# Holoweave Witness — Transaction Finality Attestation

> Holoweave Witness — Transaction Finality Attestation is a paid API for AI agents from witness.holoweave.org, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).

Returns a signed, independent attestation of a Base blockchain transaction's outcome, including USDC transfer details, finality status, and confirmations — without trusting the payment facilitator.

## Facts

- Endpoint: POST https://witness.holoweave.org/v1/tx-finality
- Price: $0.01/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-transaction-finality-attestation-5eb9aad4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bcYBr1ltoB73ETs6qCFTP

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-transaction-finality-attestation-5eb9aad4 -d '<json body>'
```

Example prompt: Can you get me an independent signed receipt for this Base transaction — 0x4a3f...b2c1 — and confirm whether it's finalized, which USDC transfers it carried, and that it sent at least 1.00 USDC to 0x9975...?

## When to prefer this

Use this endpoint when you need a cryptographically signed, independent third-party attestation of a Base blockchain transaction — especially to verify x402 payments without trusting the facilitating server. Prefer it over querying an RPC node directly when you need a portable, verifiable receipt with an ed25519 signature, or when auditing USDC transfers for dispute resolution, compliance, or agent-to-agent payment verification on Base mainnet or Sepolia.

## Known failure modes

- Invalid or malformed transaction hash returns an error before attestation
- Transaction not yet indexed or too recent may return pending finality rather than finalized
- Mismatched expected transfer (to/amount/token) returns EXPECTED_TRANSFER_ABSENT verdict
- Unsupported chain ID returns a validation error
- Passing both tx_hash and payment_response may cause ambiguity or conflict
- Network congestion on Base may slow block confirmation lookup

## 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

A signed ed25519 attestation object containing: a verdict (pass/fail), finality status (finalized/safe/pending), transaction success boolean, an array of USDC transfers with from/to addresses and amounts, block number, and confirmation count. The signature includes algorithm, base64 value, and a key ID for independent verification.

## Response schema (JSON Schema)

```json
{
 "example": {
  "signature": {
   "alg": "ed25519",
   "value": "base64...",
   "key_id": "aw-attest-2026-08"
  },
  "attestation": {
   "verdict": "pass",
   "endpoint": "tx-finality",
   "evidence": {
    "finality": "finalized",
    "succeeded": true,
    "transfers": [
     {
      "to": "0x9975…",
      "from": "0x423d…",
      "amount": "0.010000",
      "symbol": "USDC"
     }
    ],
    "block_number": 50500000,
    "confirmations": 1200
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/holoweave-witness-transaction-finality-attestation-5eb9aad4/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)