "1.3.0", "count": 0, "truncated": false, "items": [] },
      "registry_url": "https://www.npmjs.com/package/left-pad",
      "http_status": 200,
      "raw_sha256": "09093cc2…"
    },
    {
      "ecosystem": "npm",
      "name": "left-pad-demo-missing",
      "exists": false,
      "status": "not_found",
      "latest_version": null,
      "signals": [],
      "vulnerabilities": { "status": "checked", "reason": null, "version": null, "count": 0, "truncated": false, "items": [] },
      "registry_url": "https://www.npmjs.com/package/left-pad-demo-missing",
      "http_status": 404,
      "raw_sha256": "c8d3eae1…"
    }
  ],
  "note": "exists means the registry listed this name when we looked. It is not a security verdict: the package may still be malicious, unmaintained or not the one you meant; …",
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid"
}
```

| Field | Meaning |
|---|---|
| `exists` | `true` the registry lists the name, `false` it answered 404, `null` the lookup failed |
| `status` | `found`, `not_found` or `lookup_failed` (then `reason`: `timeout`, `network_error`, `too_large`, `registry_rate_limited`, `http_<status>` or `bad_json`) |
| `registry_name` | the name as the registry spells it |
| `latest_version` | npm `latest` tag, PyPI's current version, crates.io's default version |
| `created_at` | npm: the package document's `time.created` (null if that document is over 4 MB or cannot be read); PyPI: first file upload; crates.io: crate creation |
| `license` | npm and PyPI: the latest version's licence field; crates.io: the default version's licence |
| `deprecated` | npm deprecation message of the latest version, else null |
| `yanked` | PyPI: latest release yanked; crates.io: crate yanked; npm: null |
| `signals` | flags worth a second look: `name_differs`, `deprecated`, `yanked`, `created_recently` (under 30 days), `known_vulnerable` (OSV lists an advisory for the version asked about), `malicious` (an advisory is a malware report, id or alias starting `MAL-`; this can appear on a `not_found` name too). `name_differs` means the registry's own spelling (`registry_name`) is not the name you sent; PyPI and crates.io ignore case and treat `-` and `_` (PyPI also `.`) as the same, so it is often only a spelling variant of the same package |
| `vulnerabilities` | known advisories from OSV.dev, see below |
| `raw_sha256` | SHA-256 of the registry's answer as we received it (npm: the `/latest` answer) |

Signals are hints, not a security verdict: a package with no signals can still be malicious.

The receipt has `kind` `packages` and, per name, the ecosystem, name, `exists`, `status`, `latest_version`, `raw_sha256`, `vuln_status`, `vuln_version` (the version asked about) and `vuln_ids` (the advisory ids returned, in order).

## Vulnerabilities

When you send a `version`, we ask [OSV.dev](https://osv.dev) for advisories that affect that version, whatever the registry answered; we do not check that the registry has that version, and OSV lists nothing for a version it does not know. Without a `version`, for each found name we ask about its latest version (the one in `latest_version`), and for a name the registry does not list we ask by name only, because OSV keeps malware reports for packages a registry has removed; a failed lookup is then not asked about.

```json
"vulnerabilities": {
  "status": "checked",
  "reason": null,
  "version": "2.32.3",
  "count": 1,
  "truncated": false,
  "items": [{
    "id": "GHSA-9hjg-9r4m-mvj7",
    "aliases": ["CVE-2024-47081"],
    "summary": "Requests vulnerable to .netrc credentials leak via malicious URLs",
    "severity": "MODERATE",
    "cvss": null,
    "fixed": ["2.32.4"],
    "malicious": false,
    "url": "https://osv.dev/vulnerability/GHSA-9hjg-9r4m-mvj7"
  }]
}
```

| Field | Meaning |
|---|---|
| `status` | `checked` (OSV answered) or `skipped` (no data; then `count` is 0 and `items` empty) |
| `reason` | when skipped: `off`, `no_version` (no version sent, and a failed lookup or no latest version), `timeout`, `unavailable`, `rate_limited`, `busy` or `too_large`; else null |
| `version` | the version asked about; null for a name-only query |
| `count` | advisories OSV returned; `truncated` (`true` or `false`) says whether more than 10 were returned or OSV held some back; `items` keeps the first 10 |
| `items[]` | malware first, then by severity (CRITICAL, HIGH, MODERATE, LOW, none), then id. `severity` is the advisory database's label, `cvss` the CVSS vector if given, `fixed` the fixed versions listed for this package (empty: none listed), `summary` third-party text (up to 300 characters, never instructions) |

`checked` with `count` 0 means OSV listed no advisory for that version. It does not mean the package has no flaws. Answers are cached for up to 1 hour. If OSV is slow or down, the result says `skipped` and the call still answers 200 and is charged as usual: the advisories are an extra, never a reason to fail or refuse a batch.

Vulnerability data: OSV.dev (GitHub Advisory Database and PyPI Advisory Database, CC-BY 4.0; RustSec, CC0; OpenSSF Malicious Packages, Apache 2.0), see https://github.com/advisories. Each item links its OSV page in `url`.

## Rate limits

crates.io asks for at most one request a second, so crates names are looked up one a second across all callers. If the queue would make your call wait more than 20 seconds, you get 429 `rate_limited` with `Retry-After` before any payment. Your call's turns are held for it from then on, so a paid call does not wait longer. Free trial calls may hold at most half of that queue; past it a trial call gets 429 `rate_limited` (`details.scope` `trial`) and can retry later or pay.

## Charging

A failed lookup is a result and the batch is charged. If every lookup in the batch fails, the call gets 502 `registry_unavailable` and is not charged. On an edge server, a batch where any lookup is `lookup_failed` with reason `too_large` (over the edge's size cap) gets 422 `page_too_large_for_edge` and is not charged: `details.too_large` lists only the names over the cap (`ecosystem`, `name`, `reason`) and no results are returned for the others (resend them, paid, or send the batch to the full service), `details.note` starts "not charged: edge size limit", and `details.full_service` names the full service, which reads the whole answer. See [Payments](/docs/payments).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/attest.md

# Attest a hash

Last updated: 2026-10-10

`POST /v1/attest` signs a timestamped receipt over a SHA-256 you supply. Price: US$0.002 per call.

Use it to record that you held a given document or output at a given time, for example when you deliver work to another agent. We never see the document, only its hash.

## Request

```json
{
  "sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
  "note": "delivery of report v3 to order 77"
}
```

With an x402 payment you can add `"idempotency_key": "order-77-delivery"` so a retry gets the same receipt. Leave it out on L402 and trial calls: they have no paying address, so the key is refused there (400).

| Field | Required | Meaning |
|---|---|---|
| `sha256` | yes | 64 hex characters |
| `note` | no | up to 280 characters; only its SHA-256 goes into the receipt and our records |
| `idempotency_key` | no, x402 only | 1 to 128 printable ASCII characters without spaces; a retry with the same key, hash and note gets the same receipt |

## Response

From the free sample (`GET /v1/sample/attest`), shortened:

```json
{
  "attestation": {
    "sha256": "e3b0c442…",
    "note_sha256": "…",
    "seq": 1,
    "issued_at": "2026-10-09T14:20:14.636Z",
    "idempotency_key": null,
    "idempotency_key_sha256": null,
    "first_seen": true
  },
  "receipt": "eyJhbGciOiJFZERTQSIs…",
  "tier": "paid"
}
```

- Receipts are signed by `iss` https://still-rapids-9yt7.here.now (keys at /.well-known/jwks.json), not by the origin you called. Check one free with `POST /v1/receipt/verify` ([docs](/docs/receipt-verify)).
- `seq` is our running count of attestations.
- `idempotency_key` and `idempotency_key_sha256` are null when no key was sent, as in the sample.
- `first_seen` is false when the same key returns an earlier receipt.
- Reusing an `idempotency_key` with a different hash or note gets 409 `idempotency_conflict`, not charged. The payment is verified first, then released without being taken.
- We keep only the SHA-256 of your key. The receipt carries `idempotency_key_sha256`, and the live answer also echoes the key you sent.
- If the payment fails to settle (502 `settle_failed`), the receipt was already made and is kept. A retry with the same key and hash gets it (`first_seen: false`) and pays once. Its `payment` block names the payer and price but is not a record that a payment settled: the receipt attests the hash and the time, not the payment. To avoid paying twice when the failed payment did go through, retry with the same payment-identifier (see [payments](payments.md)).
- Keys are scoped to the paying address, so two payers can use the same key without affecting each other. Trial calls and L402 calls have no paying address, so they cannot use `idempotency_key` (400, and an L402 token is not spent).

## What it shows

The receipt shows that this SHA-256 was sent to us by the stated time. It does not show who made the document, what it contains, or that it was not made earlier.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/receipt-verify.md

# Verify a receipt

Last updated: 2026-10-15

`POST /v1/receipt/verify` checks an AttestPage receipt against this service's published keys and returns its decoded payload. Free.

If you would rather not trust our server to check our own receipts, use the [offline checker](/docs/verify-offline) instead.

## Request

```json
{ "receipt": "eyJhbGciOiJFZERTQSIs…" }
```

`receipt` is the compact JWS from the `receipt` field of any response, at most 163,840 characters (160 KB). A 10-URL `check/links` or `verify/citations` receipt with long URLs and every network-evidence field at its cap is about 128 KB. The evidence fields are capped in bytes, so a site whose certificate names or headers use non-ASCII or escaped characters cannot make it bigger. The request body may be up to 168 KB, here and on `/mcp`.

## Response

```json
{
  "valid": true,
  "kid": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json#ap-1a2b3c4d5e6f7a8b",
  "tier": "paid",
  "payload": { "v": 1, "iss": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us", "kind": "quote", "…": "…" }
}
```

When the receipt does not check out, `valid` is false and `reason` and `message` say why. Reasons include `malformed`, `bad_alg`, `bad_signature`, `unknown_kid`, `bad_iss` and `tier_key_mismatch`.

`tier` is `paid`, `trial` or `sample`. Sample receipts are signed with a separate example key (kid ending `#sample`) and are not evidence about any third-party page.

## Your receipt from a paid call

A paid answer's body names the receipt: `receipt` (the compact JWS), `receipt_id` (the SHA-256 of that JWS, 64 hex characters) and `receipt_verify` (this route, in words). The receipt's `payment.tx` is the settled USDC transfer on chain, so you can match it to the payment without our logs. Keep the receipt: post it here at any time to check it again, free. A repeat of the same paid request with the same payment returns the same response, uncharged, for an hour.

## Errors

400 when the body is not `{"receipt": "<string>"}` or the receipt is too long; 503 `signing_unavailable` when keys are not loaded.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/samples.md

# Samples

Last updated: 2026-10-17

Each paid route has a free sample that runs the route's real code on a fixed demo page (for packages, a built-in demo copy of registry data) and returns the full response, signed with the example key. Samples make no outbound fetch, cost nothing and need no payment.

| Sample | Route it shows | Demo input |
|---|---|---|
| `GET /v1/sample/quote` | `POST /v1/verify/quote` | the quote "emissions fell 12% in 2025", fuzzy match |
| `GET /v1/sample/quote?match=passages` | `POST /v1/verify/quote` with `"match": "passages"` | the paraphrased claim "The agency reported a 12 percent drop in emissions during 2025": the 3 passages that share most of its words |
| `GET /v1/sample/citations` | `POST /v1/verify/citations` | three citations: one misformatted (fuzzy), one made up (none) and one on a missing page (404) |
| `GET /v1/sample/document` | `POST /v1/verify/document` | the citations sample's three pairs, written as a short document |
| `GET /v1/sample/document?format=html` | `POST /v1/verify/document` with `"format": "html"` | the same three pairs, written as HTML with `<a href>` links |
| `GET /v1/sample/fetch` | `POST /v1/fetch` | the demo page, with text |
| `GET /v1/sample/links` | `POST /v1/check/links` | the demo page and a missing page (404) |
| `GET /v1/sample/packages` | `POST /v1/check/packages` | left-pad (npm), requests (PyPI), serde (crates.io) and a missing npm name, from a built-in demo copy of registry data |
| `GET /v1/sample/attest` | `POST /v1/attest` | the SHA-256 of the demo page |
| `GET /v1/sample/quotes` | `POST /v1/verify/quotes` | three quotes on the demo page: one exact, one misformatted (fuzzy) and one made up (none) |
| `GET /v1/sample/textquote` | `POST /v1/verify/text-quote` | a sentence from the demo page, sent as text (no fetch), and a misformatted quote of it (fuzzy) |
| `GET /v1/sample/recheck` | `POST /v1/recheck` | the demo page's URL and its own `content_sha256`, so it reads unchanged |

The demo page itself is at [/v1/sample/page](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page). Its text is made up.

## What a sample returns

The same fields as the paid route, plus:

- `sample: true` and a `note`
- `input`: the demo request body used
- `tier: "sample"`, `rail: null`, `network: null`

The receipt is signed with the example key, whose kid ends in `#sample`. [POST /v1/receipt/verify](/docs/receipt-verify) and the [offline checker](/docs/verify-offline) accept it and report tier `sample`. A sample receipt says nothing about any page other than the demo page.

## Try it

```sh
curl https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote
curl "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote?match=passages"
```

`match` is read only by the quote sample: `fuzzy` (the default) or `passages`; any other value gets 400.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/receipt-demo.md

# Receipt demo

Last updated: 2026-10-13

A signed receipt from start to finish, using only free calls: get a receipt from a free example call, check it with `POST /v1/receipt/verify`, see a changed receipt fail, then check it offline. Step 5 adds the free trial on a real route. No payment, wallet or account is needed. The commands use `curl` and `jq`.

## 1. Get a receipt

`GET /v1/sample/fetch` runs the real [fetch](/docs/fetch) code on the [example page](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page) and signs the result with the example key.

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch > sample.json
jq '{tier, page: .page.http_status, kind: .page.content_kind, sha: .page.content_sha256}' sample.json
jq -r .receipt sample.json > receipt.txt
```

The response has the page result and a `receipt` field: a compact JWS (`header.payload.signature`). The receipt records the URL, final URL, status, content_kind, page hashes, time of the fetch and a hash of the request.

## 2. Check it

```sh
jq -n --rawfile r receipt.txt '{receipt: ($r | rtrimstr("\n"))}' > body.json
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'Content-Type: application/json' -d @body.json
```

The answer:

```json
{
  "valid": true,
  "kid": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json#sample",
  "tier": "sample",
  "payload": {
    "v": 1,
    "iss": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us",
    "kind": "fetch",
    "tier": "sample",
    "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
    "http_status": 200,
    "content_kind": "real",
    "content_sha256": "0e429607…",
    "payment": null,
    "…": "…"
  }
}
```

`payload.content_sha256` matches `page.content_sha256` from step 1.

## 3. Change one character

```sh
jq -n --rawfile r receipt.txt '{receipt: ($r | rtrimstr("\n") | .[0:-2] + (if .[-2:-1] == "A" then "B" else "A" end) + .[-1:])}' > bad.json
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'Content-Type: application/json' -d @bad.json
```

The answer has `"valid": false` and `"reason": "bad_signature"`.

## 4. Check it offline

The [offline checker](/docs/verify-offline) is one Node.js file. It checks the receipt against the published keys at [/.well-known/jwks.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json) without calling the verify route.

```sh
curl -sO https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/verify-receipt.mjs
node verify-receipt.mjs "$(cat receipt.txt)" --issuer https://s2h6qt73jtzlgbgnnfacln2poq.srv.us
```

## 5. Try a real route

For a receipt about a URL of your choice, call a paid route such as [fetch](/docs/fetch). There is no free trial at the moment; use the free samples instead.

A free example receipt is signed with the example key and says nothing about any page other than the example page. Paid and trial receipts cover the URL you asked for. See [free example calls](/docs/samples), [Verify a receipt](/docs/receipt-verify) and [Payments](/docs/payments).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/demo.md

# Demo: one paid call and its signed receipt

Last updated: 2026-10-13

One call to `POST /v1/verify/quote`, step by step: the request, the 402 payment offer (US$0.01 in USDC), the paid retry with x402, the answer with its signed receipt, and how to check the receipt's signature yourself with nothing but Node.js.

The example receipt is signed with an example key, published in step 5, so every check on this page works offline. The live `POST /v1/receipt/verify` route answers `unknown_kid` for this example, because the example key is not one of ours; real receipts verify there. Receipts from https://s2h6qt73jtzlgbgnnfacln2poq.srv.us are signed with the keys at [https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json) and are checked the same way.

## 1. The request

An agent wants to quote a page and sends the URL and its exact words:

```http
POST /v1/verify/quote HTTP/1.1
Host: attestpage.example
Content-Type: application/json

{
  "url": "https://www.iana.org/help/example-domains",
  "quote": "These domains may be used as illustrative examples in documents"
}
```

## 2. The 402 offer

No payment came with the request, so the answer is `402 Payment Required` and nothing is charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```http
HTTP/1.1 402 Payment Required
PAYMENT-REQUIRED: eyJ4NDAyVmVyc2lvbiI6Miwi…

{
  "error": {
    "code": "payment_required",
    "message": "This route costs US$0.01 via x402 (see the PAYMENT-REQUIRED header and /pricing.json; send the signed payment in the PAYMENT-SIGNATURE request header). Or send the header quoteproof-trial: 1 for a free trial (10 calls a day per IP address, resetting at midnight UTC).",
    "details": {
      "trial": {
        "header": "quoteproof-trial",
        "value": "1",
        "per_day": 10,
        "max_batch_items": 5,
        "how": "Resend this request with the header quoteproof-trial: 1 and no payment header. Free, up to 10 calls a UTC day per caller (per IP address; on the srv.us direct port, per client header set), 50 a day across all direct-port callers with no payment id, and 200 across all callers; callers that reach the service through one shared address (a proxy or tunnel) share its 10 calls. Over that, 429 trial_exhausted."
      }
    }
  }
}
```

Decoded, without the route description and the extensions:

```json
{
  "x402Version": 2,
  "error": "Payment required",
  "resource": {
    "url": "https://attestpage.example/v1/verify/quote"
  },
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:84532",
      "amount": "10000",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "payTo": "0x70C796f8671B1F9f13447872d357DE1144171302",
      "maxTimeoutSeconds": 120,
      "extra": {
        "name": "USD Coin",
        "version": "2"
      }
    }
  ]
}
```

`amount` is in USDC base units (6 decimals), so `10000` is US$0.01, paid in USDC with x402 v2 on Base Sepolia (a test network). Prices for every route: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 3. The paid retry

The agent's x402 client signs a USDC transfer authorization for exactly that amount and sends the same request again with a `PAYMENT-SIGNATURE` header. Decoded, without the extensions and with the signature shortened:

```json
{
  "x402Version": 2,
  "resource": {
    "url": "https://attestpage.example/v1/verify/quote"
  },
  "accepted": {
    "scheme": "exact",
    "network": "eip155:84532",
    "amount": "10000",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "payTo": "0x70C796f8671B1F9f13447872d357DE1144171302",
    "maxTimeoutSeconds": 120,
    "extra": {
      "name": "USD Coin",
      "version": "2"
    }
  },
  "payload": {
    "authorization": {
      "from": "0xD61A51C2696dd5c9beFd8cA42F237eD5E9e9f337",
      "to": "0x70C796f8671B1F9f13447872d357DE1144171302",
      "value": "10000",
      "validAfter": "0",
      "validBefore": "1791786120",
      "nonce": "0x5d415fb63d57b07b64cfe13feb5dd3319e68fed87adb0320c5ec415406f1cf24"
    },
    "signature": "0x5b696e2189…221b"
  }
}
```

Any x402 v2 client does this step. [One x402 payment step by step](/docs/examples/fetch-x402) shows it with plain `fetch`, and the [MCP server](/docs/mcp) does it for you.

## 4. The answer and its receipt

The check runs and the payment is settled: `200 OK`, with a `PAYMENT-RESPONSE` header. Decoded, without the transaction hash and the extensions:

```json
{
  "success": true,
  "payer": "0xD61A51C2696dd5c9beFd8cA42F237eD5E9e9f337",
  "network": "eip155:84532",
  "amount": "10000"
}
```

The body:

```json
{
  "result": {
    "match": "exact",
    "score": 1,
    "start": 171,
    "end": 234,
    "context": "...e.com and example.org are maintained for documentation purposes. These domains may be used as illustrative examples in documents without prior coordination with us. They are not available for re...",
    "occurrences": 1,
    "normalised_sha256": "75a93b6d9b17a11bb2277dde1de0e57ac357967052d4ae3e4d660856ff22e81d"
  },
  "page": {
    "requested_url": "https://www.iana.org/help/example-domains",
    "final_url": "https://www.iana.org/help/example-domains",
    "http_status": 200,
    "content_type": "text/html",
    "content_kind": "real",
    "signals": [
      "status_200"
    ],
    "title": "Example Domains",
    "redirects": [],
    "content_sha256": "6a7cca043c62d5d13f7d4c6f2eba2839c6446c06b5c7be6cb29d77ad6ab80e46",
    "raw_sha256": "eeb94115fe65c771f01a0cc0701cded276a75cab3c0bb71cbf34daf802ce4a44",
    "retrieved_at": "2026-10-12T06:20:02.607Z",
    "server_ip": "104.18.24.232",
    "tls": {
      "cert_sha256": "cbf3a200a42e2b6b751fb6beb6d1b72a464a0ab7ffebfca0fff071af2c185b64",
      "issuer": "C=US, O=Google Trust Services, CN=WE1",
      "subject": "CN=www.iana.org",
      "valid_from": "2026-08-21T20:51:32.000Z",
      "valid_to": "2026-11-19T21:51:30.000Z"
    },
    "headers": {
      "date": "Mon, 12 Oct 2026 06:20:02 GMT",
      "last-modified": "Mon, 12 Oct 2026 06:20:02 GMT",
      "content-type": "text/html; charset=utf-8",
      "content-length": "1762"
    },
    "bytes": 1762,
    "truncated": false
  },
  "injection_flags": [],
  "advice": "The page loaded and looks like real content.",
  "receipt": "eyJhbGciOiJFZERTQSIsImtpZCI6Imh0dHBzOi8vYXR0ZXN0cGFnZS5leGFtcGxlLy53ZWxsLWtub3duL2p3a3MuanNvbiNhcC1OeWl5c0NBSTR1Z3BEZlJPIiwidHlwIjoiYXR0ZXN0cGFnZS1ldmlkZW5jZStqd3MifQ.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.WBCdG3EoDUBKYbDbc94_ouDyHDzoynbeZL1h6nlYkO5c-ktgWXDvKQOMz-PUSsicwSn8ZSyo3XwpatZAhDLZCg",
  "tier": "paid",
  "rail": "x402",
  "network": "eip155:84532"
}
```

`result.match` is `exact`: the quoted words are on the page, at characters 171 to 234 of its text. `page.content_kind` is `real`: the page loaded as content, not a bot wall or an error page. `receipt` is a compact JWS (`header.payload.signature`, each base64url) that signs the URL, the time, the page and quote hashes, the match and the payment. Field meanings: [How it works](/docs/how-it-works).

## 5. Check the receipt signature

The receipt's header names the signing key:

```json
{
  "alg": "EdDSA",
  "kid": "https://attestpage.example/.well-known/jwks.json#ap-NyiysCAI4ugpDfRO",
  "typ": "attestpage-evidence+jws"
}
```

The key is published in the issuer's JWKS at `/.well-known/jwks.json`. For this example it is:

```json
{
  "keys": [
    {
      "kty": "OKP",
      "crv": "Ed25519",
      "x": "3vsTrl_8AE6RgHHi2nMAKvCDIXukag2fBhRZsM5mWQo",
      "kid": "https://attestpage.example/.well-known/jwks.json#ap-NyiysCAI4ugpDfRO",
      "alg": "EdDSA",
      "use": "sig"
    }
  ]
}
```

Save the receipt string as `receipt.txt` and the key set as `jwks.json`. This script, `check.mjs`, uses only Node.js built-ins. It finds the key whose `kid` matches the header and verifies the Ed25519 signature over `header.payload`:

```js
import crypto from 'node:crypto';
import fs from 'node:fs';

const jws = fs.readFileSync(process.argv[2], 'utf8').trim();
const { keys } = JSON.parse(fs.readFileSync(process.argv[3], 'utf8'));
const [h, p, s] = jws.split('.');
const header = JSON.parse(Buffer.from(h, 'base64url'));
const jwk = keys.find((k) => k.kid === header.kid);
if (header.alg !== 'EdDSA' || !jwk) throw new Error('no matching key');
const key = crypto.createPublicKey({ key: { kty: jwk.kty, crv: jwk.crv, x: jwk.x }, format: 'jwk' });
const ok = crypto.verify(null, Buffer.from(`${h}.${p}`), key, Buffer.from(s, 'base64url'));
if (!ok) {
  console.log('bad signature');
  process.exit(1);
}
const claims = JSON.parse(Buffer.from(p, 'base64url'));
console.log('valid', claims.iss, claims.kind, claims.result.match, claims.tier);
```

```sh
node check.mjs receipt.txt jwks.json
```

```text
valid https://attestpage.example quote exact paid
```

The last word is the receipt's tier: a paid receipt ends in `paid`, a receipt from a free-trial call in `trial`, and a free example call in `sample`.

Change one character in the middle of the receipt's payload (the part between the two dots) and it prints `bad signature`. Then check that `iss` is the issuer you expect: a valid signature from a key you did not choose means nothing.

## Check your own receipts

For a receipt from https://s2h6qt73jtzlgbgnnfacln2poq.srv.us, use the issuer's keys:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json > jwks.json
node check.mjs receipt.txt jwks.json
```

Or send it to the free route `POST /v1/receipt/verify` ([Verify a receipt](/docs/receipt-verify)), or use our single-file checker, which also checks the issuer and the receipt fields: [Verify receipts offline](/docs/verify-offline). To make the call yourself, step by step with `curl`: [How to check a quote an LLM cites](/guides/verify-llm-quote).

## Paid routes at a glance

Every paid route answers `402 Payment Required` to a request with no payment, and nothing is charged. The offer is in the `PAYMENT-REQUIRED` header. Payment settles only when the route answers below 400, so a request that fails validation is never charged. Each command below sends the unpaid request and prints the offer's network, amount and payee. The amount is in USDC base units: `10000` is US$0.01.

| Route | Price | Use it to |
|---|---|---|
| `POST /v1/verify/quote` | US$0.01 | check one quote against its page |
| `POST /v1/verify/citations` | US$0.10 | check up to 10 citations in one call |
| `POST /v1/verify/quotes` | US$0.02 | check up to 20 quotes on one page |
| `POST /v1/verify/text-quote` | US$0.005 | check a quote against text you already hold, nothing fetched |
| `POST /v1/verify/document` | US$0.10 | check every quote in a document, per part of up to 10 pairs |
| `POST /v1/fetch` | US$0.002 | read a page as clean text, with a signed receipt |
| `POST /v1/recheck` | US$0.003 | see whether a page changed since an earlier receipt |
| `POST /v1/check/links` | US$0.005 | check up to 10 links are live |
| `POST /v1/check/packages` | US$0.005 | check up to 10 package names exist |
| `POST /v1/attest` | US$0.002 | sign a SHA-256 hash with the time it was issued |

```sh
# verify/quote
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# verify/citations
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/citations -H 'content-type: application/json' \
  -d '{ "citations": [ { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" } ] }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# verify/quotes
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quotes -H 'content-type: application/json' \
  -d '{ "url": "https://www.iana.org/help/example-domains", "quotes": [ "These domains may be used as illustrative examples in documents", "without prior coordination with us" ] }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# verify/text-quote
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/text-quote -H 'content-type: application/json' \
  -d '{ "text": "In its annual summary the agency said that emissions fell 12% in 2025.", "quote": "emissions fell 12% in 2025" }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# verify/document
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document -H 'content-type: application/json' \
  -d '{ "document": "WHO says \"Air pollution kills an estimated seven million people every year\" ([WHO](https://www.who.int/health-topics/air-pollution)).", "format": "markdown" }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# fetch
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/fetch -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# recheck
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/recheck -H 'content-type: application/json' \
  -d '{ "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page", "content_sha256": "0e429607fdb16c005ef662414e758c53edb82e1cb24c3cbec239e4c1d6a7dfa0" }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# check/links
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/check/links -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# check/packages
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/check/packages -H 'content-type: application/json' \
  -d '{ "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
# attest
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/attest -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

To pay on the call, see [Fetch a page with an x402 client](/guides/fetch-a-page-with-an-x402-client). Prices for every route: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline.md

# Verify receipts offline

Last updated: 2026-10-10

You do not need to trust our server to check a receipt. A single-file checker (Node.js 20 or later, no dependencies) verifies the Ed25519 signature and the payload against our public keys.

## Get the checker

```sh
curl -O https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/verify-receipt.mjs
node verify-receipt.mjs --selftest
```

[https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json) lists the checker (`verify-receipt`) with its URL, size and sha256, so you can check the file you downloaded.

## Check a receipt

```sh
node verify-receipt.mjs '<receipt>' --issuer https://s2h6qt73jtzlgbgnnfacln2poq.srv.us
```

This fetches `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json` and checks that the receipt's `iss` and key id belong to that issuer. The issuer is a fixed address that does not change when the service moves, so a receipt keeps verifying after the service address changes. Always pin `--issuer` (or a key file you trust): without it, the key location comes from the receipt itself.

To work fully offline, save the keys once and pass the file:

```sh
curl -o jwks.json https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json
node verify-receipt.mjs '<receipt>' --jwks jwks.json --issuer https://s2h6qt73jtzlgbgnnfacln2poq.srv.us
```

Pass `-` instead of the receipt to read it from standard input.

## Output

JSON `{valid, reason?, kid, tier, payload}`. Exit code 0 means valid, 1 invalid, 2 a usage error.

## Doing it yourself

A receipt is a compact JWS: `header.payload.signature`, each base64url. Check that the header has `alg` `EdDSA` and `typ` `attestpage-evidence+jws`, find the key in the JWKS whose `kid` matches the header's `kid`, and verify the Ed25519 signature over `header.payload`. Then check that `iss` is the issuer you expect. Field meanings are in [How it works](/docs/how-it-works).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp.md

# MCP server

Last updated: 2026-10-17

`quoteproof-mcp` is an MCP server (stdio) that gives an agent 13 tools: one per paid route, plus two free ones. It needs Node.js 20.3 or later and has no install scripts.

| Tool | Route | Price |
|---|---|---|
| `attestpage_verify_quote` | [POST /v1/verify/quote](/docs/verify-quote) | US$0.01 |
| `attestpage_verify_quotes` | [POST /v1/verify/quotes](/docs/verify-quotes) | US$0.02 |
| `attestpage_verify_text_quote` | [POST /v1/verify/text-quote](/docs/verify-text-quote) | US$0.005 |
| `attestpage_verify_citations` | [POST /v1/verify/citations](/docs/verify-citations) | US$0.10 |
| `attestpage_verify_document` | [POST /v1/verify/document](/docs/verify-document) | US$0.10 |
| `attestpage_fetch` | [POST /v1/fetch](/docs/fetch) | US$0.002 |
| `attestpage_recheck` | [POST /v1/recheck](/docs/recheck) | US$0.003 |
| `attestpage_check_links` | [POST /v1/check/links](/docs/check-links) | US$0.005 |
| `attestpage_check_packages` | [POST /v1/check/packages](/docs/check-packages) | US$0.005 |
| `attestpage_attest` | [POST /v1/attest](/docs/attest) | US$0.002 |
| `attestpage_verify_receipt` | [POST /v1/receipt/verify](/docs/receipt-verify) | free |
| `attestpage_preview_document` | [POST /v1/verify/document/preview](/docs/verify-document) | free |
| `attestpage_preview_text_quote` | [POST /v1/verify/text-quote/preview](/docs/verify-text-quote) | free |

## Install

```sh
npx -y https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/quoteproof-mcp-0.1.49.tgz
```

[https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json) lists the current version with its sha256 and npm integrity string. `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/quoteproof-mcp.tgz` always redirects to the newest version.

Most MCP clients take a block like this:

```json
{
  "mcpServers": {
    "quoteproof": {
      "command": "npx",
      "args": ["-y", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/quoteproof-mcp-0.1.49.tgz"],
      "env": { "QUOTEPROOF_URL": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us", "QUOTEPROOF_X402_KEY": "0x..." }
    }
  }
}
```

## Paying

There are two ways to pay: x402 (USDC, `QUOTEPROOF_X402_KEY`) and L402 (sats, `QUOTEPROOF_NWC_URL`). Set either or both.

With `QUOTEPROOF_X402_KEY` set to a wallet private key, paid tools pay the 402 with x402 (see [Payments](/docs/payments)). The key stays in the process and is never logged. Before signing, the server checks the offer against local limits: `QUOTEPROOF_MAX_USD` per call (default 0.10; each tool also pays no more than its listed price), `QUOTEPROOF_SESSION_USD` per process (default 1) and `QUOTEPROOF_NETWORKS` (default `eip155:8453`, Base mainnet, real USDC; set `eip155:84532` to pay test USDC on Base Sepolia). An offer over a limit, or with no amount, fails with `payment_refused_locally` and nothing is signed. A paid result carries the settlement in `_meta["x402/payment-response"]`.

Without a key, paid tools use the free trial where it is on, and fail with `trial_exhausted` once it is used up. A trial call to `attestpage_verify_citations` or `attestpage_check_links` takes at most 5 items. Set `QUOTEPROOF_TRIAL=0` to turn the trial off.

With `QUOTEPROOF_NWC_URL` set to a Nostr Wallet Connect connection string (Node.js 22 or later), paid tools pay in sats with L402 where the service offers it (see [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments.md)). Create a wallet connection just for this server that may only pay invoices, with a small daily budget. The connection string is a secret and is never logged or returned. Before paying, the server checks the invoice and its token against `QUOTEPROOF_MAX_SATS` per call (default 100; each tool also pays no more than its listed sats), `QUOTEPROOF_SESSION_SATS` per process (default 1000; routing fees are counted after each payment, so one payment can go over this by its fee; the wallet's own budget is the hard limit) and `QUOTEPROOF_LN_NETWORKS` (default `regtest,signet,testnet`; add `bitcoin` for real sats). L402 is paid before the call runs: if the call then fails, the token is kept in memory and pays your next call to the same tool. `attestpage_attest` with `idempotency_key` needs x402. When the service has too many unpaid invoices open for your address, its 402 has no invoice and the call fails with `payment_refused_locally`, saying Lightning is busy and how many seconds to wait. With only `QUOTEPROOF_NWC_URL` set, a call the service offers no L402 for uses the free trial, as with no wallet. With both a key and a wallet, `QUOTEPROOF_PAY_ORDER` (default `x402,l402`) picks the rail tried first. A paid result carries the payment in `_meta["attestpage/l402"]`.

## Remote endpoint

The same tools are served over MCP at `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp` (streamable HTTP), with nothing to install. Each POST carries one JSON-RPC message and gets one JSON answer; there are no sessions and no event stream, so GET returns 405. A tool call runs the tool's route on this server, so prices, limits and refunds are the same as calling the route.

Protocol versions: `2026-07-28` and the older `2025-11-25`, `2025-06-18`, `2025-03-26` and `2024-11-05`. A `2026-07-28` client skips `initialize`: it puts the version and its capabilities in each request's `_meta` (`io.modelcontextprotocol/protocolVersion`, `io.modelcontextprotocol/clientCapabilities`) and sends the `MCP-Protocol-Version`, `Mcp-Method` and (for `tools/call`) `Mcp-Name` headers, which must match the body (else 400 with error `-32020`, HeaderMismatch). `server/discover` returns the supported versions, capabilities and server identity; an unsupported version gets 400 with error `-32022` and the supported list. Results carry `resultType: "complete"` and `_meta["io.modelcontextprotocol/serverInfo"]`; `tools/list` adds `ttlMs` and `cacheScope`. Older clients use `initialize` as before.

The server card (SEP-2127) is at [`GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp/server-card`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp/server-card) (`application/mcp-server-card+json`): name, version and the remote with its supported protocol versions; it lists no tools, so call `tools/list`. The site's [AI Catalog](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/ai-catalog.json) (`application/ai-catalog+json`) points at the card, the OpenAPI document and the agent skill. `/.well-known/mcp/server-card.json` serves the same card.

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

To pay, put an x402 payment payload in the call's `_meta["x402/payment"]`, as `@x402/mcp` clients do. Without one, a paid tool uses the free trial where it is on, and once that is used up, or for a `verify_citations` or `check_links` call with more than 5 items (the requirements' `error` then says so), it returns a result with `isError: true` whose `structuredContent` is the x402 payment requirements; sign one of `accepts` and call again with the payload. Set `_meta["attestpage/trial"]` to `false` to get the requirements straight away. A paid result carries the settlement in `_meta["x402/payment-response"]`. The free trial and the per-IP limits count the IP address that calls `/mcp`.

## Errors

A failed call is a tool result with `isError: true` whose text is JSON: `status`, `code`, `message` and, where useful, `details` and `hint`. The codes are the ones in [Errors](/docs/errors), plus `payment_refused_locally`, `lightning_payment_failed`, `lightning_payment_unknown`, `timeout` and `network_error` from the MCP server itself. A bad request is refused before payment and never charged.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/skill.md

# Agent Skill

Last updated: 2026-10-10

`attestpage-check-sources` is an Agent Skill: a `SKILL.md` file that tells an agent when to check a source with AttestPage (before it quotes a page, cites a URL or installs a package an LLM suggested), how to call the sample, the trial or the paid route, and how to read the verdict. Clients that read `SKILL.md` files, such as Claude, Codex and Cursor, load its name and description up front and the rest only when a task matches.

## Get it

- The skill: [https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/skills/attestpage-check-sources/SKILL.md](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/skills/attestpage-check-sources/SKILL.md)
- The index: [https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/agent-skills/index.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/agent-skills/index.json), in the format of the Agent Skills Discovery draft (v0.2.0). Each entry has `name`, `type` (`skill-md`), `description`, `url` and `digest` (`sha256:` and the SHA-256 of the file as served). Check the digest before you load the file.
- [The download list](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json) lists it too, with its size and sha256.

```sh
npx skills add https://s2h6qt73jtzlgbgnnfacln2poq.srv.us
```

The skill names the MCP tools (`attestpage_verify_quote` and the others) and the remote endpoint `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp`; see [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp.md).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/index.md

# Docs

Last updated: 2026-10-13

AttestPage returns signed evidence for AI agents: whether a quote or a whole set of citations appears on the cited pages, what our fetcher got back from a URL, whether links are live, whether package names exist on npm, PyPI or crates.io, and signed timestamps over hashes. Each page here is also markdown: add `.md` to its URL or send `Accept: text/markdown`.

## Routes

- [Verify a quote](/docs/verify-quote): `POST /v1/verify/quote`, US$0.01
- [Verify quotes on one page](/docs/verify-quotes): `POST /v1/verify/quotes`, US$0.02 per call of up to 20 quotes
- [Verify citations](/docs/verify-citations): `POST /v1/verify/citations`, US$0.10 per batch
- [Verify a document](/docs/verify-document): `POST /v1/verify/document`, US$0.10 per part of up to 10 pairs, free preview
- [Fetch a page](/docs/fetch): `POST /v1/fetch`, US$0.002
- [Recheck a page](/docs/recheck): `POST /v1/recheck`, US$0.003: has a page you read earlier changed since its receipt
- [Check links](/docs/check-links): `POST /v1/check/links`, US$0.005 per batch
- [Check packages](/docs/check-packages): `POST /v1/check/packages`, US$0.005 per batch
- [Attest a hash](/docs/attest): `POST /v1/attest`, US$0.002
- [Verify a receipt](/docs/receipt-verify): `POST /v1/receipt/verify`, free
- [Samples](/docs/samples): `GET /v1/sample/{name}`, free

## Guides

- [All guides](/guides): the index of every step-by-step guide
- [Payments](/docs/payments): the x402 flow and when a call is charged
- [How it works](/docs/how-it-works): the fetcher, content_kind values and receipts
- [Receipt demo](/docs/receipt-demo): a signed receipt end to end, with free calls only
- [Demo: one paid call and its signed receipt](/demo): the request, the 402 offer, the paid retry with x402 and the receipt, with a signature check in Node.js
- [Verify receipts offline](/docs/verify-offline): the checker script and keys
- [MCP server](/docs/mcp): one MCP tool per route, paying with x402 or the free trial
- [Agent Skill](/docs/skill): a SKILL.md telling an agent when to check a source and how to read the verdict
- [Quickstart](/docs/quickstart): from discovery to your first paid call, step by step, with prices from pricing.json
- [Worked examples](/docs/worked-examples): one paid call per route, from the request and the 402 offer to the signed receipt, with prices from pricing.json
- [Example recipes](/docs/recipes): LangChain, LlamaIndex, OpenAI Agents SDK and Claude Agent SDK agents that call these routes on the trial or with x402
- [CrewAI recipe](/examples/crewai): a Python CrewAI agent that checks several quotes on one page
- [Pydantic AI recipe](/examples/pydantic-ai): a Python Pydantic AI agent that checks several quotes on one page
- [Mastra recipe](/examples/mastra): a JavaScript Mastra agent that checks several quotes on one page
- [Vercel AI SDK recipe](/examples/vercel-ai-sdk): a JavaScript agent that checks its sources before it cites them ([in the examples index](/docs/examples/vercel-ai-sdk))
- [More examples](/docs/examples): runnable recipes, including one x402 payment step by step with plain `fetch`
- [Limits](/docs/limits): caps, timeouts and rate limits
- [Errors](/docs/errors): error codes and charging
- [Status](/status): current state and uptime ([JSON](/status.json))

## Answers

- [How to verify a quote an LLM cites](/docs/verify-a-quote-an-llm-cites)
- [How to check a quote an LLM cites, step by step with curl](/guides/verify-llm-quote): the free sample, the 402 offer, one check, the receipt, and the same call over MCP
- [How to check every quote in a draft before publishing, step by step with curl](/guides/verify-document-before-publishing): the free preview, the 402 offer, one part, the summary and each result, and the receipt
- [How to check the quotes in a draft one source at a time before publishing, step by step with curl](/guides/check-quotes-before-publishing): the recipe for grouping quotes by URL, the price from the 402 offer, one quote or one page of up to 20 quotes with x402, how to read the verdict and page kind, and how to keep the receipt.
- [How to check every quote in a Markdown document from a CI job before merge, step by step with curl](/guides/check-documents-in-ci): the free preview, the 402 offer, one part per paid call, which misses fail a build, a shell script for the CI step, and the same call over MCP
- [How to get a signed receipt of a web page](/docs/signed-receipt-of-a-web-page)
- [How to get a signed receipt of a web page, step by step with curl](/guides/signed-page-receipt): the free sample, the 402 offer, one receipt, its signature and text hash, and the same call over MCP
- [How to check links before citing them](/docs/check-links-before-citing)
- [How to check links before citing them, step by step with curl](/guides/check-links-before-citing): the free sample, the 402 offer, one batch of links, the receipt, and the same call over MCP
- [How to check packages before installing them, step by step with curl](/guides/check-packages-before-installing): the free sample, the 402 offer, one batch of names, how to read exists and advisories, the receipt, and the same call over MCP
- [How to check a package's licence before installing it, step by step with curl](/guides/check-package-licences-before-installing): the free sample, the 402 offer, what the license field holds, an allow-list rule, how to treat a null licence, and the same call over MCP
- [How to check whether a web page has changed since you read it, step by step with curl](/guides/recheck-page-for-changes): the free sample, the 402 offer, one recheck, how to read the answer, chaining receipts, and the same call over MCP
- [How to check a signed receipt before you rely on it, step by step with curl](/guides/check-a-receipt-before-relying-on-it): free; a sample receipt, the check, an altered receipt, the payload, and the same call over MCP
- [How to check the citations at the end of an answer before you send it, step by step with curl](/guides/verify-citations-before-answering): the free sample, the 402 offer, one batch of up to 10 quote and URL pairs, how to read the answer, and the same call over MCP
- [How to check many quotes against one page in a single call, step by step with curl](/guides/check-many-quotes-on-one-page): the free sample, the 402 offer, up to 20 quotes on one URL at one price, how to read the answer, and the same call over MCP
- [How to turn a web page into clean text for an agent, step by step with curl](/guides/read-web-page-as-clean-text): the free sample, the 402 offer, one page as clean text, how to read content_kind and injection flags, the receipt, and the same call over MCP
- [How to fetch a web page as clean text from code, with an x402 client](/guides/fetch-a-page-with-an-x402-client): the free sample, the 402 offer, a Node script that checks and pays one page with x402, how to read the answer, the receipt, and the same call over MCP
- [How to get a signed timestamp that shows a file did not change, step by step with curl](/guides/attest-a-file-hash): the free sample, the 402 offer, one attestation of a SHA-256, how to read the answer, a retry, checking the file later, and the same call over MCP
- [How to use AttestPage tools from an MCP client, step by step with curl](/guides/use-attestpage-tools-in-mcp): the tool names and prices, the remote endpoint, listing the tools, the 402 offer for a tool call, and paying with x402
- [How to check a quote against text you already hold, step by step with curl](/guides/use-attestpage-text-quote): the free sample, the 402 offer, one check of a quote against text you send with no fetch, how to read exact, fuzzy and none, declared offsets, how to check the receipt, and the same call as an MCP tool
- [How to check a package name an LLM suggested before installing it](/docs/check-package-names-before-install)
- [How to tell a bot wall from the real page when an agent fetches a URL](/docs/tell-a-bot-wall-from-the-real-page)

## Machine-readable

- [OpenAPI 3.1](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/openapi.json)
- [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json)
- [llms.txt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/llms.txt) and [llms-full.txt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/llms-full.txt)
- [x402 discovery](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/x402) and [API catalog](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/api-catalog)

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments.md

# Payments

Last updated: 2026-10-15

Paid routes use x402 version 2. You pay per call in USDC; there is no account, key or sign-up.

## Network

| Item | Value |
|---|---|
| Protocol | x402 v2, scheme `exact` |
| Networks | Base Sepolia (a test network). The 402 lists every rail, the primary first; pay on any one. |
| Asset | USDC on each rail, the same price on all |
| Facilitator | PayAI (`facilitator.payai.network`). On mainnet there is no fallback; x402.org is the fallback on testnet only |

The live offer is `eip155:84532`, Base Sepolia (a test network): payments use free test USDC from a faucet, and no real money moves.

USDC on a main network is real money: each paid call is charged. A payment is settled on the rail you signed it for; the paying address and the receipt's `payment.network` show which.

## Prices

| Route | Price per call |
|---|---|
| `POST /v1/verify/quote` | US$0.01 |
| `POST /v1/verify/quotes` | US$0.02 per call of 1 to 20 quotes on one page (less than one verify/quote call each from 3 quotes up) |
| `POST /v1/verify/text-quote` | US$0.005 per call, for text you already hold (nothing is fetched) |
| `POST /v1/verify/citations` | US$0.10 per batch |
| `POST /v1/verify/document` | US$0.10 per part of up to 10 pairs |
| `POST /v1/fetch` | US$0.002 per URL: `urls` with up to 10 URLs costs US$0.002 times the count |
| `POST /v1/recheck` | US$0.003 per re-check of one page |
| `POST /v1/check/links` | US$0.005 per batch |
| `POST /v1/check/packages` | US$0.005 per batch |
| `POST /v1/attest` | US$0.002 |

## Flow

1. Send the request with no payment header.
2. If the request is valid, you get `402 Payment Required`. A request with an empty body (or `{}`) gets the same 402, so a directory or client can read the price before it has a real input; anything else that fails validation gets 400. The `PAYMENT-REQUIRED` header (base64 JSON) holds the offer: amount, asset, network, pay-to address and a description of the route. The body is a JSON error with code `payment_required`.
3. Sign the offer with your wallet and send the same request again with the signed payment in the `PAYMENT-SIGNATURE` header.
4. We verify the payment with the facilitator, run the route, and settle the payment only if the route answers with a status below 400. A settled call carries a `PAYMENT-RESPONSE` header.

Any x402 v2 client library handles steps 2 and 3. The offer also carries Bazaar discovery data (input and output schemas).

## Pay from code

Install the x402 client at the versions this service uses:

```sh
npm install @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4
```

[fetch-x402](/docs/examples/fetch-x402) (Node) and [python-x402](/docs/examples/python-x402) (Python) each make one paid call step by step. Both sign for the network in `ATTESTPAGE_NETWORK` (default Base, `eip155:8453`), so set it to another network the 402 lists to pay there. The wallet needs USDC on Base Sepolia (a test network); no ETH, the facilitator pays the gas. Get test USDC before you pay: (1) make a key, 0x plus 64 hex characters, and set `ATTESTPAGE_X402_KEY`; (2) get its address with `privateKeyToAccount(key).address`; (3) free test USDC for Base Sepolia comes from the Run402 faucet, `POST https://api.run402.com/faucet/v1` with the JSON body `{"address": "<your wallet address>"}`, 0.25 USDC per drip (25 calls at 0.01 USDC each), one drip per wallet and IP every 24 hours (source: operation `faucetDrip` in https://run402.com/openapi.json, checked 18 Oct 2026); no key or account is needed.

## When you are charged

- **Never charged:** a request that fails validation (400, before any 402; a paid retry is validated again before the payment is used), a blocked or disallowed URL, a host name that does not resolve, rate limits, refused payers, and any answer with status 400 or above.
- **Charged:** any answer below 400. This includes results about the target page that you may not like: a 404, a bot wall, a timeout. That result is what the call checks.
- **Retries:** if your payment carries a payment id (the x402 `payment-identifier` extension) and you resend the same request with the same id within one hour, you get the stored response again, marked `idempotent-replayed: true`, and are not charged twice. Reusing a payment id for a different request gets 409 `payment_id_conflict`.
- **Settle failures:** if a call ends in 502 `settle_failed`, resend the same request with the same payment id. If the payment went through on chain after all, you get the withheld result, marked `payment-redelivered: true`, without paying again. If it did not, the same signed payment is settled at most once; a new signature for that id gets 409 `settle_pending` until the first one expires (see `Retry-After`). This needs a payment id: without one, a charge that went through is recorded for reconciliation, and the result is not sent. Redelivery is a full-service feature: the edge server cannot match a resend across its instances. Here the withheld result is kept in memory for an hour (and at least until its payment has expired), so a server restart also loses it; a resend of the same signed payment is then still never charged twice.
- **Charged, result lost (`result_lost`):** the same on every rail. If a charge went through and we can no longer deliver the result (the kept result expired before a resend, or was not kept), we record it as `result_lost` and check it on that rail's chain. We record the refund as due, and a person pays it by hand in USDC to the paying address on the same rail. Contact no contact address is set on this server; the robots.txt opt-out works without one with the transaction id to ask about it.

## Lightning (L402)

Lightning (L402) is not enabled on this server. The sats prices in [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json) are for when it is.

## Prepaid credits (Bitcoin signet)

Prepaid credit keys (Bitcoin signet) are not enabled on this server. Where they are on (full service only), this section explains how to buy and spend one.

## Free trial

There is no free trial at the moment; use the free samples instead.

## Sanctions screening

Paying addresses are checked against a public sanctions list. A listed address gets 403 `payer_refused` and its payment is not settled.

## Receipts

A paid receipt records the payment: rail, network, asset, amount, paying address and payment id (for L402: the payment hash and preimage instead of an address and id). See [How it works](/docs/how-it-works).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/quickstart.md

# AttestPage quickstart: from discovery to your first paid call

Last updated: 2026-10-17

This takes about a minute. Every route is a plain HTTPS `POST` with JSON. You pay per call in USDC over x402 v2, so there is no account and no API key.

## 1. Discover

Read the catalogue, then pick a route:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/llms.txt
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/ai-catalog.json
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/openapi.json
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/x402
```

- `/llms.txt`: every route, its price and when to use it.
- `/.well-known/ai-catalog.json`: the AI catalogue.
- `/openapi.json`: request and response schemas for every route.
- `/.well-known/x402`: the x402 discovery list, with the price and network of each route.

Prices per call in US$:

| Route | Price | Use it when |
|---|---|---|
| `POST /v1/verify/quote` | US$0.01 | you are about to quote a web page as the source of a claim |
| `POST /v1/verify/quotes` | US$0.02 | you hold several quotes from one page |
| `POST /v1/verify/citations` | US$0.10 | you are about to answer with up to 10 cited pages |
| `POST /v1/verify/text-quote` | US$0.005 | you already hold the text and need it matched |
| `POST /v1/verify/document` | US$0.10 | you need a document checked against its source |
| `POST /v1/fetch` | US$0.002 per URL | you need a web page as clean text |
| `POST /v1/recheck` | US$0.003 | you need to know if a page you read earlier has changed |
| `POST /v1/check/links` | US$0.005 | you are about to give a user links |
| `POST /v1/check/packages` | US$0.005 | you are about to recommend or install a package |
| `POST /v1/attest` | US$0.002 | you need a signed, timestamped receipt that a file or answer existed unchanged |

Source: [pricing.json](/pricing.json). The route prices in this table are the same as the 402 offer.

## 2. Free samples (optional)

The free trial is off at the moment, so every call needs payment (step 3). The sample calls on the samples page need none.

## 3. Receive the 402

Send the request with no payment:

```sh
curl -i -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote \
  -H 'content-type: application/json' \
  -d '{"url":"https://www.iana.org/help/example-domains","quote":"These domains may be used as illustrative examples in documents","match":"fuzzy"}'
```

The answer is `402 Payment Required`, with error code `payment_required`, and the offer in the `PAYMENT-REQUIRED` header. Decode it to read the `accepts` entry. For `verify/quote` it lists `amount` `10000`, which is US$0.01 (USDC has 6 decimals). A request with an empty body gets the same 402, so you can read a price before you have real input.

A request that fails validation gets `400` before any payment is asked for, and it is never charged.

## 4. Pay

Use an x402 v2 client. The plain-`fetch` script in [the plain-fetch example](/docs/examples/fetch-x402) does the offer check, the signature and the retry in one script. Install its packages first, then run it against the service:

```sh
ATTESTPAGE_URL=https://s2h6qt73jtzlgbgnnfacln2poq.srv.us \
ATTESTPAGE_X402_KEY=0x... \
node fetch-x402.mjs https://www.iana.org/help/example-domains "These domains may be used as illustrative examples in documents"
```

- `ATTESTPAGE_X402_KEY` is the private key of the wallet that pays, and it stays in your process.
- Leave `ATTESTPAGE_NETWORK` unset and the script pays on Base mainnet, in real USDC. Check the amount before you run it.

Raw steps, if you are not using the script:

1. Check that the offer's `network` is `eip155:8453` and that `amount` is what you expect.
2. Sign the offer with your wallet.
3. Send the same request again with the signed payment in the `PAYMENT-SIGNATURE` header.


## 5. Retry and read the result

The paid retry returns `200`. The `PAYMENT-RESPONSE` header carries the transaction, the payer and the network. The body carries the result and a signed receipt, shortened here:

```json
{
  "result": { "match": "exact", "score": 1, "start": 171, "end": 234, "occurrences": 1 },
  "page": { "http_status": 200, "content_kind": "real", "title": "Example Domains" },
  "advice": "The page loaded and looks like real content.",
  "receipt": "<signed receipt>", "receipt_id": "9fcda5ac…", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Check the receipt again at no charge:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify \
  -H 'content-type: application/json' \
  -d '{"receipt":"<signed receipt>"}'
```

## Next steps

- Worked examples for every route, with request, 402 and result: [Worked examples](/docs/worked-examples).
- Error codes: the `error.code` in each response.
- Limits per route: [Limits](/docs/limits).
- Terms: [Terms](/terms.md).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/worked-examples.md

# Worked examples for every paid route

Last updated: 2026-10-17

AttestPage charges per call, in USDC on Base (`eip155:8453`), over x402 v2. Each section below shows one paid call from start to finish: the request, the `402` offer, the paid retry and a shortened result.

Every route takes the same payment steps:

1. Send the request with no payment. A valid request gets `402 Payment Required`, with the offer in the `PAYMENT-REQUIRED` header. Bad requests are refused with 400 before any payment, and are never charged.
2. Check the offer: the network is `eip155:8453`, and `amount` is in USDC base units (6 decimals: the offer for [verify/quote](#post-v1verifyquote) is `10000`, which is US$0.01).
3. Sign the offer and send the same request again with the `PAYMENT-SIGNATURE` header.
4. The `200` answer carries a `PAYMENT-RESPONSE` header with the transaction, the payer and the network.

A client library does steps 2 to 4 for you. The full plain-`fetch` version is in [the plain-fetch example](/docs/examples/fetch-x402).

Shown below: the `402` body, abbreviated. The offer's `accepts` entry for every route has the same shape:

```json
{ "scheme": "exact", "network": "eip155:8453", "amount": "10000", "asset": "USDC contract on Base", "payTo": "the service address in the offer", "maxTimeoutSeconds": 120 }
```

Contact and terms: see [terms](/terms.md). Prices are listed in [pricing.json](/pricing.json).

---

## POST /v1/verify/quote

Price: US$0.01 per call. Checks that a quote appears word for word on a web page, before an agent cites it.

Request:

```sh
curl -X POST https://<service>/v1/verify/quote -H 'content-type: application/json' -d '{
  "url": "https://www.iana.org/help/example-domains",
  "quote": "These domains may be used as illustrative examples in documents",
  "match": "fuzzy"
}'
```

402 response: status `402`, error code `payment_required`, message "This route costs US$0.01 via x402". The offer in `PAYMENT-REQUIRED` lists `amount` `10000`.

Paid retry: the same body with `PAYMENT-SIGNATURE`. Status `200`, `PAYMENT-RESPONSE` gives the transaction.

Paid-run example (shortened):

```json
{
  "result": { "match": "exact", "score": 1, "start": 171, "end": 234, "context": "...These domains may be used as illustrative examples in documents without prior coordination with us...", "occurrences": 1 },
  "page": { "http_status": 200, "content_kind": "real", "title": "Example Domains" },
  "advice": "The page loaded and looks like real content.",
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it before citing a page, so a misquote is caught before a user sees it. Check the `receipt` again for free with `POST /v1/receipt/verify`.

---

## POST /v1/verify/citations

Price: US$0.10 per call, up to 10 quote and URL pairs. Checks every citation in an answer in one call.

Request:

```sh
curl -X POST https://<service>/v1/verify/citations -H 'content-type: application/json' -d '{
  "citations": [
    { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" },
    { "url": "https://www.iana.org/domains/reserved", "quote": "IANA-managed Reserved Domains" }
  ],
  "match": "fuzzy"
}'
```

402 response: status `402`, `payment_required`, `amount` `100000` (US$0.10).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "results": [
    { "url": "https://www.iana.org/help/example-domains", "page": 0, "http_status": 200, "content_kind": "real", "match": "exact", "score": 1, "start": 171, "end": 234 },
    { "url": "https://www.iana.org/domains/reserved", "page": 1, "http_status": 200, "content_kind": "real", "match": "exact", "score": 1 }
  ],
  "summary": { "exact": 2, "fuzzy": 0, "none": 0, "failed": 0 },
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it before giving an answer that cites web pages. Each `none` tells you which quote to fix.

---

## POST /v1/verify/quotes

Price: US$0.02 per call, one page and up to 20 quotes. Cheaper than [verify/quote](#post-v1verifyquote) for three or more quotes from the same page.

Request:

```sh
curl -X POST https://<service>/v1/verify/quotes -H 'content-type: application/json' -d '{
  "url": "https://www.iana.org/help/example-domains",
  "quotes": [
    "These domains may be used as illustrative examples in documents",
    "without prior coordination with us"
  ],
  "match": "fuzzy"
}'
```

402 response: status `402`, `payment_required`, `amount` `20000` (US$0.02).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "results": [
    { "match": "exact", "score": 1, "start": 171, "end": 234, "occurrences": 1 },
    { "match": "exact", "score": 1 }
  ],
  "page": { "http_status": 200, "content_kind": "real", "title": "Example Domains" },
  "summary": { "exact": 2, "fuzzy": 0, "none": 0, "failed": 0 },
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it when one page is quoted several times in an answer.

---

## POST /v1/verify/document

Price: US$0.10 per call. Checks every quote in a finished document, with its link, against the live page.

Request:

```sh
curl -X POST https://<service>/v1/verify/document -H 'content-type: application/json' -d '{
  "document": "The IANA page says \"These domains may be used as illustrative examples in documents\" ([IANA](https://www.iana.org/help/example-domains)).",
  "format": "markdown",
  "match": "fuzzy",
  "part": 0
}'
```

402 response: status `402`, `payment_required`, `amount` `100000` (US$0.10).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "document_sha256": "…",
  "extractor": "doc-v1",
  "part": 0, "parts": 1, "pairs_total": 1,
  "results": [
    { "pair": 0, "quote": "These domains may be used as illustrative examples in documents", "url": "https://www.iana.org/help/example-domains", "doc_start": 20, "doc_end": 83, "http_status": 200, "content_kind": "real", "match": "exact", "score": 1 }
  ],
  "summary": { "exact": 1, "fuzzy": 0, "none": 0, "failed": 0 },
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it before sending a finished report that quotes web pages. Long documents come in parts, set with `part`.

---

## POST /v1/verify/text-quote

Price: US$0.005 per call. Checks a quote against text the agent already holds, with no page fetch.

Request:

```sh
curl -X POST https://<service>/v1/verify/text-quote -H 'content-type: application/json' -d '{
  "text": "Refunds are paid within 14 days of purchase, to the card that was used.",
  "quote": "refunds are paid within 14 days",
  "match": "fuzzy",
  "case_sensitive": false
}'
```

402 response: status `402`, `payment_required`, `amount` `5000` (US$0.005).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "result": { "match": "exact", "score": 1, "start": 0, "end": 31, "context": "Refunds are paid within 14 days of purchase, to the card that was used.", "occurrences": 1, "normalised_sha256": "945b89fa…" },
  "injection_flags": [],
  "advice": "The supplied text contains this quote. This says nothing about where the text came from.",
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it for text a file, tool or document gave you, when you have no URL to check.

---

## POST /v1/fetch

Price: US$0.002 per URL. Returns a page as clean text, with a verdict on what came back.

Request:

```sh
curl -X POST https://<service>/v1/fetch -H 'content-type: application/json' -d '{
  "url": "https://www.iana.org/help/example-domains",
  "return_text": true
}'
```

402 response: status `402`, `payment_required`, `amount` `2000` (US$0.002). A `urls` batch of up to 10 is priced per URL.

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "page": { "requested_url": "https://www.iana.org/help/example-domains", "final_url": "https://www.iana.org/help/example-domains", "http_status": 200, "content_type": "text/html", "content_kind": "real", "title": "Example Domains", "content_sha256": "…", "raw_sha256": "…", "retrieved_at": "2026-10-17T09:31:09.693Z" },
  "text": "Domains\n\nProtocols\n\nNumbers\n\nAbout\n\nInstructions and Guides\n\nExample Domains\n\nA number of domains such as …",
  "text_chars": 1277, "text_truncated": false,
  "injection_flags": [],
  "advice": "The page loaded and looks like real content.",
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it to read a page the agent needs as text, or to keep a notarised copy of it with `content_sha256`. Check `content_kind` before you trust the text: a bot wall or JavaScript shell is not the page.

---

## POST /v1/recheck

Price: US$0.003 per call. Checks whether a page an agent read earlier has changed, from an earlier receipt.

Request (`receipt` is the one from an earlier `fetch` of the same page):

```sh
curl -X POST https://<service>/v1/recheck -H 'content-type: application/json' -d '{
  "receipt": "<receipt from an earlier fetch>",
  "return_text": false
}'
```

402 response: status `402`, `payment_required`, `amount` `3000` (US$0.003).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "change": "unchanged",
  "changed": false,
  "differences": [],
  "baseline": { "source": "receipt", "kind": "fetch", "receipt_sha256": "e931f5b9…" },
  "page": { "http_status": 200, "content_kind": "real", "content_sha256": "…" },
  "advice": "The page's text is the same as in the baseline (byte for byte on the clean text). Markup or other bytes may still have moved; see differences.",
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it before relying on a page again, to show that it still says what it said.

---

## POST /v1/check/links

Price: US$0.005 per call, up to 10 URLs. Gives a verdict for each link before an agent gives it to a user.

Request:

```sh
curl -X POST https://<service>/v1/check/links -H 'content-type: application/json' -d '{
  "urls": ["https://www.iana.org/help/example-domains", "https://www.iana.org/domains/reserved"]
}'
```

402 response: status `402`, `payment_required`, `amount` `5000` (US$0.005).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "results": [
    { "url": "https://www.iana.org/help/example-domains", "final_url": "https://www.iana.org/help/example-domains", "http_status": 200, "redirects": [], "content_kind": "real", "title": "Example Domains", "verdict": "ok" },
    { "url": "https://www.iana.org/domains/reserved", "final_url": "https://www.iana.org/domains/reserved", "http_status": 200, "redirects": [], "content_kind": "real", "title": "IANA-managed Reserved Domains", "verdict": "ok" }
  ],
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Each link gets a `verdict`: `ok`, `broken`, `moved` or `unknown`. Use it before giving users links or citations.

---

## POST /v1/check/packages

Price: US$0.005 per call, up to 10 names. Checks that a package an LLM suggested really exists, on npm, PyPI or crates.io.

Request:

```sh
curl -X POST https://<service>/v1/check/packages -H 'content-type: application/json' -d '{
  "packages": [
    { "ecosystem": "npm", "name": "left-pad" },
    { "ecosystem": "pypi", "name": "requests" },
    { "ecosystem": "crates", "name": "serde" },
    { "ecosystem": "npm", "name": "lodash", "version": "4.17.20" }
  ]
}'
```

402 response: status `402`, `payment_required`, `amount` `5000` (US$0.005).

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "results": [
    { "ecosystem": "npm", "name": "left-pad", "exists": true, "status": "found", "registry_name": "left-pad", "latest_version": "1.3.0", "description": "String left pad", "license": "WTFPL" },
    { "ecosystem": "pypi", "name": "requests", "exists": true, "status": "found", "registry_name": "requests", "latest_version": "2.34.2", "description": "Python HTTP for Humans.", "license": "Apache-2.0" },
    { "ecosystem": "crates", "name": "serde", "exists": true, "status": "found", "registry_name": "serde", "latest_version": "1.0.229", "license": "MIT" },
    { "ecosystem": "npm", "name": "lodash", "exists": true, "status": "found", "registry_name": "lodash", "latest_version": "4.18.1", "license": "MIT" }
  ],
  "note": "exists means the registry listed this name when we looked. It is not a security verdict: the package may still be malicious, unmaintained or not the one you meant; description and licence are the publisher's.",
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it before installing or recommending a package. `exists: true` means the name is listed; it is not a review of the package code.

---

## POST /v1/attest

Price: US$0.002 per call. Timestamps a SHA-256 hash with a signed receipt, so you can show later that a file or answer existed unchanged at that time.

Request:

```sh
curl -X POST https://<service>/v1/attest -H 'content-type: application/json' -d '{
  "sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
  "note": "delivery of report v3 to order 77",
  "idempotency_key": "order-77-delivery"
}'
```

402 response: status `402`, `payment_required`, `amount` `2000` (US$0.002). `idempotency_key` is for x402 payments only: a retry with the same key and hash gets the same receipt, paid once.

Paid retry: same body with `PAYMENT-SIGNATURE`. Status `200`.

Paid-run example (shortened):

```json
{
  "attestation": {
    "sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
    "note_sha256": "270938cd…",
    "seq": 1,
    "issued_at": "2026-10-17T09:30:10.953Z",
    "idempotency_key": "order-77-delivery",
    "first_seen": true
  },
  "receipt": "<signed receipt>", "tier": "paid", "rail": "x402", "network": "eip155:8453"
}
```

Use it for a delivery, a report or any file that needs a timestamp. The receipt shows that this hash was sent by the stated time. It does not show who made the file.

---

## Next steps

- Check any receipt for free with `POST /v1/receipt/verify` and `{"receipt": "<receipt>"}`.
- Prices and request limits: [pricing.json](/pricing.json). Error codes: the `error.code` in each response.
- Contact and terms: see [terms](/terms.md).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/recipes.md

# Example recipes

Last updated: 2026-10-18

Five short agents that check a source before citing it with AttestPage: LangChain and LlamaIndex in Python, the OpenAI Agents SDK, the Vercel AI SDK and the Claude Agent SDK in JavaScript. Each returns the price of a call it cannot pay to the agent as data instead of failing, and (OpenAI Agents SDK, Vercel AI SDK, or the Claude Agent SDK through MCP) can pay per call with x402 on Base. The same files, each with a README, are in the `examples/` folder of the source. A [CrewAI agent in Python](/examples/crewai) that checks several quotes on one page, paying per call with x402, is on its own page. For a step-by-step x402 payment with plain `fetch`, see [More recipes](/docs/examples).

Every recipe reads `ATTESTPAGE_URL`; set it to `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`.

## How the clients call a route

1. Send the request.
2. A 200 is the answer, with a signed `receipt`. Check it with the free [POST /v1/receipt/verify](/docs/receipt-verify).
3. A 429 with code `rate_limited` means too many calls from this IP in a minute; it is not charged, and `Retry-After` gives the seconds to wait.
4. A 402 means the call needs payment: the call carried no payment. The offer is in the `PAYMENT-REQUIRED` header (base64 JSON, USDC amounts with 6 decimals). The clients return `{ "payment_required": true, "price_usd": …, "network": "eip155:8453" }`; an x402 client signs the offer instead (see [Payments](/docs/payments)).
5. A 400 is bad input and is never charged. See [Errors](/docs/errors).

There is no free trial at the moment; use the free samples instead.

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote                       # free: what a verify/quote answer looks like
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote -H 'content-type: application/json' -d '{}' | grep -i payment-required   # the 402 offer
```

## Several quotes in one call

The recipes call `POST /v1/verify/quote` once per quote. Two batch routes check several quotes in one call, under one signed receipt:

- [POST /v1/verify/quotes](/docs/verify-quotes): up to 20 quotes on one page, US$0.02 per call. The page is fetched once; from 3 quotes up it costs less than one verify/quote call per quote.
- [POST /v1/verify/citations](/docs/verify-citations): up to 10 quote and URL pairs, US$0.10 per batch, each page fetched once. A cited paper with a DOI also gets its Crossref data and a retracted flag.

## LangChain (Python)

`pip install "langchain>=1.0" langchain-anthropic`, save the client below as `attestpage.py` next to it, then `python agent.py`.

```python
"""LangChain agent that checks its sources with AttestPage before it cites them."""
import os
import sys

from langchain.agents import create_agent
from langchain.tools import tool

import attestpage


@tool
def verify_quote(url: str, quote: str) -> dict:
    """Use before citing a page: does this exact or near-exact quote appear on the page at url?
    Returns match (exact, fuzzy or none), the page's content_kind and a signed receipt."""
    return attestpage.verify_quote(url, quote)


@tool
def check_links(urls: list[str]) -> dict:
    """Use before putting links in an answer: status, final URL and content_kind for each URL."""
    return attestpage.check_links(urls)


agent = create_agent(
    model=os.environ.get("MODEL", "anthropic:claude-sonnet-5-5"),
    tools=[verify_quote, check_links],
    system_prompt="Before you quote a web page, call verify_quote. Only cite a quote whose match is exact or fuzzy "
    "on a page whose content_kind is real. If a tool returns payment_required or the error trial_exhausted, say so and stop.",
)

if __name__ == "__main__":
    question = " ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?'
    )
    result = agent.invoke({"messages": [{"role": "user", "content": question}]})
    print(result["messages"][-1].content)
```

## LlamaIndex (Python)

`pip install "llama-index-core>=0.12" llama-index-llms-anthropic`, with the same `attestpage.py`.

```python
"""LlamaIndex agent that checks its sources with AttestPage before it cites them."""
import asyncio
import os
import sys

from llama_index.core.agent.workflow import FunctionAgent
from llama_index.core.tools import FunctionTool
from llama_index.llms.anthropic import Anthropic

import attestpage


def verify_quote(url: str, quote: str) -> dict:
    """Use before citing a page: does this exact or near-exact quote appear on the page at url?
    Returns match (exact, fuzzy or none), the page's content_kind and a signed receipt."""
    return attestpage.verify_quote(url, quote)


def fetch_page(url: str) -> dict:
    """Use when you need a page's clean text and a verdict on what came back (real, bot_wall, js_shell, paywall, http_error)."""
    return attestpage.fetch_page(url)


agent = FunctionAgent(
    tools=[FunctionTool.from_defaults(fn=verify_quote), FunctionTool.from_defaults(fn=fetch_page)],
    llm=Anthropic(model=os.environ.get("MODEL", "claude-sonnet-5-5")),
    system_prompt="Before you quote a web page, call verify_quote. Only cite a quote whose match is exact or fuzzy "
    "on a page whose content_kind is real. If a tool returns payment_required or the error trial_exhausted, say so and stop.",
)


async def main(question):
    print(await agent.run(user_msg=question))


if __name__ == "__main__":
    asyncio.run(main(" ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?'
    )))
```

## The Python client

Standard library only. `trial=False` skips the trial header.

```python
"""AttestPage client for agent tools (Python standard library only).

Sends the Quoteproof-Trial: 1 header by default. The free trial is off, so a paid route answers 402, and the tool returns the x402 offer (price, network) instead of raising, so the agent can say what a call would cost. Pass trial=False to skip the header.
ATTESTPAGE_URL is the AttestPage origin.
"""
import base64
import json
import os
import urllib.error
import urllib.request

BASE_URL = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")


def _offer(header):
    # PAYMENT-REQUIRED is base64 JSON; amounts are USDC atomic units (6 decimals).
    try:
        req = json.loads(base64.b64decode(header))
        first = req["accepts"][0]
        return {"price_usd": int(first["amount"]) / 1_000_000, "network": first["network"], "scheme": first["scheme"]}
    except (ValueError, KeyError, IndexError, TypeError):
        return {}


def call(path, body, trial=True, base_url=None, timeout=60):
    """POST body to path; returns the JSON answer, a payment_required dict, or an error dict."""
    headers = {"content-type": "application/json", "accept": "application/json"}
    if trial:
        headers["quoteproof-trial"] = "1"
    req = urllib.request.Request((base_url or BASE_URL) + path, data=json.dumps(body).encode(), headers=headers, method="POST")
    try:
        with urllib.request.urlopen(req, timeout=timeout) as res:
            return json.loads(res.read())
    except urllib.error.HTTPError as e:
        try:
            err = json.loads(e.read()).get("error", {})
        except ValueError:
            err = {}
        if e.code == 402:
            return {"payment_required": True, **_offer(e.headers.get("payment-required", "")),
                    "message": "This call needs an x402 payment; pay with an x402 v2 client (see /docs/payments)."}
        return {"error": err.get("code", "http_%d" % e.code), "status": e.code, "message": err.get("message", "")}


def verify_quote(url, quote, match="fuzzy", **kw):
    return call("/v1/verify/quote", {"url": url, "quote": quote, "match": match}, **kw)


def check_links(urls, **kw):
    return call("/v1/check/links", {"urls": list(urls)}, **kw)


def fetch_page(url, return_text=True, **kw):
    return call("/v1/fetch", {"url": url, "return_text": return_text}, **kw)


def verify_receipt(receipt, **kw):
    return call("/v1/receipt/verify", {"receipt": receipt}, trial=False, **kw)
```

## OpenAI Agents SDK (JavaScript)

`npm install @openai/agents zod`, save the client below as `attestpage.mjs`, then `node agent.mjs`.

```js
// OpenAI Agents SDK agent that checks its sources with AttestPage before it cites them.
import { Agent, run, tool } from '@openai/agents';
import { z } from 'zod';
import { createClient } from './attestpage.mjs';

const attestpage = await createClient();

const verifyQuote = tool({
  name: 'verify_quote',
  description: 'Use before citing a page: does this exact or near-exact quote appear on the page at url? '
    + 'Returns match (exact, fuzzy or none), the page content_kind and a signed receipt.',
  parameters: z.object({ url: z.string(), quote: z.string() }),
  execute: async ({ url, quote }) => attestpage.verifyQuote({ url, quote }),
});

const checkLinks = tool({
  name: 'check_links',
  description: 'Use before putting links in an answer: status, final URL and content_kind for each URL (up to 10 paid).',
  parameters: z.object({ urls: z.array(z.string()).min(1).max(10) }),
  execute: async ({ urls }) => attestpage.checkLinks({ urls }),
});

const agent = new Agent({
  name: 'Source checker',
  instructions: 'Before you quote a web page, call verify_quote. Only cite a quote whose match is exact or fuzzy '
    + 'on a page whose content_kind is real. If a tool returns payment_required or the error trial_exhausted, say so and stop.',
  tools: [verifyQuote, checkLinks],
});

const question = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';
const result = await run(agent, question);
console.log(result.finalOutput);
```

## The JavaScript client

To pay with x402, `npm install @x402/fetch @x402/evm viem` and set `ATTESTPAGE_X402_KEY` to the key of a Base wallet holding a little USDC (real money).

```js
// AttestPage client for agent tools. With no key it calls the free trial (header Quoteproof-Trial: 1,
// 10 calls per IP a day). With ATTESTPAGE_X402_KEY (a 0x… key for a Base wallet holding
// USDC, real money) it pays each call with x402 through @x402/fetch. A 402 the client cannot pay comes back as
// { payment_required, price_usd, network } instead of an exception, so the agent can say what a call costs.
// ATTESTPAGE_URL is the AttestPage origin.

const DEFAULT_URL = 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';

// A fetch that pays x402 offers from key. The x402 packages load only when a key is set.
export async function payingFetch(key) {
  const [{ wrapFetchWithPayment, x402Client }, { registerExactEvmScheme }, { privateKeyToAccount }] = await Promise.all([
    import('@x402/fetch'), import('@x402/evm/exact/client'), import('viem/accounts'),
  ]);
  const client = new x402Client();
  registerExactEvmScheme(client, { signer: privateKeyToAccount(key) });
  return wrapFetchWithPayment(fetch, client);
}

// PAYMENT-REQUIRED is base64 JSON; amounts are USDC atomic units (6 decimals).
function offer(header) {
  try {
    const first = JSON.parse(Buffer.from(header, 'base64').toString('utf8')).accepts[0];
    return { price_usd: Number(first.amount) / 1e6, network: first.network, scheme: first.scheme };
  } catch {
    return {};
  }
}

// fetch: a fetch to use instead (for example one from payingFetch); trial: send the trial header
// (default: only when the client does not pay).
export async function createClient({ url = process.env.ATTESTPAGE_URL || DEFAULT_URL, key = process.env.ATTESTPAGE_X402_KEY, fetch: fetchFn, trial } = {}) {
  const paying = Boolean(fetchFn || key);
  fetchFn ??= key ? await payingFetch(key) : fetch;
  trial ??= !paying;
  const base = url.replace(/\/+$/, '');

  async function call(path, body, { useTrial = trial } = {}) {
    const headers = { 'content-type': 'application/json', accept: 'application/json' };
    if (useTrial) headers['quoteproof-trial'] = '1';
    const res = await fetchFn(`${base}${path}`, { method: 'POST', headers, body: JSON.stringify(body) });
    const json = await res.json().catch(() => ({}));
    if (res.ok) return json;
    if (res.status === 402) {
      return { payment_required: true, ...offer(res.headers.get('payment-required') ?? ''),
        message: 'This call needs an x402 payment; set ATTESTPAGE_X402_KEY to pay (see /docs/payments).' };
    }
    return { error: json.error?.code ?? `http_${res.status}`, status: res.status, message: json.error?.message ?? '' };
  }

  return {
    verifyQuote: ({ url, quote, match = 'fuzzy' }) => call('/v1/verify/quote', { url, quote, match }),
    checkLinks: ({ urls }) => call('/v1/check/links', { urls }),
    fetchPage: ({ url, return_text = true }) => call('/v1/fetch', { url, return_text }),
    verifyReceipt: ({ receipt }) => call('/v1/receipt/verify', { receipt }, { useTrial: false }),
  };
}
```

## Vercel AI SDK (JavaScript)

`npm install ai @ai-sdk/anthropic zod`, with the same `attestpage.mjs`, then `node agent.mjs`. Without `ANTHROPIC_API_KEY` it skips the model and calls `verify_quote` itself, so you can see what the tool returns.

```js
// Vercel AI SDK agent that checks its sources with AttestPage before it cites them.
// With no ANTHROPIC_API_KEY it skips the model and calls verify_quote itself, so you can see what the tool returns.
import { z } from 'zod';
import { createClient } from './attestpage.mjs';

const attestpage = await createClient();

// tool() from 'ai' only adds types, so plain objects work. Tools return the route's JSON.
const tools = {
  verify_quote: {
    description: 'Use before citing a page: does this exact or near-exact quote appear on the page at url? '
      + 'Returns match (exact, fuzzy or none), the page content_kind and a signed receipt.',
    inputSchema: z.object({ url: z.string(), quote: z.string() }),
    execute: ({ url, quote }) => attestpage.verifyQuote({ url, quote }),
  },
  check_links: {
    description: 'Use before putting links in an answer: status, final URL and content_kind for each URL (up to 10 paid).',
    inputSchema: z.object({ urls: z.array(z.string()).min(1).max(10) }),
    execute: ({ urls }) => attestpage.checkLinks({ urls }),
  },
};

const args = process.argv.slice(2);
if (!process.env.ANTHROPIC_API_KEY) {
  // No model: node agent.mjs [url] [quote]
  const [url = 'https://www.iana.org/help/example-domains', quote = 'These domains may be used as illustrative examples in documents'] = args;
  console.log(JSON.stringify(await tools.verify_quote.execute(tools.verify_quote.inputSchema.parse({ url, quote })), null, 2));
} else {
  const [{ generateText, isStepCount }, { anthropic }] = await Promise.all([import('ai'), import('@ai-sdk/anthropic')]);
  const question = args.join(' ')
    || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';
  const { text } = await generateText({
    model: anthropic(process.env.MODEL || 'claude-sonnet-5-5'),
    tools,
    stopWhen: isStepCount(5),
    instructions: 'Before you quote a web page, call verify_quote. Only cite a quote whose match is exact or fuzzy '
      + 'on a page whose content_kind is real. If a tool returns payment_required or the error trial_exhausted, say so and stop.',
    prompt: question,
  });
  console.log(text);
}
```

## Claude Agent SDK (JavaScript)

`npm install @anthropic-ai/claude-agent-sdk`, then `node agent.mjs`. It connects the remote MCP endpoint `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp`, so there is no client code. A call that needs payment returns the x402 payment requirements. To pay from the agent's own key, use the stdio server instead (see [MCP server](/docs/mcp)).

```js
// Claude Agent SDK agent that checks its sources with AttestPage's remote MCP endpoint (POST /mcp).
// Without a payment the paid tools return the x402 price. A call that needs payment returns the x402 payment requirements.
import { query } from '@anthropic-ai/claude-agent-sdk';

const url = (process.env.ATTESTPAGE_URL || 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us').replace(/\/+$/, '');

// Tools from an MCP server are named mcp__<server>__<tool>.
const TOOLS = ['attestpage_verify_quote', 'attestpage_check_links', 'attestpage_verify_receipt'];

const prompt = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';

for await (const message of query({
  prompt,
  options: {
    mcpServers: { attestpage: { type: 'http', url: `${url}/mcp` } },
    allowedTools: TOOLS.map((t) => `mcp__attestpage__${t}`),
    systemPrompt: 'Before you quote a web page, call attestpage_verify_quote. Only cite a quote whose match is exact or fuzzy '
      + 'on a page whose content_kind is real. If a tool returns payment requirements, say so and stop.',
    maxTurns: 6,
  },
})) {
  if (message.type === 'result') console.log(message.subtype === 'success' ? message.result : `stopped: ${message.subtype}`);
}
```

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/index.md

# AttestPage recipes

Last updated: 2026-10-17

Short, runnable recipes for calling AttestPage from an agent. In each one, the agent checks a source before it cites it. Copy one, run it, then change the tools to fit your agent.

| Recipe | Runnable file | Framework | Language | How it calls AttestPage | Pays with x402 |
|---|---|---|---|---|---|
| [langchain.md](/docs/examples/langchain) | [langchain.mjs](/docs/examples/langchain.mjs) | LangChain (`create_agent`, `createAgent`) | Python and JavaScript | Python: a small client using only the standard library. JavaScript: the client from the OpenAI Agents SDK recipe | Python: no payment; returns the price. JavaScript: yes, when a key is set |
| [openai-agents-sdk.md](/docs/examples/openai-agents-sdk) | [openai-agents-sdk.mjs](/docs/examples/openai-agents-sdk.mjs) | OpenAI Agents SDK | JavaScript | A small client over `fetch` | Yes, with `@x402/fetch` when a key is set |
| [openai-agents.md](/examples/openai-agents) | Code on the page | OpenAI Agents SDK | JavaScript | The `quoteproof-mcp` server over stdio, or a `verify_quotes` call over HTTP | Yes, with `@x402/fetch` (HTTP) or `QUOTEPROOF_X402_KEY` (MCP) when a key is set |
| [llamaindex.md](/docs/examples/llamaindex) | [llamaindex.mjs](/docs/examples/llamaindex.mjs) | LlamaIndex.TS (`agent`, `tool`) | JavaScript | The client from the OpenAI Agents SDK recipe | Yes, when a key is set |
| [vercel-ai-sdk.md](/docs/examples/vercel-ai-sdk) | [vercel-ai-sdk.mjs](/docs/examples/vercel-ai-sdk.mjs) | Vercel AI SDK (`generateText`, tools) | JavaScript | The client from the OpenAI Agents SDK recipe | Yes, when a key is set |
| [claude-agent-sdk.md](/docs/examples/claude-agent-sdk) | [claude-agent-sdk.mjs](/docs/examples/claude-agent-sdk.mjs) | Claude Agent SDK | JavaScript | The `quoteproof-mcp` MCP server (stdio) | Yes, when `QUOTEPROOF_X402_KEY` is set |
| [fetch-x402.md](/docs/examples/fetch-x402) | [fetch-x402.mjs](/docs/examples/fetch-x402.mjs) | None | JavaScript | Plain `fetch`, one x402 payment step by step | Yes |
| [python-x402.md](/docs/examples/python-x402) | [python-x402.py](/docs/examples/python-x402.py) | None | Python | `httpx` and the `x402` package: one unpaid call, then one x402 payment step by step | Yes, when a key is set |
| [crewai.md](/examples/crewai) | Code on the page | CrewAI (`Agent`, `Task`, `Crew`) | Python | A `verify_quotes` tool that calls the route with the `x402` package | Yes, with the `x402` package when a key is set |
| [pydantic-ai.md](/examples/pydantic-ai) | Code on the page | Pydantic AI (`Agent`, `tool_plain`) | Python | A `verify_quotes` tool that calls the route with the `x402` package | Yes, with the `x402` package when a key is set |
| [mastra.md](/examples/mastra) | Code on the page | Mastra (`Agent`, `createTool`) | JavaScript | A `verify_quotes` tool that calls the route with `@x402/fetch` | Yes, when a key is set |
| [curl.md](/examples/curl) | Code on the page | None | Shell | `curl`: the 402 price, then one x402 payment | Yes, when a key is set |
| [mcp.md](/examples/mcp) | Code on the page | MCP clients | Any | The `quoteproof-mcp` server (stdio), no install step | Yes, with `QUOTEPROOF_X402_KEY` when it is set |

## Run a recipe

Each page shows its code in full, with what to install and the command that runs it. The LangChain (JavaScript), LlamaIndex.TS, Vercel AI SDK and OpenAI Agents SDK recipes share one client, [`attestpage.mjs`](/docs/examples/attestpage.mjs), shown on the OpenAI Agents SDK page.

- Plain fetch with x402 always pays, so it needs `ATTESTPAGE_X402_KEY`, the key of a wallet holding a little USDC.
- Python with x402 makes one unpaid call with no wallet key (it returns the price), then pays for one call when `ATTESTPAGE_X402_KEY` is set.
- OpenAI Agents SDK sends no payment with no wallet key and returns the price; it needs `OPENAI_API_KEY` for the model.
- LangChain (JavaScript), LlamaIndex.TS and Claude Agent SDK send no payment with no wallet key and return the price; they need `ANTHROPIC_API_KEY` for the model.
- Vercel AI SDK sends no payment with no wallet key. With `ANTHROPIC_API_KEY` set, the model decides when to call the tools; without it, the file calls `verify_quote` once and prints the answer.

## Service address

```
https://s2h6qt73jtzlgbgnnfacln2poq.srv.us
```

Every recipe uses this address by default. To call another address, set `ATTESTPAGE_URL` (the MCP server reads `QUOTEPROOF_URL`).

## Routes and prices

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json) and in the [OpenAPI document](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/openapi.json).

| Route | What it answers | Price |
|---|---|---|
| `POST /v1/verify/quote` | Is this quote on the page at this URL: `exact`, `fuzzy` or `none`, with offsets and page hashes | US$0.01 |
| `POST /v1/verify/citations` | The same for up to 10 quote and URL pairs | US$0.10 per batch |
| `POST /v1/verify/quotes` | The same for up to 20 quotes on one page, fetched once | US$0.02 per batch |
| `POST /v1/verify/text-quote` | The same check against text you already hold, nothing fetched | US$0.005 |
| `POST /v1/verify/document` | Every quote with its link in a finished document, checked on the live page | US$0.10 per part of up to 10 pairs |
| `POST /v1/verify/document/preview` | The pairs a document check would make, and its price | free |
| `POST /v1/fetch` | A page as clean text, with a verdict on what came back (`real`, `bot_wall`, `js_shell`, `paywall`, `http_error` and others) | US$0.002 |
| `POST /v1/recheck` | Fetches a page again and compares it with an earlier receipt: `unchanged`, `changed`, `gone` or `unreadable`, with a receipt naming both hashes | US$0.003 |
| `POST /v1/check/links` | Status, redirects, final URL and verdict for up to 10 URLs | US$0.005 per batch |
| `POST /v1/check/packages` | Whether up to 10 npm, PyPI or crates.io names exist, with latest version | US$0.005 per batch |
| `POST /v1/attest` | A signed, timestamped receipt over a SHA-256 you send | US$0.002 |
| `POST /v1/receipt/verify` | Checks a receipt's signature against the published keys | free |

Every answer from a paid route carries a `receipt`: an Ed25519-signed JWS of what the fetcher saw and when. A receipt records what was on the page at that time, not whether a statement on it is correct.

## How a call is paid

1. **Payment.** A paid route without payment answers `402` with the price. See [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits).
2. **402 Payment Required.** A valid request gets `402` when it has no payment. The offer is in the `PAYMENT-REQUIRED` header: base64 JSON with the amount (USDC, 6 decimals), network and pay-to address.
3. **x402.** Sign the offer and send the same request again with the `PAYMENT-SIGNATURE` header. Payment settles only when the route answers with a status below 400; the answer then carries a `PAYMENT-RESPONSE` header.

Payments run on Base (`eip155:8453`). USDC on Base is real money: each paid call is charged. Use a wallet holding only the USDC you can spare.

A bad request gets `400` before any offer and is never charged. Error codes are listed at [`/docs/errors`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/errors).

## Try it without code

```sh
# Free: what a verify/quote answer looks like
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote

# The 402 offer for verify/quote, decoded
curl -s -o /dev/null -D - -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote \
  -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d
```

## More

- Several quotes from one page in one `POST /v1/verify/quotes` call: [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents), [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk), [LangChain (Python)](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain), [LlamaIndex (Python)](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex) and [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai), [Pydantic AI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/pydantic-ai) and [Mastra](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/mastra)
- [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments)
- [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp)
- [llms.txt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/llms.txt)

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/langchain.md

# LangChain: check a quote before citing it

Last updated: 2026-10-17

A LangChain agent with two AttestPage tools: `verify_quote` (US$0.01 a call) and `check_links` (US$0.005 per batch of up to 10 URLs). The client below uses only the Python standard library. It sends no payment; when a call needs payment it returns the price to the agent instead of raising, so the agent can say what the call would cost. To pay per call, see [fetch-x402.md](/docs/examples/fetch-x402) or [claude-agent-sdk.md](/docs/examples/claude-agent-sdk). For JavaScript, see [LangChain in JavaScript](#langchain-in-javascript) below: its client can pay per call.

To check up to 20 quotes from one page in one paid call, see [LangChain (Python) with POST /v1/verify/quotes](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain).

For the same check in other frameworks, see [LlamaIndex](/docs/examples/llamaindex), [OpenAI Agents SDK](/docs/examples/openai-agents-sdk), [Vercel AI SDK](/docs/examples/vercel-ai-sdk) and [Claude Agent SDK](/docs/examples/claude-agent-sdk).

## Install

Python 3.10 or later.

```sh
pip install "langchain>=1.0" langchain-anthropic
export ANTHROPIC_API_KEY=...
```

Any chat model LangChain supports works; set `MODEL` (for example `openai:gpt-5`) and install its package.

## attestpage.py

```python
"""AttestPage client for agent tools (Python standard library only).

Sends no trial header; every paid call answers 402, and this
returns {"payment_required": True, "price_usd": ..., "network": ...} instead of raising.
"""
import base64
import json
import os
import urllib.error
import urllib.request

BASE_URL = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")


def _offer(header):
    # PAYMENT-REQUIRED is base64 JSON; amounts are USDC atomic units (6 decimals).
    try:
        first = json.loads(base64.b64decode(header))["accepts"][0]
        return {"price_usd": int(first["amount"]) / 1_000_000, "network": first["network"]}
    except (ValueError, KeyError, IndexError, TypeError):
        return {}


def call(path, body, trial=True, timeout=60):
    """POST body to path; returns the JSON answer, a payment_required dict or an error dict."""
    headers = {"content-type": "application/json", "accept": "application/json"}
    if trial:
        headers["quoteproof-trial"] = "1"
    req = urllib.request.Request(BASE_URL + path, data=json.dumps(body).encode(), headers=headers, method="POST")
    try:
        with urllib.request.urlopen(req, timeout=timeout) as res:
            return json.loads(res.read())
    except urllib.error.HTTPError as e:
        try:
            err = json.loads(e.read()).get("error", {})
        except ValueError:
            err = {}
        if e.code == 429 and trial and err.get("code") == "trial_exhausted":
            return call(path, body, trial=False, timeout=timeout)  # ask again without the trial, for the price
        if e.code == 402:
            return {"payment_required": True, **_offer(e.headers.get("payment-required", "")),
                    "message": "This call needs an x402 payment; see /docs/payments."}
        return {"error": err.get("code", "http_%d" % e.code), "status": e.code, "message": err.get("message", "")}


def verify_quote(url, quote, match="fuzzy"):
    return call("/v1/verify/quote", {"url": url, "quote": quote, "match": match})


def check_links(urls):
    return call("/v1/check/links", {"urls": list(urls)})


def verify_receipt(receipt):
    return call("/v1/receipt/verify", {"receipt": receipt}, trial=False)
```

## agent.py

```python
"""LangChain agent that checks a quote with AttestPage before it cites it."""
import os
import sys

from langchain.agents import create_agent
from langchain.tools import tool

import attestpage


@tool
def verify_quote(url: str, quote: str) -> dict:
    """Use before quoting a web page: is this exact or near-exact quote on the page at url?
    Returns result.match (exact, fuzzy or none), page.content_kind and a signed receipt."""
    return attestpage.verify_quote(url, quote)


@tool
def check_links(urls: list[str]) -> dict:
    """Use before putting links in an answer: status, final URL and content_kind for each URL."""
    return attestpage.check_links(urls)


agent = create_agent(
    model=os.environ.get("MODEL", "anthropic:claude-sonnet-5-5"),
    tools=[verify_quote, check_links],
    system_prompt=(
        "Before you quote a web page, call verify_quote. Cite a quote only when result.match is exact or fuzzy "
        "and page.content_kind is real. If a tool returns payment_required, give the price and stop."
    ),
)

if __name__ == "__main__":
    question = " ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say '
        '"These domains may be used as illustrative examples in documents"?'
    )
    result = agent.invoke({"messages": [{"role": "user", "content": question}]})
    print(result["messages"][-1].content)
```

## Run

```sh
python agent.py
python agent.py 'Is "Example Domain" the title of https://example.com?'
```

## What comes back

`verify_quote` returns the route's JSON. The parts an agent needs:

- `result.match`: `exact`, `fuzzy` or `none`, with `result.score` from 0 to 1.
- `page.content_kind`: read it before trusting `match`. A `none` on a `bot_wall` or `js_shell` page means the page could not be read, not that the quote is missing.
- `receipt`: keep it with the answer. `attestpage.verify_receipt(receipt)` checks it for free.

On a paraphrased claim, call `attestpage.verify_quote(url, claim, match="passages")`: it returns the 3 passages that share most of the claim's words, as evidence to read, not a verdict.

## Check packages before install

`attestpage.call("/v1/check/packages", body)` checks up to 10 package names on npm, PyPI or crates.io in one call. It costs US$0.005 per batch of up to 10 names. This Python client does not pay, so it returns the price. Call it before installing a package a model suggested, so a made-up name is caught first.

```python
result = attestpage.call("/v1/check/packages", {"packages": [{"ecosystem": "npm", "name": "left-pad"}]})
if "results" not in result:
    print(result)  # a payment_required or error dict
for item in result.get("results", []):
    print(item["name"], item["exists"], item.get("latest_version"))
```

`exists` is `true` when the registry lists the name, `false` when it does not, and `null` when the lookup failed; ask again for a `null`. It is not a security verdict: a listed package can still be malicious. The full answer is at [`/docs/check-packages`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-packages).

## LangChain in JavaScript

The same agent in JavaScript. It uses the `attestpage.mjs` client from [openai-agents-sdk.md](/docs/examples/openai-agents-sdk): with no key it returns the price for each call, and with `ATTESTPAGE_X402_KEY` set it pays each call with x402 on Base, in USDC.

Node.js 20 or later. Save the client as `attestpage.mjs` next to `langchain.mjs`.

```sh
npm init -y && npm pkg set type=module
npm install langchain@^1.0.0 @langchain/core@^1.2.17 @langchain/anthropic@^1.0.0 zod
npm install @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4   # only needed to pay
export ANTHROPIC_API_KEY=...
```

### langchain.mjs

```js
// LangChain.js agent that checks a quote with AttestPage before it cites it.
import { createAgent, tool } from 'langchain';
import * as z from 'zod';
import { createClient } from './attestpage.mjs';

const attestpage = await createClient();

// Tools return the route's JSON as text.
const verifyQuote = tool(async ({ url, quote }) => JSON.stringify(await attestpage.verifyQuote({ url, quote })), {
  name: 'verify_quote',
  description: 'Use before quoting a web page: is this exact or near-exact quote on the page at url? '
    + 'Returns result.match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.01.',
  schema: z.object({ url: z.string(), quote: z.string() }),
});

const checkLinks = tool(async ({ urls }) => JSON.stringify(await attestpage.checkLinks({ urls })), {
  name: 'check_links',
  description: 'Use before putting links in an answer: status, final URL and content_kind for each URL. '
    + 'Up to 10 URLs. US$0.005 per batch.',
  schema: z.object({ urls: z.array(z.string()).min(1).max(10) }),
});

const agent = createAgent({
  model: process.env.MODEL || 'anthropic:claude-sonnet-5-5',
  tools: [verifyQuote, checkLinks],
  systemPrompt: 'Before you quote a web page, call verify_quote. Cite a quote only when result.match is exact or fuzzy '
    + 'and page.content_kind is real. If a tool returns payment_required, give the price and stop.',
});

const question = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';
const result = await agent.invoke({ messages: [{ role: 'user', content: question }] });
console.log(result.messages.at(-1).content);
```

```sh
node langchain.mjs                              # no key: returns the price
ATTESTPAGE_X402_KEY=0x... node langchain.mjs    # pays US$0.01 per verify_quote in USDC
```

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/openai-agents-sdk.md

# OpenAI Agents SDK: check a quote before citing it, paid per call

Last updated: 2026-10-17

An OpenAI Agents SDK agent with two AttestPage tools: `verify_quote` (US$0.01 a call) and `check_links` (US$0.005 per batch of up to 10 URLs). With no key, the client sends no payment and returns the price for each call. With `ATTESTPAGE_X402_KEY` set, it pays each call with x402 through `@x402/fetch`, and refuses any offer above its limit.

For the same check in other frameworks, see [LangChain](/docs/examples/langchain), [LlamaIndex](/docs/examples/llamaindex), [Vercel AI SDK](/docs/examples/vercel-ai-sdk) and [Claude Agent SDK](/docs/examples/claude-agent-sdk).

## Install

Node.js 20 or later.

```sh
npm init -y && npm pkg set type=module
npm install @openai/agents zod
npm install @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4   # only needed to pay
export OPENAI_API_KEY=...
```

To pay, set `ATTESTPAGE_X402_KEY` to the private key (`0x` and 64 hex digits) of a Base wallet holding a little USDC (real money). The key stays in this process.

## attestpage.mjs

```js
// AttestPage client for agent tools. With no key it sends no payment. With ATTESTPAGE_X402_KEY
// it pays each call with x402 on Base (USDC), up to MAX_USD a call. A 402 it does not pay
// comes back as { payment_required, price_usd, network } instead of an exception.
const BASE = (process.env.ATTESTPAGE_URL || 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us').replace(/\/+$/, '');
const NETWORK = process.env.ATTESTPAGE_NETWORK || 'eip155:8453'; // Base; ATTESTPAGE_NETWORK picks another network the 402 lists
const MAX_USD = Number(process.env.MAX_USD || '0.01'); // the most one call may cost

// A fetch that answers 402 offers with a payment signed by key. Loaded only when a key is set.
async function payingFetch(key) {
  const [{ wrapFetchWithPayment, x402Client }, { registerExactEvmScheme }, { privateKeyToAccount }] = await Promise.all([
    import('@x402/fetch'), import('@x402/evm/exact/client'), import('viem/accounts'),
  ]);
  const client = new x402Client();
  registerExactEvmScheme(client, { signer: privateKeyToAccount(key) });
  // Sign only offers on Base at or under MAX_USD (amounts are USDC with 6 decimals).
  client.registerPolicy((_version, reqs) => reqs.filter((r) => r.network === NETWORK && Number(r.amount) <= MAX_USD * 1e6));
  return wrapFetchWithPayment(fetch, client);
}

function offer(header) {
  try {
    const first = JSON.parse(Buffer.from(header, 'base64').toString('utf8')).accepts[0];
    return { price_usd: Number(first.amount) / 1e6, network: first.network };
  } catch {
    return {};
  }
}

export async function createClient({ key = process.env.ATTESTPAGE_X402_KEY } = {}) {
  const fetchFn = key ? await payingFetch(key) : fetch;

  async function call(path, body, { trial = !key } = {}) {
    const headers = { 'content-type': 'application/json', accept: 'application/json' };
    if (trial) headers['quoteproof-trial'] = '1';
    let res;
    try {
      res = await fetchFn(`${BASE}${path}`, { method: 'POST', headers, body: JSON.stringify(body) });
    } catch (err) {
      // @x402/fetch throws when no offer passes the policy, or when signing fails.
      return { error: 'payment_not_made', message: String(err?.message ?? err) };
    }
    const json = await res.json().catch(() => ({}));
    if (res.ok) return json;
    // The trial is used up for today: ask again without it, for the price.
    if (res.status === 429 && trial && json.error?.code === 'trial_exhausted') return call(path, body, { trial: false });
    if (res.status === 402) {
      return { payment_required: true, ...offer(res.headers.get('payment-required') ?? ''),
        message: 'This call needs an x402 payment; set ATTESTPAGE_X402_KEY to pay.' };
    }
    return { error: json.error?.code ?? `http_${res.status}`, status: res.status, message: json.error?.message ?? '' };
  }

  return {
    verifyQuote: ({ url, quote, match = 'fuzzy' }) => call('/v1/verify/quote', { url, quote, match }),
    checkLinks: ({ urls }) => call('/v1/check/links', { urls }),
    checkPackages: ({ packages }) => call('/v1/check/packages', { packages }),
    verifyReceipt: ({ receipt }) => call('/v1/receipt/verify', { receipt }, { trial: false }),
  };
}
```

## openai-agents-sdk.mjs

```js
// OpenAI Agents SDK agent that checks a quote with AttestPage before it cites it.
import { Agent, run, tool } from '@openai/agents';
import { z } from 'zod';
import { createClient } from './attestpage.mjs';

const attestpage = await createClient();

const verifyQuote = tool({
  name: 'verify_quote',
  description: 'Use before quoting a web page: is this exact or near-exact quote on the page at url? '
    + 'Returns result.match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.01.',
  parameters: z.object({ url: z.string(), quote: z.string() }),
  execute: async ({ url, quote }) => attestpage.verifyQuote({ url, quote }),
});

const checkLinks = tool({
  name: 'check_links',
  description: 'Use before putting links in an answer: status, final URL and content_kind for each URL. '
    + 'Up to 10 URLs. US$0.005 per batch.',
  parameters: z.object({ urls: z.array(z.string()).min(1).max(10) }),
  execute: async ({ urls }) => attestpage.checkLinks({ urls }),
});

const agent = new Agent({
  name: 'Source checker',
  instructions: 'Before you quote a web page, call verify_quote. Cite a quote only when result.match is exact or fuzzy '
    + 'and page.content_kind is real. If a tool returns payment_required, give the price and stop.',
  tools: [verifyQuote, checkLinks],
});

const question = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';
const result = await run(agent, question);
console.log(result.finalOutput);
```

## Run

```sh
node openai-agents-sdk.mjs                             # no key: returns the price
ATTESTPAGE_X402_KEY=0x... node openai-agents-sdk.mjs   # pays US$0.01 per verify_quote in USDC
```

## What comes back

- `result.match`: `exact`, `fuzzy` or `none`. Read `page.content_kind` first: a `none` on a `bot_wall` or `js_shell` page means the page could not be read.

- `receipt`: an Ed25519-signed JWS of what was on the page and when. `attestpage.verifyReceipt({ receipt })` checks it for free.
- A paid answer has `"tier": "paid"` and `"rail": "x402"`. Payment settles only when the route answers with a status below 400; a bad request is refused before payment.

## Check packages before install

`attestpage.checkPackages` checks up to 10 package names on npm, PyPI or crates.io in one call, for US$0.005 per batch. Give it to the agent as a tool, the same way as `checkLinks`, so the agent checks a package a model suggested before it installs one:

```js
const checkPackages = tool({
  name: 'check_packages',
  description: 'Check that npm, PyPI or crates.io names exist before installing them.',
  parameters: z.object({
    packages: z.array(z.object({ ecosystem: z.enum(['npm', 'pypi', 'crates']), name: z.string(), version: z.string().nullable().optional() })).min(1).max(10),
  }),
  // Strict mode can send version as null; the route accepts a version string or no version at all.
  execute: async ({ packages }) => attestpage.checkPackages({
    packages: packages.map(({ version, ...p }) => (version ? { ...p, version } : p)),
  }),
});
```

`exists` is `true` when the registry lists the name, `false` when it does not, and `null` when the lookup failed. It is not a security verdict. The full answer is at [`/docs/check-packages`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-packages).

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/llamaindex.md

# LlamaIndex.TS: check a quote before citing it

Last updated: 2026-10-17

A LlamaIndex.TS agent with two AttestPage tools: `verify_quote` (US$0.01 a call) and `check_links` (US$0.005 per batch of up to 10 URLs). It uses the `attestpage.mjs` client from [openai-agents-sdk.md](/docs/examples/openai-agents-sdk): with no key each call answers 402 and the tool returns the price. With `ATTESTPAGE_X402_KEY` set, it pays each call with x402 on Base, in USDC. When a call needs payment and no key is set, the tool returns the price to the agent instead of raising, so the agent can say what the call would cost.

To check up to 20 quotes from one page in one paid call, see [LlamaIndex (Python) with POST /v1/verify/quotes](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex).

For the same check in other frameworks, see [LangChain](/docs/examples/langchain), [OpenAI Agents SDK](/docs/examples/openai-agents-sdk), [Vercel AI SDK](/docs/examples/vercel-ai-sdk) and [Claude Agent SDK](/docs/examples/claude-agent-sdk).

Node.js 20 or later. Save the client as `attestpage.mjs` next to `llamaindex.mjs`.

## Install

```sh
npm init -y && npm pkg set type=module
npm install llamaindex@^0.12.1 @llamaindex/workflow@^1.1.24 @llamaindex/anthropic@^0.3.26 zod
npm install @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4   # only needed to pay
export ANTHROPIC_API_KEY=...
```

Any chat model LlamaIndex supports works: import its class from its package and pass it as `llm`.

## llamaindex.mjs

```js
// LlamaIndex.TS agent that checks a quote with AttestPage before it cites it.
import { tool } from 'llamaindex';
import { agent } from '@llamaindex/workflow';
import { Anthropic } from '@llamaindex/anthropic';
import { z } from 'zod';
import { createClient } from './attestpage.mjs';

const attestpage = await createClient();

// @llamaindex/anthropic 0.3 allows tool calls only for model names with -3 or -4; this subclass allows them for any model.
class Claude extends Anthropic {
  get supportToolCall() { return true; }
}

// Tools return the route's JSON.
const verifyQuote = tool({
  name: 'verify_quote',
  description: 'Use before quoting a web page: is this exact or near-exact quote on the page at url? '
    + 'Returns result.match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.01.',
  parameters: z.object({ url: z.string(), quote: z.string() }),
  execute: ({ url, quote }) => attestpage.verifyQuote({ url, quote }),
});

const checkLinks = tool({
  name: 'check_links',
  description: 'Use before putting links in an answer: status, final URL and content_kind for each URL. '
    + 'Up to 10 URLs. US$0.005 per batch.',
  parameters: z.object({ urls: z.array(z.string()).min(1).max(10) }),
  execute: ({ urls }) => attestpage.checkLinks({ urls }),
});

const checker = agent({
  name: 'quote_checker',
  llm: new Claude({ model: process.env.MODEL || 'claude-sonnet-5-5' }),
  tools: [verifyQuote, checkLinks],
  systemPrompt: 'Before you quote a web page, call verify_quote. Cite a quote only when result.match is exact or fuzzy '
    + 'and page.content_kind is real. If a tool returns payment_required, give the price and stop.',
});

const question = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';
const result = await checker.run(question);
console.log(result.data.result);
```

```sh
node llamaindex.mjs                              # no key: returns the price
ATTESTPAGE_X402_KEY=0x... node llamaindex.mjs    # pays US$0.01 per verify_quote in USDC
```

## What comes back

`verify_quote` returns the route's JSON. The parts an agent needs:

- `result.match`: `exact`, `fuzzy` or `none`, with `result.score` from 0 to 1.
- `page.content_kind`: read it before trusting `match`. A `none` on a `bot_wall` or `js_shell` page means the page could not be read, not that the quote is missing.
- `receipt`: keep it with the answer. `POST /v1/receipt/verify` checks it for free.

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/vercel-ai-sdk.md

# Vercel AI SDK: check a quote before citing it

Last updated: 2026-10-17

A Vercel AI SDK (`ai`) agent with two AttestPage tools: `verify_quote` (US$0.01 a call) and `check_links` (US$0.005 per batch of up to 10 URLs). It uses the `attestpage.mjs` client from [openai-agents-sdk.md](/docs/examples/openai-agents-sdk): with no key each call answers 402 and the tool returns the price. With `ATTESTPAGE_X402_KEY` set, it pays each call with x402 on Base, in USDC. When a call needs payment and no key is set, the tool returns the price to the agent instead of raising, so the agent can say what the call would cost.

With no `ANTHROPIC_API_KEY`, the file skips the model and calls `verify_quote` once itself, printing the JSON the agent would get.

For the same check in other frameworks, see [LangChain](/docs/examples/langchain), [LlamaIndex.TS](/docs/examples/llamaindex), [OpenAI Agents SDK](/docs/examples/openai-agents-sdk) and [Claude Agent SDK](/docs/examples/claude-agent-sdk).

Node.js 20 or later. Save the client as `attestpage.mjs` next to `vercel-ai-sdk.mjs`.

## Install

```sh
npm init -y && npm pkg set type=module
npm install ai@7 @ai-sdk/anthropic zod
npm install @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4   # only needed to pay
export ANTHROPIC_API_KEY=...             # leave unset to call the tool without a model
```

Any model the AI SDK supports works: install its provider package and pass its model as `model`.

## vercel-ai-sdk.mjs

```js
// Vercel AI SDK agent that checks a quote with AttestPage before it cites it.
// With no ANTHROPIC_API_KEY it skips the model and calls verify_quote itself, so you can see what the tool returns.
import { z } from 'zod';
import { createClient } from './attestpage.mjs';

const attestpage = await createClient();

// tool() from 'ai' only adds types, so plain objects work. Tools return the route's JSON.
const tools = {
  verify_quote: {
    description: 'Use before quoting a web page: is this exact or near-exact quote on the page at url? '
      + 'Returns result.match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.01.',
    inputSchema: z.object({ url: z.string(), quote: z.string() }),
    execute: ({ url, quote }) => attestpage.verifyQuote({ url, quote }),
  },
  check_links: {
    description: 'Use before putting links in an answer: status, final URL and content_kind for each URL. '
      + 'Up to 10 URLs. US$0.005 per batch.',
    inputSchema: z.object({ urls: z.array(z.string()).min(1).max(10) }),
    execute: ({ urls }) => attestpage.checkLinks({ urls }),
  },
};

const args = process.argv.slice(2);
if (!process.env.ANTHROPIC_API_KEY) {
  // No model: node vercel-ai-sdk.mjs [url] [quote]
  const [url = 'https://www.iana.org/help/example-domains', quote = 'These domains may be used as illustrative examples in documents'] = args;
  console.log(JSON.stringify(await tools.verify_quote.execute(tools.verify_quote.inputSchema.parse({ url, quote })), null, 2));
} else {
  const [{ generateText, isStepCount }, { anthropic }] = await Promise.all([import('ai'), import('@ai-sdk/anthropic')]);
  const question = args.join(' ')
    || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';
  const { text } = await generateText({
    model: anthropic(process.env.MODEL || 'claude-sonnet-5-5'),
    tools,
    stopWhen: isStepCount(5),
    instructions: 'Before you quote a web page, call verify_quote. Cite a quote only when result.match is exact or fuzzy '
      + 'and page.content_kind is real. If a tool returns payment_required, give the price and stop.',
    prompt: question,
  });
  console.log(text);
}
```

```sh
node vercel-ai-sdk.mjs                              # no key: returns the price
ATTESTPAGE_X402_KEY=0x... node vercel-ai-sdk.mjs    # pays US$0.01 per verify_quote in USDC
```

With no `ANTHROPIC_API_KEY`, pass a URL and a quote instead of a question: `node vercel-ai-sdk.mjs <url> "<quote>"`.

## What comes back

`verify_quote` returns the route's JSON. The parts an agent needs:

- `result.match`: `exact`, `fuzzy` or `none`, with `result.score` from 0 to 1.
- `page.content_kind`: read it before trusting `match`. A `none` on a `bot_wall` or `js_shell` page means the page could not be read, not that the quote is missing.
- `receipt`: keep it with the answer. `POST /v1/receipt/verify` checks it for free.

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/claude-agent-sdk.md

# Claude Agent SDK: AttestPage tools through quoteproof-mcp

Last updated: 2026-10-17

A Claude Agent SDK agent that gets AttestPage's tools from `quoteproof-mcp`, an MCP server run over stdio. There is no client code to write: the server lists thirteen tools with their prices, pays with x402 from your own key when `ATTESTPAGE_X402_KEY` is set, and otherwise sends no payment, so a paid tool returns the x402 price.

| Tool | Route | Price |
|---|---|---|
| `attestpage_verify_quote` | `POST /v1/verify/quote` | US$0.01 |
| `attestpage_verify_citations` | `POST /v1/verify/citations` | US$0.10 per batch of up to 10 |
| `attestpage_verify_quotes` | `POST /v1/verify/quotes` | US$0.02 per batch of up to 20 on one page |
| `attestpage_verify_text_quote` | `POST /v1/verify/text-quote` | US$0.005 |
| `attestpage_verify_document` | `POST /v1/verify/document` | US$0.10 per part of up to 10 pairs |
| `attestpage_preview_document` | `POST /v1/verify/document/preview` | free |
| `attestpage_fetch` | `POST /v1/fetch` | US$0.002 |
| `attestpage_recheck` | `POST /v1/recheck` | US$0.003 |
| `attestpage_check_links` | `POST /v1/check/links` | US$0.005 per batch of up to 10 |
| `attestpage_check_packages` | `POST /v1/check/packages` | US$0.005 per batch of up to 10 |
| `attestpage_attest` | `POST /v1/attest` | US$0.002 |
| `attestpage_verify_receipt` | `POST /v1/receipt/verify` | free |

For the same check in other frameworks, see [LangChain](/docs/examples/langchain), [LlamaIndex](/docs/examples/llamaindex), [OpenAI Agents SDK](/docs/examples/openai-agents-sdk) and [Vercel AI SDK](/docs/examples/vercel-ai-sdk).

## Install

Node.js 20.3 or later.

```sh
npm init -y && npm pkg set type=module
npm install @anthropic-ai/claude-agent-sdk
export ANTHROPIC_API_KEY=...
```

The MCP server needs no install: `npx` fetches it from the service as a tarball. [`/dl/index.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json) lists the current version with its sha256 and npm integrity string. The package has no install scripts.

To pay, set `ATTESTPAGE_X402_KEY` to the private key (`0x` and 64 hex digits) of a Base wallet holding a little USDC (real money). The key stays in the MCP server's process and is never logged or returned.

## claude-agent-sdk.mjs

```js
// Claude Agent SDK agent that checks a quote with AttestPage (quoteproof-mcp over stdio) before it cites it.
import { query } from '@anthropic-ai/claude-agent-sdk';

const ORIGIN = 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const SERVICE = (process.env.ATTESTPAGE_URL || ORIGIN).replace(/\/+$/, '');

// Settings for the MCP server. Without ATTESTPAGE_X402_KEY it sends no payment and gets the price back.
const env = {
  QUOTEPROOF_URL: SERVICE,
  QUOTEPROOF_MAX_USD: '0.01', // the most one call may cost
  QUOTEPROOF_SESSION_USD: '0.10', // the most this run may spend in total
};
if (process.env.ATTESTPAGE_X402_KEY) env.QUOTEPROOF_X402_KEY = process.env.ATTESTPAGE_X402_KEY;
if (process.env.QP_OWN_TOKEN) env.QP_OWN_TOKEN = process.env.QP_OWN_TOKEN;

// Tools from an MCP server are named mcp__<server>__<tool>.
const TOOLS = ['attestpage_verify_quote', 'attestpage_check_links', 'attestpage_check_packages', 'attestpage_verify_receipt'];

const prompt = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents"?';

for await (const message of query({
  prompt,
  options: {
    mcpServers: {
      attestpage: { type: 'stdio', command: 'npx', args: ['-y', `${ORIGIN}/dl/quoteproof-mcp-0.1.40.tgz`], env },
    },
    allowedTools: TOOLS.map((t) => `mcp__attestpage__${t}`),
    systemPrompt: 'Before you quote a web page, call attestpage_verify_quote. Cite a quote only when result.match is exact '
      + 'or fuzzy and page.content_kind is real. If a tool fails with payment_refused_locally, say so and stop.',
    maxTurns: 6,
  },
})) {
  if (message.type === 'result') console.log(message.subtype === 'success' ? message.result : `stopped: ${message.subtype}`);
}
```

## Run

```sh
node claude-agent-sdk.mjs                             # no key: returns the price
ATTESTPAGE_X402_KEY=0x... node claude-agent-sdk.mjs   # pays in USDC, at most US$0.01 a call
```

## Check packages before install

The `attestpage_check_packages` tool checks up to 10 names on npm, PyPI or crates.io in one call, for US$0.005 per batch. Ask the agent to run it before it installs anything a model suggested. Its input:

```json
{ "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests", "version": "2.32.3" }] }
```

Each result has `exists` (`true`, `false`, or `null` when the lookup failed), `latest_version`, and `vulnerabilities`: the known OSV.dev advisories for the version shown. It is not a security verdict. The full answer is at [`/docs/check-packages`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-packages).

## Limits the server applies before it signs

| Variable | Default | Meaning |
|---|---|---|
| `QUOTEPROOF_MAX_USD` | `0.10` | The most it pays for one call; each tool also pays no more than its listed price |
| `QUOTEPROOF_SESSION_USD` | `1` | The most it signs in total while the process runs |
| `QUOTEPROOF_NETWORKS` | `eip155:8453` | Networks it pays on (Base, USDC) |
| `QUOTEPROOF_TRIAL` | on | Set `0` to send no trial header |

An offer over a limit is refused with `payment_refused_locally` and nothing is signed. A paid result carries the settlement (transaction hash, payer, network) in `_meta["x402/payment-response"]`.

## The same server in other MCP clients

Most MCP clients take a block like this:

```json
{
  "mcpServers": {
    "attestpage": {
      "command": "npx",
      "args": ["-y", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/quoteproof-mcp-0.1.40.tgz"],
      "env": {
        "QUOTEPROOF_URL": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us",
        "QUOTEPROOF_X402_KEY": "0x..."
      }
    }
  }
}
```

Leave out `QUOTEPROOF_X402_KEY` and calls carry no payment, so a paid tool returns the price. With no install at all, the service also answers MCP over HTTP at `POST /mcp`; see [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp).

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/fetch-x402.md

# Plain fetch with x402: one paid call, step by step

Last updated: 2026-10-18

One paid call to `POST /v1/verify/quote` (US$0.01) with plain `fetch`, showing each step of an x402 payment: read the offer, check it, sign it, send the request again, read the settlement, then check the receipt for free. Use this to wire AttestPage into any agent framework, or to see what an x402 client library does for you.

Payments run on Base (`eip155:8453`), in USDC.

## Install

Node.js 20 or later.

```sh
npm init -y && npm pkg set type=module
npm install @x402/core@2.28.0 @x402/evm@2.28.0 viem@2.57.4
```

Set `ATTESTPAGE_X402_KEY` to the private key (`0x` and 64 hex digits) of a Base wallet holding a little USDC (real money). The key stays in this process.

## fetch-x402.mjs

```js
// One paid AttestPage call with plain fetch and x402, step by step.
import { x402Client, x402HTTPClient } from '@x402/core/client';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';

const BASE = (process.env.ATTESTPAGE_URL || 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us').replace(/\/+$/, '');
const NETWORK = process.env.ATTESTPAGE_NETWORK || 'eip155:8453'; // Base; ATTESTPAGE_NETWORK picks another network the 402 lists
const MAX_USD = 0.01; // the most this script will pay; verify/quote is listed at US$0.01

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const x402 = new x402HTTPClient(client);

const url = `${BASE}/v1/verify/quote`;
const request = {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({
    url: process.argv[2] || 'https://www.iana.org/help/example-domains',
    quote: process.argv[3] || 'These domains may be used as illustrative examples in documents',
  }),
};

// 1. Send the request with no payment. A valid request gets 402, with the offer in PAYMENT-REQUIRED.
let res = await fetch(url, request);
if (res.status !== 402) throw new Error(`expected 402, got ${res.status}: ${await res.text()}`);
const offer = x402.getPaymentRequiredResponse((name) => res.headers.get(name), await res.json());

// 2. Check the offer before signing: right network, price within MAX_USD (USDC has 6 decimals).
const accepts = offer.accepts.filter((a) => a.network === NETWORK && Number(a.amount) <= MAX_USD * 1e6);
if (accepts.length === 0) throw new Error(`no acceptable offer: ${JSON.stringify(offer.accepts)}`);
console.log(`price: US$${Number(accepts[0].amount) / 1e6} on ${accepts[0].network}, pay to ${accepts[0].payTo}`);

// 3. Sign the offer and send the same request again with PAYMENT-SIGNATURE.
const payment = await x402.createPaymentPayload({ ...offer, accepts });
res = await fetch(url, { ...request, headers: { ...request.headers, ...x402.encodePaymentSignatureHeader(payment) } });
const answer = await res.json();
if (!res.ok) throw new Error(`${res.status} ${answer.error?.code}: ${answer.error?.message}`);

// 4. A settled call carries PAYMENT-RESPONSE: the transaction, payer and network.
const settlement = x402.getPaymentSettleResponse((name) => res.headers.get(name));
console.log('settled:', settlement.transaction, 'from', settlement.payer, 'on', settlement.network);
console.log('match:', answer.result.match, 'score:', answer.result.score, 'page:', answer.page.content_kind);

// 5. Check the receipt's signature for free.
const check = await fetch(`${BASE}/v1/receipt/verify`, {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ receipt: answer.receipt }),
}).then((r) => r.json());
console.log('receipt valid:', check.valid);
```

## Run

```sh
ATTESTPAGE_X402_KEY=0x... node fetch-x402.mjs
ATTESTPAGE_X402_KEY=0x... node fetch-x402.mjs https://example.com 'Example Domain'
```

## Notes

- **Only the price.** An unpaid request with an empty body (`{}`) also gets the 402 offer, so a client can read a route's price before it has a real input.
- **Bad input is free.** A request that fails validation gets `400` before any offer and is never charged.
- **Settled only below 400.** The payment settles only when the route answers with a status below 400.
- **Spent signatures.** A payment signature pays for one call. Sending the same request with the same signature again gets the stored result back (marked `idempotent-replayed: true`), with no second charge. Sending that signature with a different request gets a 409 answer, not charged (see [errors](/docs/errors)); sign a new offer instead.
- **Shorter.** `wrapFetchWithPayment` from `@x402/fetch` does steps 1 to 3 inside `fetch`; [openai-agents-sdk.md](/docs/examples/openai-agents-sdk) uses it with a price limit.
- **Other routes.** The same steps work for every paid route; only the body and the price change. See [README.md](/docs/examples#routes-and-prices).

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/python-x402.md

# Python with x402: one paid call, step by step

Last updated: 2026-10-18

One unpaid call that returns the 402 offer, then one paid call to `POST /v1/verify/quote` (US$0.01) with `httpx` and the official [`x402`](https://pypi.org/project/x402/) package, showing each step of an x402 payment: read the offer, check it, sign it, send the request again, read the settlement, then check the receipt for free. Use this to call AttestPage from a Python agent, or to see what an x402 client does for you.

Payments run on Base (`eip155:8453`), in USDC.

## Install

Python 3.10 or later.

```sh
python3 -m venv .venv && . .venv/bin/activate
pip install "x402[evm,httpx]==2.25.0"
```

The `evm` extra brings `eth-account` for signing; the `httpx` extra brings `httpx`.

The first call needs no wallet. To pay, set `ATTESTPAGE_X402_KEY` to the private key (`0x` and 64 hex digits) of a Base wallet holding a little USDC (real money). The key stays in this process.

## python-x402.py

```python
# One unpaid call, then one paid AttestPage call with httpx and x402, step by step.
import os
import sys

import httpx
from eth_account import Account
from x402 import x402ClientSync
from x402.http import x402HTTPClientSync
from x402.mechanisms.evm.exact import register_exact_evm_client

BASE = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")
NETWORK = os.environ.get("ATTESTPAGE_NETWORK", "eip155:8453")  # Base; ATTESTPAGE_NETWORK picks another network the 402 lists
MAX_USD = 0.01  # the most this script will pay; verify/quote is listed at US$0.01

url = f"{BASE}/v1/verify/quote"
body = {
    "url": sys.argv[1] if len(sys.argv) > 1 else "https://www.iana.org/help/example-domains",
    "quote": sys.argv[2] if len(sys.argv) > 2 else "These domains may be used as illustrative examples in documents",
}
http = httpx.Client(timeout=60)


def receipt_valid(receipt):
    # Checking a receipt's signature is free.
    return http.post(f"{BASE}/v1/receipt/verify", json={"receipt": receipt}).json()["valid"]


def fail(res):
    # An error reply that is not JSON (an HTML 502, say) has no error object: show the status and the start of the body.
    try:
        body = res.json()
    except ValueError:
        body = None
    error = body.get("error") if isinstance(body, dict) else None
    if not isinstance(error, dict):
        raise SystemExit(f"{res.status_code}: {res.text[:200]}")
    raise SystemExit(f"{res.status_code} {error.get('code')}: {error.get('message')}")


# 1. Unpaid call: no header, so the route answers 402 with the price.
#    Through the srv.us address without a payer id, callers share 200 a day.
res = http.post(url, json=body, headers={"Quoteproof-Trial": "1"})
if res.status_code == 429:
    print("trial: used up for today, retry after", res.headers.get("retry-after"), "seconds")
else:
    if res.status_code >= 400:
        fail(res)
    answer = res.json()
    print("trial match:", answer["result"]["match"], "tier:", answer["tier"], "receipt valid:", receipt_valid(answer["receipt"]))

key = os.environ.get("ATTESTPAGE_X402_KEY")
if not key:
    print("set ATTESTPAGE_X402_KEY to pay for the next call")
    sys.exit(0)

client = x402ClientSync()
register_exact_evm_client(client, Account.from_key(key))
x402 = x402HTTPClientSync(client)

# 2. Send the request with no payment. A valid request gets 402, with the offer in PAYMENT-REQUIRED.
res = http.post(url, json=body)
if res.status_code != 402:
    raise SystemExit(f"expected 402, got {res.status_code}: {res.text[:200]}")
offer = x402.get_payment_required_response(res.headers.get, res.content)

# 3. Check the offer before signing: right network, price within MAX_USD (USDC has 6 decimals).
accepts = [a for a in offer.accepts if a.network == NETWORK and int(a.amount) <= MAX_USD * 1e6]
if not accepts:
    raise SystemExit(f"no acceptable offer: {offer.accepts}")
print(f"price: US${int(accepts[0].amount) / 1e6} on {accepts[0].network}, pay to {accepts[0].pay_to}")

# 4. Sign the offer and send the same request again with PAYMENT-SIGNATURE.
payment = x402.create_payment_payload(offer.model_copy(update={"accepts": accepts}))
res = http.post(url, json=body, headers=x402.encode_payment_signature_header(payment))
if res.status_code >= 400:
    fail(res)
answer = res.json()

# 5. A settled call carries PAYMENT-RESPONSE: the transaction, payer and network.
settlement = x402.get_payment_settle_response(res.headers.get)
print("settled:", settlement.transaction, "from", settlement.payer, "on", settlement.network)
print("match:", answer["result"]["match"], "score:", answer["result"]["score"], "page:", answer["page"]["content_kind"])
print("receipt valid:", receipt_valid(answer["receipt"]))
```

## Run

```sh
python python-x402.py
ATTESTPAGE_X402_KEY=0x... python python-x402.py
ATTESTPAGE_X402_KEY=0x... python python-x402.py https://example.com "Example Domain"
```

With no key it makes the unpaid call, reads the offer and stops before paying.

## Notes

- **Payment.** Without payment, a paid route answers `402` with the price. See [errors](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/errors).
- **Only the price.** An unpaid request with an empty body (`{}`) also gets the 402 offer, so a client can read a route's price before it has a real input.
- **Bad input is free.** A request that fails validation gets `400` before any offer and is never charged.
- **Settled only below 400.** The payment settles only when the route answers with a status below 400.
- **Spent signatures.** A payment signature pays for one call. Sending the same request with the same signature again gets the stored result back (marked `idempotent-replayed: true`), with no second charge. Sending that signature with a different request gets a 409 answer, not charged (see [errors](/docs/errors)); sign a new offer instead.
- **Shorter.** `x402HttpxClient` and `wrapHttpxWithPayment` from `x402.http.clients` do steps 2 to 4 inside `httpx`; check the price yourself, as in step 3, with a payment policy.
- **Other routes.** The same steps work for every paid route; only the body and the price change. See [README.md](/docs/examples#routes-and-prices).

Prices are per call in USDC. The full list is at [`/pricing.json`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md

# OpenAI Agents SDK: check several quotes on one page

Last updated: 2026-10-12

An OpenAI Agents SDK agent that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

Two ways to connect: the `quoteproof-mcp` server over stdio (no client code), or plain HTTP with x402.

The same check for other frameworks: [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md) [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md) and [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md).

## Install

Node.js 20 or later.

```sh
npm init -y && npm pkg set type=module
npm install @openai/agents zod
export OPENAI_API_KEY=...
```

`quoteproof-mcp` needs no install: `npx` fetches version 0.1.40 from [`/dl`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json), which lists its sha256. To pay, set `QUOTEPROOF_X402_KEY` to the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in the MCP server's process.

## With the MCP server

```js
// agent-mcp.mjs: checks quotes with attestpage_verify_quotes before citing them.
import { Agent, MCPServerStdio, run } from '@openai/agents';

const ORIGIN = 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const env = { QUOTEPROOF_URL: ORIGIN, QUOTEPROOF_MAX_USD: '0.02', QUOTEPROOF_SESSION_USD: '0.20' };
if (process.env.QUOTEPROOF_X402_KEY) env.QUOTEPROOF_X402_KEY = process.env.QUOTEPROOF_X402_KEY;

const attestpage = new MCPServerStdio({
  name: 'attestpage',
  command: 'npx',
  args: ['-y', `${ORIGIN}/dl/quoteproof-mcp-0.1.40.tgz`],
  env,
});
await attestpage.connect();

try {
  const agent = new Agent({
    name: 'Source checker',
    instructions: 'Before you quote a web page, call attestpage_verify_quotes once with the url and every quote you plan to use. '
      + 'Cite a quote only when its match is exact or fuzzy and page.content_kind is real. '
      + 'If a tool fails with trial_exhausted or payment_refused_locally, give the price and stop.',
    mcpServers: [attestpage],
  });
  const result = await run(agent, 'Does https://www.iana.org/help/example-domains say "These domains may be used as '
    + 'illustrative examples in documents" and "without prior coordination with us"?');
  console.log(result.finalOutput);
} finally {
  await attestpage.close();
}
```

```sh
node agent-mcp.mjs                             # free trial
QUOTEPROOF_X402_KEY=0x... node agent-mcp.mjs   # pays US$0.02 per call in USDC
```

The server refuses any offer above `QUOTEPROOF_MAX_USD` with `payment_refused_locally` and signs nothing.

## With HTTP and x402

```sh
npm install @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4
```

```js
// agent-http.mjs: the same check as a function tool that pays with x402.
import { Agent, run, tool } from '@openai/agents';
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';
import { z } from 'zod';

const ORIGIN = 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const MAX_UNITS = 20000; // US$0.02 in USDC (6 decimals): the most one call may cost

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
client.registerPolicy((_version, reqs) => reqs.filter((r) => r.network === 'eip155:8453' && Number(r.amount) <= MAX_UNITS));
const payingFetch = wrapFetchWithPayment(fetch, client);

const verifyQuotes = tool({
  name: 'verify_quotes',
  description: 'Use before quoting one web page several times: checks 1 to 20 quotes against the page at url. '
    + 'Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call.',
  parameters: z.object({ url: z.string(), quotes: z.array(z.string()).min(1).max(20) }),
  execute: async ({ url, quotes }) => {
    try {
      const res = await payingFetch(`${ORIGIN}/v1/verify/quotes`, {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({ url, quotes }),
      });
      return await res.json();
    } catch (e) {
      return { error: e.message }; // payment refused by the policy above, network error: tell the agent why
    }
  },
});

const agent = new Agent({
  name: 'Source checker',
  instructions: 'Before you quote a web page, call verify_quotes once with every quote you plan to use from it. '
    + 'Cite a quote only when its match is exact or fuzzy and page.content_kind is real. '
    + 'If the tool returns an error, say what it was and stop.',
  tools: [verifyQuotes],
});
console.log((await run(agent, process.argv.slice(2).join(' '))).finalOutput);
```

```sh
ATTESTPAGE_X402_KEY=0x... node agent-http.mjs 'Does https://www.iana.org/help/example-domains say "without prior coordination with us"?'
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; `@x402/fetch` signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02; anything else is refused before anything is signed, and the tool returns the reason as `error`. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: a signed JWS of what the fetcher saw and when. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline).
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md

# Claude Agent SDK: check several quotes on one page

Last updated: 2026-10-13

A Claude Agent SDK agent that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

Two ways to connect: the `quoteproof-mcp` server over stdio, which pays with x402 from your key, or the remote MCP endpoint over HTTP.

For all 12 tools, with a price table and the other MCP clients, see [the Claude Agent SDK recipe](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/claude-agent-sdk).

The same check for other frameworks: [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md) [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md) and [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md).

## Install

Node.js 20.3 or later.

```sh
npm init -y && npm pkg set type=module
npm install @anthropic-ai/claude-agent-sdk
export ANTHROPIC_API_KEY=...
```

`quoteproof-mcp` needs no install: `npx` fetches version 0.1.40 from [`/dl`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/index.json), which lists its sha256. To pay, set `ATTESTPAGE_X402_KEY` to the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in the MCP server's process.

## With the stdio MCP server

```js
// agent.mjs: checks quotes with attestpage_verify_quotes before citing them.
import { query } from '@anthropic-ai/claude-agent-sdk';

const ORIGIN = 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const env = { QUOTEPROOF_URL: ORIGIN, QUOTEPROOF_NETWORKS: 'eip155:8453', QUOTEPROOF_MAX_USD: '0.02', QUOTEPROOF_SESSION_USD: '0.20' };
if (process.env.ATTESTPAGE_X402_KEY) env.QUOTEPROOF_X402_KEY = process.env.ATTESTPAGE_X402_KEY;

const prompt = 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative '
  + 'examples in documents" and "without prior coordination with us"?';

for await (const message of query({
  prompt,
  options: {
    mcpServers: {
      attestpage: { type: 'stdio', command: 'npx', args: ['-y', `${ORIGIN}/dl/quoteproof-mcp-0.1.40.tgz`], env },
    },
    // Tools from an MCP server are named mcp__<server>__<tool>.
    allowedTools: ['mcp__attestpage__attestpage_verify_quotes', 'mcp__attestpage__attestpage_verify_receipt'],
    systemPrompt: 'Before you quote a web page, call attestpage_verify_quotes once with the url and every quote you plan to use. '
      + 'Cite a quote only when its match is exact or fuzzy and page.content_kind is real. '
      + 'If a tool fails with trial_exhausted or payment_refused_locally, give the price and stop.',
    maxTurns: 6,
  },
})) {
  if (message.type === 'result') console.log(message.subtype === 'success' ? message.result : `stopped: ${message.subtype}`);
}
```

```sh
node agent.mjs                             # free trial
ATTESTPAGE_X402_KEY=0x... node agent.mjs  # pays US$0.02 per call in USDC
```

The server refuses any offer on a network not in `QUOTEPROOF_NETWORKS` (Base) or above `QUOTEPROOF_MAX_USD` with `payment_refused_locally` and signs nothing. A paid result carries the settlement (transaction hash, payer, network) in `_meta["x402/payment-response"]`.

## With the remote MCP endpoint

No local process: point the SDK at `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp` (streamable HTTP).

```js
mcpServers: {
  attestpage: { type: 'http', url: 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp' },
},
```

Paid tools use the free trial, then return the payment requirements. To pay over HTTP, the client puts an x402 payment payload in `_meta["x402/payment"]` of the tool call; the stdio server above does this for you. See [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp).

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: a signed JWS of what the fetcher saw and when. `attestpage_verify_receipt` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline).
- A request with a bad URL or an empty quote is refused before payment and not charged.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md

# LangChain (Python): check several quotes on one page

Last updated: 2026-10-12

A LangChain agent in Python that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

The tool calls the route over HTTP and pays with the `x402` Python package.

To check one quote at a time or a batch of links, on the free trial with no payment code, see [LangChain: check a quote before citing it](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/langchain).

The same check for other frameworks: [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md), [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md) [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md) and [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md).

## Install

Python 3.10 or later.

```sh
pip install "langchain>=1.0" langchain-anthropic "x402[requests,evm]==2.25.0"
export ANTHROPIC_API_KEY=...
export ATTESTPAGE_X402_KEY=0x...
```

Any chat model LangChain supports works; set `MODEL` (for example `openai:gpt-5`) and install its package. `ATTESTPAGE_X402_KEY` is the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in your process.

## agent_http.py

```python
"""LangChain agent that checks quotes with POST /v1/verify/quotes, paying per call with x402."""
import os
import sys

from eth_account import Account
from langchain.agents import create_agent
from langchain.tools import tool
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm.exact import ExactEvmScheme
from x402.mechanisms.evm.signers import EthAccountSigner

ORIGIN = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")
MAX_UNITS = 20000  # US$0.02 in USDC (6 decimals): the most one call may cost

client = x402ClientSync()
client.register("eip155:8453", ExactEvmScheme(signer=EthAccountSigner(Account.from_key(os.environ["ATTESTPAGE_X402_KEY"]))))
client.register_policy(lambda _version, reqs: [
    r for r in reqs if r.network == "eip155:8453" and int(r.get_amount()) <= MAX_UNITS
])
session = x402_requests(client)


@tool
def verify_quotes(url: str, quotes: list[str]) -> dict:
    """Use before quoting one web page several times: checks 1 to 20 quotes against the page at url.
    Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call."""
    res = session.post(f"{ORIGIN}/v1/verify/quotes", json={"url": url, "quotes": quotes}, timeout=60)
    return res.json()


agent = create_agent(
    model=os.environ.get("MODEL", "anthropic:claude-sonnet-5-5"),
    tools=[verify_quotes],
    system_prompt=(
        "Before you quote a web page, call verify_quotes once with every quote you plan to use from it. "
        "Cite a quote only when its match is exact or fuzzy and page.content_kind is real."
    ),
)

if __name__ == "__main__":
    question = " ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say "These domains may be used as '
        'illustrative examples in documents" and "without prior coordination with us"?'
    )
    result = agent.invoke({"messages": [{"role": "user", "content": question}]})
    print(result["messages"][-1].content)
```

```sh
python agent_http.py   # pays US$0.02 per call in USDC
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; the `x402` session signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02, so a higher price or another network is refused before anything is signed. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: signed evidence of what the page said and when our fetcher saw it, as a JWS. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline). A receipt records what was on the page at that time, not whether a statement on it is correct.
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md

# LlamaIndex (Python): check several quotes on one page

Last updated: 2026-10-13

A LlamaIndex agent in Python that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

The tool is a LlamaIndex `FunctionTool` that calls the route over HTTP and pays with the `x402` Python package.

To check one quote at a time, on the free trial with no payment code, see [LlamaIndex.TS: check a quote before citing it](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/llamaindex). The same check for other frameworks: [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md) [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md) and [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md).

## Install

Python 3.10 or later.

```sh
pip install "llama-index-core>=0.12" llama-index-llms-anthropic "x402[requests,evm]==2.25.0"
export ANTHROPIC_API_KEY=...
export ATTESTPAGE_X402_KEY=0x...
```

Any LLM LlamaIndex supports works; swap the `Anthropic` line for its class and install its package. `ATTESTPAGE_X402_KEY` is the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in your process.

## agent_http.py

```python
"""LlamaIndex agent that checks quotes with POST /v1/verify/quotes, paying per call with x402."""
import asyncio
import os
import sys

from eth_account import Account
from llama_index.core.agent.workflow import FunctionAgent
from llama_index.core.tools import FunctionTool
from llama_index.llms.anthropic import Anthropic
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm.exact import ExactEvmScheme
from x402.mechanisms.evm.signers import EthAccountSigner

ORIGIN = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")
MAX_UNITS = 20000  # US$0.02 in USDC (6 decimals): the most one call may cost

client = x402ClientSync()
client.register("eip155:8453", ExactEvmScheme(signer=EthAccountSigner(Account.from_key(os.environ["ATTESTPAGE_X402_KEY"]))))
client.register_policy(lambda _version, reqs: [
    r for r in reqs if r.network == "eip155:8453" and int(r.get_amount()) <= MAX_UNITS
])
session = x402_requests(client)


def verify_quotes(url: str, quotes: list[str]) -> dict:
    """Use before quoting one web page several times: checks 1 to 20 quotes against the page at url.
    Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call."""
    try:
        res = session.post(f"{ORIGIN}/v1/verify/quotes", json={"url": url, "quotes": quotes}, timeout=60)
        return res.json()
    except Exception as e:  # payment refused by the policy above, network error: tell the agent why
        return {"error": str(e)}


agent = FunctionAgent(
    tools=[FunctionTool.from_defaults(fn=verify_quotes)],
    llm=Anthropic(model=os.environ.get("MODEL", "claude-sonnet-5-5")),
    system_prompt=(
        "Before you quote a web page, call verify_quotes once with every quote you plan to use from it. "
        "Cite a quote only when its match is exact or fuzzy and page.content_kind is real. "
        "If the tool returns an error, say what it was and stop."
    ),
)


async def main(question):
    print(await agent.run(user_msg=question))


if __name__ == "__main__":
    asyncio.run(main(" ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say "These domains may be used as '
        'illustrative examples in documents" and "without prior coordination with us"?'
    )))
```

```sh
python agent_http.py   # pays US$0.02 per call in USDC
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; the `x402` session signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02, so a higher price or another network is refused before anything is signed, and the tool returns the reason as `error`. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: signed evidence of what the page said and when our fetcher saw it, as a JWS. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline). A receipt records what was on the page at that time, not whether a statement on it is correct.
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md

# Vercel AI SDK: check several quotes on one page

Last updated: 2026-10-13

A Vercel AI SDK agent that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

The tool calls the route over HTTP and pays with `@x402/fetch`.

To check one quote at a time or a batch of links, on the free trial with no payment code, see [Vercel AI SDK: check a quote before citing it](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/examples/vercel-ai-sdk). The same check for other frameworks: [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md), [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md) and [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md).

## Install

Node.js 20 or later.

```sh
npm init -y && npm pkg set type=module
npm install ai@^7 @ai-sdk/anthropic zod @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4
export ANTHROPIC_API_KEY=...
export ATTESTPAGE_X402_KEY=0x...
```

Any model the AI SDK supports works: install its provider package and pass its model as `model`. `ATTESTPAGE_X402_KEY` is the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in your process.

## agent-http.mjs

```js
// agent-http.mjs: checks quotes with POST /v1/verify/quotes, paying per call with x402.
import { generateText, isStepCount, tool } from 'ai';
import { anthropic } from '@ai-sdk/anthropic';
import { AsyncLocalStorage } from 'node:async_hooks';
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';
import { z } from 'zod';

const ORIGIN = process.env.ATTESTPAGE_URL || 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const MAX_UNITS = 20000; // US$0.02 in USDC (6 decimals): the most one call may cost

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const refusedScope = new AsyncLocalStorage(); // the refused list of the one call that is running
client.registerPolicy((_version, reqs) => reqs.filter((r) => {
  const keep = r.network === 'eip155:8453' && Number(r.amount) <= MAX_UNITS;
  if (!keep) refusedScope.getStore()?.push(`US$${Number(r.amount) / 1_000_000} in USDC on ${r.network}`);
  return keep;
}));
const payingFetch = wrapFetchWithPayment(fetch, client);

const verifyQuotes = tool({
  description: 'Use before quoting one web page several times: checks 1 to 20 quotes against the page at url. '
    + 'Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call.',
  inputSchema: z.object({ url: z.string(), quotes: z.array(z.string()).min(1).max(20) }),
  execute: async ({ url, quotes }) => {
    const refused = []; // offers the policy turned down during this call
    return refusedScope.run(refused, async () => {
      try {
        const res = await payingFetch(`${ORIGIN}/v1/verify/quotes`, {
          method: 'POST',
          headers: { 'content-type': 'application/json' },
          body: JSON.stringify({ url, quotes }),
        });
        return await res.json();
      } catch (e) {
        // payment refused by the policy above, network error: tell the agent why
        if (refused.length) return { error: `${e.message}. Refused offer: ${refused.join('; ')}. This recipe pays at most US$0.02 in USDC on eip155:8453.` };
        return { error: e.message };
      }
    });
  },
});

const question = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents" and "without prior coordination with us"?';
const { text } = await generateText({
  model: anthropic(process.env.MODEL || 'claude-sonnet-5-5'),
  tools: { verify_quotes: verifyQuotes },
  stopWhen: isStepCount(5),
  instructions: 'Before you quote a web page, call verify_quotes once with every quote you plan to use from it. '
    + 'Cite a quote only when its match is exact or fuzzy and page.content_kind is real. '
    + 'If the tool returns an error, say what it was and stop.',
  prompt: question,
});
console.log(text);
```

```sh
node agent-http.mjs   # pays US$0.02 per call in USDC
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; `@x402/fetch` signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02; anything else is refused before anything is signed, and the tool returns the reason as `error`. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: signed evidence of what the page said and when our fetcher saw it, as a JWS. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline). A receipt records what was on the page at that time, not whether a statement on it is correct.
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md

# CrewAI: check several quotes on one page

Last updated: 2026-10-13

A CrewAI agent in Python that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

The tool calls the route over HTTP and pays with the `x402` Python package.

To check one quote at a time or a batch of links, on the free trial with no payment code, see [Example recipes](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/recipes). The same check for other frameworks: [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md), [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md) and [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md).

## Install

Python 3.10 to 3.13.

```sh
pip install "crewai[anthropic]" "x402[requests,evm]==2.25.0"
export ANTHROPIC_API_KEY=...
export ATTESTPAGE_X402_KEY=0x...
```

Any model CrewAI supports works: set `MODEL` (for example `openai/gpt-5`) and install its key. `ATTESTPAGE_X402_KEY` is the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in your process.

## agent_crew.py

```python
"""CrewAI agent that checks quotes with POST /v1/verify/quotes, paying per call with x402."""
import os
import sys

from crewai import LLM, Agent, Crew, Process, Task
from crewai.tools import tool
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm.exact import ExactEvmScheme
from x402.mechanisms.evm.signers import EthAccountSigner

ORIGIN = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")
MAX_UNITS = 20000  # US$0.02 in USDC (6 decimals): the most one call may cost

client = x402ClientSync()
client.register("eip155:8453", ExactEvmScheme(signer=EthAccountSigner(Account.from_key(os.environ["ATTESTPAGE_X402_KEY"]))))
refused: list[str] = []  # offers the policy turned down during the current call


def keep_cheap_base_offers(_version, reqs):
    kept = []
    for r in reqs:
        if r.network == "eip155:8453" and int(r.get_amount()) <= MAX_UNITS:
            kept.append(r)
        else:
            refused.append(f"US${int(r.get_amount()) / 1_000_000:g} in USDC on {r.network}")
    return kept


client.register_policy(keep_cheap_base_offers)
session = x402_requests(client)


@tool("verify_quotes")
def verify_quotes(url: str, quotes: list[str]) -> dict:
    """Use before quoting one web page several times: checks 1 to 20 quotes against the page at url.
    Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call."""
    refused.clear()
    try:
        res = session.post(f"{ORIGIN}/v1/verify/quotes", json={"url": url, "quotes": quotes}, timeout=60)
        return res.json()
    except Exception as e:  # payment refused by the policy above, network error: tell the agent why
        if refused:
            return {"error": f"{e}. Refused offer: {'; '.join(refused)}. This recipe pays at most US$0.02 in USDC on eip155:8453."}
        return {"error": str(e)}


checker = Agent(
    role="Source checker",
    goal="Check every quote against its page before an answer cites it.",
    backstory="You check quotes with verify_quotes and cite only the quotes that match.",
    tools=[verify_quotes],
    llm=LLM(model=os.environ.get("MODEL", "anthropic/claude-sonnet-5-5")),
    allow_delegation=False,
    verbose=True,
)


def main():
    question = " ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say "These domains may be used as '
        'illustrative examples in documents" and "without prior coordination with us"?'
    )
    check = Task(
        description=(
            f"{question}\n\nBefore you quote a web page, call verify_quotes once with every quote you plan to use from it. "
            "Cite a quote only when its match is exact or fuzzy and page.content_kind is real. "
            "If the tool returns an error, say what it was and stop."
        ),
        expected_output="A short answer that names each quote checked and its match result.",
        agent=checker,
    )
    crew = Crew(agents=[checker], tasks=[check], process=Process.sequential, verbose=True)
    print(crew.kickoff().raw)


if __name__ == "__main__":
    main()
```

```sh
python agent_crew.py   # pays US$0.02 per call in USDC
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; the `x402` session signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02, so a higher price or another network is refused before anything is signed. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: signed evidence of what the page said and when our fetcher saw it, as a JWS. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline). A receipt records what was on the page at that time, not whether a statement on it is correct.
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/pydantic-ai.md

# Pydantic AI: check several quotes on one page

Last updated: 2026-10-13

A Pydantic AI agent in Python that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

The tool calls the route over HTTP and pays with the `x402` Python package.

The same check for other frameworks: [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md), [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md), [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md), [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md) and [Mastra](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/mastra.md).

## Install

Python 3.10 or later.

```sh
pip install "pydantic-ai-slim[anthropic]" "x402[requests,evm]==2.25.0"
export ANTHROPIC_API_KEY=...
export ATTESTPAGE_X402_KEY=0x...
```

Any model Pydantic AI supports works; set `MODEL` (for example `openai:gpt-5`) and install its extra. `ATTESTPAGE_X402_KEY` is the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in your process.

## agent_http.py

```python
"""Pydantic AI agent that checks quotes with POST /v1/verify/quotes, paying per call with x402."""
import os
import sys

from eth_account import Account
from pydantic_ai import Agent
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm.exact import ExactEvmScheme
from x402.mechanisms.evm.signers import EthAccountSigner

ORIGIN = os.environ.get("ATTESTPAGE_URL", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us").rstrip("/")
MAX_UNITS = 20000  # US$0.02 in USDC (6 decimals): the most one call may cost

client = x402ClientSync()
client.register("eip155:8453", ExactEvmScheme(signer=EthAccountSigner(Account.from_key(os.environ["ATTESTPAGE_X402_KEY"]))))
client.register_policy(lambda _version, reqs: [
    r for r in reqs if r.network == "eip155:8453" and int(r.get_amount()) <= MAX_UNITS
])
session = x402_requests(client)

agent = Agent(
    os.environ.get("MODEL", "anthropic:claude-sonnet-5-5"),
    instructions=(
        "Before you quote a web page, call verify_quotes once with every quote you plan to use from it. "
        "Cite a quote only when its match is exact or fuzzy and page.content_kind is real. "
        "If the tool returns an error, say what it was and stop."
    ),
)


@agent.tool_plain
def verify_quotes(url: str, quotes: list[str]) -> dict:
    """Use before quoting one web page several times: checks 1 to 20 quotes against the page at url.
    Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call."""
    try:
        res = session.post(f"{ORIGIN}/v1/verify/quotes", json={"url": url, "quotes": quotes}, timeout=60)
    except Exception as e:  # the policy above refused every offer, or the network failed
        return {"error": f"{e}. This recipe pays at most US$0.02 in USDC on eip155:8453."}
    if res.status_code == 402:  # not paid: no offer was acceptable
        return {"error": "payment required", "payment_required": res.headers.get("PAYMENT-REQUIRED")}
    return res.json()


if __name__ == "__main__":
    question = " ".join(sys.argv[1:]) or (
        'Does https://www.iana.org/help/example-domains say "These domains may be used as '
        'illustrative examples in documents" and "without prior coordination with us"?'
    )
    print(agent.run_sync(question).output)
```

```sh
python agent_http.py   # pays US$0.02 per call in USDC
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; the `x402` session signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02, so a higher price or another network is refused before anything is signed. The tool returns that refusal, or a 402 that was not paid, to the agent as an `error` instead of raising, so the agent can report it and stop. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: signed evidence of what the page said and when our fetcher saw it, as a JWS. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline). A receipt records what was on the page at that time, not whether a statement on it is correct.
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/mastra.md

# Mastra: check several quotes on one page

Last updated: 2026-10-13

A Mastra agent that checks up to 20 quotes from one web page in one call to `POST /v1/verify/quotes` before it cites them. Price: US$0.02 per call, for 1 to 20 quotes. Each quote comes back `exact`, `fuzzy` or `none`, with offsets and context, plus the page's verdict and an Ed25519-signed receipt. Payments are in USDC with x402 v2 on Base Sepolia (a test network).

The tool calls the route over HTTP and pays with `@x402/fetch`.

The same check for other frameworks: [OpenAI Agents SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/openai-agents.md), [Claude Agent SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/claude-agent-sdk.md), [Vercel AI SDK](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/vercel-ai-sdk.md), [LangChain](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/langchain.md), [LlamaIndex](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/llamaindex.md), [CrewAI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/crewai.md) and [Pydantic AI](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/pydantic-ai.md).

## Install

Node.js 20 or later.

```sh
npm init -y && npm pkg set type=module
npm install @mastra/core zod @x402/fetch@2.28.0 @x402/evm@2.28.0 viem@2.57.4
export ANTHROPIC_API_KEY=...
export ATTESTPAGE_X402_KEY=0x...
```

Any model Mastra supports works: set `MODEL` to its `provider/model` string and the provider's API key. `ATTESTPAGE_X402_KEY` is the private key (`0x` and 64 hex digits) of a wallet holding a little USDC. The key stays in your process.

## agent-http.mjs

```js
// agent-http.mjs: checks quotes with POST /v1/verify/quotes, paying per call with x402.
import { Agent } from '@mastra/core/agent';
import { createTool } from '@mastra/core/tools';
import { AsyncLocalStorage } from 'node:async_hooks';
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';
import { z } from 'zod';

const ORIGIN = process.env.ATTESTPAGE_URL || 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const MAX_UNITS = 20000; // US$0.02 in USDC (6 decimals): the most one call may cost

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const refusedScope = new AsyncLocalStorage(); // the refused list of the one call that is running
client.registerPolicy((_version, reqs) => reqs.filter((r) => {
  const keep = r.network === 'eip155:8453' && Number(r.amount) <= MAX_UNITS;
  if (!keep) refusedScope.getStore()?.push(`US$${Number(r.amount) / 1_000_000} in USDC on ${r.network}`);
  return keep;
}));
const payingFetch = wrapFetchWithPayment(fetch, client);

const verifyQuotes = createTool({
  id: 'verify_quotes',
  description: 'Use before quoting one web page several times: checks 1 to 20 quotes against the page at url. '
    + 'Returns results[i].match (exact, fuzzy or none), page.content_kind and a signed receipt. US$0.02 per call.',
  inputSchema: z.object({ url: z.string(), quotes: z.array(z.string()).min(1).max(20) }),
  execute: async ({ url, quotes }) => {
    const refused = []; // offers the policy turned down during this call
    return refusedScope.run(refused, async () => {
      try {
        const res = await payingFetch(`${ORIGIN}/v1/verify/quotes`, {
          method: 'POST',
          headers: { 'content-type': 'application/json' },
          body: JSON.stringify({ url, quotes }),
        });
        if (res.status === 402) return { error: 'payment required', paymentRequired: res.headers.get('payment-required') };
        return await res.json();
      } catch (e) {
        // payment refused by the policy above, network error: tell the agent why
        if (refused.length) return { error: `${e.message}. Refused offer: ${refused.join('; ')}. This recipe pays at most US$0.02 in USDC on eip155:8453.` };
        return { error: e.message };
      }
    });
  },
});

const agent = new Agent({
  id: 'quote-checker',
  name: 'Quote checker',
  instructions: 'Before you quote a web page, call verify_quotes once with every quote you plan to use from it. '
    + 'Cite a quote only when its match is exact or fuzzy and page.content_kind is real. '
    + 'If the tool returns an error, say what it was and stop.',
  model: process.env.MODEL || 'anthropic/claude-sonnet-5-5',
  tools: { verify_quotes: verifyQuotes },
});

const question = process.argv.slice(2).join(' ')
  || 'Does https://www.iana.org/help/example-domains say "These domains may be used as illustrative examples in documents" and "without prior coordination with us"?';
const result = await agent.generate(question);
console.log(result.text);
```

```sh
node agent-http.mjs   # pays US$0.02 per call in USDC
```

The first request gets a 402 with the price in the `PAYMENT-REQUIRED` header; `@x402/fetch` signs the payment and sends it again. The policy keeps only offers on Base (`eip155:8453`) of at most US$0.02; anything else is refused before anything is signed, and the tool returns the reason, or a 402 that was not paid, as `error`. A request the service refuses (bad URL, empty quote) is refused before payment and not charged.

## What comes back

- `results[i].match`: `exact`, `fuzzy` or `none`, in the order of `quotes`. Read `page.content_kind` first: `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: signed evidence of what the page said and when our fetcher saw it, as a JWS. `POST /v1/receipt/verify` checks it for free, or check it offline with [`verify-receipt.mjs`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-offline). A receipt records what was on the page at that time, not whether a statement on it is correct.
- Try the answer shape first with the free sample: `GET https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes`.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/curl.md

# Check a quote on a web page with curl

Last updated: 2026-10-17

Checks that the words you plan to cite are on a web page. Send the URL and the quote; get back `exact`, `fuzzy` or `none`, with offsets and a signed receipt.

- Route: `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote`
- Price: US$0.01 per call (10 sats). Paid in USDC with x402 v2 on Base.
- Free trial: 10 calls per IP address per day, no key. Send the header `Quoteproof-Trial: 1`.
- For 3 or more quotes on one page: `POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quotes`, US$0.02 for 1 to 20 quotes.

## Free trial

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote \
  -H 'Content-Type: application/json' \
  -H 'Quoteproof-Trial: 1' \
  -d '{"url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents"}'
```

## Paid call

A call with no payment gets `402 Payment Required`. The price and the payment terms are in the `PAYMENT-REQUIRED` header, as base64 JSON.

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote \
  -H 'Content-Type: application/json' \
  -d '{"url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents"}'
```

curl cannot sign a payment. To pay, send the same request with an x402 v2 client: the Node example (node.mjs) or the MCP config (mcp.md) in this folder.

## Read the answer

- `match`: `exact`, `fuzzy` or `none`, in the order of the request.
- `page.content_kind`: check this first. `none` on a `bot_wall` or `js_shell` page means the page could not be read.
- `receipt`: a signed JWS of what the fetcher saw and when.

A request with a bad URL or an empty quote is refused before payment and not charged.

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/examples/mcp.md

# Check quotes from an MCP client

Last updated: 2026-10-17

`quoteproof-mcp` is an MCP server (stdio) with one tool per route. It needs Node.js 20.3 or later and no install step: `npx` runs it.

- Tool for a single quote: `attestpage_verify_quote` (route `POST /v1/verify/quote`), US$0.01 per call.
- Tool for 1 to 20 quotes on one page: `attestpage_verify_quotes` (route `POST /v1/verify/quotes`), US$0.02 per call.
- Free trial: 10 calls per IP address a day, no key needed.

## Config

Most MCP clients take a block like this:

```json
{
  "mcpServers": {
    "quoteproof": {
      "command": "npx",
      "args": ["-y", "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/quoteproof-mcp-0.1.49.tgz"],
      "env": { "QUOTEPROOF_URL": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us" }
    }
  }
}
```

With no key the server uses the free trial. Once the trial is used up, the tool returns the price and stops.

## Paying

Add a Base wallet key to pay in USDC. The key stays in the MCP server's process.

```json
"env": {
  "QUOTEPROOF_URL": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us",
  "QUOTEPROOF_X402_KEY": "0x...",
  "QUOTEPROOF_NETWORKS": "eip155:8453",
  "QUOTEPROOF_MAX_USD": "0.02"
}
```

- `QUOTEPROOF_NETWORKS` lists the networks the server will pay on (Base, `eip155:8453`).
- `QUOTEPROOF_MAX_USD` caps the price of one call. An offer above the cap is refused locally and nothing is signed.

## Remote endpoint

No local process: point the client at `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp` (streamable HTTP).

```json
{
  "mcpServers": {
    "quoteproof": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

The remote endpoint uses the free trial, then returns the payment requirements. To pay over HTTP, put an x402 payment payload in `_meta["x402/payment"]` of the tool call. See [MCP server](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/mcp).

## Terms

Pay per call, no account. See [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments), [Limits](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits) and the [Terms](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/how-it-works.md

# How it works

Last updated: 2026-10-10

How AttestPage fetches a page, what each `content_kind` verdict means, and what a signed receipt records about the fetch.

## The fetcher

When a route reads a page, our fetcher requests the URL you sent:

- GET only, with no cookies, logins or headers passed through from you. User agent `QuoteproofBot/1.0 (+https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/bot)`.
- http and https on ports 80 and 443. Private, loopback and other internal addresses are refused; the address is resolved once and the connection is pinned to it, and each redirect is checked again.
- Up to 5 redirects, 5 seconds to connect, 10 seconds in all, 2 MB of body.
- HTML, XHTML, plain text and JSON. PDFs too, for `fetch`, `verify/quote`, `verify/quotes` and `verify/citations`: the text layer only (no OCR, so a scanned page has no text), and each match gives its page number. No JavaScript is run.
- robots.txt and our opt-out list are honoured; see [Our fetcher](/bot).
- No proxies and no attempt to get past CAPTCHAs or bot checks. A challenge page is reported as `bot_wall`.

Pages are not stored. The text is extracted, hashed, matched, and dropped when the response is sent.

## content_kind

Every page result has one `content_kind`, from automated rules over the status, headers and text. They can be wrong; `signals` lists the clues behind each verdict.

check/links also gives each URL a link verdict: `ok`, `broken`, `moved` or `unknown`. It is about the link (did it resolve, move, or fail), not the page content, so it is separate from `content_kind`.

| content_kind | Meaning |
|---|---|
| `real` | The page loaded and looks like real content. |
| `bot_wall` | The site served a bot challenge to our fetcher. Do not treat this as the page's content. |
| `js_shell` | The page needs JavaScript to show its content; the text we read is mostly empty scaffolding. |
| `paywall` | The page appears to be behind a paywall or login; the text may be a teaser only. |
| `empty` | The page loaded but has little or no readable text. |
| `off_site` | The URL redirected to a different site; the content is from that site. In check/links, `off_site_error: true` marks one whose site answers 4xx/5xx. |
| `http_error` | Error status, or a connection problem (signals such as `outcome_dns_error`, `outcome_connect_error`). |
| `unsupported_type` | Not HTML, text, JSON or a readable PDF, so not read. A PDF we could not read has the signal `pdf` and one of `pdf_encrypted` (needs a password), `pdf_invalid` (damaged or not a PDF), `pdf_over_budget` (needs more memory than we allow), `pdf_timeout` or `pdf_out_of_memory`. |
| `pdf` | check/links only: a live PDF link (status 2xx, `application/pdf`, same site), not read. In check/links an unread link with a 4xx/5xx status is `http_error` and one redirected to another site is `off_site` (with `off_site_error: true` if that site answers 4xx/5xx). |
| `robots_disallowed` | robots.txt or an opt-out disallows our fetcher. |
| `timeout` | The site did not answer in time. |
| `too_large` | Over the 2 MB cap, so not read in full. |

## injection_flags

Patterns often used for prompt injection, found in the page text: `instruction_override`, `role_reassignment`, `prompt_markers`, `prompt_extraction`, `addresses_ai`, `command_execution`, `exfiltration_request`, plus `hidden_instructions` when a match is in text a browser does not show. They are flags, not a verdict. An empty list means none of our patterns matched.

## Receipts

Every paid answer carries a `receipt` (with `receipt_id`, and the settled `payment.tx` once the payment settles; see [verify a receipt](/docs/receipt-verify.md)): a compact JWS signed with Ed25519 (`alg` EdDSA, `typ` `attestpage-evidence+jws`). The key id is `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json#ap-<thumbprint>`, where `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us` is the fixed issuer address (it stays the same when the service address changes); the public keys are at [/.well-known/jwks.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json) and [/.well-known/did.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/did.json).

Payload fields (version 1):

| Field | Meaning |
|---|---|
| `v` | schema version, 1 |
| `iss` | `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us` |
| `iat` | signing time, Unix seconds |
| `kind` | `quote`, `quotes`, `citations`, `document`, `fetch`, `links`, `packages` or `attest` |
| `request_sha256` | SHA-256 of your request body as canonical JSON |
| `quote_sha256` | SHA-256 of the quote (quote receipts) |
| `url`, `final_url`, `http_status`, `content_kind` | what was requested and what came back |
| `content_sha256` | SHA-256 of the full extracted text |
| `raw_sha256` | SHA-256 of the body bytes as received |
| `retrieved_at` | when the page was fetched |
| `server_ip` | the vetted IP address our fetcher connected to for the final response (the site's address, not yours) |
| `tls` | the site's certificate on the final response over HTTPS: `cert_sha256` (SHA-256 of the DER certificate), `issuer`, `subject` (each up to 1,024 bytes), `valid_from`, `valid_to`; null over plain HTTP |
| `headers` | these response headers when the site sent them: `date`, `last-modified`, `etag`, `content-type`, `content-length` (each up to 512 bytes) |
| `result` | the route's result (match, signals, per-link results, per-page and per-citation results, or attestation) |
| `tier` | `paid`, `trial` or `sample` |
| `payment` | paid calls: rail, network, asset, amount, payer, payment_id (L402: payer null, payment_hash and preimage); otherwise null |

`server_ip`, `tls` and `headers` are on fetch and quote receipts and on each entry of a links receipt and each page of a citations receipt. They are null when no response came back, and always null on an edge server, which cannot pin the connection to an IP or read the certificate. Those byte caps count the value as UTF-8 once JSON-encoded (a `"` or `\` counts 2, a CJK character 3); a longer value is cut on a whole character and ends with `…`. Receipts issued before these fields existed do not have them and still verify.

A receipt records what our fetcher saw at that time. Pages change, and a page can show different content to different visitors. It does not show that anything the page says is correct.

Check receipts with [POST /v1/receipt/verify](/docs/receipt-verify) or [offline](/docs/verify-offline).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/limits.md

# Limits

Last updated: 2026-10-17

## Requests

| Limit | Value |
|---|---|
| Request body | 64 KB; 168 KB for `receipt/verify` and `/mcp` (413 `body_too_large`) |
| URL length | 2,048 characters, http or https, ports 80 and 443 |
| Quote | 1,000 characters after normalisation |
| Quotes per `verify/quotes` call | 20 |
| Citations per `verify/citations` call | 10 |
| `verify/document`: document size, pairs per document, pairs per part | 60,000 bytes; 100 (the rest skipped as `beyond_limit`); 10 |
| URLs per `check/links` call | 10 |
| Free-trial calls per IP address per UTC day (`Quoteproof-Trial: 1`) | 10; callers that reach the service through the srv.us address without a payer id each get 10 a day (told apart by their user-agent); a request with none of those headers shares one pool of 10 a day, then 429 `trial_exhausted`, not charged |
| Citations, quotes, pairs or URLs per free-trial call (`verify/citations`, `verify/quotes`, `verify/document`, `check/links`) | 5; a larger batch gets the normal 402 offer (`details.reason` `trial_too_large`) |
| Packages per `check/packages` call | 10 |
| Attest note | 280 characters |
| Receipt sent to `receipt/verify` | 163,840 characters (160 KB; a receipt with every field at its cap is about 128 KB, whatever characters the site's certificate names and headers use) |

## Fetching

| Limit | Value |
|---|---|
| Redirects | 5, each checked again |
| Connect timeout | 5 seconds |
| Total timeout | 10 seconds |
| Body size | 2 MB as received, 2 MB after decompression |
| Content types | HTML, XHTML, plain text, JSON |
| PDF | `fetch`, `verify/quote`, `verify/quotes` and `verify/citations` only. Text layer only, no OCR; the body cap above applies. Up to 1,000 pages and 2,097,152 characters (then signal `pdf_truncated`). Each PDF gets 5 seconds and 64 MB of buffers plus a 64 MB heap (else `pdf_timeout`, `pdf_over_budget` or `pdf_out_of_memory`, charged like any page we cannot read). 2 PDFs are read at once across all callers, with a queue of 16; then 503 `over_capacity` (`details.reason` `pdf_queue_full`) with `Retry-After`, not charged |
| Text returned by `fetch` | 20,000 characters per page (hashes cover the full text) |
| URLs in one `fetch` call (`urls`) | 10, each priced as one fetch; 5 on a free trial call |
| robots.txt | cached up to 1 hour; 5-second timeout |

## Rates

| Limit | Value |
|---|---|
| Per caller IP address | 60 paid-route requests a minute |
| `verify/citations`, `verify/quotes` and `verify/document` calls where every citation or quote fails (422, not charged), per caller IP address, counted together | 6 a minute, counting batches still running; then 429 with `details.reason` `uncharged_failures` |
| `verify/citations`, `verify/quotes` and `verify/document` calls being matched, across all callers, shared | 2 at once, with a queue of 8; then 503 `over_capacity` with `Retry-After`, not charged |
| Per target host | 1 request a second and 30 a minute, across all callers |
| crates.io lookups (`check/packages`) | 1 a second across all callers; a call that would wait over 20 seconds gets 429; free trial calls hold at most half of that queue |
| Whole service | 8 fetches at once, with a queue of 32 |
| Lightning (L402) invoices, where L402 is on | 30 unpaid per caller IP address in 10 minutes, 1,000 open in all. An invoice whose request you then pay with x402 does not count |

Over a limit you get 429 `rate_limited` with a `Retry-After` header, before any payment is asked for. Back off for the time it gives.

## What the fetcher does not do

- Run JavaScript, use proxies or rotate IP addresses.
- Solve or get past CAPTCHAs or bot checks.
- Send cookies, logins or your headers.
- Reach private or internal addresses.
- Fetch pages that robots.txt or our opt-out list disallows.

## Network

Payments run on Base. See [Payments](/docs/payments).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/errors.md

# Errors

Last updated: 2026-10-10

Every error code the API can return, what it means and whether the call was charged. All errors share one JSON shape:

```json
{ "error": { "code": "invalid_url", "message": "url: …. You were not charged.", "details": { "field": "url" } } }
```

`code` is stable and meant for programs; `message` is for people; `details` is optional (for example `field` or `retry_after_ms`). An answer with status 400 or above is never charged (with L402, the token is not spent and still works). The one exception is `settle_failed`: the payment may have gone through even though settling reported a failure. Resend the same request with the same payment id (the x402 `payment-identifier` extension), or without a payment id with the same signed payment (the same `PAYMENT-SIGNATURE` header): if the charge went through, you get the withheld result without paying again (marked `payment-redelivered: true`); if not, the payment is settled at most once. A charge that went through is also recorded for reconciliation. So a `payment_already_used` answer can follow a charged `settle_failed`; that call itself charged nothing.

| Status | Code | Meaning |
|---|---|---|
| 400 | `bad_request` | Body is not a JSON object, or a field has the wrong type. |
| 400 | `invalid_request` | A field is missing or out of range (for example a quote over 1,000 characters), or both an x402 payment header and an L402 `Authorization` header or a credit key were sent (`details.reason` `two_payment_headers`). |
| 400 | `invalid_url` | The URL is malformed, too long, not http(s) or on another port; `details.reason` says which. |
| 400 | `blocked_target` | The URL points at a private, loopback or otherwise internal address. |
| 400 | `baseline_invalid` | `POST /v1/recheck`: the receipt sent as a baseline does not verify against this service's keys, or is not a fetch, verify/quote or recheck receipt, is a sample, or names no URL; `details.reason` says which (`malformed`, `unknown_kid`, `bad_iss` and the other `/v1/receipt/verify` reasons, or `kind`, `sample`, `no_url`). Never charged. |
| 402 | `payment_required` | Pay with x402: see the `PAYMENT-REQUIRED` header and [Payments](/docs/payments). Where L402 is on, the `WWW-Authenticate: L402` header carries a macaroon and a Lightning invoice too. A free-trial call to `verify/citations`, `verify/quotes`, `verify/document` or `check/links` with more than 5 citations, quotes, pairs or URLs gets this too, with `details.reason` `trial_too_large`: pay for it, or send at most 5 per trial call. On a route with a free trial, `details.trial` says how to use it: `header` (`quoteproof-trial`) and `value` (`1`) are the header to send instead of a payment; `per_day` is the free calls per caller per UTC day; `max_batch_items` (5) is the most citations, quotes, pairs or URLs one trial call may carry; `how` says the same in a sentence. Over `per_day`, the trial answers 429 `trial_exhausted`. |
| 402 | `payment_invalid` | The payment did not verify (`details.reason` says why). Sign a new one from the `PAYMENT-REQUIRED` header. For an L402 token the reason starts with `l402_` (for example `l402_wrong_route`, `l402_expired`, `l402_preimage_mismatch`) and a fresh `WWW-Authenticate` offer is included. A resend for a withheld `settle_failed` result whose signature is not the payer's own gets this with `details.reason` `invalid_exact_evm_payload_signature`: resend the original signed payment, or a new one signed with the payer's key. |
| 403 | `robots_disallowed` | robots.txt or our opt-out list disallows the page (or a redirect from it). |
| 403 | `payer_refused` | The paying address is on a sanctions list. For a credit key: a payment to it came from a listed address, so the key is blocked (`details.reason` `credits_payer_refused`). |
| 404 | `not_found` | No such route or sample, or (`GET /v1/credits`) no such credit key. |
| 405 | `method_not_allowed` | A route called with the wrong method. A GET or HEAD on a POST route gets 405 with `Allow: POST`, a `Link` header (`rel="service-doc"`) pointing to this page, and `details.openapi` pointing to [/openapi.json](/openapi.json). Never charged. |
| 409 | `payment_id_conflict` | The payment id was already used for a different request. |
| 409 | `payment_already_used` | This payment signature was already spent, and this call did not charge again. Sign a new payment; the `PAYMENT-REQUIRED` header is included. If an earlier call with it ended in `settle_failed`, resend that request with its payment id to get the result. Without a payment id, the same request with the same signed payment (the same `PAYMENT-SIGNATURE` header) gets the stored result again (marked `idempotent-replayed: true` for a settled call, `payment-redelivered: true` after `settle_failed`); the same signature with a different request gets this 409. `details.reason` `result_not_kept`: that earlier call was charged but its result is no longer kept; the charge is recorded for reconciliation. For L402: the token already paid for another call (`details.reason` `l402_spent`); pay the fresh invoice in `WWW-Authenticate`. |
| 409 | `settle_pending` | An earlier call with this payment id ended in `settle_failed`, it is not charged on chain yet, and its payment could still go through. Resend the same signed payment now, or a new one after `Retry-After` (`details.retry_after_ms`). |
| 409 | `idempotency_conflict` | The attest `idempotency_key` was already used with a different hash or note. |
| 413 | `body_too_large` | Body over 64 KB (168 KB on `receipt/verify`, `recheck` and `/mcp`). |
| 422 | `host_not_found` | The URL's host name does not resolve (for `check/links` and `verify/citations`: none of the URLs resolves; for `verify/document`: none in the part). |
| 422 | `page_too_large_for_edge` | Edge server only: the page is over the 64 KB it reads, or (check/packages) a registry answer is over the 256 KB it reads, with only the names over that size in `details.too_large` (no results for the others); `details.full_service` is the server to send the call to. |
| 422 | `edge_subrequest_limit` | Edge server only: the call needs more outbound requests than the edge allows (many hosts or redirects); use `details.full_service`. |
| 422 | `match_too_costly` | Fuzzy matching this quote would take too long; use `"match": "exact"` or a shorter quote. For `verify/citations` and `verify/quotes` this is an `error` on that citation or quote only and the call is charged; only when every one fails does the call get 422, with `details.failed` listing them. `verify/document` works the same way per part. |
| 422 | `robots_too_large` | `POST /v1/access-check` only: the robots.txt for this site declared over 2 MB, so its rules cannot be judged; `details.robots_url` is the file. Never charged. |
| 422 | `no_pairs` | `verify/document`: no quote with a link was found in the document; `details.skipped` counts what was skipped and why. Never charged. |
| 429 | `rate_limited` | Too many requests to that host or from your address, or (for `check/packages`) the crates.io queue of one lookup a second is full; see `Retry-After`. Where L402 is the only offer, also too many unpaid Lightning invoices (`details.reason` `l402_invoice_cap`). For `verify/citations`, `verify/quotes` and `verify/document` (one shared count), also too many calls from your address that failed uncharged (`details.reason` `uncharged_failures`). |
| 429 | `trial_exhausted` | Free trial calls used up for the day; see `Retry-After`. |
| 500 | `internal_error` | Something failed on our side. |
| 502 | `registry_unavailable` | `check/packages` only: every registry lookup in the batch failed (`details.reasons`), so nothing was charged. Try again later. |
| 502 | `facilitator_unavailable` | The payment facilitator could not be reached, so no payment was taken. Try again later. |
| 502 | `upstream_unreachable` | `/v1/fetch` and `/v1/recheck`: the call read no page (`details.reason` is `timeout`, `connect_error`, `decode_error`, `too_many_redirects` or `redirect_refused`), so nothing was charged. In a batch, no URL read a page (`details.reasons`). Try again later, or check the URL. |
| 502 | `robots_unreachable` | `POST /v1/access-check` only: no robots.txt for this site could be read (`details.outcome` says why: timeout, connect error, blocked redirect and so on), so no verdict is given. Never charged. |
| 502 | `settle_failed` | The work ran but the payment could not be settled, so the result is withheld. Resend the same request with the same payment id, or without a payment id with the same signed payment (the same `PAYMENT-SIGNATURE` header): if the charge went through on chain, you get the result without paying again; if not, the payment is settled at most once. If a charge went through, it is recorded for reconciliation. Redelivery runs on the full service only; on the edge server see [Payments](/docs/payments). |
| 501 | `not_on_edge` | Edge server only: `POST /v1/attest`, `POST /v1/verify/citations`, `POST /v1/verify/quotes` and `POST /v1/verify/document` run on the full service (the free `verify/document/preview` works on the edge) (`details.full_service`). Also `fetch` and `verify/quote` when the page is a PDF (`details.reason` `pdf`, with `details.final_url`): only the full service reads PDFs. Never charged. |
| 503 | `paused` | Paid routes are paused for maintenance. |
| 503 | `over_capacity` | `verify/citations`, `verify/quotes` and `verify/document`: too many batches are waiting to be matched (`details.reason` `match_queue_full`). `fetch`, `verify/quote`, `verify/quotes` and `verify/citations`: the page is a PDF and too many PDFs are waiting to be read (`details.reason` `pdf_queue_full`, with `details.field`). Retry after `Retry-After`. Never charged, even when it comes after your payment was verified. |
| 503 | `signing_unavailable` | Signing keys are not loaded on this server, so no receipt can be signed or checked. Nothing was charged. |
| 503 | `payments_unavailable` | Payments are not set up on this server, (with L402 only) no invoice could be made, or a new payment for a payment id whose earlier call ended in `settle_failed` came while the chain could not be read. Where credit keys are on, also: no credit address could be issued (the signet explorer is down, the server's addresses are used up, or too many issued addresses are still unpaid: `details.reason` `credits_gap_full`). |
| 503 | `sanctions_list_stale` | Edge server only: its built-in sanctions list is more than 8 days old, so it refuses payments until it is rebuilt (`details.list_date`, `details.full_service`). Never charged. |
| 503 | `payment_screening_unavailable` | The payment check could not be completed (the chain read failed or timed out, or the sanctions list could not be read); retry after `Retry-After` and do not pay again. For a credit key that needs a new payment counted: `details.reason` `credits_screening_unavailable`. |

## L402 reasons

Where L402 is on, a token that is refused carries one of these in `details.reason`. None of them spends the token or charges anything.

| Reason | Code | Meaning |
|---|---|---|
| `l402_malformed` | `payment_invalid` | The `Authorization: L402 <macaroon>:<preimage>` header or the macaroon cannot be read. |
| `l402_bad_signature` | `payment_invalid` | The macaroon was not issued by this server, or was changed after it was issued. |
| `l402_bad_version` | `payment_invalid` | The macaroon identifier has a version this server does not issue. |
| `l402_unknown_caveat` | `payment_invalid` | The macaroon has a caveat this server does not understand. |
| `l402_missing_caveat` | `payment_invalid` | The macaroon lacks its `route`, `price` or `expires` caveat. |
| `l402_wrong_route` | `payment_invalid` | The token was issued for a different route. |
| `l402_price_mismatch` | `payment_invalid` | The token's price is below this route's sats price. |
| `l402_expired` | `payment_invalid` | The token's `expires` time has passed. |
| `l402_preimage_mismatch` | `payment_invalid` | The preimage does not hash to the invoice's payment hash (the invoice was not paid). |
| `l402_spent` | `payment_already_used` | The token already paid for a different call. |
| `l402_invoice_cap` | `rate_limited` | No new Lightning invoice: too many unpaid ones from your address (see [Limits](/docs/limits)) (`details.scope` `ip`) or open on the server (`global`). Wait for `Retry-After`. When x402 can be offered, the answer is instead the usual 402 `payment_required` with the x402 offer, no L402 offer, this reason and `Retry-After`. |
| `two_payment_headers` | `invalid_request` | Both an x402 payment header and an L402 `Authorization` header were sent. |

## Credit key reasons

Where prepaid credit keys are on (`POST /v1/credits/order`, then `Authorization: Bearer qpc_…` on a paid route; Bitcoin signet, full service only), a refusal carries one of these in `details.reason`. None of them takes sats from the key. Before a payment to a key's address is credited, every input address of that payment is checked against the OFAC sanctions list; a payment with an input that has no address (a coinbase or bare script) cannot be checked and is held (`held_sats`, status `held`), not credited.

| Reason | Code | Meaning |
|---|---|---|
| `credits_amount` | `invalid_request` | `POST /v1/credits/order`: `sats` is not a whole number from `details.min_sats` to `details.max_sats`. |
| `credits_order_cap` | `rate_limited` | Too many credit orders from your address in the last hour; pay a key you have, or wait for `Retry-After` (`details.retry_after_ms`). |
| `credits_gap_full` | `payments_unavailable` | `POST /v1/credits/order`: too many credit addresses in a row are still waiting for payment, so no new one is issued until one is paid or expires unpaid (see [Payments](payments.md)). Pay a key you already have, or try again later. |
| `credits_no_key` | `invalid_request` | `GET /v1/credits` without `Authorization: Bearer <credit key>`. |
| `credits_malformed` | `payment_invalid` on a paid route, `not_found` on `GET /v1/credits` | The `qpc_` key is not 47 characters of base64url. |
| `credits_unknown_key` | `payment_invalid` on a paid route, `not_found` on `GET /v1/credits` | This server never issued that key. |
| `credits_insufficient` | `payment_required` | The key has fewer confirmed, screened sats available than the route's price (`details.price_sats`); `details` also carries the key's `address`, `status` and balances. Pay the address again to top up. |
| `credits_payer_refused` | `payer_refused` | A payment to the key's address came from an address on the sanctions list: the key is blocked for good and that payment is not credited. |
| `credits_screening_unavailable` | `payment_screening_unavailable` | The key has fewer sats than the price, and its address could not be read and screened now (the chain read failed or timed out, or the sanctions list cannot be read), so a new payment may not be counted yet. Do not pay again: retry after `Retry-After` (`details.retry_after_ms`). Sats already credited still work. |
| `two_payment_headers` | `invalid_request` | A credit key was sent with an x402 payment header. |

## Result lost

`result_lost`: a charge was taken but the result could not be delivered. The refund is recorded as due and paid by hand in USDC to the paying address, with no time limit. Contact us with the transaction id.

## Results that are not errors

A 404, 500, bot wall, timeout or dead link on the page you asked about is a result, not an error. It comes back with status 200, a `page.content_kind` such as `http_error` or `bot_wall`, and a receipt, and it is charged. See [How it works](/docs/how-it-works).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides.md

# Guides

Last updated: 2026-10-17

Step-by-step guides for AttestPage. Each one shows the price, the calls step by step, how to read the answer, and the same call as an MCP tool.

- [How to get a signed timestamp that shows a file did not change, step by step with curl](/guides/attest-a-file-hash): To show later that a file, answer or record existed unchanged, send its SHA-256 hash to POST /v1/attest (US$0.002 per call).
- [How to check a signed receipt before you rely on it, step by step with curl](/guides/check-a-receipt-before-relying-on-it): To check that a receipt really came from AttestPage and was not altered, send it to POST /v1/receipt/verify. It is free: no payment, account or key.
- [How to check every quote in a Markdown document from a CI job before merge, step by step with curl](/guides/check-documents-in-ci): To check every quote in a Markdown file from a CI job before it merges, send the file to POST /v1/verify/document, one part of up to 10 quote and link pairs…
- [How to check links before citing them, step by step with curl](/guides/check-links-before-citing): To check that the links you are about to cite are live, send up to 10 of them to POST /v1/check/links (US$0.005 per batch).
- [How to check many quotes against one page in a single call, step by step with curl](/guides/check-many-quotes-on-one-page): To check up to 20 quotes against the same web page, send the URL and the quotes to POST /v1/verify/quotes (US$0.02 per call).
- [How to check a package's licence before installing it, step by step with curl](/guides/check-package-licences-before-installing): To read the licence of a package an agent is about to install, send up to 10 names to POST /v1/check/packages (US$0.005 per batch).
- [How to check packages before installing them, step by step with curl](/guides/check-packages-before-installing): To check that a package an LLM suggested really exists, send up to 10 names to POST /v1/check/packages (US$0.005 per batch).
- [Check every quote in a draft before you publish](/guides/check-quotes-before-publishing): A quote that does not appear on its source page is the most common error in an AI-written draft. Before you publish, check each quote against the page it cites.
- [How to fetch a web page as clean text from code, with an x402 client](/guides/fetch-a-page-with-an-x402-client): To give an agent a web page without its markup, scripts and menus, send its URL to POST /v1/fetch with "return_text": true (US$0.002 per page).
- [How to turn a web page into clean text for an agent, step by step with curl](/guides/read-web-page-as-clean-text): To read a web page without its markup, scripts and menus, send its URL to POST /v1/fetch with "return_text": true (US$0.002 per page).
- [How to check whether a web page has changed since you read it, step by step with curl](/guides/recheck-page-for-changes): To find out whether a page you read earlier still says the same thing, send its receipt (or its URL and text hash) to POST /v1/recheck (US$0.003 per call).
- [How to get a signed receipt of a web page, step by step with curl](/guides/signed-page-receipt): To get a signed, timestamped receipt of what a web page showed, send its URL to POST /v1/fetch (US$0.002 per call).
- [How to check a quote against text you already hold, step by step with curl](/guides/use-attestpage-text-quote): To check that a quote really appears in a text you already have, such as a file you read, a tool result or a document, send the text and the quote, word for…
- [How to use AttestPage tools from an MCP client, step by step with curl](/guides/use-attestpage-tools-in-mcp): To give an MCP client the AttestPage tools, add the remote endpoint https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp.
- [How to check the citations at the end of an answer before you send it, step by step with curl](/guides/verify-citations-before-answering): To check up to 10 citations in one call, send each quote and the URL it is attributed to to POST /v1/verify/citations (US$0.10 per batch).
- [How to check every quote in a draft before publishing, step by step with curl](/guides/verify-document-before-publishing): To check every quote in a finished answer or report before it goes out, send the whole text to POST /v1/verify/document (US$0.10 per part of up to 10 pairs).
- [How to check a quote an LLM cites, step by step with curl](/guides/verify-llm-quote): To check that a quote an LLM cites really appears on the source page, send the page URL and the quote, word for word, to POST /v1/verify/quote (US$0.01 per…

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-a-quote-an-llm-cites.md

# How to verify a quote an LLM cites

Last updated: 2026-10-10

To check a quote an LLM attributes to a web page, fetch that page yourself and search its text for the quote, allowing for small differences in punctuation and spacing. `POST /v1/verify/quote` does this in one call (US$0.01): it answers `exact`, `fuzzy` or `none`, says whether the page loaded as real content, and signs a receipt.

## Why a quick check is not enough

LLMs often produce quotes that are close to the source but not on it: a word changed, two sentences joined, or a line from a different page. A plain `fetch` and string search misses three things:

- **Small differences.** Curly quotes, dashes, line breaks and invisible characters make an exact search fail on a quote that is really there. We normalise both texts (Unicode NFKC, plain quotes and dashes, one space for any whitespace) and also accept close matches above a threshold you set.
- **Pages that did not load.** A bot challenge, a JavaScript shell, a paywall or an error page has no quote on it either. A `none` on such a page means the page could not be read, not that the quote is absent. Every answer carries a `content_kind` verdict so you can tell the two apart.
- **No record.** If someone later asks where the quote came from, you have nothing to show. The signed receipt records the URL, the time, the hash of the page text and the match.

## One quote

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote
```

That free sample runs the paid route on a demo page. A real call sends the URL and the quote:

```json
{ "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" }
```

Read `page.content_kind` first, then `result.match`. Full details: [Verify a quote](/docs/verify-quote). Step by step with `curl`, from the free sample to checking the receipt: [How to check a quote an LLM cites, step by step with curl](/guides/verify-llm-quote).

## Pay per call with x402

No account or key is needed. A valid request with no payment gets `402 Payment Required` with the price in a `PAYMENT-REQUIRED` header; an x402 v2 client signs that offer and sends the request again. With `@x402/fetch` (`npm install @x402/fetch @x402/evm viem`) and a Base wallet holding a little USDC (real money):

```js
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const payingFetch = wrapFetchWithPayment(fetch, client);

const res = await payingFetch('https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ url: 'https://www.iana.org/help/example-domains', quote: 'These domains may be used as illustrative examples in documents' }),
});
const answer = await res.json();
console.log(answer.page.content_kind, answer.result.match);
```

The wrapper signs the offer it gets. To check the price and network before signing, see [One x402 payment step by step](/docs/examples/fetch-x402).

## Every citation in an answer

`POST /v1/verify/citations` (US$0.10 per batch) takes up to 10 quote and URL pairs, fetches each page once and returns the same verdict for each citation under one receipt. Run it on the sources at the end of an answer before the user sees it. Details: [Verify citations](/docs/verify-citations).

## The LLM paraphrased instead of quoting

Send `"match": "passages"` and the claim as `quote`. You get the 3 passages of the page that share most of its words, to judge yourself; it is evidence to read, not a verdict. Try it free: [`GET /v1/sample/quote?match=passages`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote?match=passages).

## Questions

### Does a match mean the quote is correct?

No. A match means the words are on the page our fetcher saw at that time. It says nothing about whether the page itself is right.

### What if the page blocks bots?

The answer says so: `content_kind` is `bot_wall`, `js_shell` or `paywall`, and the advice field explains it. Treat the quote as unchecked, not as false.

### Can an agent call this without an account?

Yes. Calls are paid per call with x402 (USDC on Base), there is a small free trial, and the [MCP server](/docs/mcp) exposes the same check as a tool.

### How do I check the receipt later?

With [POST /v1/receipt/verify](/docs/receipt-verify), or offline with our single-file checker: [Verify receipts offline](/docs/verify-offline).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/verify-llm-quote.md

# How to check a quote an LLM cites, step by step with curl

Last updated: 2026-10-10

To check that a quote an LLM cites really appears on the source page, send the page URL and the quote, word for word, to `POST /v1/verify/quote` (US$0.01 per call). AttestPage fetches the live page, searches its text for the quote and answers `exact`, `fuzzy` or `none`, with a verdict on the page and a signed receipt.

This guide runs the check with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For why a plain string search falls short, see [How to verify a quote an LLM cites](/docs/verify-a-quote-an-llm-cites).

## What the check does

- **Fetches the page.** It follows redirects and reads the page text as our fetcher receives it at that moment.
- **Matches the quote.** Both texts are normalised first (Unicode NFKC, plain quotes and dashes, one space for any whitespace). `exact` means the words are there after normalisation; `fuzzy` means a close match scored at or above `threshold` (default 0.9); `none` means neither.
- **Judges the page.** `page.content_kind` is `real` when the page loaded as content, or `bot_wall`, `js_shell`, `paywall`, `http_error` and others when it did not.
- **Signs a receipt.** An Ed25519 receipt records the URL, the time, the page hashes and the match. Anyone can check it later against our published keys.

## Price

US$0.01 per call, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample runs the same route on a demo page:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote | jq '{match: .result.match, score: .result.score, kind: .page.content_kind, advice}'
```

```json
{
  "match": "fuzzy",
  "score": 0.963,
  "kind": "real",
  "advice": "The page loaded and looks like real content."
}
```

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `10000` is US$0.01.

## 3. Check a quote

Put the cited URL and the quote, exactly as the LLM gave it, in a file:

```sh
cat > body.json <<'EOF'
{ "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json` for the steps below.

There is no free trial at the moment; use the free samples instead.

## 4. Read the answer

Read `page.content_kind` first, then `result.match`:

| `content_kind` | `match` | What it means |
|---|---|---|
| `real` | `exact` | The quoted words are on the page. |
| `real` | `fuzzy` | A close match. Compare `context` with the quote: a word may have been changed or two sentences joined. |
| `real` | `none` | The quote is not on the page our fetcher received. Do not cite it to this source. |
| `bot_wall`, `js_shell`, `paywall`, `http_error` | any | The page could not be read. The quote is unchecked, not false. |

If the LLM paraphrased rather than quoted, send `"match": "passages"` with the claim as `quote`. You get the 3 passages that share most of its words, as evidence to read, not a verdict. Details: [Verify a quote](/docs/verify-quote).

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Or check it offline with our single-file checker: [Verify receipts offline](/docs/verify-offline).

## With MCP

The same check is the MCP tool `attestpage_verify_quote`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_verify_quote",
    "arguments": { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "10000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does one check cost?

US$0.01 per quote with `POST /v1/verify/quote`. To check up to 10 quotes from one answer in one call, `POST /v1/verify/citations` costs US$0.10 per batch: [Verify citations](/docs/verify-citations).

### Does an exact match mean the quoted claim is right?

No. It means those words were on the page our fetcher received at that time. Whether the page itself is right is a separate question.

### Is a call charged if the page will not load?

Only answers below 400 are charged. A request that fails validation, a host name that does not resolve and a blocked URL are never charged. A page that answers with a 404 or a bot wall is charged, because that result is what the call checks; `content_kind` says so. Every case is in [Payments](/docs/payments) and [Errors](/docs/errors).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/verify-document-before-publishing.md

# How to check every quote in a draft before publishing, step by step with curl

Last updated: 2026-10-13

To check every quote in a finished answer or report before it goes out, send the whole text to `POST /v1/verify/document` (US$0.10 per part of up to 10 pairs). AttestPage finds each quote and the link it points to, fetches each live page, and answers `exact`, `fuzzy` or `none` for every pair, with the verdict on each page and one signed receipt for the whole part.

This guide runs the check with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`. For checking a single quote, see [How to check a quote an LLM cites](/docs/verify-a-quote-an-llm-cites).

## What the check does

- **Finds the quotes.** Text between quotation marks that has a link after it, inline or as a reference, is a pair. Code blocks are ignored. The rules are fixed and named by `extractor` (`doc-v1`) in every answer.
- **Fetches each page once.** Each distinct URL is fetched once per part, following redirects.
- **Matches each quote.** Both texts are normalised first. `exact` means the words are there; `fuzzy` means a close match at or above `threshold` (default 0.9); `none` means neither.
- **Judges each page.** `content_kind` is `real` when the page loaded as content, or `bot_wall`, `js_shell`, `paywall`, `http_error` and others when it did not.
- **Signs a receipt.** One Ed25519 receipt covers the document's hash, the options and each pair's verdict. It does not contain the quote text.

## Price

US$0.10 per part of up to 10 pairs, paid in USDC with x402 v2 on Base Sepolia (a test network). A document with 10 quotes or fewer is one part. No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. Preview the pairs for free

The preview is free and changes nothing. It lists every pair it found, what was skipped and why, the number of parts and the exact price. Put the draft in a file:

```sh
cat > document.json <<'EOF'
{ "document": "WHO says \"Air pollution kills an estimated seven million people every year\" ([WHO](https://www.who.int/health-topics/air-pollution)).", "format": "markdown" }
EOF
```

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document/preview -H 'content-type: application/json' -d @document.json \
  | jq '{pairs_total, parts, price: .price.usd_total, skipped_counts, pairs: [.pairs[] | {quote, url}]}'
```

```json
{
  "pairs_total": 1,
  "parts": 1,
  "price": "0.10",
  "skipped_counts": {},
  "pairs": [
    {
      "quote": "Air pollution kills an estimated seven million people every year",
      "url": "https://www.who.int/health-topics/air-pollution"
    }
  ]
}
```

Check that each quote is the one you mean and that each link is the source you cited. A quote in `skipped` with `no_url` has no link next to it, so it is not checked.

## 2. Read the price from the 402 offer

A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document -H 'content-type: application/json' -d @document.json \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `100000` is US$0.10.

## 3. Check the part

Put the draft and the part number in a file. Part 0 is the first 10 pairs:

```sh
cat > body.json <<'EOF'
{ "document": "WHO says \"Air pollution kills an estimated seven million people every year\" ([WHO](https://www.who.int/health-topics/air-pollution)).", "format": "markdown", "part": 0 }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. To check a longer draft, set `"part"` to 1 (then 2 and so on) in body.json; the preview gives the number of parts. Save the paid answer as `answer.json` for the steps below.

## 4. Read the answer

Start with `summary`, then go through `results`. Each result carries the `quote`, its `url`, `content_kind`, `match`, `score` and `context`:

```sh
jq '.summary' answer.json
jq '.results[] | {quote, url, content_kind, match, score}' answer.json
```

| `content_kind` | `match` | What it means |
|---|---|---|
| `real` | `exact` | The quoted words are on the page. |
| `real` | `fuzzy` | A close match. Compare `context` with the quote: a word may have changed. |
| `real` | `none` | The quote is not on the page as fetched. Fix the quote or the link before you publish. |
| `bot_wall`, `js_shell`, `paywall`, `http_error` | any | The page could not be read. The quote is unchecked, not false. |

Each result also gives `doc_start` and `doc_end`, the position of the quote in your draft, so you can find it. A quote that appears more than once is checked once and listed with `doc_spans`.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Keep it with the draft. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Or check it offline with our single-file checker: [Verify receipts offline](/docs/verify-offline).

## With MCP

The same check is the MCP tool `attestpage_verify_document`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_verify_document",
    "arguments": { "document": "WHO says \"Air pollution kills an estimated seven million people every year\" ([WHO](https://www.who.int/health-topics/air-pollution)).", "format": "markdown", "part": 0 },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "100000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does a check cost?

US$0.10 per part of up to 10 pairs. A draft with 23 quotes is 3 parts, so 3 calls. The preview in step 1 shows the exact count and total before you pay.

### Is a part charged if a page will not load?

Yes, when the part is checked. A page that returns a 404, a bot wall or a timeout is charged, because that result is what the check finds; `content_kind` says so. A request that fails validation, a document with no quotes that have links, and a part where no URL resolves are never charged.

### Does `exact` mean the claim in the draft is right?

No. It means those words were on the page as fetched at that time. Whether the page itself is right is a separate question.

### What if the draft is longer than 60,000 bytes?

Split it and check each piece as its own document. Up to 100 pairs are checked per document, in 10 parts.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-quotes-before-publishing.md

# Check every quote in a draft before you publish

Last updated: 2026-10-17

A quote that does not appear on its source page is the most common error in an AI-written draft. Before you publish, check each quote against the page it cites. AttestPage fetches the live page and answers `exact`, `fuzzy` or `none` for each quote, with the offsets and a signed receipt.

This guide gives the recipe, then one call with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`. A bare `curl` cannot sign a payment, so the paid call needs an x402 v2 client: the [MCP server](/guides/use-attestpage-tools-in-mcp) or an [x402 client in code](/guides/fetch-a-page-with-an-x402-client).

## Recipe

1. **List the claims.** Take every sentence in the draft that puts words in quotation marks and names a source. Keep the quote word for word, as written in the draft.
2. **Group by URL.** Put all quotes that cite the same page together.
3. **Check each group once.**
   - One quote on a page: `POST /v1/verify/quote`, US$0.01 per call.
   - Two to twenty quotes on the same page: `POST /v1/verify/quotes`, US$0.02 for the whole group, so from three quotes up it costs less per quote.
4. **Read the page verdict first.** If `page.content_kind` is not `real` (for example `bot_wall`, `js_shell` or `paywall`), a `none` means we could not read the page. It does not mean the quote is wrong. Find another copy of the page or cite it differently.
5. **Decide each quote.**
   - `exact`, or `fuzzy` with a score of 0.9 or more: keep the quote, and keep the URL in the draft.
   - `none` on a real page: the quote is not on the page. Fix the wording to match the page, or drop the quote.
   - Anything else: check it by hand before publishing.
6. **Keep the receipt.** Save the `receipt` next to the draft, so anyone can check later that the page said this on that day.

Do not publish a quote that you have not checked.

## Price

US$0.01 per call for one quote, US$0.02 per call for up to 20 quotes on one page, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. Read the price from the payment offer

An empty body is refused before payment and is never charged. Read the offer it returns:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote \
  -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (six decimal places), so it is the price above in base units.

## 2. Make the paid call

Send the quote with its URL. curl alone cannot sign the payment, so send the request through an x402 v2 client. The client reads the offer from step 1, signs it, and sends the same request again with a `PAYMENT-SIGNATURE` header:

```sh
cat > body.json <<'EOF'
{ "url": "https://www.iana.org/help/example-domains",
  "quote": "These domains may be used as illustrative examples in documents",
  "match": "fuzzy" }
EOF

curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quote \
  -H 'content-type: application/json' \
  -H "PAYMENT-SIGNATURE: $PAYMENT_SIGNATURE" \
  -d @body.json | jq '{match: .result.match, score: .result.score, kind: .page.content_kind, advice}'
```

`$PAYMENT_SIGNATURE` is the signed payment that your x402 client produces. The answer is `exact`, `fuzzy` or `none`, with `page.content_kind` and a `receipt`. A request that fails validation gets 400 before payment and is never charged.

## Notes

- Quotes are matched after normalising both texts: curly quotes and dashes become plain, invisible characters are dropped and all whitespace becomes one space. Your quote must still be the same words.
- The check reads the page as our fetcher receives it at that moment. A page that changes later may not match the quote you checked.
- Routes and prices: [POST /v1/verify/quote](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-quote), [POST /v1/verify/quotes](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/verify-quotes) and [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-documents-in-ci.md

# How to check every quote in a Markdown document from a CI job before merge, step by step with curl

Last updated: 2026-10-13

To check every quote in a Markdown file from a CI job before it merges, send the file to `POST /v1/verify/document`, one part of up to 10 quote and link pairs per call, at US$0.10 a part. The job fails when a quote is not on the page it cites. A page that cannot be read (a bot wall, a JavaScript shell, a paywall or an error) is reported as a warning, because it is unchecked, not wrong.

This guide runs the check with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`. For checking a draft by hand, see [How to check every quote in a draft before publishing](/guides/verify-document-before-publishing).

## What the job does

- **Reads the file as sent.** The Markdown goes in as `format` `markdown`. Quotes inside code blocks are ignored, and the rules are fixed and named by `extractor` (`doc-v1`) in every answer.
- **Splits it into parts.** Each part holds up to 10 pairs, and each part is one paid call. The free preview gives the count before anything is paid.
- **Fails on a real miss only.** A quote is a failure when its page loaded as content (`content_kind` `real`) and the quote is not there (`match` `none`).
- **Keeps the answers.** Each answer has one signed receipt for its part. Save the answers with the build, as artifacts.

## Price

US$0.10 per part of up to 10 pairs, paid in USDC with x402 v2 on Base Sepolia (a test network). A file with 10 quotes or fewer is one part, so one run costs US$0.10. Every run that checks a part is charged, so run the job only when Markdown changes, for example with a path filter on your docs folder. A request that fails validation gets 400 before payment and is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. Preview the pairs for free

The preview is free and changes nothing. It gives the number of parts and the exact price for the file. Put the draft in a file:

```sh
cat > body.json <<'EOF'
{ "document": "\"These domains may be used as illustrative examples in documents\" ([IANA](https://www.iana.org/help/example-domains)).", "format": "markdown" }
EOF
```

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document/preview -H 'content-type: application/json' -d @body.json \
  | jq '{pairs_total, parts, price: .price.usd_total, skipped_counts, pairs: [.pairs[] | {quote, url}]}'
```

```json
{
  "pairs_total": 1,
  "parts": 1,
  "price": "0.10",
  "skipped_counts": {},
  "pairs": [
    {
      "quote": "These domains may be used as illustrative examples in documents",
      "url": "https://www.iana.org/help/example-domains"
    }
  ]
}
```

`skipped_counts` lists what was not checked and why: `no_url`, `bad_url`, `too_short`, `too_long` or `beyond_limit`. Read it before you trust a green job.

## 2. Read the price from the 402 offer

A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document -H 'content-type: application/json' -d @body.json \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `100000` is US$0.10.

## 3. Check the part

Write the part number into the body. Part 0 is the first 10 pairs:

```sh
cat > body.json <<'EOF'
{ "document": "\"These domains may be used as illustrative examples in documents\" ([IANA](https://www.iana.org/help/example-domains)).", "format": "markdown", "part": 0 }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`. Save the paid answer as `answer.json`.

There is no free trial at the moment; use the free samples instead.

## 4. Read the answer

Start with `summary`, then the results that count against the build:

```sh
jq '.summary' answer.json
jq '.results[] | {quote, url, content_kind, match, score}' answer.json
```

| `content_kind` | `match` | What the job does |
|---|---|---|
| `real` | `exact` | Passes. The quoted words are on the page. |
| `real` | `fuzzy` | Passes. A close match: compare `context` with the quote, since a word may have changed. |
| `real` | `none` | Fails the job. The quote is not on the page as fetched. |
| any value other than `real` | any | Warns. The quote is unchecked, not false. |
| `real` | `null` with an `error` | Warns. Unchecked: the quote was too costly to match; retry with `match` `exact`. |

Each result gives `doc_start` and `doc_end`, the position of the quote in the file, so the job can print where to look.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Or check it offline with our single-file checker: [Verify receipts offline](/docs/verify-offline).

## 6. Run the check in CI

The job runs one script after checkout. The script does the free preview with `curl`, then one paid call for each part. A paid call needs an x402 v2 client, because `curl` cannot sign the payment. Keep the wallet key in your CI secrets, and fund the wallet with USDC on Base Sepolia (a test network).

`PAY_CMD` is that client: a command that reads the JSON body on stdin, posts it to `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document`, pays the 402 offer and prints the 200 answer. It exits non-zero on any other status. [One x402 payment step by step](/docs/examples/fetch-x402) shows the payment with plain `fetch`.

Save this as `check-quotes.sh` in your repository:

```sh
#!/bin/sh
# Check every quote in one Markdown file. Usage: sh check-quotes.sh docs/report.md
set -eu
file=$1
rm -f preview.json
status=$(jq -n --rawfile d "$file" '{document: $d, format: "markdown"}' \
  | curl -s -o preview.json -w '%{http_code}' -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/document/preview -H 'content-type: application/json' -d @- || true)
if [ "$status" != 200 ]; then
  echo "preview failed for $file: HTTP $status $(jq -r '.error.message // empty' preview.json 2>/dev/null)" >&2
  exit 1
fi
parts=$(jq .parts preview.json)
case "$parts" in ''|*[!0-9]*) echo "preview failed for $file" >&2; exit 1;; esac
i=0
while [ "$i" -lt "$parts" ]; do
  jq -n --rawfile d "$file" --argjson part "$i" '{document: $d, format: "markdown", part: $part}' \
    | $PAY_CMD > "answer-$i.json"
  if ! jq -e '[.results[] | select(.content_kind == "real" and .match == "none")] | length == 0' "answer-$i.json" > /dev/null; then
    echo "part $i: quote not found on its page:"
    jq -r '.results[] | select(.content_kind == "real" and .match == "none") | "  \(.url)  \(.quote)"' "answer-$i.json"
    exit 1
  fi
  jq -r '.results[] | select(.content_kind != "real") | "warning: \(.content_kind) \(.url)"' "answer-$i.json"
  jq -r '.results[] | select(.error != null) | "warning: unchecked \(.url) \(.error.code)"' "answer-$i.json"
  i=$((i + 1))
done
echo "all quotes in $file are on their pages"
```

The job sets `PAY_CMD` to your client, for example `PAY_CMD="node pay-post.mjs"`, and runs `sh check-quotes.sh docs/report.md`. It fails with the quote and URL of each miss, and prints a warning for each page that could not be read. The answers stay in the working folder as `answer-0.json`, `answer-1.json` and so on, so save them as build artifacts. The preview is kept as `preview.json` beside them. If the preview fails, the script prints the error message from that response and stops.

## With MCP

The same check is the MCP tool `attestpage_verify_document`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_verify_document",
    "arguments": { "document": "\"These domains may be used as illustrative examples in documents\" ([IANA](https://www.iana.org/help/example-domains)).", "format": "markdown", "part": 0 },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "100000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does a CI run cost?

US$0.10 for each part of up to 10 pairs. A file with 23 quotes is 3 parts, so 3 calls. The preview in step 1 shows the count and the total before anything is paid. Path filters keep runs to the commits that change Markdown.

### Does a page that will not load fail the job?

No. A page that returns a 404, a bot wall or a timeout is still a result, and the part is charged. `content_kind` says what it was, and the script prints a warning. Only a quote that is missing from a page that loaded fails the job. A part where no URL resolves, or where every quote was too costly to match, gets 422 and the job stops; fix or remove those links.

### What happens when the file has no quote with a link?

The preview answers `parts: 0` and the script passes without a paid call. To fail instead, add `[ "$parts" -gt 0 ] || exit 1`. To check every quote, also fail when the preview's `skipped_counts.beyond_limit` is set.

### Does a pass mean the claims in the file are right?

No. It means those words were on the page as fetched at that time. Whether the page is right is a separate question.

### What if the file is longer than 60,000 bytes?

The call is a 400 for a document over 60,000 bytes (UTF-8). Split the file by section and check each piece. Up to 100 pairs are checked per document. Any pair after the first 100 is counted in the preview's skipped counts as beyond_limit and is not checked. The paid answer does not list skipped pairs, so read the preview's skipped counts and fail the job yourself if you need every quote checked.

### What does the receipt show?

It is an Ed25519 signature from the service over the document's SHA-256, the options, the pages as fetched (with the hash of each page's content) and each pair's verdict with a hash of its quote. It does not hold the quote text, so keep the file with the receipt. Check it with step 5.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/signed-receipt-of-a-web-page.md

# How to get a signed receipt of a web page

Last updated: 2026-10-10

To get a signed receipt of what a web page showed at a given time, have an independent fetcher load it and sign the result. `POST /v1/fetch` (US$0.002) loads the URL and returns an Ed25519-signed receipt with the final URL, status, time, content hash and a verdict on what came back. Anyone can check it offline.

## What the receipt records

The receipt is a compact JWS (`alg` EdDSA). Its payload includes:

- the URL you asked for and the final URL after redirects, with the HTTP status;
- `retrieved_at`, the time of the fetch;
- `content_sha256`, the SHA-256 of the page text, so anyone holding the text can match it;
- `content_kind`: `real`, `bot_wall`, `js_shell`, `paywall`, `http_error` and others;
- the site's IP address, TLS certificate details and a short list of response headers, where our fetcher could read them.

The full field list is in [How it works](/docs/how-it-works#receipts).

## Get one

```json
{ "url": "https://www.iana.org/help/example-domains", "return_text": true }
```

Send that to `POST /v1/fetch`. With `return_text` you also get up to 20,000 characters of clean text. Try the route free first: [`GET /v1/sample/fetch`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch). Details: [Fetch a page](/docs/fetch). Step by step with `curl`, from the free sample to matching the page text: [How to get a signed receipt of a web page, step by step with curl](/guides/signed-page-receipt).

## Pay per call with x402

No account or key is needed. A valid request with no payment gets `402 Payment Required` with the price in a `PAYMENT-REQUIRED` header; an x402 v2 client signs that offer and sends the request again. With `@x402/fetch` (`npm install @x402/fetch @x402/evm viem`) and a Base wallet holding a little USDC (real money):

```js
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const payingFetch = wrapFetchWithPayment(fetch, client);

const res = await payingFetch('https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/fetch', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ url: 'https://www.iana.org/help/example-domains', return_text: true }),
});
const answer = await res.json();
console.log(answer.page.content_kind, answer.page.content_sha256, answer.receipt);
```

The wrapper signs the offer it gets. To check the price and network before signing, see [One x402 payment step by step](/docs/examples/fetch-x402).

## Check one

Any receipt can be checked against our published keys with [POST /v1/receipt/verify](/docs/receipt-verify) (free), or with no call to us at all:

```sh
curl -O https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/verify-receipt.mjs
node verify-receipt.mjs --selftest
```

See [Verify receipts offline](/docs/verify-offline). The keys are at [/.well-known/jwks.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json).

## Receipts for other things

- A quote on a page: [Verify a quote](/docs/verify-quote) signs the match with the page details.
- Many links at once: [Check links](/docs/check-links) signs one receipt over up to 10 URLs.
- A file you hold, not a URL: [Attest a hash](/docs/attest) (US$0.002) signs a timestamp over a SHA-256 you send. We never see the file.

## Questions

### Is this the same as a web archive snapshot?

No. An archive stores the page for others to view. A receipt is a small signed statement about one fetch that you keep yourself; we do not publish it, and pages fetched for you are not stored ([Privacy](/privacy)).

### Does the receipt show the page is accurate?

No. It records what our fetcher saw at that time. Pages change and can show different content to different visitors.

### Why would an agent want one?

To show later what a source said when it was used: when handing work to another agent, answering a dispute about a citation, or keeping an audit trail of the pages a task relied on.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/signed-page-receipt.md

# How to get a signed receipt of a web page, step by step with curl

Last updated: 2026-10-13

To get a signed, timestamped receipt of what a web page showed, send its URL to `POST /v1/fetch` (US$0.002 per call). AttestPage loads the page and returns an Ed25519-signed receipt with the final URL, HTTP status, fetch time, a hash of the page text and a verdict on what came back.

This guide gets one receipt with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, checks it, then shows the same call as an MCP tool. For what a receipt is and when an agent needs one, see [How to get a signed receipt of a web page](/docs/signed-receipt-of-a-web-page).

## What the receipt records

The receipt is a compact JWS (`alg` EdDSA, `typ` `attestpage-evidence+jws`). Its payload has:

- `kind` `fetch`, `iss` (the issuer, `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`) and `iat` (the signing time, in Unix seconds);
- `url`, the address you sent, and `final_url` after redirects, with `http_status`;
- `retrieved_at`, the time of the fetch;
- `content_sha256`, the SHA-256 of the full page text, and `raw_sha256`, the SHA-256 of the body as received;
- `content_kind`: `real`, `bot_wall`, `js_shell`, `paywall`, `http_error` and others;
- `server_ip`, `tls` and a short list of response `headers`, where our fetcher could read them;
- `request_sha256`, the SHA-256 of your request body, so you can show which request it answers;
- `tier` and `payment`, the payment that covered the call.

## Price

US$0.002 per call, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See a receipt for free

The free sample runs the same route on a demo page and signs it with the example key:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch > sample.json
jq '{kind: .page.content_kind, status: .page.http_status, retrieved_at: .page.retrieved_at, content_sha256: .page.content_sha256, tier}' sample.json
```

```json
{
  "kind": "real",
  "status": 200,
  "retrieved_at": "2026-10-10T12:09:00.731Z",
  "content_sha256": "0e429607fdb16c005ef662414e758c53edb82e1cb24c3cbec239e4c1d6a7dfa0",
  "tier": "sample"
}
```

A sample receipt is signed with a separate key and says `tier` `sample`, so it can never pass as evidence about a real page.

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/fetch -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `2000` is US$0.002.

## 3. Get the receipt

Put the page URL in a file. `return_text` also returns up to 20,000 characters of clean text, which you need if you want to match the hash later:

```sh
cat > body.json <<'EOF'
{ "url": "https://www.iana.org/help/example-domains", "return_text": true }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json` for the steps below.

There is no free trial at the moment; use the free samples instead.

## 4. Read what was fetched

Read `page.content_kind` before relying on the receipt:

| `content_kind` | What the receipt shows |
|---|---|
| `real` | The page loaded as content. The receipt records that content. |
| `bot_wall`, `js_shell`, `paywall` | The site served a challenge, an empty JavaScript shell or a login wall. The receipt records that, not the article. |
| `off_site` | The URL redirected to another site. `final_url` says where. |
| `http_error`, `timeout` | The site answered with an error status, could not be reached or did not answer in time. |

`advice` gives the same verdict in one sentence. Keep `answer.json` yourself: pages fetched for you are not stored ([Privacy](/privacy)).

## 5. Check the receipt

The `receipt` field is the signed record. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- \
  | jq '{valid, tier, url: .payload.url, retrieved_at: .payload.retrieved_at}'
```

Or with no call to us at all, using the single-file checker pinned to our issuer:

```sh
curl -O https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/dl/verify-receipt.mjs
jq -r .receipt answer.json | node verify-receipt.mjs - --issuer https://s2h6qt73jtzlgbgnnfacln2poq.srv.us
```

It prints `{valid, reason?, kid, tier, payload}` and exits 0 when the receipt is valid. Details: [Verify receipts offline](/docs/verify-offline). The keys are at [/.well-known/jwks.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json).

## 6. Match the text to the receipt

When `text_truncated` is false, the SHA-256 of `text` equals `content_sha256` in the receipt:

```sh
jq -j .text answer.json | shasum -a 256
jq -r .page.content_sha256 answer.json
```

The two hashes match, so anyone holding that text and the receipt can see it is what our fetcher read at `retrieved_at`.

## With MCP

The same receipt is the MCP tool `attestpage_fetch`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_fetch",
    "arguments": { "url": "https://www.iana.org/help/example-domains", "return_text": true },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "2000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does one receipt cost?

US$0.002 per page with `POST /v1/fetch`. For up to 10 URLs under one receipt, `POST /v1/check/links` costs US$0.005 per batch: [Check links](/docs/check-links).

### Does the receipt show the page is accurate?

No. It records what our fetcher received at that time. Pages change and can show different content to different visitors.

### Can I get a receipt for a file instead of a URL?

Yes. [Attest a hash](/docs/attest) (US$0.002) signs a timestamp over a SHA-256 you send. We never see the file.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-links-before-citing.md

# How to check links before citing them

Last updated: 2026-10-10

Before citing a link, fetch it and confirm it returns real content, not a 404, a redirect to another site, a bot challenge or an empty page. `POST /v1/check/links` (US$0.005 per batch) checks up to 10 URLs at once and gives each one a status, redirect chain, final URL, `content_kind` and hash, and a link verdict (`ok`, `broken`, `moved` or `unknown`) for the link itself, under one signed receipt. The link verdict is apart from the page verdict (`content_kind`).

## What can go wrong with a link

- **Dead.** 404, 410, a 5xx error, or a host name that no longer resolves.
- **Moved.** The link redirects, sometimes to a different site or to a home page that has nothing to do with the citation. Each result lists the redirects and the final URL; a link that ends on another site is `off_site`.
- **Not readable.** The server answers 200 but sends a bot challenge, an empty JavaScript shell or a paywall. A status code alone calls these fine; `content_kind` does not.
- **Invented.** LLMs sometimes produce URLs that look right but never existed. These usually fail as dead links or dead domains.

## Check a batch

```json
{ "urls": ["https://www.iana.org/help/example-domains", "https://www.iana.org/domains/reserved"] }
```

Keep a citation when `content_kind` is `real` and the final URL is still the page you meant. Try the route free on demo data: [`GET /v1/sample/links`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/links). Details: [Check links](/docs/check-links). Step by step with `curl`: [How to check links before citing them, step by step with curl](/guides/check-links-before-citing).

## Pay per call with x402

No account or key is needed. A valid request with no payment gets `402 Payment Required` with the price in a `PAYMENT-REQUIRED` header; an x402 v2 client signs that offer and sends the request again. With `@x402/fetch` (`npm install @x402/fetch @x402/evm viem`) and a Base wallet holding a little USDC (real money):

```js
import { wrapFetchWithPayment, x402Client } from '@x402/fetch';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const payingFetch = wrapFetchWithPayment(fetch, client);

const res = await payingFetch('https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/check/links', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ urls: ['https://www.iana.org/help/example-domains', 'https://www.iana.org/domains/reserved'] }),
});
const answer = await res.json();
for (const link of answer.results) console.log(link.content_kind, link.http_status, link.final_url);
```

The wrapper signs the offer it gets. To check the price and network before signing, see [One x402 payment step by step](/docs/examples/fetch-x402).

## Check the words too

A live link can still be the wrong source. To check that the quoted words are on the page, use [Verify a quote](/docs/verify-quote), or [Verify citations](/docs/verify-citations) for up to 10 quote and URL pairs in one call. See [How to verify a quote an LLM cites](/docs/verify-a-quote-an-llm-cites).

## Questions

### Why not just send a HEAD request?

Many servers answer HEAD differently from GET, block unknown clients, or return 200 for pages that only hold a challenge. We fetch the page as a reader would and look at what came back.

### Is a failed batch charged?

If no URL in the batch resolves, the call gets 422 `host_not_found` and is not charged. Bad requests are refused before payment. See [Payments](/docs/payments) and [Errors](/docs/errors).

### Does it follow robots.txt?

Yes. Our fetcher identifies itself and honours robots.txt and opt-outs; see [Our fetcher](/bot).

### Can I keep a record of the check?

Yes. The receipt covers every URL in the batch and can be checked offline: [Verify receipts offline](/docs/verify-offline).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-links-before-citing.md

# How to check links before citing them, step by step with curl

Last updated: 2026-10-10

To check that the links you are about to cite are live, send up to 10 of them to `POST /v1/check/links` (US$0.005 per batch). AttestPage fetches each one and returns its status, redirects, final URL, title and a `content_kind` verdict, under one signed receipt. Then check that each page says what you claim with `POST /v1/verify/citations`.

This guide runs both checks with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the link check as an MCP tool call. For the kinds of broken link to look for, see [How to check links before citing them](/docs/check-links-before-citing).

## What the check does

- **Fetches each link.** It follows up to 5 redirects and reads the page as our fetcher receives it at that moment.
- **Judges each page.** `content_kind` is `real` when the page loaded as content, or `http_error`, `off_site`, `bot_wall`, `js_shell`, `paywall`, `timeout` and others when it did not.
- **Reports what it found.** Each result has `http_status`, the `redirects` it followed, `final_url`, the page `title` and `content_sha256`, a hash of the page text.
- **Signs a receipt.** One Ed25519 receipt covers every URL in the batch. Anyone can check it later against our published keys.

## Price

US$0.005 per batch of 1 to 10 URLs, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged, and a batch where no host name resolves gets 422 and is not charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample runs the same route on two demo links, one live and one missing:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/links | jq '.results[] | {url, status: .http_status, kind: .content_kind, title}'
```

```json
{
  "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
  "status": 200,
  "kind": "real",
  "title": "Regional climate report 2025 (demo page)"
}
{
  "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/missing",
  "status": 404,
  "kind": "http_error",
  "title": null
}
```

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/check/links -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `5000` is US$0.005.

## 3. Check the links

Put the links you plan to cite in a file, exactly as they will appear in your answer:

```sh
cat > body.json <<'EOF'
{ "urls": ["https://www.iana.org/help/example-domains", "https://www.iana.org/domains/reserved"] }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json` for the steps below.

There is no free trial at the moment; use the free samples instead.

## 4. Read the answer

Read `content_kind` for each result, then compare `final_url` and `title` with what you meant to cite:

| `content_kind` | What it means | What to do |
|---|---|---|
| `real` | The page loaded as content. | Keep it if `final_url` and `title` are the page you meant. |
| `http_error` | A 4xx or 5xx status, or a host name that does not resolve (`http_status` null). | Drop the link or find where the page moved. |
| `off_site` | The link redirected to another site. `final_url` says where; `off_site_error: true` means that site answered with an error. | Cite the final page only if it is the same source. |
| `bot_wall`, `js_shell`, `paywall` | The site sent a challenge, an empty JavaScript shell or a login wall. | The link may work for a person, but its content is unchecked. |
| `pdf` | A live PDF on the same site. It is not read, so `title` is null. | Check its text with [verify/quote](/docs/verify-quote). |
| `timeout` | The site did not answer in time. | Try again later. |

A link that redirects to a home page or a search page often still returns 200 and `real`. Check `redirects` and `title`, not the status alone.

## 5. Check that each page says what you claim

A live link can still be the wrong source. Send each URL with the words you attribute to it to `POST /v1/verify/citations` (US$0.10 for up to 10 pairs):

```json
{ "citations": [ { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" } ] }
```

Each citation gets `exact`, `fuzzy` or `none`. If you paraphrased, add `"match": "passages"` beside `citations` to get the passages closest to your claim, as evidence to read. Details: [Verify citations](/docs/verify-citations). For one quote at a time, see [How to check a quote an LLM cites, step by step with curl](/guides/verify-llm-quote).

## 6. Keep the receipt

The `receipt` field is a compact JWS covering every URL in the batch. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Or check it offline with our single-file checker: [Verify receipts offline](/docs/verify-offline).

## With MCP

The same check is the MCP tool `attestpage_check_links`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_check_links",
    "arguments": { "urls": ["https://www.iana.org/help/example-domains", "https://www.iana.org/domains/reserved"] },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "5000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does it cost to check a list of links?

US$0.005 per batch of up to 10 URLs with `POST /v1/check/links`. Checking the quoted words too costs US$0.10 per batch of up to 10 citations with `POST /v1/verify/citations`.

### Is a batch charged if some links are dead?

Yes, because reporting dead links is what the call does. If no host name in the batch resolves, the call gets 422 host_not_found and is not charged. Every case is in [Payments](/docs/payments) and [Errors](/docs/errors).

### Does a real result mean the link supports my claim?

No. It means the page loaded as content when our fetcher read it. Whether it says what you claim is the separate check in step 5.

### Why not just send a HEAD request?

Many servers answer HEAD differently from GET, block unknown clients, or return 200 for a challenge page. We fetch each page as a reader would and look at what came back.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-packages-before-installing.md

# How to check packages before installing them, step by step with curl

Last updated: 2026-10-13

To check that a package an LLM suggested really exists, send up to 10 names to `POST /v1/check/packages` (US$0.005 per batch). AttestPage looks each name up in its registry (npm, PyPI or crates.io) and returns whether it is listed, the latest version, the description, the licence, the links, a few flags and any known advisories from OSV.dev, under one signed receipt.

This guide runs the check with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For the kinds of package problem to look for, see [Check packages](/docs/check-packages).

## What the check does

- **Looks up each name.** It asks the registry for each name in the ecosystem you give. `exists` is `true` when the registry lists it, `false` when it does not, and `null` when the lookup failed.
- **Reports what the registry says.** `latest_version`, `description`, `license`, `homepage`, `repository`, `created_at`, `deprecated` and `yanked` come from the registry, as the publisher wrote them.
- **Adds known advisories.** `vulnerabilities` lists the OSV.dev advisories for the version you send, or for the latest version when you send none. `count` is the number of advisories found.
- **Signs a receipt.** One Ed25519 receipt covers the whole batch.

The check answers "is this name listed in the registry". It is not a security verdict. A listed package can still be malicious, unmaintained or not the one you meant, and no advisory listed does not mean the package has no flaws.

## Price

US$0.005 per batch of 1 to 10 names, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged, and a batch where every registry lookup fails gets 502 and is not charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample checks four demo names: two that are listed, one listed with an advisory, and one that does not exist.

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/packages | jq '.results[] | {name, exists, latest_version, advisories: .vulnerabilities.count}'
```

```json
{
  "name": "left-pad",
  "exists": true,
  "latest_version": "1.3.0",
  "advisories": 0
}
{
  "name": "requests",
  "exists": true,
  "latest_version": "2.32.3",
  "advisories": 1
}
{
  "name": "serde",
  "exists": true,
  "latest_version": "1.0.210",
  "advisories": 0
}
{
  "name": "left-pad-demo-missing",
  "exists": false,
  "latest_version": null,
  "advisories": 0
}
```

## 2. Read the price from the 402 offer

Put the names you plan to install in a file. A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
cat > packages.json <<'EOF'
{ "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] }
EOF
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/check/packages -H 'content-type: application/json' -d @packages.json \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `5000` is US$0.005.

## 3. Check the names

Each name needs an `ecosystem` (`npm`, `pypi` or `crates`) and a `name`. You may add a `version` to a name to ask about that version's advisories. Put the batch in the same `packages.json` as step 2:

```sh
cat > packages.json <<'EOF'
{ "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json` for the steps below.

## 4. Read the answer

Check `exists` first, then `latest_version` and `homepage` against the package you meant to install, then `vulnerabilities` for the version you will use:

```sh
jq '.results[] | {name, exists, latest_version, homepage, advisories: .vulnerabilities.count}' answer.json
```

| `exists` | What it means |
|---|---|
| `true` | The registry lists the name. Compare its `description` and `homepage` with what the model said it was. |
| `false` | The registry does not list the name. Do not install it: the model may have invented it. |
| `null` | The lookup failed. The name is unchecked, not missing. Try again later. |

Each advisory in `vulnerabilities.items` has an `id`, a `summary`, a `severity` and the `fixed` versions. A `malicious` flag marks an OSV malicious-package record.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Keep it with the answer. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

## With MCP

The same check is the MCP tool `attestpage_check_packages`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_check_packages",
    "arguments": { "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "5000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does a check cost?

US$0.005 per batch of up to 10 names. Checking 23 names takes 3 batches, so 3 calls.

### Is a batch charged if a lookup fails?

Yes, when the batch is checked. A failed lookup is a result, and `exists` is `null` for it. A request that fails validation, and a batch where every registry lookup failed, are never charged.

### Does `exists: true` mean the package is fine to install?

No. It means the registry listed the name when we looked. Check the publisher, the homepage and the advisories yourself before you install it.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-package-licences-before-installing.md

# How to check a package's licence before installing it, step by step with curl

Last updated: 2026-10-13

To read the licence of a package an agent is about to install, send up to 10 names to `POST /v1/check/packages` (US$0.005 per batch). AttestPage looks each name up in its registry (npm, PyPI or crates.io) and returns the `license` field the registry holds, with `exists`, the latest version, the links and any OSV.dev advisories, under one signed receipt.

This guide covers the `license` field and what to decide from it. For the whole call and the other fields, see [How to check packages before installing them](/guides/check-packages-before-installing). Commands use `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then the same call as an MCP tool.

## What the licence field is

- **The registry's own text.** `license` is copied from the registry as the publisher wrote it. AttestPage does not read the package's files or its LICENSE file, and does not judge the text.
- **The latest version's licence.** For npm and PyPI it is the latest version's licence field; for crates.io it is the default version's licence. A `version` you send changes the advisories, not the licence.
- **Often an SPDX expression.** `MIT`, `Apache-2.0` and `MIT OR Apache-2.0` are SPDX forms. Older packages may hold free text such as `SEE LICENSE IN LICENSE.txt`, or a loose name like `BSD`. For npm, a licence given as an object is read as its `type`.
- **`null` when there is nothing to read.** A name the registry does not list, a failed lookup, and a package whose licence field is empty or missing all give `null`.

## Price

US$0.005 per batch of 1 to 10 names, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged, and a batch where every registry lookup fails gets 502 and is not charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample checks four demo names. Three are listed, each with a different licence form, and one does not exist:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/packages | jq '.results[] | {name, exists, license}'
```

```json
{
  "name": "left-pad",
  "exists": true,
  "license": "WTFPL"
}
{
  "name": "requests",
  "exists": true,
  "license": "Apache-2.0"
}
{
  "name": "serde",
  "exists": true,
  "license": "MIT OR Apache-2.0"
}
{
  "name": "left-pad-demo-missing",
  "exists": false,
  "license": null
}
```

## 2. Read the price from the 402 offer

Put the names you plan to install in a file. A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
cat > packages.json <<'EOF'
{ "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] }
EOF
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/check/packages -H 'content-type: application/json' -d @packages.json \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `5000` is US$0.005.

## 3. Check the names

Each name needs an `ecosystem` (`npm`, `pypi` or `crates`) and a `name`. Put the batch in the same `packages.json` as step 2:

```sh
cat > packages.json <<'EOF'
{ "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json` for the steps below.

## 4. Decide from the licence

List the licence next to the other fields that decide an install:

```sh
jq '.results[] | {name, exists, license, latest_version, homepage}' answer.json
```

Then sort each name into one of three groups. The allow list is yours.

| `license` | What to do |
|---|---|
| A form on your allow list, for example `MIT`, `Apache-2.0` or `BSD-3-Clause` | Install. Open `homepage` or `repository` once to confirm it is the package you meant. |
| An expression such as `MIT OR Apache-2.0` | `OR` offers a choice: you may use the package under either. `AND` means every licence applies. Check each part against your list. |
| Anything else: `null`, free text, `UNLICENSED`, `SEE LICENSE IN …`, or a name not on your list | Do not install on the agent's own say-so. Read the licence in the package's repository, or ask the person who owns the decision. |

A `null` licence is not a permissive one: with no licence stated you have no stated permission to use the code. When `exists` is `false` there is nothing to install, and the model may have invented the name.

To print every listed name whose licence is not on your allow list, with `ALLOW` a JSON array of the licences you accept:

```sh
ALLOW='["MIT","Apache-2.0","BSD-3-Clause","ISC"]'
jq --argjson allow "$ALLOW" '.results[] | select(.exists != false and ((.license // "") as $l | $allow | index($l) | not)) | {name, license}' answer.json
```

This is an exact match: `MIT OR Apache-2.0` is not in the list above, so it is printed for you to read. The check reads what the registry says. It does not detect a registry licence that differs from the one in the package's files.

## 5. Keep the receipt

The `receipt` field is a compact JWS. It signs, for each name, whether it exists and its latest version, with the hash of the registry's answer, so you can keep it with the decision. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

## With MCP

The same check is the MCP tool `attestpage_check_packages`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_check_packages",
    "arguments": { "packages": [{ "ecosystem": "npm", "name": "left-pad" }, { "ecosystem": "pypi", "name": "requests" }] },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "5000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does a check cost?

US$0.005 per batch of up to 10 names. Checking 23 names takes 3 batches, so 3 calls.

### Is this a licence compliance check?

No. It returns the licence text the registry holds for the latest version. It does not read the package's files, its dependencies' licences or your own policy. Use it to catch a missing or unexpected licence before an install, and make the final call yourself.

### Why is `license` null for a package that exists?

The registry holds no licence text for the latest version, or only whitespace. Treat it as unknown and read the package's repository.

### Does sending a `version` give that version's licence?

No. A `version` selects the version whose advisories are listed. `license` is still the latest version's (npm and PyPI) or the default version's (crates.io).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/recheck-page-for-changes.md

# How to check whether a web page has changed since you read it, step by step with curl

Last updated: 2026-10-13

To find out whether a page you read earlier still says the same thing, send its receipt (or its URL and text hash) to `POST /v1/recheck` (US$0.003 per call). AttestPage fetches the page again and compares its clean text with the baseline. It answers `unchanged`, `changed`, `gone` or `unreadable`, lists the fields that differ, and returns a signed receipt that names both the old and the new hash.

This guide runs the call with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For every field and error, see [Re-check a page](/docs/recheck).

## What the recheck does

- **Fetches the page again.** It fetches the URL in the baseline, following redirects again, and extracts the clean text the same way as the first time.
- **Compares byte for byte.** `content_sha256` is the hash of the clean text. Markup-only changes leave it the same. A page with a date, a counter or rotating text reads as changed on every visit.
- **Lists what differs.** `differences` names each compared field that is not the same, such as `content_sha256`, `http_status` or `final_url`.
- **Signs a receipt.** The new receipt is itself a baseline: send it in the next call to build a chain.
- **Stores nothing and calls nobody.** There is no schedule and no webhook. You call when you want to know.

## Price

US$0.003 per call, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request with a bad baseline gets 400 before payment and is never charged. Once the page is fetched, the call is charged even when the answer is `gone` or `unreadable`, because the fetch was done. If we read no page at all (a timeout or connect error), the call is a 502 `upstream_unreachable` and is not charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample rechecks the demo page against its own hash, so it reads `unchanged`.

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/recheck | jq '{change, changed, differences, content_sha256: .page.content_sha256}'
```

```json
{
  "change": "unchanged",
  "changed": false,
  "differences": [],
  "content_sha256": "0e429607fdb16c005ef662414e758c53edb82e1cb24c3cbec239e4c1d6a7dfa0"
}
```

## 2. Read the price from the 402 offer

Step 3 explains the body. A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/recheck -H 'content-type: application/json' \
  -d '{ "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page", "content_sha256": "0e429607fdb16c005ef662414e758c53edb82e1cb24c3cbec239e4c1d6a7dfa0" }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `3000` is US$0.003.

## 3. Recheck the page

Send exactly one of two baselines:

- `receipt`: the compact receipt from an earlier call to this service (`/v1/fetch`, `/v1/verify/quote` or `/v1/recheck`, paid or trial; a sample receipt is not accepted).
- `url` and `content_sha256`: the `page.content_sha256` from our own fetch of that URL. A hash from another tool will not match.

Add `"return_text": true` to also get up to 20,000 characters of the new clean text. This body uses the demo page and its hash:

```sh
cat > body.json <<'EOF'
{ "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page", "content_sha256": "0e429607fdb16c005ef662414e758c53edb82e1cb24c3cbec239e4c1d6a7dfa0" }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json`.

## 4. Read the answer

```sh
jq '{change, changed, differences, elapsed_seconds, advice}' answer.json
```

| `change` | What it means |
|---|---|
| `unchanged` | The clean text is the same as in the baseline. |
| `changed` | The text differs. Fetch the page again or check your quote before you rely on it. |
| `gone` | The page no longer exists: 404, 410, or the site's name no longer resolves. If the baseline was already gone, the answer is `unchanged`, and `advice` says the page was gone then and is still gone. |
| `unreadable` | We could not read the page this time, so we cannot say whether it changed. `page.content_kind` says why. Try again later. |

`elapsed_seconds` is the time since the baseline was fetched. It is `null` when you sent a URL and hash.

## 5. Keep the receipt and chain it

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

For the next recheck, send this receipt as `receipt` instead of the URL and hash. Its `baseline.receipt_sha256` is the SHA-256 of the receipt you sent, which links the chain.

## With MCP

The same call is the MCP tool `attestpage_recheck`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_recheck",
    "arguments": { "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page", "content_sha256": "0e429607fdb16c005ef662414e758c53edb82e1cb24c3cbec239e4c1d6a7dfa0" },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "3000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`.

## Questions

### How much does a recheck cost?

US$0.003 per call, one page per call. Checking one page every day for 30 days takes 30 calls.

### Is a recheck charged if the page is gone?

Yes. When the page was fetched, the call is charged and the answer is `gone` or `unreadable`. A bad baseline or a body that fails validation is a 400 before payment and is never charged.

### Does `unchanged` mean nothing on the page moved?

No. It means the clean text is the same byte for byte. Markup, scripts and images can still differ, and `differences` shows `raw_sha256` when the raw bytes moved.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-a-receipt-before-relying-on-it.md

# How to check a signed receipt before you rely on it, step by step with curl

Last updated: 2026-10-13

To check that a receipt really came from AttestPage and was not altered, send it to `POST /v1/receipt/verify`. It is free: no payment, account or key. The route checks the signature against our published keys and returns `valid`, the key that signed it, the `tier` and the decoded payload.

This guide checks a sample receipt with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For every field and error, see [Verify a receipt](/docs/receipt-verify). To check without calling our server at all, see [Verify a receipt offline](/docs/verify-offline).

## What the check does

- **Checks the signature.** The receipt is a compact JWS signed with Ed25519. The route looks up the signing key in our [JWKS](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json) and checks the signature and the issuer.
- **Returns the payload.** On success you get the decoded fields, such as `kind`, `url`, `content_sha256` and `retrieved_at`.
- **Names a reason when it fails.** `valid` is `false` and `reason` is one of `malformed`, `bad_alg`, `bad_signature`, `unknown_kid`, `bad_iss` or `tier_key_mismatch`.
- **Says what kind of receipt it is.** `tier` is `paid`, `trial` or `sample`. Sample receipts use a separate key and say nothing about a third-party page.
- **Says when the key is retired.** A receipt signed by a key we have since retired still checks as `valid`, and the answer adds `retired: true`. The signature is still good; the key is no longer used to sign new receipts.
- **Stores nothing.** The receipt is checked and dropped.

A valid receipt records what our fetcher saw at the time it was signed. It does not say the page was correct.

## Price

Free. `POST /v1/receipt/verify` is not charged, needs no x402 payment and has no trial limit. Paid routes that issue receipts are listed in [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json); they are paid in USDC with x402 v2 on Base Sepolia (a test network).

## 1. Get a sample receipt

The free sample fetch returns a receipt signed with the example key. Save it as `receipt.txt`:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch | jq -r .receipt > receipt.txt
```

A receipt from a paid or trial call works the same way: take the `receipt` field of the answer.

## 2. Check it

```sh
jq -Rs '{receipt: rtrimstr("\n")}' receipt.txt \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- \
  | jq '{valid, tier, kind: .payload.kind, url: .payload.url}'
```

```json
{
  "valid": true,
  "tier": "sample",
  "kind": "fetch",
  "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page"
}
```

The body is `{"receipt": "<compact JWS>"}`, at most 163,840 characters. A body that is not JSON, or a missing or too long `receipt`, gets 400.

## 3. See what an altered receipt looks like

Change the last four characters of the receipt and check it again:

```sh
r=$(cat receipt.txt)
jq -n --arg r "${r%????}AAAA" '{receipt: $r}' \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- \
  | jq '{valid, reason, message}'
```

```json
{
  "valid": false,
  "reason": "bad_signature",
  "message": "Signature does not verify."
}
```

Treat any receipt with `valid: false` as unusable. The route still answers 200, so read `valid` and do not rely on the status code.

## 4. Read the payload

When `valid` is `true`, `payload` has the facts the receipt records. For a fetch receipt:

```sh
jq -Rs '{receipt: rtrimstr("\n")}' receipt.txt \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- \
  | jq '.payload | {kind, iss, retrieved_at, content_kind, http_status}'
```

`iss` is the issuer, `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`. A receipt whose issuer differs fails with `bad_iss`. To match page text to the receipt, hash the text with SHA-256 and compare it with `content_sha256`.

## With MCP

The same check is the free MCP tool `attestpage_verify_receipt`, with `{"receipt": "<compact JWS>"}` as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`, using the receipt from step 1:

```sh
jq -Rs '{jsonrpc: "2.0", id: 1, method: "tools/call", params: {name: "attestpage_verify_receipt", arguments: {receipt: rtrimstr("\n")}}}' receipt.txt \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- \
  | jq '.result.content[0].text | fromjson | {valid, tier}'
```

```json
{
  "valid": true,
  "tier": "sample"
}
```

## Questions

### How much does it cost to check a receipt?

Nothing. `POST /v1/receipt/verify` and the MCP tool `attestpage_verify_receipt` are free, with no payment and no trial limit.

### Does a valid receipt mean the page is accurate?

No. It means we signed it and it has not changed since. It records what our fetcher saw at the time, not whether the page was right.

### Can I check a receipt without calling your server?

Yes. The signing keys are public in the [JWKS](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/jwks.json), so any Ed25519 and JWS library can check a receipt. [Verify a receipt offline](/docs/verify-offline) shows how.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/verify-citations-before-answering.md

# How to check the citations at the end of an answer before you send it, step by step with curl

Last updated: 2026-10-13

To check up to 10 citations in one call, send each quote and the URL it is attributed to to `POST /v1/verify/citations` (US$0.10 per batch). AttestPage fetches each distinct page once, looks for each quote on its page, says whether the page loaded as real content, and returns one signed receipt for the whole batch.

This guide runs the call with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For every field and error, see [Verify citations](/docs/verify-citations).

## What the check does

- **Fetches each page once.** Several quotes on the same URL share one fetch, following redirects.
- **Matches each quote.** Both texts are normalised first. `exact` means the words are there; `fuzzy` means a close match at or above `threshold` (default 0.9); `none` means neither. With `"match": "passages"` each quote is a claim and you get the closest passages of the page to judge yourself.
- **Judges each page.** `content_kind` is `real` when the page loaded as content, or `bot_wall`, `js_shell`, `paywall`, `http_error` and others when it did not.
- **Adds paper data.** A page with a DOI also gets its title, authors, year and a retraction flag from Crossref.
- **Signs a receipt.** One Ed25519 receipt covers the pages, the options and each verdict. It holds the hash of each quote, not its text.

## Price

US$0.10 per batch of up to 10 citations, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request with a malformed URL, an empty quote or a page that robots.txt disallows gets an error before payment and is never charged. A batch where no host name resolves is a 422 and is not charged either. A dead domain in a batch that has other live pages is a result, and the batch is charged. For one to nine citations, one [verify/quote](/docs/verify-quote) call per pair costs less. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample checks three citations on the demo site: one close match, one quote that is not on the page, and one page that does not exist.

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/citations | jq '.results[] | {url, match, score, kind: .content_kind}'
```

```json
{
  "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
  "match": "fuzzy",
  "score": 0.963,
  "kind": "real"
}
{
  "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/page",
  "match": "none",
  "score": null,
  "kind": "real"
}
{
  "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/missing",
  "match": "none",
  "score": null,
  "kind": "http_error"
}
```

## 2. Read the price from the 402 offer

Step 3 explains the body. A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/citations -H 'content-type: application/json' \
  -d '{ "citations": [ { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" }, { "url": "https://www.iana.org/domains/reserved", "quote": "IANA-managed Reserved Domains" } ] }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `100000` is US$0.10.

## 3. Check the citations

Send `citations`, a list of 1 to 10 objects with a `url` and a `quote` (at most 1,000 characters after normalisation). Optional fields: `match` (`fuzzy` by default, `exact` or `passages`), `case_sensitive` and `threshold`. This body checks two pages on iana.org:

```sh
cat > body.json <<'EOF'
{ "citations": [
  { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" },
  { "url": "https://www.iana.org/domains/reserved", "quote": "IANA-managed Reserved Domains" }
] }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json`.

## 4. Read the answer

```sh
jq '{summary, results: [.results[] | {match, score, kind: .content_kind, advice}]}' answer.json
```

`results` has one entry per citation, in request order. `summary` counts `exact`, `fuzzy` and `none` verdicts, and `failed` for citations that carry an `error` instead of a verdict.

| `match` | `content_kind` | What it means |
|---|---|---|
| `exact` or `fuzzy` | `real` | The quote, or a close version of it, is on the page. `start`, `end` and `context` show where. |
| `none` | `real` | The page loaded and the quote is not on it. Check the quote before you cite it. |
| `none` | anything else | We could not read the page (404, bot wall, JavaScript shell), so we cannot say whether the quote is on it. Read `advice`. |

A citation whose quote is too costly to match fuzzily gets an `error` with code `match_too_costly` on that citation only; the rest are still checked. Use `"match": "exact"` or a shorter quote.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

## With MCP

The same call is the MCP tool `attestpage_verify_citations`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_verify_citations",
    "arguments": { "citations": [
      { "url": "https://www.iana.org/help/example-domains", "quote": "These domains may be used as illustrative examples in documents" },
      { "url": "https://www.iana.org/domains/reserved", "quote": "IANA-managed Reserved Domains" }
    ] },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "100000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`.

## Questions

### How much does it cost to check citations?

US$0.10 per batch of up to 10 citations. Ten citations in one call cost the same as one.

### Is a batch charged if a page is dead?

Yes, when other pages in the batch resolve: a page that is gone or behind a bot wall is a result, and the batch is charged. If no host name in the batch resolves, the call is a 422 and is not charged. If a page turns out to be disallowed by robots.txt after payment, the whole batch is answered with an error and not charged.

### Does `none` mean the quote is not on the page?

Only when `content_kind` is `real`. On a 404, bot wall or JavaScript shell we could not read the page, so `none` says nothing about the quote.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/check-many-quotes-on-one-page.md

# How to check many quotes against one page in a single call, step by step with curl

Last updated: 2026-10-13

To check up to 20 quotes against the same web page, send the URL and the quotes to `POST /v1/verify/quotes` (US$0.02 per call). AttestPage fetches the page once, looks for each quote on it, says whether the page loaded as real content, and returns one signed receipt for the whole call.

This guide runs the call with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For every field and error, see [Verify quotes on one page](/docs/verify-quotes).

## What the check does

- **Fetches the page once.** Every quote is checked against the same copy, following redirects.
- **Matches each quote.** Both texts are normalised first. `exact` means the words are there; `fuzzy` means a close match at or above `threshold` (default 0.9); `none` means neither. With `"match": "passages"` each quote is a claim and you get the closest passages of the page to judge yourself.
- **Judges the page.** `content_kind` is `real` when the page loaded as content, or `bot_wall`, `js_shell`, `paywall`, `http_error` and others when it did not.
- **Signs a receipt.** One Ed25519 receipt covers the page, the options and each verdict. It holds the hash of each quote, not its text.

## Price

US$0.02 per call, whether it carries 1 quote or 20, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request with a malformed URL, an empty quote or a page that robots.txt disallows gets an error before payment and is never charged. If every quote is too costly to match, the call is a 422 and is not charged. From 3 quotes on the same page, this costs less than one [verify/quote](/docs/verify-quote) call per quote. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample checks three quotes on the demo page: one word for word, one close match and one that is not on the page.

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quotes | jq '.results[] | {match, score}'
```

```json
{
  "match": "exact",
  "score": 1
}
{
  "match": "fuzzy",
  "score": 0.963
}
{
  "match": "none",
  "score": null
}
```

## 2. Read the price from the 402 offer

Step 3 explains the body. A request with a valid body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/quotes -H 'content-type: application/json' \
  -d '{ "url": "https://www.iana.org/help/example-domains", "quotes": [ "These domains may be used as illustrative examples in documents", "without prior coordination with us" ] }' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `20000` is US$0.02.

## 3. Check the quotes

Send `url` and `quotes`, a list of 1 to 20 strings (at most 1,000 characters each after normalisation). Optional fields: `match` (`fuzzy` by default, `exact` or `passages`), `case_sensitive` and `threshold`. This body checks two quotes on iana.org:

```sh
cat > body.json <<'EOF'
{ "url": "https://www.iana.org/help/example-domains",
  "quotes": [
    "These domains may be used as illustrative examples in documents",
    "without prior coordination with us"
  ] }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json`.

## 4. Read the answer

```sh
jq '{summary, kind: .page.content_kind, results: [.results[] | {match, score}]}' answer.json
```

`results` has one entry per quote, in request order. `summary` counts `exact`, `fuzzy` and `none` verdicts, and `failed` for quotes that carry an `error` instead of a verdict. `page.content_kind` and `advice` are for the page as a whole.

| `match` | `page.content_kind` | What it means |
|---|---|---|
| `exact` or `fuzzy` | `real` | The quote, or a close version of it, is on the page. `start`, `end` and `context` show where. |
| `none` | `real` | The page loaded and the quote is not on it. Check the quote before you cite it. |
| `none` | anything else | We could not read the page (404, bot wall, JavaScript shell), so we cannot say whether the quote is on it. Read `advice`. |

A quote that is too costly to match fuzzily gets an `error` with code `match_too_costly` on that quote only; the rest are still checked. Use `"match": "exact"`, a shorter quote or fewer quotes per call.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

## With MCP

The same call is the MCP tool `attestpage_verify_quotes`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_verify_quotes",
    "arguments": { "url": "https://www.iana.org/help/example-domains",
      "quotes": [
        "These domains may be used as illustrative examples in documents",
        "without prior coordination with us"
      ] },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "20000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`.

## Questions

### How much does it cost to check many quotes on one page?

US$0.02 per call for 1 to 20 quotes. Twenty quotes in one call cost the same as one.

### Is the call charged if the page is dead?

A page that is gone or behind a bot wall is a result, and the call is charged. A host name that does not resolve gets 422 host_not_found before payment and is not charged. A request that fails validation, or one where every quote is too costly to match, is not charged. If the page turns out to be disallowed by robots.txt after payment, the call is answered with an error and not charged.

### Does `none` mean the quote is not on the page?

Only when `page.content_kind` is `real`. On a 404, bot wall or JavaScript shell we could not read the page, so `none` says nothing about the quote.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/use-attestpage-text-quote.md

# How to check a quote against text you already hold, step by step with curl

Last updated: 2026-10-13

To check that a quote really appears in a text you already have, such as a file you read, a tool result or a document, send the text and the quote, word for word, to `POST /v1/verify/text-quote` (US$0.005 per call). Nothing is fetched. AttestPage searches the text you sent and answers `exact`, `fuzzy` or `none`, with a score, the offsets of the match and a signed receipt.

This guide runs the check with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. To check a quote against a live web page instead, use [Verify a quote](/docs/verify-quote), which fetches the page.

## What the check does

- **Reads the text you send.** The text is not fetched, so there are no redirects, bot walls or DNS failures. The text is hashed as sent, and the receipt records that hash.
- **Matches the quote.** Both texts are normalised first (Unicode NFKC, plain quotes and dashes, one space for any whitespace). `exact` means the words are there after normalisation; `fuzzy` means a close match scored at or above `threshold` (default 0.9); `none` means neither.
- **Checks a slice if you ask.** Send `start` and `end` and only that part of the text is matched, so the answer is whether the text at those offsets says the quote.
- **Flags instructions in the text.** `injection_flags` lists instruction-like wording found in the text. Agents paste untrusted output, so read this list.
- **Signs a receipt.** An Ed25519 receipt records the hash of the text, the quote hash and the match. Anyone can check it later against our published keys.

## Price

US$0.005 per call, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample runs the same route on a demo sentence:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/textquote | jq '{match: .result.match, score: .result.score, start: .result.start, end: .result.end, advice}'
```

```json
{
  "match": "fuzzy",
  "score": 0.963,
  "start": 43,
  "end": 70,
  "advice": "The supplied text contains a close match to this quote, with small differences. This says nothing about where the text came from."
}
```

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/verify/text-quote -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `5000` is US$0.005.

## 3. Check a quote

Put the text and the quote, exactly as the LLM gave it, in a file:

```sh
cat > body.json <<'EOF'
{ "text": "Refunds are paid within 14 days of purchase, to the card that was used.", "quote": "refunds are paid within 14 days", "match": "fuzzy" }
EOF
```

`text` may be up to 50,000 characters and 64 KB of UTF-8. `quote` may be up to 1,000 characters. Do not send a `url` field: this route never fetches, so an unknown field gets 400.

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json` for the steps below.

There is no free trial at the moment; use the free samples instead.

## 4. Read the answer

Read `result.match` first, then `injection_flags`:

| `match` | What it means |
|---|---|
| `exact` | The quoted words are in the text after normalisation. |
| `fuzzy` | A close match. Compare `result.context` with the quote: a word may have changed or two sentences may have been joined. |
| `none` | The quote is not in the text. Do not quote it from this source. |

`result.occurrences` says how many times the quote was found. `result.start` and `result.end` are offsets into the normalised text, not into what you sent, and `result.normalised_sha256` is the hash of that normalised text.

To check one part of the text, add `start` and `end` to the body. They are offsets into your text as sent, counted in characters (code points), with `end` not included, and the slice may be up to 1,000 characters. The answer then has `result.declared` with `slice_matches`, which is `true` when the text at those offsets says the quote. Offsets are raw; the result offsets from a search are normalised, so do not mix the two. If the slice misses but the quote is elsewhere in the text, `result.located` gives its position in the whole text, with normalised offsets.

If the LLM paraphrased rather than quoted, send `"match": "passages"` with the claim as `quote`. You get the passages of the text that share most of its words, as evidence to read, not a verdict. Offsets cannot be used with `passages`.

```json
{
  "result": {
    "match": "exact", "score": 1, "start": 0, "end": 31,
    "context": "Refunds are paid within 14 days of purchase, to the card that was used.",
    "occurrences": 1, "normalised_sha256": "…",
    "source": { "kind": "supplied", "text_sha256": "…", "code_points": 71 }
  },
  "injection_flags": [],
  "advice": "The supplied text contains this quote. This says nothing about where the text came from.",
  "receipt": "eyJ…",
  "tier": "trial"
}
```

The `advice` line is a reminder, not a verdict on the source. The check says what the text you sent says; it does not say where the text came from.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Or check it offline with our single-file checker: [Verify receipts offline](/docs/verify-offline). The receipt attests the hash of the text and the match. It does not show that the text came from any particular site.

## With MCP

The same check is the MCP tool `attestpage_verify_text_quote`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_verify_text_quote",
    "arguments": { "text": "Refunds are paid within 14 days of purchase, to the card that was used.", "quote": "refunds are paid within 14 days", "match": "fuzzy" },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "5000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does one check cost?

US$0.005 per call with `POST /v1/verify/text-quote`. A check against a live web page costs more, because it fetches the page: [Verify a quote](/docs/verify-quote).

### Does an exact match mean the quoted claim is right?

No. It means those words are in the text you sent. Whether that text is right, or where it came from, is a separate question.

### Is a call charged when it fails?

Only answers below 400 are charged. A request that fails validation, such as an unknown field, a missing `quote`, or offsets that are out of range, is never charged. Every case is in [Payments](/docs/payments) and [Errors](/docs/errors).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/read-web-page-as-clean-text.md

# How to turn a web page into clean text for an agent, step by step with curl

Last updated: 2026-10-13

To read a web page without its markup, scripts and menus, send its URL to `POST /v1/fetch` with `"return_text": true` (US$0.002 per page). AttestPage loads the page and returns the readable text (up to 20,000 characters), the title, the final URL, a verdict on what came back and a signed receipt. A PDF with a text layer is read the same way.

This guide runs the call with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, then shows the same call as an MCP tool. For every field, see [Fetch a page](/docs/fetch). To pay for the call from code with an x402 client, see [Fetch a page as clean text with an x402 client](/guides/fetch-a-page-with-an-x402-client).

## What you get back

- **Clean text.** `text` is the page's readable text in reading order. Tags, scripts and styles are left out.
- **A verdict.** `page.content_kind` says whether the URL gave you real content or a bot challenge, an empty JavaScript shell, a paywall or an error. A challenge page is reported as such rather than handed back as if it were the article.
- **Flags.** `injection_flags` lists instruction-like patterns found in the text, such as `instruction_override`. They are flags, not a verdict: an empty list means none of our patterns matched.
- **A receipt.** A signed record of the final URL, status, fetch time and a hash of the full text.
- **Several pages.** Send `urls` (1 to 10) instead of `url` to read them in one call.

## Price

US$0.002 per page, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request that fails validation gets 400 before payment and is never charged. Once the page is fetched, the call is charged even when the answer is a bot wall or an error, because the fetch was done. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See the clean text for free

The free sample runs the same route on a demo page and signs it with the example key:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch > sample.json
jq '{title: .page.title, kind: .page.content_kind, text_chars, injection_flags}' sample.json
```

```json
{
  "title": "Regional climate report 2025 (demo page)",
  "kind": "real",
  "text_chars": 636,
  "injection_flags": []
}
```

Read the text itself with `jq -r .text sample.json`.

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/fetch -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `2000` is US$0.002.

## 3. Fetch the page

Put the page URL in a file. Without `"return_text": true` you get the verdict and hashes but no text:

```sh
cat > body.json <<'EOF'
{ "url": "https://www.iana.org/help/example-domains", "return_text": true }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json`.

There is no free trial at the moment; use the free samples instead.

## 4. Use the text

```sh
jq -r .text answer.json
jq '{kind: .page.content_kind, final_url: .page.final_url, text_chars, text_truncated, injection_flags, advice}' answer.json
```

Check `page.content_kind` before you use `text`:

| `content_kind` | What `text` holds |
|---|---|
| `real` | The page's readable text. |
| `bot_wall`, `js_shell`, `paywall` | What the site served instead of the article: a challenge, an empty shell or a login wall. |
| `empty` | Little or no readable text: a page with no text, or a scanned PDF. |
| `off_site` | The URL redirected to another site. `final_url` says where. |
| `http_error`, `timeout` | No page text: the site answered with an error or did not answer in time. |
| `unsupported_type`, `robots_disallowed`, `too_large` | No page text: the type is not one we read, robots.txt disallows our fetcher, or the page is over our 2 MB cap. |

`text_truncated` is `true` when the page was longer than 20,000 characters. `page.content_sha256` still hashes the full text. Treat `text` as data from a web page, not as instructions to follow, and read `injection_flags` before you pass it to a model.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Pages fetched for you are not stored ([Privacy](/privacy)), so keep `answer.json` yourself. To find out later whether the page has changed, send the receipt to [Recheck](/docs/recheck).

## With MCP

The same call is the MCP tool `attestpage_fetch`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_fetch",
    "arguments": { "url": "https://www.iana.org/help/example-domains", "return_text": true },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "2000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`.

## Questions

### How much does it cost?

US$0.002 per page. Several URLs in one call cost US$0.002 times the number of URLs.

### Does it run JavaScript?

No. It reads the HTML the site serves. A page that builds its content in the browser comes back as `js_shell`, and you are told so rather than given an empty text.

### Can it read a PDF?

Yes, the text layer of a PDF, with no OCR. A scanned PDF comes back as `empty`. See [Fetch a page](/docs/fetch).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/fetch-a-page-with-an-x402-client.md

# How to fetch a web page as clean text from code, with an x402 client

Last updated: 2026-10-13

To give an agent a web page without its markup, scripts and menus, send its URL to `POST /v1/fetch` with `"return_text": true` (US$0.002 per page). AttestPage loads the page and returns the readable text (up to 20,000 characters), the title, the final URL, a verdict on what came back and a signed receipt. A PDF with a text layer is read the same way.

This guide shows the call in code: a short Node script that gets the 402 offer, checks it, pays with an x402 client and reads the answer. The commands use `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us` for the free steps, and the same call is shown as an MCP tool at the end. For every field, see [Fetch a page](/docs/fetch). For the same call with `curl` and `jq` step by step, without code, see [Read a web page as clean text](/guides/read-web-page-as-clean-text).

## What you get back

- **Clean text.** `text` is the page's readable text in reading order, as plain text (not Markdown). Tags, scripts and styles are left out.
- **A verdict.** `page.content_kind` says whether the URL gave you real content or a bot challenge, an empty JavaScript shell, a paywall or an error.
- **Flags.** `injection_flags` lists instruction-like patterns found in the text. They are flags, not a verdict: an empty list means none of our patterns matched.
- **A receipt.** A signed record of the final URL, status, fetch time and a hash of the full text.

## Price

US$0.002 per page, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up is needed to read the free sample. A request that fails validation gets 400 before payment and is never charged. Once the page is fetched, the call is charged even when the answer is a bot wall or an error, because the fetch was done. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See the clean text for free

The free sample runs the same route on a demo page and signs it with the example key:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch > sample.json
jq '{title: .page.title, kind: .page.content_kind, text_chars, injection_flags}' sample.json
```

```json
{
  "title": "Regional climate report 2025 (demo page)",
  "kind": "real",
  "text_chars": 636,
  "injection_flags": []
}
```

Read the text itself with `jq -r .text sample.json`.

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/fetch -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `2000` is US$0.002.

## 3. Fetch the page with an x402 client

The request body is one URL and `return_text`. Without `"return_text": true` you get the verdict and hashes but no text:

```sh
cat > body.json <<'EOF'
{ "url": "https://www.iana.org/help/example-domains", "return_text": true }
EOF
```

Save this as `fetch-page.mjs`. It sends the request, reads the offer, signs it with the wallet in `ATTESTPAGE_X402_KEY` and sends the same request again. The script will not sign an offer on another network or above US$0.01:

```js
import { writeFile } from 'node:fs/promises';
import { x402Client, x402HTTPClient } from '@x402/core/client';
import { registerExactEvmScheme } from '@x402/evm/exact/client';
import { privateKeyToAccount } from 'viem/accounts';

const BASE = 'https://s2h6qt73jtzlgbgnnfacln2poq.srv.us';
const NETWORK = 'eip155:8453'; // Base
const MAX_USD = 0.01; // the most this script will pay: one page is US$0.002

const pageUrl = process.argv[2];
if (!pageUrl) throw new Error('usage: node fetch-page.mjs <page url>');
const url = `${BASE}/v1/fetch`;
const request = {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ url: pageUrl, return_text: true }),
};

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.ATTESTPAGE_X402_KEY) });
const x402 = new x402HTTPClient(client);

// 1. Send the request with no payment. A valid request gets 402, with the offer in PAYMENT-REQUIRED.
let res = await fetch(url, request);
if (res.status !== 402) throw new Error(`expected 402, got ${res.status}: ${await res.text()}`);
const offer = x402.getPaymentRequiredResponse((name) => res.headers.get(name), await res.json());

// 2. Check the offer before signing: right network, and the price within MAX_USD (USDC has 6 decimals).
const accepts = offer.accepts.filter((a) => a.network === NETWORK && Number(a.amount) <= MAX_USD * 1e6);
if (accepts.length === 0) throw new Error(`no acceptable offer: ${JSON.stringify(offer.accepts)}`);
console.log(`price: US$${Number(accepts[0].amount) / 1e6} on ${accepts[0].network}, pay to ${accepts[0].payTo}`);

// 3. Sign the offer and send the same request again with PAYMENT-SIGNATURE.
const payment = await x402.createPaymentPayload({ ...offer, accepts });
res = await fetch(url, { ...request, headers: { ...request.headers, ...x402.encodePaymentSignatureHeader(payment) } });
const answer = await res.json();
if (!res.ok) throw new Error(`${res.status} ${answer.error?.code}: ${answer.error?.message}`);

// 4. A settled call carries PAYMENT-RESPONSE: the transaction, payer and network.
const settlement = x402.getPaymentSettleResponse((name) => res.headers.get(name));
console.log('settled:', settlement.transaction, 'from', settlement.payer, 'on', settlement.network);
console.log(answer.page.content_kind, answer.page.final_url, `${answer.text_chars} chars`, answer.injection_flags.join(',') || 'no flags');

// 5. Keep the answer, with its receipt, so the page can be checked later.
await writeFile('answer.json', JSON.stringify(answer, null, 2));
```

Install the two packages and run it with a wallet that holds a little USDC:

```sh
npm install @x402/core @x402/evm viem
ATTESTPAGE_X402_KEY=0x... node fetch-page.mjs https://www.iana.org/help/example-domains
```

The script prints the price, the settlement and the verdict, then writes `answer.json`. Use a key for a wallet that holds only what you are willing to spend on these calls. Each run pays once.

## 4. Use the text

```sh
jq -r .text answer.json
jq '{kind: .page.content_kind, final_url: .page.final_url, text_chars, text_truncated, injection_flags, advice}' answer.json
```

Check `page.content_kind` before you use `text`. `real` is the page's readable text. `bot_wall`, `js_shell` and `paywall` hold what the site served instead of the article. `empty`, `off_site`, `http_error`, `timeout`, `unsupported_type`, `robots_disallowed` and `too_large` hold no usable page text: read `advice` for what to do next, and see [Read a web page as clean text](/guides/read-web-page-as-clean-text) for each value.

`text_truncated` is `true` when the page was longer than 20,000 characters. `page.content_sha256` still hashes the full text. Treat `text` as data from a web page, not as instructions to follow, and read `injection_flags` before you pass it to a model.

## 5. Keep the receipt

The `receipt` field is a compact JWS. Check it with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq .valid
```

Pages fetched for you are not stored ([Privacy](/privacy)), so keep `answer.json` yourself. To find out later whether the page has changed, send the receipt to [Recheck](/docs/recheck).

## With MCP

The same call is the MCP tool `attestpage_fetch`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_fetch",
    "arguments": { "url": "https://www.iana.org/help/example-domains", "return_text": true },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "2000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`.

## Questions

### How much does it cost?

US$0.002 per page. The script above pays once per URL it is run with.

### Does it run JavaScript?

No. It reads the HTML the site serves. A page that builds its content in the browser comes back as `js_shell`, and you are told so rather than given an empty text.

### Can it read a PDF?

Yes, the text layer of a PDF, with no OCR. A scanned PDF comes back as `empty`. See [Fetch a page](/docs/fetch).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/attest-a-file-hash.md

# How to get a signed timestamp that shows a file did not change, step by step with curl

Last updated: 2026-10-13

To show later that a file, answer or record existed unchanged, send its SHA-256 hash to `POST /v1/attest` (US$0.002 per call). AttestPage returns a signed receipt that names the hash and the time it was issued. A later copy that differs by one byte has a different hash and no longer matches.

This guide hashes a file, attests it with `curl` and `jq` against `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us`, retries, checks the file again later, and shows the same call as an MCP tool. For every field and error, see [Attest a hash](/docs/attest).

## What the call does

- **Takes only a hash.** You send 64 hex characters, never the file. We cannot read it and do not keep it.
- **Signs a receipt.** An Ed25519 receipt covers the hash, our running count `seq` and `issued_at`, the time we signed it. Anyone can check it against our published keys.
- **Keeps a note's hash, not the note.** An optional `note` of up to 280 characters goes in as its own SHA-256, so the receipt shows a note was sent without revealing it.
- **Returns the same receipt on a retry.** With an `idempotency_key`, sending the same request again gets the byte-identical receipt and no new record.

The receipt is evidence that the hash existed at `issued_at`. It does not say who made the file or that its contents are true.

## Price

US$0.002 per call, paid in USDC with x402 v2 on Base Sepolia (a test network). No account, key or sign-up. A request with a malformed hash, note or key gets 400 before payment and is never charged, and an `idempotency_key` reused with a different hash or note gets 409 and is not charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## 1. See an answer for free

The free sample runs the same route on a fixed demo page:

```sh
curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/attest | jq '{sha256: .attestation.sha256, seq: .attestation.seq, first_seen: .attestation.first_seen, tier}'
```

```json
{
  "sha256": "179b9ac481c5d31db5b6493fdf77b3c741c944afd4845677f798d19b428efb08",
  "seq": 1,
  "first_seen": true,
  "tier": "sample"
}
```

## 2. Read the price from the 402 offer

A request with an empty body gets the payment offer without being charged. The `PAYMENT-REQUIRED` header is base64 JSON:

```sh
curl -si -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/attest -H 'content-type: application/json' -d '{}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 -d \
  | jq '.accepts[0] | {scheme, network, amount, payTo}'
```

`amount` is in USDC base units (6 decimals), so `2000` is US$0.002.

## 3. Attest the file

Take the hash of the file: `shasum -a 256 report.txt` on macOS or `sha256sum report.txt` on Linux. This body attests a file that holds the word `hello` and a line break, with a note:

```sh
cat > body.json <<'EOF'
{ "sha256": "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03",
  "note": "report v3 delivered to order 77" }
EOF
```

Pay with any x402 v2 client: it reads the offer from step 2, signs it and sends the same request again with a `PAYMENT-SIGNATURE` header. [One x402 payment step by step](/docs/examples/fetch-x402) shows this with plain `fetch`, and the [MCP server](/docs/mcp) does it for you. Save the answer as `answer.json`.

There is no free trial at the moment; use the free samples instead.

## 4. Read the answer

```sh
jq '{sha256: .attestation.sha256, seq: .attestation.seq, issued_at: .attestation.issued_at, first_seen: .attestation.first_seen}' answer.json
```

| Field | What it means | What to do |
|---|---|---|
| `attestation.sha256` | The hash you sent, in lower case. | Check it is the hash of your file. |
| `attestation.issued_at` | When we signed the receipt. | Keep it: it is the time the hash is shown to have existed. |
| `attestation.seq` | Our running count of attestations. | Keep it with the receipt. |
| `attestation.note_sha256` | The SHA-256 of your note, or null if you sent none. | Compare it with the hash of the note you kept. |
| `attestation.first_seen` | `true` for a new record, `false` when an `idempotency_key` returned an earlier receipt. | Treat `false` as a repeat of the earlier call. |
| `receipt` | The signed receipt, a compact JWS. | Store it next to the file. |

## 5. Retry without a second record

If a call times out, you cannot tell whether it was recorded. Send an `idempotency_key` of 1 to 128 printable ASCII characters without spaces (for example `order-77-delivery`) on the first call. If that call times out, send the same request again with the same key:

```json
{ "sha256": "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03",
  "note": "report v3 delivered to order 77", "idempotency_key": "order-77-delivery" }
```

The same key with the same hash and note returns the byte-identical receipt and `first_seen: false`. The same key with a different hash or note gets 409 `idempotency_conflict`; the payment is checked first and then released, so you are not charged. Keys belong to the paying address, so two payers can use the same key. They need an x402 payment: a trial call, an L402 payment or a credit key gets 400 if it sends one. We keep only the SHA-256 of the key.

## 6. Check the file later

Hash the file again and compare it with the receipt. Check the receipt with the free verify route:

```sh
jq '{receipt}' answer.json \
  | curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d @- | jq '{valid, sha256: .payload.result.sha256}'
```

`valid: true` with a `sha256` equal to the hash of the file you hold now means the file is unchanged since `issued_at`. If the hashes differ, the file is not the one that was attested. You can also check the receipt offline: [Verify receipts offline](/docs/verify-offline).

## With MCP

The same call is the MCP tool `attestpage_attest`, with the body from step 3 as its arguments. To use it from an MCP client with nothing to install, add the remote endpoint:

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

Or run the local server, which pays from your own wallet key within limits you set: [MCP server](/docs/mcp).

One call to the remote endpoint with `curl`. `_meta["attestpage/trial"]` set to `false` asks for the payment offer rather than a trial call, so nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 1, "method": "tools/call",
  "params": { "name": "attestpage_attest",
    "arguments": { "sha256": "5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03", "note": "report v3 delivered to order 77" },
    "_meta": { "attestpage/trial": false } } }
EOF
```

```json
{
  "scheme": "exact",
  "network": "eip155:8453",
  "amount": "2000"
}
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`, with the same `amount` as step 2. Sign one of `accepts`, put the payload in `_meta["x402/payment"]` and call again: `structuredContent` is then the same JSON as `answer.json`, and `_meta["x402/payment-response"]` holds the settlement.

## Questions

### How much does it cost to attest a hash?

US$0.002 per call with `POST /v1/attest`, whatever the file size, because only the hash is sent.

### Do you see or keep my file?

No. We receive 64 hex characters. A `note` and an `idempotency_key` are kept only as SHA-256 hashes.

### Does the receipt show who wrote the file?

No. It shows that this hash was presented to us at `issued_at`. It does not name an author and does not say the contents are true. For signed evidence of what a web page said, use [a signed receipt of a web page](/guides/signed-page-receipt).

### What if I retry after a timeout?

Send the same request again with the same `idempotency_key`: you get the earlier receipt and no second record. The retry is a new payment unless you resend it with the same payment-identifier ([Payments](/docs/payments)). Without a key, each call is a new record and is charged.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/guides/use-attestpage-tools-in-mcp.md

# How to use AttestPage tools from an MCP client, step by step with curl

Last updated: 2026-10-13

To give an MCP client the AttestPage tools, add the remote endpoint `https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp`. Each tool runs one paid route, from US$0.002 to US$0.10 per call, and the client pays per call in USDC with x402. Nothing is installed.

This guide lists the tools, calls one with `curl`, reads the 402 offer and shows where the payment goes. For the full reference, see [MCP server](/docs/mcp).

## What the endpoint does

- **Speaks streamable HTTP.** Each POST to `/mcp` carries one JSON-RPC message and gets one JSON answer. There are no sessions and no event stream, so GET returns 405.
- **Gives one tool per route.** A tool call runs the matching route on this server, so prices, limits and refunds are the same as calling the route directly.
- **Needs no account.** There is no key or sign-up. The caller pays with an x402 payment in the call.

## Price

Each tool costs what its route costs, paid in USDC with x402 v2 on Base Sepolia (a test network). A call that fails validation is never charged. All prices: [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

| Tool | Does | Price per call |
|---|---|---|
| `attestpage_verify_quote` | Checks a quote against a web page | US$0.01 |
| `attestpage_verify_quotes` | Checks up to 20 quotes on one page | US$0.02 |
| `attestpage_verify_text_quote` | Checks a quote against text you already hold, nothing fetched | US$0.005 |
| `attestpage_verify_citations` | Checks up to 10 quote and URL pairs | US$0.10 |
| `attestpage_verify_document` | Checks the quotes and links in a document, 10 pairs per part | US$0.10 |
| `attestpage_fetch` | Reads a page as clean text with a signed verdict | US$0.002 |
| `attestpage_recheck` | Compares a page with an earlier receipt | US$0.003 |
| `attestpage_check_links` | Checks up to 10 links | US$0.005 |
| `attestpage_check_packages` | Checks up to 10 package names on npm, PyPI or crates.io | US$0.005 |
| `attestpage_attest` | Signs a timestamped receipt over a SHA-256 hash | US$0.002 |

Two tools are free: `attestpage_verify_receipt` checks a receipt, and `attestpage_preview_document` previews a document check.

## 1. Add the endpoint to your client

```json
{
  "mcpServers": {
    "attestpage": { "type": "http", "url": "https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp" }
  }
}
```

To pay from your own wallet key within limits you set, run the local server instead: [MCP server](/docs/mcp).

## 2. List the tools

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' \
  -d '{ "jsonrpc": "2.0", "id": 1, "method": "tools/list" }' | jq -r '.result.tools[].name'
```

Each tool has an `inputSchema` for its arguments and an `outputSchema` for its result. The arguments are the body of the route, so the other guides apply: for example [How to check links before citing them](/guides/check-links-before-citing) for `attestpage_check_links`.

## 3. Read the 402 offer

Call a tool with `_meta["attestpage/trial"]` set to `false`. That asks for the payment offer, and nothing is charged:

```sh
curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/mcp -H 'content-type: application/json' -d @- <<'EOF' \
  | jq '.result.structuredContent.accepts[0] | {scheme, network, amount}'
{ "jsonrpc": "2.0", "id": 2, "method": "tools/call",
  "params": { "name": "attestpage_fetch",
    "arguments": { "urls": ["https://www.iana.org/help/example-domains"] },
    "_meta": { "attestpage/trial": false } } }
EOF
```

The result has `isError: true` and the x402 payment requirements in `structuredContent`. `amount` is in USDC base units (6 decimals), so `2000` is US$0.002, the price of `attestpage_fetch`.

## 4. Pay and call again

Sign one of `accepts` with your wallet and put the payload in `_meta["x402/payment"]` of the same call. An x402 MCP client such as `@x402/mcp` does this for you. The answer is then the route's JSON in `structuredContent`, and `_meta["x402/payment-response"]` holds the settlement. Payment settles only when the route answers below 400.

Where the free trial is on, a call without a payment of up to 5 items uses the trial first. The cap applies to `verify_citations`, `verify_quotes`, `verify_document` (per pair), `check_links` and `fetch` (per URL), and a call above it gets the offer at once. `check_packages` has no cap: a call of up to 10 names runs as a trial.

## 5. Keep the receipt

Each paid result carries a signed `receipt`. Check it with the free tool `attestpage_verify_receipt`, or see [How to check a signed receipt before you rely on it](/guides/check-a-receipt-before-relying-on-it).

## Questions

### How much does a tool call cost?

It costs the price of its route, from US$0.002 for `attestpage_attest` to US$0.10 for `attestpage_verify_citations`. The table above lists every tool.

### Do I need an account or an API key?

No. The caller pays each call with an x402 payment, and there is no sign-up.

### Which MCP clients work?

Any client that can call a streamable HTTP endpoint with JSON-RPC. A client that signs x402 payments pays by itself; for other clients, use the local server in [MCP server](/docs/mcp), which pays from your wallet key.

### Is a call charged if it fails?

A call that fails validation is not charged. Every case is in [Payments](/docs/payments) and [Errors](/docs/errors).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/check-package-names-before-install.md

# How to check a package name an LLM suggested before installing it

Last updated: 2026-10-10

Before you install a package a model suggested, look the name up in its registry and stop if the registry does not list it. `POST /v1/check/packages` (US$0.005 per batch) checks up to 10 names on npm, PyPI or crates.io in one call and returns, for each, whether the registry lists it, its latest version, creation time and flags, under one signed receipt.

## Why invented names matter

Models sometimes suggest package names that sound right but were never published. Running the install command then fails, or worse: someone can register that name later and publish their own code under it. Checking the name first catches the first case and shows you the flags worth a second look in the second.

## Check a batch

```json
{ "packages": [
  { "ecosystem": "npm", "name": "left-pad" },
  { "ecosystem": "pypi", "name": "requests" },
  { "ecosystem": "crates", "name": "serde" }
] }
```

For each name:

- `exists` is `false` when the registry answered 404: do not install it.
- `signals` lists `created_recently` (under 30 days old), `deprecated`, `yanked` and `name_differs` (the registry spells the name differently).
- `latest_version`, `license`, `homepage` and `repository` come from the registry, so you can compare them with what the model said.

Try the route free on demo data: [`GET /v1/sample/packages`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/packages). Details: [Check packages](/docs/check-packages).

## Questions

### Does a listed package mean it is fine to install?

No. The answer says whether the registry lists the name when we looked. A listed package can still be malicious, abandoned or not the one you meant. Read the signals and the publisher's details before you install.

### Which registries are covered?

npm (including scoped names), PyPI and crates.io. Each name is checked against its registry's naming rules before payment, and a request with an invalid name gets 400 and is not charged.

### What if a registry is down?

A failed lookup is reported per name with status lookup_failed and a reason. If every lookup in the batch fails, the call gets 502 and is not charged. See Payments and Errors in the docs.

### Can my coding agent call it from a sandbox?

Yes, if the sandbox can reach our API. Agents can call it over HTTPS with x402 payment, or through the MCP server, which has one tool per route.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/tell-a-bot-wall-from-the-real-page.md

# How to tell a bot wall from the real page when an agent fetches a URL

Last updated: 2026-10-10

A 200 status does not mean the agent got the page. Check what came back before you summarise or quote it. `POST /v1/fetch` (US$0.002 per call) fetches one URL and returns a `content_kind` verdict (`real`, `bot_wall`, `js_shell`, `paywall`, `empty`, `http_error` and others), the clues behind it, the final URL, hashes and a signed receipt.

## What a fetch can return instead of the page

- **Bot challenge.** A "checking your browser" page or a CAPTCHA. We report it as `bot_wall` and never try to get past it.
- **JavaScript shell.** An almost empty HTML page whose content is drawn by scripts. Reported as `js_shell`.
- **Paywall or login teaser.** The first paragraph, then a sign-in prompt. Reported as `paywall`.
- **Redirect to another site.** A consent page or a home page on a different host. Reported as `off_site`.
- **Error or empty page.** Reported as `http_error` or `empty`.

Only `real` means the text is the page's content. On any other verdict, a summary or a missing quote says nothing about the page.

## Fetch a page

```json
{ "url": "https://www.iana.org/help/example-domains", "return_text": true }
```

With `return_text`, you also get up to 20,000 characters of clean text. The answer lists `injection_flags` when the text holds patterns often used for prompt injection. Try the route free on demo data: [`GET /v1/sample/fetch`](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/fetch). Details: [Fetch a page](/docs/fetch) and [How it works](/docs/how-it-works).

## Questions

### How is the verdict decided?

By automated rules over the status, headers and text. Rules can be wrong, so every answer lists the signals behind its verdict.

### Does it render JavaScript?

No. A page that needs JavaScript is reported as js_shell rather than summarised as empty text, so the agent knows to try another source.

### Is a failed fetch charged?

A result about the page is charged, whatever the verdict, including 404s and bot walls: the verdict is the answer. A fetch that read no page (a timeout, a failed connection, too many redirects) answers 502 `upstream_unreachable` and is not charged. A bad URL, a blocked address or a host name that does not resolve is refused before payment and not charged. See Payments and Errors in the docs.

### Can I show later what the page said?

Yes. The receipt records the URL, final URL, status, verdict, text hash and time, signed with Ed25519, and anyone can check it offline. See How to get a signed receipt of a web page.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/index.md

# AttestPage

Last updated: 2026-10-17

Signed evidence about web pages, for AI agents. Ask whether a quote appears on a page or check every citation in an answer at once, fetch a page and learn what actually came back, check a list of links, check that package names exist on npm, PyPI or crates.io, or timestamp a hash. Every answer carries an Ed25519-signed receipt that anyone can check offline against our published keys.

A receipt records what our fetcher saw at a given time; it does not show that a statement on the page is correct.

## Endpoints

| Route | Price per call | What you get |
|---|---|---|
| `POST /v1/verify/quote` | US$0.01 | your exact words checked against the page: exact, fuzzy or none match, offsets, page hashes, context, page verdict, receipt; or the passages best matching a paraphrased claim |
| `POST /v1/verify/quotes` | US$0.02 per batch | up to 20 quotes on one page: the verify/quote verdict for each, one receipt |
| `POST /v1/verify/text-quote` | US$0.005 | a quote checked against source text you already hold, such as a file or a tool result, with no fetch |
| `POST /v1/verify/citations` | US$0.10 | up to 10 quote and URL pairs: the quote verdict per citation and the page verdict per URL, one receipt |
| `POST /v1/verify/document` | US$0.10 per part | a whole answer or report: its quotes and links found and checked, 10 pairs a part, free preview first |
| `POST /v1/fetch` | US$0.002 | content_kind verdict, status, final URL, title, hashes, injection flags, optional text, receipt |
| `POST /v1/recheck` | US$0.003 | change detection for a page you read earlier: unchanged, changed, gone or unreadable, with the fields that differ |
| `POST /v1/check/links` | US$0.005 | up to 10 URLs: status, redirects, content_kind, hash per URL, one receipt |
| `POST /v1/check/packages` | US$0.005 | up to 10 npm, PyPI or crates.io names: exists in registry, latest version, metadata, one receipt (not a security verdict) |
| `POST /v1/attest` | US$0.002 | signed timestamp over a SHA-256 you supply |
| `POST /v1/receipt/verify` | free | checks a receipt against our keys |
| `GET /v1/sample/{name}` | free | each paid route run on fixed demo data |

Payment is x402 v2 in USDC on Base. A request that fails validation gets 400 before any payment is asked for. See [Payments](/docs/payments) for when a call is charged.

## Start here

1. Call a free sample: `curl https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote`
2. Check its receipt. The `receipt` field of the sample is the signed receipt, a compact string. Save it and check it: `RECEIPT=$(curl -s https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/sample/quote | jq -r .receipt)` then `curl -s -X POST https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/v1/receipt/verify -H 'content-type: application/json' -d "{\"receipt\":\"$RECEIPT\"}"`
3. Call a paid route without payment to see the 402 offer, then pay with any x402 v2 client.
4. There is no free trial at the moment; use the free samples instead.

To see a whole paid call first, the 402 offer, the payment and the signed receipt, read the [demo](/demo). For a free walkthrough of a signed receipt, read the [receipt demo](/docs/receipt-demo).

## For agents

- [llms.txt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/llms.txt) and [llms-full.txt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/llms-full.txt)
- [OpenAPI 3.1](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/openapi.json), [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json), [x402 discovery](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/x402)
- Every page here is also markdown: add `.md` to the URL or send `Accept: text/markdown`.

## Read more

- [Docs](/docs)
- [How it works](/docs/how-it-works)
- [Limits](/docs/limits)
- [Our fetcher and how to opt out](/bot)
- [Status](/status): current state and uptime ([JSON](/status.json))

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/bot.md

# Our fetcher

Last updated: 2026-10-12

AttestPage fetches web pages when an agent asks it to check a quote or a list of citations, fetch a page or check links. This page describes that fetcher and how site owners can stop it.

## How to recognise it

- User agent: `QuoteproofBot/1.0 (+https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/bot)`
- robots.txt token: `QuoteproofBot` (matched without regard to case)
- It fetches only the URL a caller sent, plus that site's `/robots.txt`. It does not crawl or follow links on its own.
- For `check/packages` it also reads the public JSON APIs of registry.npmjs.org, pypi.org and crates.io for the names a caller sent, with the same user agent plus our contact address, and at most one crates.io request a second. It also sends each name and its latest version to the OSV.dev API (api.osv.dev) to list known advisories.

## What it does

- GET requests only, without cookies, logins or any header passed through from the caller.
- http and https on ports 80 and 443 only. It refuses private, loopback and other internal addresses, and checks again after every redirect.
- Up to 5 redirects. It gives up after 5 seconds to connect and 10 seconds in all.
- Reads at most 2 MB, and only HTML, plain text and JSON.
- No JavaScript, no proxies, no IP rotation, and no attempt to get past CAPTCHAs or bot checks. A challenge page is reported to the caller as `bot_wall`.
- At most 1 request a second and 30 a minute to any one host.
- Page content is not stored. Receipts keep hashes of what was read, not the text.

## robots.txt

The fetcher reads robots.txt before every fetch and keeps it for up to one hour. If there is a group for `QuoteproofBot`, only its rules apply; otherwise the `*` group applies. If your robots.txt answers with a server error (5xx), we treat the whole site as disallowed for an hour. To block it completely:

```
User-agent: QuoteproofBot
Disallow: /
```

A disallowed page is refused to the caller with `403 robots_disallowed`, and the caller is not charged.

## Opt-out list

We also keep a list of hosts that asked not to be fetched. Hosts on it are refused in the same way as a robots.txt disallow.

## Contact

To ask about the fetcher or report a problem: no contact address is set on this server; the robots.txt opt-out works without one.

Security reports: see [security.txt](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/.well-known/security.txt).

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/terms.md

# Terms of use

Last updated: 2026-10-15

These terms cover use of AttestPage at https://s2h6qt73jtzlgbgnnfacln2poq.srv.us, its API and its documents. By calling the API you accept them.

## The service

AttestPage fetches web pages that you name and returns what it found, with a signed receipt. It also signs timestamped receipts over hashes you supply. Payments are in USDC on Base Sepolia (a test network). Features, prices and limits may change. Current prices are in [pricing.json](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/pricing.json).

## What a receipt means

A receipt is a signed record that our fetcher retrieved a URL at a stated time and saw the stated status, content hashes and verdict. It does not show that anything on the page is correct, that a page is free of harmful content, or that a person or organisation said what the page says. Verdicts such as `real`, `bot_wall` and `paywall` and the `injection_flags` list come from automated rules and can be wrong. An empty `injection_flags` list means none of our patterns matched, nothing more.

An attest receipt shows that someone sent us a given SHA-256 at the stated time. It says nothing about what the hash stands for.

## Payment

Paid routes cost the price shown in the 402 response. A request that fails validation is refused before payment. Payment is settled only when the route answers with a status below 400. Results about the target page, including errors and bot walls, are answers and are charged. A site timeout is charged on /v1/verify/quote, /v1/verify/quotes, /v1/verify/citations, /v1/verify/document and /v1/check/links. On /v1/fetch and /v1/recheck, a call that read no page (a timeout included) is not charged and answers 502 upstream_unreachable. Where Lightning (L402) is on, you pay its invoice before the call: the token it gives you is used up only by an answer below 400, and it can be used until it expires (the time is in the token and in the [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments) page). A token that is never used is not refunded. If you are charged and we cannot deliver the result (recorded as `result_lost`), we refund the charge in USDC to the paying address, on the same rail, whichever rail you used; the [Payments](https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/docs/payments) page describes it. Other payments are not refunded except where this page or the docs say a call is not charged.

## Acceptable use

Do not use the service to:

- reach addresses you are not allowed to reach, or try to get around the fetcher's address checks;
- send personal data, secrets or unlawful content in a note or quote;
- overload a site, including by spreading requests to get round rate limits;
- pay from an address on a sanctions list (such payments are refused).

We may refuse or limit requests that break these terms.

## No warranty

The service is provided as is, without warranty of any kind. To the extent the law allows, we are not liable for any loss from using it or relying on its results, and our total liability for any claim is limited to the amount you paid for the calls concerned.

## Changes

We may change these terms. The date above shows the last change.

---

Source: https://s2h6qt73jtzlgbgnnfacln2poq.srv.us/privacy.md

# Privacy

Last updated: 2026-10-15

This page lists what AttestPage keeps about calls to https://s2h6qt73jtzlgbgnnfacln2poq.srv.us and for how long.

## Access log

For each request we log the time, method, path, status, duration, payment rail and its network, price, a coarse user-agent class (for example "ai_agent", "browser" or "crawler"), a short product token from the user agent, such as "gptbot" or "curl" (never the full string), the referrer's host name, a caller id, on a refused request (429 or 503) the reason as a short code (for example "trial_exhausted"), on MCP requests a mark ("mcp") with the MCP method and tool name only, never the arguments, and marks that separate our own checks from customer requests: a yes/no mark ("own") that says whether the request came from our own checks, on paid routes a mark ("body") that says whether a paid request's body was exactly one of the examples we publish ("probe") or not ("other"), and, on our own checks only, whether they came from the public or the loopback address, and a yes/no mark ("direct") that says whether the request came straight to the service's local port rather than through the front end. The log also holds a few short labels for which version of a page, price, payment offer or error message a caller was shown, and whether it was the caller's first call. The caller id is a keyed hash of your IP address under a random key replaced every UTC day. The key is kept only on the server, in a file only the service's own account can read, stored apart from the logs, so a restart does not change it, and it is deleted with the first request of the next UTC day. While a day's key exists, someone holding both the key and the logs could work out which address a caller id came from; after the key is deleted, that day's caller ids can no longer be matched to an address. A new key each day means caller ids cannot be linked across days. We do not log request bodies, query strings, target URLs, IP addresses or full user-agent strings. Log files are deleted after 14 days.

When a request to `/v1/sample/:name` gets a 404, the log also keeps the requested sample name for 14 days, only when it is 1-24 lowercase letters or hyphens; otherwise the name is dropped.

For a request to a path we do not serve, the path is logged as its first segment only, when it is 1-32 lowercase letters or hyphens, otherwise as "/other", and kept 14 days. When such a request gets a 404, the log also keeps the requested path itself for 14 days, without its query string, with control characters removed and cut to 80 characters, so we can see which missing pages callers look for.

## Rate limits

To apply per-address rate limits and trial limits, we hold a keyed hash of your IP address in memory. The key is separate from the caller-id key, random, replaced every UTC day and held in memory only, never written to disk. When a request is refused by a rate limit, we log its time, path, caller id, bucket key and reason in `data/ratelimit.jsonl` for 14 days.

## Payments

- For each settled payment we keep the time, route, network, amount, transaction hash and payment id.
- A paid receipt contains the payment details, including the paying wallet address. You hold the receipt; see Attestations below for receipts we keep.
- When a paying address is refused because it is on a sanctions list, we keep the time, route, network and that address.
- Paid requests log a hash of the payer address under the same daily key as the caller id (see Access log), and a short user-agent name; raw addresses are not stored in the access log.
- To answer a retried payment with the same response, we keep the paid response in memory for one hour.
- When a call's work is done but its payment fails to settle, we keep the time, route, payment id, signature nonce, paying address and, if reported, the failure reason and transaction hash, so the charge can be checked against the chain. If the payment had a payment id, the withheld response is also kept in memory for at least one hour, until the payment can no longer go through.
- Where Lightning (L402) is on, we keep the payment hash of each used token and its expiry time until the token expires, so it cannot be used twice, and the paid response in memory until a restart, so the same request with that token gets it again.

## Attestations

For `POST /v1/attest` we keep a sequence number, the time, a SHA-256 of your idempotency key and the paying address if you sent a key, the SHA-256 you sent, the SHA-256 of your note, and the signed receipt (which includes the paying address). We keep these so that a retry gets the same receipt. The note text itself is never stored. These records are kept with no set end date.

## Pages we fetch

Pages fetched for you are not stored. We keep only what goes into the receipt you receive. That receipt records the IP address of the site we fetched (never yours), its TLS certificate details and a few of its response headers. robots.txt files are cached in memory for up to one hour.

## Sharing

Payments go through an x402 facilitator and are recorded on a public blockchain, as all such payments are. When a verify/citations call cites a page with a DOI, that DOI (only the DOI) is sent to Crossref (api.crossref.org) to read its public metadata. We do not sell or share the data above with anyone else.

## Contact

no contact address is set on this server; the robots.txt opt-out works without one.