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AgentIndex x402 Fact-Check
x402
AgentIndex x402 Fact-Check is a paid API for AI agents from x402.agentindex.world, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-13).
Verifies a factual claim against live web sources and returns a verdict with supporting evidence and confidence score
Price / call$0.05
Success—
StatusUnknown
How this service works
Read and search the web for AI agents. Nothing else. A pay-per-call kit for AI agents in USDC on Base (x402/MPP): search, pdf, web-read, extract, summarize, fact-check, and the free detect-language entry point - see GET /capabilities. Plus two tools outside the kit: translate and jobs.
Output
A JSON object containing the original claim, a verdict ('supported', 'refuted', or 'inconclusive'), a confidence score between 0 and 1, and a list of sources each with a URL, title, and stance ('supports' or 'refutes') drawn from live web retrieval.
Example use cases
Verifying viral social media claims
“I saw a post saying 'Humans only use 10% of their brain' — can you check if that's actually true using live web sources and tell me what the verdict is?”
Journalist source cross-checking
“Fact-check this for my article: 'Electric vehicles produce zero lifetime carbon emissions' — I need a verdict, a confidence score, and the URLs of sources that support or refute it.”
Debunking health misinformation
“Someone told me that 'Drinking eight glasses of water a day is scientifically proven' — can you verify that claim against current web sources and tell me if it's supported?”
Technical details
Endpoint
POSThttps://x402.agentindex.world/fact-checkWhen to prefer
Choose this endpoint when you need a structured, sourced verdict on a specific factual claim backed by live web retrieval — especially when you need a machine-readable confidence score and stance-labeled citations. Prefer it over generic search when you need a binary or graded fact-check output rather than raw search results. Best suited for agents performing misinformation detection, research validation, or automated journalism workflows.
Side effects
- Claim is ambiguous or too broad — may return low confidence or inconclusive verdict
- Live web sources unavailable or unreachable — may result in error or reduced source count
- Claim involves highly niche or recent events not yet indexed — may return inconclusive with few sources
- Malformed or empty claim field — returns validation error
- Payment failure via x402 protocol — returns 402 Payment Required
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| claim | string | The factual claim to check against live web sources. |
Output
Schema · Response
{
"type": "json",
"example": {
"claim": "The Eiffel Tower is taller than the Statue of Liberty.",
"sources": [
{
"url": "https://example.com/eiffel-tower-facts",
"title": "Eiffel Tower Facts",
"stance": "supports"
}
],
"verdict": "supported",
"confidence": 0.92
}
}Tags
x402
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