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Agent Evidence API – Claim Verification
x402
Agent Evidence API – Claim Verification 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 a claim or fact-checks a statement against up to 5 public web sources, returning cited evidence passages that support, contradict, or fail to settle the claim.
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 evidence passages from the provided URLs, each labeled as supporting, contradicting, or failing to settle the claim. Every excerpt includes the source URL it was retrieved from, the retrieval timestamp, and a content hash for auditability. No charge is incurred if no relevant content is retrieved.
Example use cases
Debunking a viral social media claim
“There's a viral post saying 'Drinking coffee reverses Alzheimer's disease.' Can you check that claim against https://www.nih.gov/news-events/news-releases/coffee-alzheimers and https://www.alz.org/alzheimers-dementia/research_and_practice and return the passages that support, contradict, or don't settle it?”
Verifying a company's public sustainability pledge
“Our compliance team needs to verify whether our supplier actually claimed 'carbon neutral by 2025' on their public site. Please check the statement against https://www.suppliercorp.com/sustainability and https://suppliercorp.com/annual-report-2023 and give me cited excerpts with retrieval timestamps.”
Checking a political fact before publishing
“Before we publish, can you fact-check the claim that 'The US national debt exceeded $30 trillion in January 2022' against https://fiscaldata.treasury.gov/datasets/debt-to-the-penny/ and https://www.cbo.gov/topics/budget and show me the exact evidence passages with their content hashes?”
Technical details
Endpoint
POSThttps://agent-evidence.thx93.dev/weather/mcp?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need cited, auditable evidence from specific URLs to verify a claim — not just a web search. It is ideal when you have known source URLs and need exact passage excerpts with timestamps and content hashes for compliance, journalism, or research. Prefer it over generic search APIs when auditability and per-source attribution are required. The free 'sample' tool makes it safe to evaluate output quality before committing to paid calls.
Side effects
- No content retrieved from provided URLs — no charge applied, empty result returned
- URL is inaccessible, paywalled, or returns a non-200 response — that source is skipped
- Claim is too ambiguous for the retrieved content to settle — passages returned as 'inconclusive'
- More than 5 URLs supplied — only up to 5 are processed
- Malformed MCP input schema or missing required 'toolName' field — validation error returned
- Rate limiting or payment failure via x402 — request rejected before processing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"result": [
{
"area": "Central Virginia",
"event": "Winter Storm Warning",
"severity": "Severe",
"description": "Heavy snow expected.",
"instructions": "Avoid travel."
}
]
}
}Tags
x402
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