# Rubric Protocol C2PA Verdict Attestation

> Rubric Protocol C2PA Verdict Attestation is a paid API for AI agents from rubric-protocol.com, paid per call via x402, $0.25/call, status unknown (last checked 2026-09-14).

Validates and attests C2PA content provenance of a raw digital asset (up to 25MB), returning a signed, sandboxed verdict proving authenticity or tampering

## Facts

- Endpoint: POST https://rubric-protocol.com/v1/c2pa/verdict-attest
- Price: $0.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rubric-protocol-c2pa-verdict-attestation-e35cc7f9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SW4ScCM-kaZjc84kn-Ltq

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability rubric-protocol-c2pa-verdict-attestation-e35cc7f9 -d '<json body>'
```

Example prompt: Check this image file for a valid C2PA provenance signature and give me an attested verdict — I need to know if it's authentic or tampered with before we use it in our campaign.

## When to prefer this

Choose this endpoint when you need a tamper-evident, third-party attested C2PA provenance verdict rather than a simple client-side check. It is especially appropriate when legal defensibility, audit trails, or regulatory compliance require a signed, sandboxed attestation from an independent verifier. Prefer it over DIY C2PA library validation when the verdict itself must be cryptographically provable to a third party.

## Known failure modes

- Asset exceeds 25MB size limit — rejected with payload too large error
- Asset has no C2PA manifest — verdict returned as no provenance found
- Invalid or corrupted binary payload — parsing error returned
- Sandbox validation timeout for large or complex assets
- Payment failure (x402) — request blocked before processing
- Unsupported file format — validation cannot be performed

## How this service works

C2PA verdict attestation Tier A. POST raw asset bytes (max 25MB). Rubric runs Google Credentio validation in-sandbox, an

## Output

A signed, sandboxed C2PA verdict attesting the authenticity or tamper-status of the submitted asset. The attestation is produced via Google Credentio validation run in an isolated environment, yielding a verifiable cryptographic proof of the content provenance decision.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "binary"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "format": {
     "type": "string"
    },
    "example": {}
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rubric-protocol-c2pa-verdict-attestation-e35cc7f9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from rubric-protocol.com](https://www.zero.xyz/host/rubric-protocol.com/llms.txt)