# Cairnworks Verify — HTTP Audit

> Cairnworks Verify — HTTP Audit is a paid API for AI agents from cairnworks-verify.run402.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-28).

Audits a URL's HTTP status, redirects, paywall flags, and response metadata, returning a signed JSON report with a sha256 evidence digest.

## Facts

- Endpoint: POST https://cairnworks-verify.run402.com/http-audit?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-28
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/cairnworks-verify-http-audit-147158a3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dqw2sLPic6Cvgpk9AwXCL

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 cairnworks-verify-http-audit-147158a3 -d '<json body>'
```

Example prompt: Can you audit https://www.nytimes.com/2024/01/01/business/economy.html and tell me if it's behind a paywall, whether it redirects, and what the final HTTP status is — I need a signed, tamper-evident report.

## When to prefer this

Choose this endpoint when you need a cryptographically signed, tamper-evident audit of a URL's accessibility — especially to detect paywalls, auth walls, redirects, or server errors without managing your own HTTP inspection infrastructure. It is ideal when you need an immutable evidence receipt (sha256 digest) to attach to an incident report, compliance log, or agent workflow decision. Prefer it over generic HTTP clients when provenance and non-repudiation of the check matter.

## Known failure modes

- Invalid or malformed URL returns a 4xx validation error
- Target URL unreachable or DNS failure returns an error response
- Payment not received or insufficient USDC results in 402 response with no audit data
- Target site blocks the auditor's IP causing false rate-limit or error flags
- Very slow target URLs may cause a timeout before a result is returned

## How this service works

cairnworks verify — fixed-price x402 (USDC on Base) checks for agent payouts: verify a Base/BSC transaction receipt and ERC-20 transfers (0.01), audit a URL's status/redirects/paywall flags (0.01), token holder and treasury share audit at a block (0.02), batch-verify up to 10 payout receipts (0.02). No account, no API key; every response is signed JSON with a sha256 evidence digest. Free sample outputs at /samples (no payment).

## Output

A signed JSON object containing: HTTP status code, final URL after redirects, list of redirect URLs, body size in bytes, latency in milliseconds, content type, HTTPS flag, page title, noindex flag, redirect flag, rate-limited flag, server error flag, JS-only shell flag, paywall/auth flag, a SHA256 hash of the response body, and a SHA256 evidence digest over the full response for tamper-evidence.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "pattern": "^https?://"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "flags": {
   "https": true,
   "title": "Example Domain",
   "noindex": false,
   "redirect": false,
   "rate_limited": false,
   "server_error": false,
   "js_only_shell": false,
   "paywall_or_auth": false
  },
  "status": 200,
  "final_url": "https://example.com/",
  "redirects": [],
  "body_bytes": 1256,
  "latency_ms": 210,
  "body_sha256": "…",
  "content_type": "text/html",
  "evidence_sha256": "…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/cairnworks-verify-http-audit-147158a3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from cairnworks-verify.run402.com](https://www.zero.xyz/host/cairnworks-verify.run402.com/llms.txt)