# x402 Merchant Audit

> x402 Merchant Audit is a paid API for AI agents from merchant-audit.clankerceo.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Audits an x402 paid API endpoint before payment by live-probing reachability, detecting price drift, checking settlement history, and verifying on-chain payment flows.

## Facts

- Endpoint: GET https://merchant-audit.clankerceo.workers.dev/verify-merchant
- 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/x402-merchant-audit-57f2ce0c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_jhRIVE2eQXJIsGFYKSxU5

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 x402-merchant-audit-57f2ce0c
```

Example prompt: Before I pay for it, audit the x402 merchant at https://some-api.example.com/data-endpoint — I want to know if it's reachable, actually emits 402, has real settlement history, and whether the price has been drifting.

## When to prefer this

Use this endpoint when an AI agent or user is about to pay an x402 merchant and needs pre-flight verification of legitimacy, price stability, and real usage history. Prefer this over generic HTTP probes when you specifically need x402-aware checks like 402 emission detection, on-chain USDC settlement verification, and price drift analysis — capabilities no standard health-check or uptime monitor provides.

## Known failure modes

- Target URL is unreachable — reachable flag set to false, verdict likely CAUTION or RISKY
- Target does not emit HTTP 402 — emits_402 false, may indicate misconfigured or non-x402 endpoint
- No on-chain settlement data found — onchain_inflow_usdc returns 0, has_buyers false
- Invalid or non-HTTPS target URL — request rejected with validation error
- Merchant-audit service itself is temporarily unavailable — Cloudflare Worker error response

## How this service works

Audit any x402 merchant before you pay it. Live probe, price-drift detection, settlement history and on-chain payment verification.

## Output

Returns a JSON object with a top-level verdict (e.g. CAUTION, SAFE, RISKY), a set of boolean/numeric checks (reachable, emits_402, has_buyers, price_drift, onchain_inflow_usdc), and an array of human-readable reason strings explaining the verdict.

## 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",
    "queryParams"
   ],
   "properties": {
    "type": {
     "enum": [
      "http"
     ],
     "type": "string"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "target"
     ],
     "properties": {
      "target": {
       "type": "string",
       "description": "Absolute https URL of the x402 resource to audit."
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "enum": [
      "json"
     ],
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "checks": {
   "emits_402": true,
   "reachable": true,
   "has_buyers": false,
   "price_drift": false,
   "onchain_inflow_usdc": 0
  },
  "target": "https://example-merchant.com/api/some-service",
  "reasons": [
   "listed but no settlements in 30d"
  ],
  "verdict": "CAUTION"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-merchant-audit-57f2ce0c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from merchant-audit.clankerceo.workers.dev](https://www.zero.xyz/host/merchant-audit.clankerceo.workers.dev/llms.txt)