Pay-per-KYA: an agent pays to verify another agent's post-quantum identity + scope credent

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "30000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "30000",
    "maxTimeoutSeconds": 300
  }
]

{
  "bazaar": {
    "body": {
      "credential": {
        "claim": {},
        "credential_id": "…",
        "public_key": "BASE64",
        "signature": "BASE64"
      }
    },
    "bodyType": "json",
    "description": "Pay-per-KYA: an agent pays to verify another agent's post-quantum identity + scope credential (Dilithium-2, NIST FIPS 204), with a live FRC-55 on-chain reputation read. ERC-8004-aligned Know Your Agent for autonomous agent-to-agent commerce. x402-native.",
    "info": {
      "input": {
        "body": {
          "credential": {
            "claim": {},
            "credential_id": "…",
            "public_key": "BASE64",
            "signature": "BASE64"
          }
        },
        "bodyType": "json",
        "method": "POST",
        "type": "http"
      },
      "output": {
        "example": {
          "algorithm": "ml-dsa-65",
          "valid": true,
          "verified_credential_algorithm": "dilithium2"
        },
        "type": "json"
      }
    },
    "method": "POST",
    "output": {
      "example": {
        "algorithm": "ml-dsa-65",
        "valid": true,
        "verified_credential_algorithm": "dilithium2"
      },
      "schema": {
        "properties": {
          "algorithm": {
            "description": "ml-dsa-65 — algorithm of the served attestation signature this route produces.",
            "type": "string"
          },
          "algorithm_label": {
            "description": "ML-DSA-65 / Dilithium-3 (NIST FIPS 204).",
            "type": "string"
          },
          "attestation_digest": {
            "description": "sha256 hex of the canonical verdict that the served signature covers.",
            "type": "string"
          },
          "claim": {
            "description": "The echoed KYA claim (agent_id, operator, scope, validity window).",
            "type": "object"
          },
          "not_expired": {
            "description": "True iff the credential is still in-date.",
            "type": "boolean"
          },
          "payment": {
            "description": "Settlement receipt (scheme, network, asset, txHash, payer, settled).",
            "type": "object"
          },
          "public_key": {
            "description": "Base64 ML-DSA-65 public key (1952 bytes) that verifies the served signature.",
            "type": "string"
          },
          "reason": {
            "description": "Human-readable explanation of the verdict.",
            "type": "string"
          },
          "reputation": {
            "description": "Live FRC-55 on-chain reputation snapshot, when referenced and available (else null).",
            "type": "object"
          },
          "seconds_until_expiry": {
            "description": "Seconds until expiry (negative if expired).",
            "type": "number"
          },
          "signature": {
            "description": "Base64 ML-DSA-65 / Dilithium-3 (NIST FIPS 204) signature (3309 bytes) over the 3-line message FRACTALAI-x402-served-v1\\nx402-verify-agent\\n<attestation_digest>, attesting this exact verdict.",
            "type": "string"
          },
          "signed_message": {
            "description": "The EXACT bytes the served signature covers: the 3-line FRACTALAI-x402-served-v1\\nx402-verify-agent\\n<attestation_digest>. Verify offline: ml_dsa65.verify(b64(signature), utf8(signed_message), b64(public_key)).",
            "type": "string"
          },
          "stage": {
            "description": "Which check decided the verdict: structure | credential_id | signature | expiration | ok.",
            "type": "string"
          },
          "valid": {
            "description": "True iff the post-quantum signature verifies, integrity holds, and the credential is in-date.",
            "type": "boolean"
          },
          "verified_credential_algorithm": {
            "description": "Algorithm of the INPUT credential that was verified: dilithium2 (ML-DSA-44, NIST FIPS 204).",
            "type": "string"
          }
        },
        "required": [
          "valid",
          "stage",
          "reason",
          "signature",
          "algorithm",
          "public_key"
        ],
        "type": "object"
      },
      "type": "json"
    },
    "route_key": "POST /api/x402/verify-agent",
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "body": {
              "type": "object"
            },
            "bodyType": {
              "enum": [
                "json",
                "form-data",
                "text"
              ],
              "type": "string"
            },
            "headers": {
              "additionalProperties": {
                "type": "string"
              },
              "type": "object"
            },
            "method": {
              "enum": [
                "POST",
                "PUT",
                "PATCH"
              ],
              "type": "string"
            },
            "queryParams": {
              "additionalProperties": {
                "type": "string"
              },
              "type": "object"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method",
            "bodyType",
            "body"
          ],
          "type": "object"
        },
        "output": {
          "properties": {
            "example": {
              "type": "object"
            },
            "type": {
              "type": "string"
            }
          },
          "required": [
            "type"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    },
    "serviceName": "FractalAI Know-Your-Agent",
    "tags": [
      "kya",
      "agent-identity",
      "reputation",
      "erc-8004",
      "post-quantum"
    ],
    "type": "http"
  }
}

curl "https://fractalai.net.co/api/x402/verify-agent"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

const res = await fetch("https://fractalai.net.co/api/x402/verify-agent");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

import httpx
res = httpx.get("https://fractalai.net.co/api/x402/verify-agent")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header