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SignalHarness Prompt Output Contract Extractor
x402
SignalHarness Prompt Output Contract Extractor 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).
Extracts structured output contracts (schemas, constraints, and response formats) from prompt/request JSON submitted by the caller
Price / call$0.005
Success—
StatusUnknown
How this service works
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Output
Returns an analysis_json field containing the extracted output contract (schema, constraints, expected format) derived from the submitted request_json, along with a warnings array noting that caller-supplied data should be verified, and an evidence_scope field indicating the data source was caller-supplied. Includes a full cryptographic receipt with payment details on Base network.
Example use cases
Validate LLM prompt output schema
“I have this prompt JSON that I'm sending to an LLM and I need to know exactly what output contract it's specifying — can you extract the expected response structure and any constraints from it?”
Audit agent request contracts
“Here's a JSON request payload from one of my agents: extract what output format and schema it's expecting so I can verify it matches what the downstream tool actually returns.”
Document API prompt contracts
“I'm building documentation for my prompt library — take this request JSON and extract the output contract it defines so I can generate schema docs automatically.”
Technical details
Endpoint
POSThttps://signalharness.ai/api/agent/services/prompt_output_contract_extract/invokeWhen to prefer
Choose this endpoint when you need to programmatically extract the implicit or explicit output contract (expected response schema, format constraints, field definitions) from a prompt or API request JSON. Best used when building agent pipelines, documentation tooling, or contract-validation layers that need to understand what structured output a given prompt demands. At $0.005 USDC per call it is cost-effective for high-volume prompt auditing workflows.
Side effects
- Malformed or invalid JSON in request_json returns a parsing error
- request_json below 2 characters or above 65536 characters is rejected by schema validation
- Ambiguous or underspecified prompts may yield low-confidence extractions with warnings
- Payment failure on Base network prevents execution
- No output contract detectable in the submitted JSON returns minimal or empty analysis_json
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| request_json | string |
Output
Schema · Response
{
"type": "json",
"example": {
"replay": false,
"result": {
"warnings": [
"Verify the caller-supplied data before relying on this result."
],
"service_id": "prompt_output_contract_extract",
"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_output_contract_extract",
"executionId": "example-execution",
"startedAtMs": 0,
"amountAtomic": "5000",
"resultSha256": "7af4cc5f7368220a143b1ff501065116b4277d0af8c9535abfc00c88bf134b63",
"serviceVersion": "1.0.0",
"settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
},
"artifacts": [],
"requestId": "example-request",
"executionId": "example-execution"
}
}Tags
x402
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