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SignalHarness LLM Response Schema Validator
x402
SignalHarness LLM Response Schema Validator is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).
Validates a JSON string produced by an LLM against an expected schema, returning warnings and analysis about schema compliance.
Price / call$0.005
Success—
StatusUnknown
How this service works
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Output
Returns a JSON object containing a status field ('succeeded'), a result object with an analysis_json string (schema compliance findings), a list of warnings about caller-supplied data, and a signed receipt with payment details, request/execution IDs, result hash, and latency metrics.
Example use cases
Guard rails for LLM pipeline output
“My AI pipeline just generated this JSON response — can you check if it's valid and flag any schema issues before I pass it to the next step: '{"product_id":"abc123","price":"not-a-number","in_stock":true}'?”
Verify AI-generated form data
“I had an LLM fill out a structured form and got back this JSON. Can you validate it and tell me what's wrong with it: '{"email":"user@","age":-1,"terms_accepted":"yes"}'?”
Automated schema check for agent output
“Before I store this LLM-generated record, validate this JSON for schema compliance and return any warnings: '{"user_id":null,"timestamp":"2024-13-45","score":102}'”
Technical details
Endpoint
POSThttps://signalharness.ai/api/agent/services/llm_response_schema_validate/invokeWhen to prefer
Use this endpoint when you need a fast, pay-per-call schema validation of LLM-generated JSON output inside an agent pipeline, especially when you want a receipt-backed audit trail via x402/Base USDC micropayments. Prefer this over manual JSON parsing when you need structured compliance feedback with warnings, or when operating in an autonomous agent context that already uses SignalHarness x402 services.
Side effects
- Invalid or non-parseable JSON string submitted as request_json — may return error or empty analysis
- request_json exceeds 65536 character limit — request rejected
- Malformed input that is not a JSON string — validation cannot proceed
- Network or payment failure — receipt status may reflect failed settlement
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": "llm_response_schema_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": "llm_response_schema_validate",
"executionId": "example-execution",
"startedAtMs": 0,
"amountAtomic": "5000",
"resultSha256": "96eda6321d55be5af1bceb5cc506ca685922635a7cdbe2635bd1f5b7eabd45c7",
"serviceVersion": "1.0.0",
"settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
},
"artifacts": [],
"requestId": "example-request",
"executionId": "example-execution"
}
}Tags
x402
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