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SignalHarness Agent Tool Call Validator
x402
SignalHarness Agent Tool Call Validator is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).
Validates an AI agent tool call JSON payload for correctness, schema compliance, and potential issues before execution
Price / call$0.005
Success—
StatusUnknown
How this service works
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Output
Returns a validation result object containing a status (succeeded/failed), a boolean replay flag, an analysis_json string with structured findings, a list of warnings about the payload, an evidence_scope label (e.g. caller_supplied_data), and a full receipt with payment metadata, latency, and a SHA-256 hash of the result.
Example use cases
Pre-flight check for agent action
“Before my agent fires off this tool call, validate this JSON to make sure it won't fail: {"tool": "create_calendar_event", "params": {"title": "Team Sync", "date": "2025-06-01", "duration_minutes": 30}}”
Debugging malformed agent payload
“My agent keeps erroring on this tool invocation — can you run it through the validator and tell me what's wrong with this JSON: {"tool": "query_database", "params": {"table": "orders", "limit": "ten"}}?”
Quality gate in automated agent pipeline
“I'm building an agent pipeline and want to validate every outgoing tool call before execution — check this one for schema errors or warnings: {"tool": "charge_card", "params": {"amount": 99.99, "currency": "USD", "customer_id": "cust_123"}}”
Technical details
Endpoint
POSThttps://signalharness.ai/api/agent/services/agent_tool_call_validate/invokeWhen to prefer
Choose this endpoint when you need a lightweight, pay-per-call validation layer for AI agent tool call JSON before execution — especially useful in automated pipelines where catching malformed payloads early prevents downstream failures. Prefer it over manual schema checks when you want a structured analysis with warnings and an auditable receipt, or when operating within a Base USDC x402 payment environment.
Side effects
- Malformed or non-JSON request_json string returns a validation error
- Payload exceeding 65,536 characters is rejected
- Missing required request_json field causes a bad request response
- Ambiguous or empty JSON (below 2 characters) is rejected by minLength constraint
- Payment failure on the x402 protocol may prevent invocation
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": "agent_tool_call_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": "agent_tool_call_validate",
"executionId": "example-execution",
"startedAtMs": 0,
"amountAtomic": "5000",
"resultSha256": "c824d3b775a0c55472193d1aa39beb5925c92b05148ebe3af552a8f049a96277",
"serviceVersion": "1.0.0",
"settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
},
"artifacts": [],
"requestId": "example-request",
"executionId": "example-execution"
}
}Tags
x402
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