# Council of AI x402 Conformance Checker

> Council of AI x402 Conformance Checker is a paid API for AI agents from councilof.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-02).

Checks whether a given public HTTPS URL correctly implements the x402 payment protocol and returns a signed conformance receipt

## Facts

- Endpoint: GET https://councilof.ai/api/ras/x402-check?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/council-of-ai-x402-conformance-checker-943913b4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RoinOWTFnmduoUirm7fjF

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 council-of-ai-x402-conformance-checker-943913b4
```

Example prompt: Can you check whether https://myapi.example.com/premium-data correctly implements the x402 payment protocol and get me a signed conformance receipt showing whether it passes?

## When to prefer this

Use this endpoint when you need independent, cryptographically signed third-party verification that a specific public HTTPS URL correctly implements the x402 payment protocol per version 2 of the spec. Prefer this over manual inspection when you need a checkable, publishable conformance receipt — especially for auditing partner APIs, validating your own implementation before launch, or debugging x402 compliance failures.

## Known failure modes

- URL is unreachable or times out — state returned as UNREACHABLE
- URL does not return HTTP 402 — conformant field is false
- Missing PAYMENT-REQUIRED response header — conformant field is false
- x402Version in body is not 2 — conformant field is false
- Missing extensions.bazaar block — conformant field is false
- Non-HTTPS URL provided — rejected by input schema validation
- Receipt may be unsigned (sig_ed25519 null) for supporting runs

## How this service works

We measure how AI systems behave against frozen, published tests and publish checkable evidence. Issued measurement cards are signed; unsigned supporting runs are labelled. Read the live board and corrections ledger.

## Output

A JSON object with a 'kind' of 'receipt', containing a 'result' block that includes the HTTP status code, whether the endpoint is conformant, the x402 version detected, presence of the payment-required header, and whether the bazaar extension block is present. Also includes a 'state' field (CONFORMANT, NOT_CONFORMANT, or UNREACHABLE), the schema version, and a cryptographic receipt with a SHA-256 hash and optional ed25519 signature.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "pattern": "^https://",
       "description": "public https x402 resource URL, exactly as a buyer would GET it"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "kind": "receipt",
  "result": {
   "row": {
    "status": 402,
    "conformant": true,
    "x402_version": 2,
    "has_bazaar_extension": true,
    "payment_required_header": true
   },
   "kind": "csoai.ras.x402-check/0.1",
   "rule": "Conformant = HTTP 402 AND a PAYMENT-REQUIRED response header AND x402Version 2 in the body AND an extensions.bazaar block.",
   "state": "CONFORMANT | NOT_CONFORMANT | UNREACHABLE"
  },
  "schema": "csoai.ras.x402-check/0.1",
  "receipt": {
   "sha256": "<hex>",
   "sig_ed25519": "<hex or null>"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/council-of-ai-x402-conformance-checker-943913b4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from councilof.ai](https://www.zero.xyz/host/councilof.ai/llms.txt)