# Holoweave Witness — URL Witness (Batch URL Verification with Signed Attestations)

> Holoweave Witness — URL Witness (Batch URL Verification with Signed Attestations) is a paid API for AI agents from witness.holoweave.org, paid per call via x402, $0.05/call, status down (last checked 2026-09-15).

Fetches and verifies up to 10 URLs, returning signed Ed25519 attestations with HTTP status, body hash, change detection, and optional full-text extraction.

## Facts

- Endpoint: POST https://witness.holoweave.org/v1/urls-witness
- Price: $0.05/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/holoweave-witness-url-witness-batch-url-verification-with-signed-3a6d1333
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_psVlSAiRJ6lTuTyeJO76W

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 holoweave-witness-url-witness-batch-url-verification-with-signed-3a6d1333 -d '<json body>'
```

Example prompt: Can you witness and verify these two URLs — https://example.com/terms and https://docs.myapp.com/api — check that they're reachable, return their body hashes, and give me a signed attestation I can use as proof?

## When to prefer this

Choose this endpoint when you need tamper-evident, cryptographically signed proof that a URL was reachable and served specific content at a given time — especially when change detection (via SHA-256 comparison) or independent third-party attestation is required. Prefer over simple HTTP HEAD checks when auditability, non-repudiation, or content integrity proof matters. Also useful for batch verification of up to 10 URLs in a single signed response.

## Known failure modes

- URL unreachable or DNS failure — marked as 'unreachable' in summary
- HTTP non-200 status code — recorded with actual status, verdict may be 'fail'
- Body hash mismatch when expect_sha256 provided — flagged as 'changed'
- Request exceeds 10 URL limit — schema validation error
- robots.txt disallows read — text extraction skipped when read:true
- Payment failure — x402 payment required before response is returned
- Invalid URL format — item-level error in response

## How this service works

Web bot auth debugging for AI agents, priced per check at $0.01. RFC 7638 keyid thumbprint verification, RFC 9421 Ed25519 signature verification, and per-verifier acceptance rules. Signed attestations, published fixtures, sources with dates.

## Output

Returns a JSON object containing a signed Ed25519 attestation (algorithm, base64 signature value, key ID) and an attestation body with a per-URL verdict ('pass'/'fail'), HTTP status code, body SHA-256 hash, optional 'UNCHANGED' finding when an expected hash matches, and aggregate summary counts of pass/fail/unreachable/changed URLs.

## Response schema (JSON Schema)

```json
{
 "example": {
  "signature": {
   "alg": "ed25519",
   "value": "base64...",
   "key_id": "aw-attest-2026-08"
  },
  "attestation": {
   "verdict": "pass",
   "endpoint": "urls-witness",
   "evidence": {
    "count": 2,
    "items": [
     {
      "url": "https://example.com/terms",
      "index": 0,
      "status": 200,
      "verdict": "pass",
      "findings": [],
      "body_sha256": "9f2b…"
     },
     {
      "url": "https://www.iana.org/",
      "index": 1,
      "status": 200,
      "verdict": "pass",
      "findings": [
       "UNCHANGED"
      ],
      "body_sha256": "9f2b…",
      "expect_sha256": "9f2b…"
     }
    ],
    "summary": {
     "fail": 0,
     "pass": 2,
     "changed": [],
     "unreachable": [],
     "indeterminate": 0
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/holoweave-witness-url-witness-batch-url-verification-with-signed-3a6d1333/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from witness.holoweave.org](https://www.zero.xyz/host/witness.holoweave.org/llms.txt)