Pay-per-Attestation: an AI agent pays to seal its own decision (input hash, output, model,

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "50000",
    "maxTimeoutSeconds": 300
  }
]

{
  "bazaar": {
    "body": {
      "agent_id": "agent-42",
      "input": "ctx",
      "output": "decision"
    },
    "bodyType": "json",
    "description": "Pay-per-Attestation: an AI agent pays to seal its own decision (input hash, output, model, timestamp) in FractalAI's post-quantum L1 — Dilithium-2 (NIST FIPS 204) signed, Black-Box chained, on-chain anchored (VAID-1). Returns a re-verifiable receipt. Built for EU AI Act Art.12 record-keeping. x402-native.",
    "info": {
      "input": {
        "body": {
          "agent_id": "agent-42",
          "input": "ctx",
          "output": "decision"
        },
        "bodyType": "json",
        "method": "POST",
        "type": "http"
      },
      "output": {
        "example": {
          "algorithm": "ml-dsa-65",
          "attestation_hash": "0x…",
          "permalink": "https://fractalai.net.co/attestation/0x…",
          "signature": "BASE64_ML_DSA65"
        },
        "type": "json"
      }
    },
    "method": "POST",
    "output": {
      "example": {
        "algorithm": "ml-dsa-65",
        "attestation_hash": "0x…",
        "permalink": "https://fractalai.net.co/attestation/0x…",
        "signature": "BASE64_ML_DSA65"
      },
      "schema": {
        "properties": {
          "algorithm": {
            "description": "ml-dsa-65 (the served signature algorithm).",
            "type": "string"
          },
          "attestation_hash": {
            "description": "On-chain (VAID-1) attestation hash — re-verifiable proof the decision was sealed.",
            "type": "string"
          },
          "entry_hash": {
            "description": "Black Box entry hash: sha256 of the chained, canonical decision content.",
            "type": "string"
          },
          "entry_public_key": {
            "description": "Base64 Dilithium-2 public key that verifies entry_signature.",
            "type": "string"
          },
          "entry_signature": {
            "description": "Base64 Dilithium-2 (NIST FIPS 204) signature over the Black-Box entry hash — the chained on-chain-anchored seal.",
            "type": "string"
          },
          "input_hash": {
            "description": "sha256 of the declared input.",
            "type": "string"
          },
          "output_hash": {
            "description": "sha256 of the declared output.",
            "type": "string"
          },
          "payment": {
            "description": "Settlement receipt (scheme, network, asset, txHash, payer, settled).",
            "type": "object"
          },
          "permalink": {
            "description": "Permalink to the on-chain Dilithium-2 anchor (VAID-1), when the L1 anchor succeeds.",
            "type": "string"
          },
          "prev_hash": {
            "description": "Hash of the previous Black Box entry this one is chained to (tamper-evident order).",
            "type": "string"
          },
          "public_key": {
            "description": "Base64 ML-DSA-65 public key (1952 bytes) that verifies the served signature.",
            "type": "string"
          },
          "seq": {
            "description": "Append-only sequence number of this decision in the agent Black Box.",
            "type": "number"
          },
          "signature": {
            "description": "Base64 ML-DSA-65 / Dilithium-3 (NIST FIPS 204) SERVED signature (3309 bytes) over the EXACT bytes echoed in `signed_message` = FRACTALAI-x402-served-v1\\nx402-attest-decision\\n<sha256(canonical decision message)> (route-separated, 3 lines). Verify offline: ml_dsa65.verify(b64(signature), utf8(signed_message), b64(public_key)).",
            "type": "string"
          },
          "signed_message": {
            "description": "The EXACT UTF-8 bytes the served signature covers (FRACTALAI-x402-served-v1\\nx402-attest-decision\\n<sha256(canonical)>). Pass verbatim to ml_dsa65.verify.",
            "type": "string"
          }
        },
        "required": [
          "entry_hash",
          "input_hash",
          "output_hash",
          "signature",
          "public_key"
        ],
        "type": "object"
      },
      "type": "json"
    },
    "route_key": "POST /api/x402/attest-decision",
    "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 Notary",
    "tags": [
      "ai-provenance",
      "decision",
      "audit",
      "eu-ai-act",
      "on-chain"
    ],
    "type": "http"
  }
}

curl "https://fractalai.net.co/api/x402/attest-decision"
# -> 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/attest-decision");
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/attest-decision")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header