# Quartermaster x402 Endpoint Auditor

> Quartermaster x402 Endpoint Auditor is a paid API for AI agents from quartermaster.surewhynot.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Audits an x402-enabled paid endpoint for protocol compliance, scoring its 402 challenge, payment fields, Bazaar discovery metadata, and discovery surfaces with a 0-100 score and actionable fixes.

## Facts

- Endpoint: GET https://quartermaster.surewhynot.app/v1/x402-audit
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quartermaster-x402-endpoint-auditor-f7b0154b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_L1KE_MrN6npphx3AoRQKW

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 quartermaster-x402-endpoint-auditor-f7b0154b
```

Example prompt: Run a full x402 compliance audit on my paid endpoint at https://api.example.com/v1/my-resource — I want to see the score, which checks pass or fail, and what I need to fix to get it listed on the Bazaar.

## When to prefer this

Use this endpoint when you need a comprehensive, multi-dimensional compliance report for an x402 paid endpoint — covering the full protocol stack including 402 challenge format, payment fields, Bazaar discovery metadata, and all standard discovery surfaces. Prefer this over manual inspection or partial checks when you want a single scored report with actionable fixes.

## Known failure modes

- Target URL is not reachable or returns unexpected status codes
- Target URL does not implement x402 at all, resulting in low/zero score
- Malformed URL input causes validation error
- Discovery surfaces (llms.txt, openapi.json, etc.) are inaccessible or return errors
- Network timeout when probing the target endpoint

## How this service works

Full x402 endpoint audit: verifies the 402 challenge, payment fields, Bazaar discovery metadata, and the origin's discovery surfaces (llms.txt, openapi.json, .well-known/x402, discovery/resources), returning a 0-100 score, pass/warn/fail checks with evidence, and recommended fixes.

## Output

Returns a 0-100 compliance score, a list of pass/warn/fail checks with evidence for each (covering the 402 challenge, payment fields, Bazaar discovery metadata, and discovery surfaces including llms.txt, openapi.json, .well-known/x402, and discovery/resources), plus recommended fixes for any failing checks.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "description": "x402 paid endpoint to audit"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quartermaster-x402-endpoint-auditor-f7b0154b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from quartermaster.surewhynot.app](https://www.zero.xyz/host/quartermaster.surewhynot.app/llms.txt)