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Factstamp Package Dependency Checker
x402
Factstamp Package Dependency Checker is a paid API for AI agents from agents.factstamp.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-21).
Checks a specific package version against existence, deprecation/yanked status, and all OSV security advisories at install time
Price / call$0.02
Success—
StatusUnknown
How this service works
Reports on a dependency at the point of installation. 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.
Output
A JSON object containing a verdict (one of: verified, advisory, yanked, not_found, or unknown), the OSV advisory list (with IDs, severity, and details) if any exist, whether the version is yanked or deprecated, and — if the version was never published — the nearest real versions that do exist in that ecosystem.
Example use cases
Pre-deploy dependency audit
“We're about to deploy and I want to make sure requests 2.28.0 on PyPI is safe — can you check if that version exists, whether it's been yanked, and if there are any known security advisories against it?”
Rust crate vulnerability check
“Check crates.io for serde version 1.0.150 — does it exist, is it yanked, and are there any OSV advisories I should know about before adding it to our Cargo.toml?”
Investigate suspicious npm package version
“Someone pinned our project to left-pad version 1.1.3 on npm — can you verify that version actually exists, whether it's deprecated, and if any security advisories apply to it?”
Technical details
Endpoint
POSThttps://agents.factstamp.dev/package?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a point-in-time, authoritative check on a specific package version at install or ship time — combining existence, yanked/deprecated status, and full OSV advisory data in a single call. Prefer it over querying npm/PyPI/OSV APIs separately when you need a single structured verdict. Particularly valuable in CI/CD pipelines, agent-driven dependency resolution, or document fact-checking workflows where a clear verdict enum (verified/advisory/yanked/not_found/unknown) is needed rather than raw registry data.
Side effects
- Package ecosystem not supported — returns unknown verdict
- Version never published — returns not_found with nearest real versions
- Package name misspelled or nonexistent — returns not_found
- OSV data temporarily unavailable — may return unknown
- Malformed request body — HTTP 400 error
- Payment not attached or insufficient — HTTP 402 error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| outputrequired | object |
Tags
x402
Reviews
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Zero review prompt (fires after every successful call)
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