# FractalAI x402 Agent Credential Verifier

> FractalAI x402 Agent Credential Verifier is a paid API for AI agents from fractalai.net.co, paid per call via x402, $0.03/call, status unknown (last checked 2026-10-13).

Validates an AI agent's KYA (Know Your Agent) credential using post-quantum ML-DSA-65 cryptography and returns a signed attestation of the verification result

## Facts

- Endpoint: POST https://fractalai.net.co/api/x402/verify-agent?utm_source=zero.xyz
- Price: $0.03/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fractalai-x402-agent-credential-verifier-5b2f84be
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sJH5gUD-o8XRHE3YdsA0u

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 fractalai-x402-agent-credential-verifier-5b2f84be -d '<json body>'
```

Example prompt: Can you verify my AI agent's KYA credential — agent_id 'agent-abc123', operator 'MyOrg', scope 'trading' — and give me a signed post-quantum attestation confirming it's valid and not expired?

## When to prefer this

Choose this endpoint when you need post-quantum-secure verification of AI agent KYA credentials with a signed, tamper-evident attestation you can store or relay. It is specifically designed for AI agent identity workflows on the FractalAI blockchain ecosystem and produces ML-DSA-65 (NIST FIPS 204) signatures suitable for compliance audit trails. Prefer this over classical ECDSA or RSA credential verifiers when quantum resistance is a requirement, or when you need on-chain FRC-55 reputation data alongside credential validity.

## Known failure modes

- Invalid credential structure returns valid=false with stage='structure' and a descriptive reason
- Unrecognized credential_id returns valid=false with stage='credential_id'
- Post-quantum signature mismatch returns valid=false with stage='signature'
- Expired credential returns valid=false with stage='expiration' and negative seconds_until_expiry
- Missing x402 payment header returns HTTP 402 Payment Required
- Malformed request body returns HTTP 400 with error detail
- Reputation snapshot unavailable returns null for the reputation field

## How this service works

The first AI-native Layer 1 blockchain built from scratch in Rust. Post-quantum cryptography (CRYSTALS-Dilithium), Proof of Fractal Work consensus, WASM smart contracts, and 460+ RPC endpoints. Mine FRAC tokens with fractal analysis instead of hash puzzles.

## Output

Returns a JSON object with: a boolean 'valid' field indicating whether the agent credential passed all checks; 'stage' showing which check determined the verdict (structure, credential_id, signature, expiration, or ok); 'reason' with a human-readable explanation; a base64 ML-DSA-65 (Dilithium-3, NIST FIPS 204) 'signature' (3309 bytes) over a canonical message attesting the verdict; the corresponding 'public_key' (1952 bytes) for offline verification; 'algorithm' and 'algorithm_label' fields; 'attestation_digest' (SHA-256 hex); 'signed_message' for offline verification; 'not_expired' boolean; 'seconds_until_expiry'; optionally the echoed 'claim' object, 'payment' settlement receipt, and 'reputation' on-chain FRC-55 snapshot.

## 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",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "valid": true,
  "algorithm": "ml-dsa-65",
  "verified_credential_algorithm": "dilithium2"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fractalai-x402-agent-credential-verifier-5b2f84be/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fractalai.net.co](https://www.zero.xyz/host/fractalai.net.co/llms.txt)