Check a claim against live web sources
Check a claim against live web sources - a verdict, a confidence level, and the sources that support or contradict it, each with its URL and stance. Returns 'inconclusive' rather than a guess when the sources don't clearly settle it. Try GET /fact-check/sample. Part of the AgentIndex content kit (pdf, web-read, extract, summarize, detect-language) - see GET /capabilities.
Answeringour last check, 2026-10-10
1 of 1checks answered this week
902 msmedian answer time
$0.01listed price per call
$0.01price it asked us
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://x402.agentindex.world/fact-check
| Category | Search and research |
|---|---|
| Provider host | x402.agentindex.world |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 0 from 0 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-10 | valid payment request | 402 | $0.01 | 902 ms |
Example input (from the provider)
{
"body": {
"claim": "The Eiffel Tower is taller than the Statue of Liberty."
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"body": {
"properties": {
"claim": {
"description": "The factual claim to check against live web sources.",
"type": "string"
}
},
"required": [
"claim"
]
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
},
"method": {
"enum": [
"POST",
"PUT",
"PATCH"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method",
"bodyType",
"body"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"claim": {
"type": "string"
},
"confidence": {
"description": "0.0-1.0 confidence in the verdict.",
"type": "number"
},
"sources": {
"items": {
"properties": {
"stance": {
"enum": [
"supports",
"contradicts",
"neutral"
],
"type": "string"
},
"title": {
"description": "Source page title, when known."
},
"url": {
"type": "string"
}
},
"type": "object"
},
"type": "array"
},
"verdict": {
"description": "'inconclusive' is returned instead of a guess whenever confidence is low or no source clearly supports/contradicts the claim - never a confident-sounding verdict the sources don't actually back up.",
"enum": [
"supported",
"contradicted",
"mixed",
"unverifiable",
"inconclusive"
],
"type": "string"
},
"x402_receipt": {
"description": "Billing and provenance receipt for this call.",
"type": "object"
}
},
"required": [
"claim",
"verdict",
"confidence",
"sources"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}