# SignalHarness Agent Execution Diff

> SignalHarness Agent Execution Diff is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

Analyzes and diffs agent execution data provided as JSON, returning structured analysis with warnings and evidence scope metadata.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/agent_execution_diff/invoke
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-agent-execution-diff-b945df4e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EYQxUb0HE7ORTUKLHH1Tv

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-execution-diff-b945df4e -d '<json body>'
```

Example prompt: Can you run a diff analysis on this agent execution JSON and tell me what warnings or discrepancies come up? Here's the payload: {"run_a": {"steps": 3, "output": "foo"}, "run_b": {"steps": 4, "output": "bar"}}.

## When to prefer this

Choose this endpoint when you need lightweight, pay-per-call agent execution diffing without standing up your own comparison infrastructure. It is particularly useful when you want a structured analysis of JSON-formatted agent execution data with evidence-scoped warnings, and when you are already operating in a Base USDC x402 payment context. Prefer alternatives if you need real-time streaming diffs, multi-file comparisons, or deep semantic code analysis beyond JSON data.

## Known failure modes

- Malformed or non-JSON request_json input returns a validation error
- Payload exceeding 65536 character limit is rejected
- Caller-supplied data that cannot be parsed as valid JSON results in analysis failure
- Payment not received or insufficient USDC balance causes 402 response
- Network or settlement issues on Base may cause receipt status anomalies

## 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 containing: a status field ('succeeded' or error), an analysis_json string with structured diff/analysis results, a list of warnings (e.g. data provenance notices), an evidence_scope label indicating data origin (e.g. 'caller_supplied_data'), and a receipt with payment metadata including paymentId, requestId, executionId, latency, and a resultSha256 hash for integrity verification.

## 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_execution_diff",
   "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_execution_diff",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "10000",
   "resultSha256": "8c6e115df223dba1d771a4aab84acdd9bb7d15c557ce60301683da91c5e78f8c",
   "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-execution-diff-b945df4e/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)