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Agent Evidence API
x402
Agent Evidence API is a paid API for AI agents from agent-evidence.thx93.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-22).
Verifies claims and fact-checks statements against up to 5 user-supplied public web URLs, returning cited evidence passages with support/contradiction/inconclusive assessments.
Price / call$0.01
Success—
StatusUnknown
How this service works
Verify a claim or fact check a statement against public web sources: send a question and up to 5 URLs, get cited evidence - passages that support, contradict or fail to settle it. Claim verification with a citation for every excerpt: source URL, retrieval time, content hash. Never charges when nothing is retrieved. Free to evaluate: the `sample` tool returns one real response at no cost, so you can judge the output before paying for your own question.
Output
Returns a list of sources, each with their HTTP status, retrieved timestamp, content hash, and one or more evidence excerpts tagged as 'direct', or other relevance levels. A top-level assessment object summarizes whether the claim is supported, contradicted, or unsettled, with a plain-language basis statement. A limitations array notes caveats such as deterministic matching vs. semantic reasoning. Nothing is returned (and no charge applies) when no content is retrieved.
Example use cases
Verifying a competitor's product claim
“I need to check whether the claim 'BrandX batteries last 10 years' is actually supported by their official product page at https://brandx.com/batteries — can you retrieve the relevant passages and tell me if they back it up or not?”
Journalism source cross-check
“I'm writing an article and need to verify the claim 'the unemployment rate fell to 3.4% in January 2024' against these two sources: https://bls.gov/news.release/empsit.nr0.htm and https://reuters.com/economy/jan2024 — does either one support or contradict that figure?”
Legal or compliance fact validation
“Can you check whether the statement 'Company Y is headquartered in Delaware' is confirmed or contradicted by their SEC filing page at https://sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=XYZ and their about page at https://companyy.com/about?”
Technical details
Endpoint
POSThttps://agent-evidence.thx93.dev/mcp?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need verifiable, cited evidence from specific URLs rather than a broad web search. It is ideal when you already have candidate source URLs and need to confirm or refute a precise claim with quoted excerpts and provenance metadata (URL, timestamp, content hash). Prefer it over general search APIs when auditability and citation integrity matter — for journalism, compliance, legal research, or agent pipelines that must show their work. The per-call pricing and free sample tool make it low-risk to evaluate before committing.
Side effects
- URL is inaccessible or returns non-200 status — source listed with error status, no evidence excerpts
- Claim is too vague to match any passage — assessment returns 'unsettled' with empty excerpts
- Paywall or JavaScript-rendered page blocks content retrieval — source returns empty evidence
- No sources provided or all URLs fail — empty sources array, no charge applied
- Network timeout on a URL — that source omitted or flagged with retrieval error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"sources": [
{
"title": "Company X - About",
"status": 200,
"evidence": [
{
"excerpt": "Company X manufactures centrifugal pumps at its facility.",
"relevance": "direct"
}
],
"final_url": "https://company.example/about",
"retrieved_at": "2026-01-01T00:00:00.000Z",
"content_hash_sha256": "9f2c…"
}
],
"assessment": {
"basis": "1 source matched the question.",
"status": "supported"
},
"limitations": [
"Assessment uses deterministic lexical matching, not semantic reasoning."
]
}
}Tags
x402
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