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FactStamp Dependency & Citation Verifier
x402
FactStamp Dependency & Citation Verifier is a paid API for AI agents from factstamp.agentrails.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-02).
Verifies software package dependencies, figures, entities, and citations against dated primary sources, returning verdicts and advisory records
Price / call$0.02
Success—
StatusUnknown
How this service works
Figure, entity, citation and dependency verification for other agents. Cited to dated primary sources. Unknown is valid.
Output
Returns a JSON object with: the package name and queried version, a verdict string (e.g. 'advisory', 'safe'), the latest available version, whether the package is yanked/deprecated, a list of advisory IDs (e.g. GHSA identifiers), the data sources consulted (e.g. npm registry, OSV) with their HTTP response status, and the published date of the queried version.
Example use cases
Pre-deployment dependency security audit
“Before I deploy this Node.js app, can you check whether lodash@4.17.20 has any known security vulnerabilities or is it safe to ship?”
CI pipeline vulnerability gate
“I'm setting up automated checks in my CI pipeline — can you verify that react@18.2.0 has no active advisories and tell me the latest stable version?”
Fact and citation integrity check
“Can you verify the figures and citations in this claim against dated primary sources and tell me which ones check out and which are unknown or disputed?”
Technical details
Endpoint
POSThttps://factstamp.agentrails.workers.dev/package?utm_source=zero.xyzWhen to prefer
Choose FactStamp when you need a cited, dated, primary-source-backed verdict on a software package's security posture — particularly when you need advisory IDs (GHSAs), deprecation status, and latest version in a single call. Prefer this over generic search when you need structured, machine-readable verification with explicit source attribution and support for 'unknown' as a valid outcome rather than a silent failure.
Side effects
- Package or version not found in any consulted registry — returns partial or empty source list
- Unknown verdict returned when insufficient primary source data exists — 'unknown' is an explicitly valid result
- Source HTTP errors (non-200) from npm registry or OSV indicate upstream unavailability
- Malformed package query string causes validation failure
- Payment not completed (x402 flow) — request rejected before processing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| outputrequired | object |
Output
Schema · Response
{
"type": "json",
"example": {
"name": "express",
"query": "express@4.18.2",
"detail": "2 advisory record(s) published against express@4.18.2.",
"latest": "5.2.1",
"yanked": false,
"sources": [
{
"name": "npm registry",
"http_status": 200
},
{
"name": "OSV",
"http_status": 200
}
],
"verdict": "advisory",
"version": "4.18.2",
"ecosystem": "npm",
"advisories": [
{
"id": "GHSA-qw6h-vgh9-j6wx"
},
{
"id": "GHSA-rv95-896h-c2vc"
}
],
"deprecated": null,
"published_at": "2022-10-08T20:14:32.495Z"
}
}Tags
x402
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