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Council of AI Coverage Evidence API
x402
Council of AI Coverage Evidence API is a paid API for AI agents from councilof.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-02).
Returns a signed cryptographic measurement artifact for an AI system, including a SHA-256 content address and Ed25519 attestation signature, verifiable against the public CSOAI ledger.
Price / call$0.02
Success—
StatusUnknown
How this service works
UK AI measurement infrastructure operated by CSOAI Ltd. Read current measurements, verify signed evidence for free and inspect the public corrections ledger.
Output
Returns a JSON object containing a measurement artifact with a SHA-256 content address, an Ed25519 signature (signed under did:web:csoai.org#board-attestation-1 when the key is provisioned, otherwise null with an unsigned_reason field), a list of unmeasured items, the artifact schema identifier, a verification URL (https://councilof.ai/gspc-verify), and a human-readable note clarifying the artifact is a measurement record and not a grade, rank, score, or certificate.
Example use cases
Verify AI product measurement claims
“We're listing our AI assistant on a procurement portal that requires independent measurement evidence — can you pull the signed CSOAI coverage artifact for it so I can confirm the SHA-256 hash and check for any unmeasured items?”
Audit AI supplier compliance
“I need to check that our AI vendor's system has a valid, cryptographically signed measurement from the Council of AI — can you retrieve their coverage evidence artifact and tell me if the Ed25519 signature is present or if there's an unsigned reason listed?”
Publish verifiable AI transparency report
“We're publishing our AI transparency report and want to include the Council of AI measurement artifact — please fetch the latest signed coverage evidence, including the SHA-256 content address and the verification link we can share publicly.”
Technical details
Endpoint
POSThttps://councilof.ai/api/coverage-evidence?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a tamper-evident, cryptographically signed measurement artifact for an AI system from an independent UK measurement body. It is uniquely suited for compliance workflows, supplier audits, procurement due diligence, or transparency reporting where verifiable third-party attestation (not a self-reported score or badge) is required. Prefer this over AI benchmarks or leaderboards when you need a public, re-checkable evidence artifact with a cryptographic hash rather than a numeric grade or ranking.
Side effects
- Missing or malformed required input fields returns a validation error
- Payment not received or x402 protocol failure results in 402 Payment Required
- Ed25519 key not yet provisioned results in sig_ed25519 being null with an unsigned_reason explanation
- No measurement data available for the requested subject returns an empty or partial artifact
- Network timeout or service unavailability returns a 5xx error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"note": "Measurement artefact — never a grade, rank, score, or certificate.",
"schema": "<the door's csoai artifact schema>",
"verify": "https://councilof.ai/gspc-verify",
"artifact": {
"sha256": "<64-hex content address>",
"unmeasured": [],
"sig_ed25519": "<Ed25519 under did:web:csoai.org#board-attestation-1 when the Pages key is provisioned, else null with unsigned_reason>"
}
}
}Tags
x402
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