# SignalHarness Prompt Structure Analyzer

> SignalHarness Prompt Structure Analyzer 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).

Analyzes the structure of a prompt or JSON payload and returns structural analysis with warnings and evidence scope metadata.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/prompt_structure_analyze/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-prompt-structure-analyzer-0c9e50d1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PDb5OPnJ98OQGasRpLU60

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-prompt-structure-analyzer-0c9e50d1 -d '<json body>'
```

Example prompt: Can you analyze the structure of this prompt JSON and flag any structural issues or warnings: '{"system":"You are a helpful assistant.","user":"Summarize the following text:","context":"..."}' ?

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-call structural analysis of a prompt or JSON payload without setting up a full validation pipeline. Ideal for agent systems that want to audit prompt quality, detect structural anomalies, or log evidence scope before forwarding prompts downstream. At $0.01 USDC per call it is cost-effective for high-frequency pre-flight checks.

## Known failure modes

- Input JSON string is malformed or below minimum length (2 chars) — request rejected
- Payload exceeds 65536 character limit — request rejected with size error
- Payment not processed — 402 response requiring USDC payment on Base network
- Service unavailable — execution fails with non-succeeded status in receipt
- Empty or null request_json field — validation error returned

## 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 an analysis_json field with structural findings, a list of warnings about the caller-supplied data, an evidence_scope label indicating data provenance ('caller_supplied_data'), and a full payment receipt including network, asset, amounts, latency, and execution IDs.

## 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": "prompt_structure_analyze",
   "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": "prompt_structure_analyze",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "10000",
   "resultSha256": "6b047b91ee7b7d1e3a2b619cfc346765179da744159ce369408d85730cb2f0df",
   "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-prompt-structure-analyzer-0c9e50d1/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)