# SignalHarness Agent Trace Timeline

> SignalHarness Agent Trace Timeline is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-15).

Generates a structured timeline analysis of an agent execution trace from caller-supplied JSON data

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/agent_trace_timeline/invoke
- Price: $0.015/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-trace-timeline-ca0805a7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tZJETcJz2tYY0DEqnjKRu

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-trace-timeline-ca0805a7 -d '<json body>'
```

Example prompt: Can you build a trace timeline for this agent run? Here's the execution JSON: {"session_id": "abc123", "steps": [{"action": "tool_call", "ts": 1700000001}, {"action": "llm_response", "ts": 1700000003}]}

## When to prefer this

Choose this endpoint when you need to reconstruct a chronological execution timeline from raw agent trace JSON, particularly for debugging, auditing, or optimizing AI agent workflows. It is purpose-built for agent observability use cases and returns structured analysis with explicit data-provenance warnings, making it suitable when you need a documented audit trail rather than just log parsing.

## Known failure modes

- Malformed or invalid request_json causes parsing failure
- request_json too short (under 2 chars) or too long (over 65536 chars) triggers validation error
- Caller-supplied data may be flagged with warnings if it cannot be verified
- Payment failure on Base network results in non-execution
- Empty or schema-invalid trace data returns a warning-annotated result rather than a deep analysis

## 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 an analysis_json string containing the reconstructed trace timeline and structured findings, along with any warnings about caller-supplied data reliability, a status field, and a full payment receipt with execution metadata including latency, payment ID, and settlement reference on Base network.

## 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_trace_timeline",
   "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_trace_timeline",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "15000",
   "resultSha256": "70c210e905b8d854ad13245867919e41163209bcf5ac253a115a12fbb6ac3c3b",
   "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-trace-timeline-ca0805a7/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)