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Council of AI — AI Marking Evidence Checker (art50)
x402
Council of AI — AI Marking Evidence Checker (art50) is a paid API for AI agents from councilof.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Checks a given URL for AI content marking evidence (e.g. C2PA manifests) and returns a signed verification card with detection results
Price / call$0.01
Success—
StatusUnknown
How this service works
Explore the current GSPC measurements, see the published change record, verify signed evidence, and access the supported public feeds.
Output
A signed JSON card (CSOAI schema card-v0) containing: the kind identifier (csoai.art50.marking-evidence/0.1), an array of checked methods with their results (e.g. c2pa.manifest-store: NOT_DETECTED), human-readable statements summarizing the findings, a list of unmeasured methods (e.g. root_inclusion, watermark.synthid), the surface name (art50.marking-evidence), and an ed25519 signature (hex or null) for cryptographic verification.
Example use cases
Verify AI watermark on media
“I found this image online at https://news-site.com/images/viral-photo.jpg — can you check if it has any AI marking like C2PA or SynthID so I know if it was AI-generated and signed?”
Audit content for GSPC compliance
“We need to confirm our published AI content at https://myblog.com/ai-article-cover.png has been properly marked — can you run it through the GSPC Art50 marking evidence check and give me the signed card?”
Investigate unsigned AI claim
“Someone shared a card claiming this video at https://mediahost.io/clip.mp4 is AI-generated and properly marked — can you verify that claim against the Council of AI marking evidence check?”
Technical details
Endpoint
GEThttps://councilof.ai/api/art50/marking-evidenceWhen to prefer
Use this endpoint when you need to programmatically verify whether a specific URL's content carries AI provenance marking (C2PA, SynthID, etc.) and want a cryptographically signed, structured evidence card backed by the GSPC Art50 standard. Prefer this over generic C2PA tools when you need a signed, auditable record from a neutral third-party council, or when integrating with GSPC-compatible workflows.
Side effects
- Invalid or unreachable URL returns an error or empty result
- URL scheme other than HTTPS is rejected by schema validation
- Content type at URL is unsupported for marking detection
- Payment not completed (x402 payment required) — returns 402 before processing
- Signature field may be null if signing is unavailable
- Some marking methods (e.g. SynthID, root_inclusion) are always listed as unmeasured if not supported
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"schema": "csoai.art50.marking-evidence/0.1",
"measurement": {
"checked": []
}
}
}Tags
x402
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