# SignalHarness Merkle Proof Verifier

> SignalHarness Merkle Proof Verifier is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Verifies a caller-supplied Merkle proof and returns a cryptographic verification result with evidence scope and warnings

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/merkle_proof_verify/invoke
- 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/signalharness-merkle-proof-verifier-989eaf79
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6u_vN2d4KVRf2XFFLIqPA

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 signalharness-merkle-proof-verifier-989eaf79 -d '<json body>'
```

Example prompt: Can you verify this Merkle proof for me and tell me if it's valid? Here's the proof data: {base64-encoded or JSON Merkle proof string}.

## When to prefer this

Use this endpoint when you need a lightweight, pay-per-call cryptographic Merkle proof verification service that returns structured results with auditability receipts. It is especially useful for agent-driven workflows that need to verify blockchain or dataset inclusion proofs on demand without running a full node or maintaining local cryptographic infrastructure.

## Known failure modes

- Invalid or malformed Merkle proof string causes verification failure
- Proof string exceeds 65536 character limit, rejected by schema
- Proof string is too short (under 2 characters), rejected by schema
- Payment not received or insufficient USDC, returns 402
- Network or execution timeout results in non-succeeded status

## How this service works

Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.

## Output

Returns a JSON object with a verification status ('succeeded'), a result object containing the merkle_proof_verification outcome, evidence_scope ('caller_supplied_data'), and any warnings, plus a full receipt with payment ID, request ID, execution ID, latency, and a SHA-256 hash of the result for auditability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "merkle_proof_request": {
   "type": "string",
   "maxLength": 65536,
   "minLength": 2
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Proof validity does not authenticate the meaning of the leaf."
   ],
   "service_id": "merkle_proof_verify",
   "evidence_scope": "caller_supplied_data",
   "merkle_proof_verification": "{\"computed_root\":\"0x71d8979cbfae9b197a4fbcc7d387b1fae9560e2f284d30b4e90c80f6bc074f57\",\"expected_root\":\"0x71d8979cbfae9b197a4fbcc7d387b1fae9560e2f284d30b4e90c80f6bc074f57\",\"sorted_pairs\":true,\"valid\":true}"
  },
  "status": "succeeded",
  "receipt": {
   "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "usage": [],
   "status": "succeeded",
   "network": "eip155:8453",
   "artifacts": [],
   "endedAtMs": 0,
   "latencyMs": 0,
   "paymentId": "example-payment",
   "receiptId": "example-receipt",
   "requestId": "example-request",
   "serviceId": "merkle_proof_verify",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "10000",
   "resultSha256": "3e3976e3b41746abaeac3bddf91a64cdd61ea9aaba49f5dc6471e94c2086f3a4",
   "serviceVersion": "1.0.0",
   "settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
  },
  "artifacts": [],
  "requestId": "example-request",
  "executionId": "example-execution"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signalharness-merkle-proof-verifier-989eaf79/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from signalharness.ai](https://www.zero.xyz/host/signalharness.ai/llms.txt)