Discover / factstamp.agentrails.workers.dev

factstamp.agentrails.workers.dev

■ Challenge detected

Check a citation before repeating it. Give a DOI, an arXiv ID or a paper title; the answer says whether the work exists, what it is (title, authors, year, container) and whether it has been retracted. A title that is absent from both Crossref and arXiv returns not_found, and a near title match is never reported as verified. Cited to the source record with its retrieval time. Verdicts: verified, ambiguous, retracted, not_found, unknown.

Listed price
$0.02
Challenge detected
2 of the last 8 checks
Median response
307 ms
Last checked
16 Oct, 16:44 UTC
In our index since
6 Oct 2026

Endpoint

curl -i https://factstamp.agentrails.workers.dev/citation
# 402 Payment Required: pay with an x402 client (USDC on Base),
# then send the same request again with the payment attached.
9 listed endpoints · on x402 Bazaar

Checks and payment terms on this page refer to the endpoint above. Other listed endpoints have not been checked individually.

Base URLhttps://factstamp.agentrails.workers.dev

  • POST/check$0.05Check a dated figure you are about to act on against the publisher's own series, and receive verified, stale, contradicted or unknown with the as-of date. Call it before committing a number to a page, deck, model or decision. Coverage today is Australian primary sources; anything outside coverage returns unknown rather than a guess.
  • POST/watch$0.5Buy a standing re-check of one citation or one package version, when an answer has to stay true rather than be true once: re-checked every day for 30 days. US$0.50 the month — 1.7 cents a check, under a 2-cent lookup. The first check is answered and signed on purchase, and each real change (a retraction, a new advisory, a yanked version) gets its own signed receipt. Pay per call here, or redeem a prepaid pack code (10 credits). Returns a read URL and a token shown once.
  • POST/citation$0.02Check a citation before repeating it. Give a DOI, an arXiv ID or a paper title; the answer says whether the work exists, what it is (title, authors, year, container) and whether it has been retracted. A title that is absent from both Crossref and arXiv returns not_found, and a near title match is never reported as verified. Cited to the source record with its retrieval time. Verdicts: verified, ambiguous, retracted, not_found, unknown.
  • POST/entity$0.1Verify whether a legal entity exists and is currently registered, from open primary registers: the GLEIF LEI index, US SEC EDGAR and the Australian Business Register (ABN, ACN, GST, status). Call it before naming a company in a contract, invoice or filing, or when you need an identifier (ABN, ACN, LEI, CIK) for a company you know only by name. Returns found, ambiguous, not_found or unknown, cited to the register with its retrieval time. A near name match is never reported as a match.
  • POST/watch/portfolio$5Watch a whole list at once, when a bibliography or a dependency manifest has to stay true: up to 25 citations or package versions re-checked every day for 30 days under one token. US$5 a portfolio — 20 cents a reference, under a cent a check. Every reference is answered and signed on purchase, and each real change gets its own signed receipt. Nothing is sent when nothing changed. Pay per call here, or redeem a prepaid pack code (100 credits).
  • POST/entity-file$0.4381When you need the whole picture of one company before you sign, onboard, pay or acquire, call the entity file: ONE answer holding identity and standing, the registered office, SIC activity and previous names, the filing position, a sanctions screen across four lists, and the ownership chain to the ultimate parent — with ONE coverage block naming every register consulted and every one not. One call and one receipt instead of four. Unknown is a first-class answer.
  • POST/document$0.25Call it before you send, file or publish a document that quotes figures, names companies or cites papers. Post the text and every checkable claim comes back verified against dated primary sources, as one signed bundle with a per-claim receipt and its licence. Claims we cannot answer are named and never charged, and the preview is free. Verdicts: verified, stale, contradicted, unknown.
  • POST/package$0.02Check a dependency before installing it. Give a package and, optionally, a version with its ecosystem (npm, PyPI, crates.io); the answer says whether that exact version exists, whether it is yanked or deprecated, and every advisory OSV lists against it. A version that was never published returns not_found with the real versions nearest to it. Verdicts: verified, advisory, yanked, not_found, unknown.
  • POST/bulk$0.12Check a whole bibliography or dependency manifest in one round trip, before you rely on the list: up to 12 items at a flat US$0.12 — 1 cent an item, against 2 cents for the same lookups one at a time. Every item is answered by the same door that answers a single call, so the verdicts cannot disagree. Pay per call here, or redeem a prepaid pack code (one answer-pack credit per three items, up to 25 items on that rail).

A dash means the listing gives no price or method. Copy buttons copy the full URL.

Showing 9 of 9 listed endpoints.

Agents can find it through the Superstables MCP server and JSON API: GET /api/v1/services/factstamp.agentrails.workers.dev

Recent checks

6 Oct 2026One bar per check, showing up to 20 recent checks. Coloured bars show relative response time, with a minimum visible height; full-height grey bars mean no challenge was detected. “Challenge detected” means HTTP 402 or another detected payment-challenge signal.16 Oct 2026
All 8 checks
When (UTC)ResultHTTPResponse
16 Oct, 16:44 UTCChallenge detected402312ms
15 Oct, 08:20 UTCChallenge detected402301ms
13 Oct, 22:50 UTCNo challenge detected405512ms
11 Oct, 19:34 UTCNo challenge detected405389ms
10 Oct, 03:32 UTCNo challenge detected405357ms
8 Oct, 21:32 UTCNo challenge detected405361ms
7 Oct, 18:39 UTCNo challenge detected405476ms
6 Oct, 15:34 UTCNo challenge detected405229ms

Questions

Did our last probe detect a payment challenge?

At our last probe on 16 Oct, 16:44 UTC, it returned HTTP 402 or another detected payment-challenge signal. This check did not test payment, delivery or compatibility with the Superstables client.

What price is recorded for factstamp.agentrails.workers.dev?

Its listed price is $0.02.

What payment terms does factstamp.agentrails.workers.dev advertise?

The listing advertises x402, Base and USDC. It names cdp as its facilitator. Check the seller's current payment challenge and authentication requirements before paying.

Where is factstamp.agentrails.workers.dev listed?

In x402 Bazaar. Superstables first indexed it on 6 Oct 2026.

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