# SignalHarness Agent Tool Result Validator

> SignalHarness Agent Tool Result Validator is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Validates and analyzes the JSON result returned by an agent tool call, returning warnings and structured analysis with a cryptographic receipt.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/agent_tool_result_validate/invoke
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-agent-tool-result-validator-cf116ea9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PVJUo7EAPolA6rzYUKfv8

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-agent-tool-result-validator-cf116ea9 -d '<json body>'
```

Example prompt: Can you validate this tool result JSON I got back from my agent pipeline and tell me if it's safe to use — here's the raw JSON string: '{"status":"ok","data":{"value":42}}'?

## When to prefer this

Choose this endpoint when your agent pipeline needs to validate, audit, or verify the integrity of a tool call result JSON before using it downstream, especially when a tamper-proof blockchain receipt (on Base via x402/USDC) is required as proof of validation. Prefer this over manual JSON schema checks when you need a structured analysis with warnings and a cryptographic audit trail rather than just a boolean pass/fail.

## Known failure modes

- Malformed or non-JSON request_json string causes validation error
- Input exceeds 65536 character limit returns rejection
- Payment not confirmed results in 402 response before execution
- Caller-supplied data warnings always present — result is not independently sourced
- Network issues on Base blockchain may delay receipt finalization

## 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 validation status ('succeeded'), an analysis_json string with structured findings, a list of warnings about the caller-supplied data, a SHA-256 hash of the result for integrity verification, and a full execution receipt including payment ID, network, asset address, latency, and settlement reference on Base (EIP-155:8453).

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Verify the caller-supplied data before relying on this result."
   ],
   "service_id": "agent_tool_result_validate",
   "analysis_json": "{\"example\":\"schema-valid caller-supplied data\"}",
   "evidence_scope": "caller_supplied_data"
  },
  "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": "agent_tool_result_validate",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "5000",
   "resultSha256": "743544cd40f8e0d218086f4273e573721eb1683fd3a680cff3880523d37ff29b",
   "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-agent-tool-result-validator-cf116ea9/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)