Determine whether a previously accepted x402 service payment contract is still equivalent

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xdb7b2b54f80479826222749a2ea73a8acc306e1e",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "maxTimeoutSeconds": 60
  }
]

{
  "bazaar": {
    "info": {
      "description": "Determine whether a previously accepted x402 service payment contract is still equivalent enough to proceed. Compares one live unpaid 402 challenge, using a caller-supplied GET or POST request shape, against a caller-held baseline bound to that request identity. Not uptime monitoring, a trust score, a webhook, a marketplace crawl, or a generic POST {} probe of every x402 resource.",
      "input": {
        "body": {
          "method": "POST",
          "resource_url": "https://api.agentmercantile.com/v1/url-context"
        },
        "bodyType": "json",
        "method": "POST",
        "type": "http"
      },
      "output": {
        "example": {
          "decision": "BASELINE_CREATED",
          "limitations": [
            "Caller holds the baseline. Direct-service 402 is payment authority."
          ],
          "machine": "VM08",
          "methodology_version": "x402-service-change-snapshot-0.1.0",
          "status": "OK"
        },
        "type": "json"
      }
    },
    "schema": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "properties": {
        "input": {
          "additionalProperties": false,
          "properties": {
            "body": {
              "additionalProperties": false,
              "properties": {
                "baseline": {
                  "description": "Optional caller-held reusable payment-contract baseline bound to this request identity.",
                  "type": "object"
                },
                "body": {
                  "description": "Optional JSON object for POST probes only.",
                  "type": "object"
                },
                "method": {
                  "description": "Required unpaid 402 probe method. Not inferred from discovery.",
                  "enum": [
                    "GET",
                    "POST"
                  ],
                  "type": "string"
                },
                "resource_url": {
                  "description": "One public HTTPS x402 resource URL on port 443.",
                  "format": "uri",
                  "type": "string"
                }
              },
              "required": [
                "resource_url",
                "method"
              ],
              "type": "object"
            },
            "bodyType": {
              "enum": [
                "json",
                "form-data",
                "text"
              ],
              "type": "string"
            },
            "method": {
              "enum": [
                "POST"
              ],
              "type": "string"
            },
            "type": {
              "const": "http",
              "type": "string"
            }
          },
          "required": [
            "type",
            "method",
            "bodyType",
            "body"
          ],
          "type": "object"
        },
        "output": {
          "properties": {
            "example": {
              "additionalProperties": true,
              "properties": {
                "decision": {
                  "enum": [
                    "BASELINE_CREATED",
                    "CONTINUE",
                    "REVIEW",
                    "STOP",
                    "UNKNOWN"
                  ],
                  "type": "string"
                },
                "limitations": {
                  "items": {
                    "type": "string"
                  },
                  "type": "array"
                },
                "machine": {
                  "enum": [
                    "VM08"
                  ],
                  "type": "string"
                },
                "methodology_version": {
                  "enum": [
                    "x402-service-change-snapshot-0.1.0"
                  ],
                  "type": "string"
                },
                "status": {
                  "enum": [
                    "OK",
                    "PARTIAL",
                    "HOLD"
                  ],
                  "type": "string"
                }
              },
              "required": [
                "status",
                "machine",
                "methodology_version",
                "decision",
                "limitations"
              ],
              "type": "object"
            },
            "type": {
              "type": "string"
            }
          },
          "required": [
            "type"
          ],
          "type": "object"
        }
      },
      "required": [
        "input"
      ],
      "type": "object"
    }
  }
}

curl "https://api.agentmercantile.com/v1/x402-service-change-snapshot"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

const res = await fetch("https://api.agentmercantile.com/v1/x402-service-change-snapshot");
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://api.agentmercantile.com/v1/x402-service-change-snapshot")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header