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SignalHarness NFT Metadata Validator
x402
SignalHarness NFT Metadata Validator is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).
Validates NFT metadata supplied by the caller and returns structured validation results with warnings and evidence scope.
Price / call$0.005
Success—
StatusUnknown
How this service works
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Output
Returns a JSON object with a 'result' field containing: 'nft_metadata_validation' (the main validation output), 'warnings' (an array of warning strings found in the metadata), and 'evidence_scope' (indicating the data source, e.g. 'caller_supplied_data'). Also includes a 'status' field ('succeeded' on success), a signed receipt with payment and execution details, and an artifacts array.
Example use cases
Pre-mint metadata quality check
“Before I mint this NFT, can you validate the metadata JSON I'm about to submit and tell me if there are any warnings or problems: '{"name":"Pixel Punk #7","description":"A pixelated punk character","image":"ipfs://QmXyz...","attributes":[{"trait_type":"Hat","value":"Cap"}]}'?”
NFT collection metadata audit
“I'm launching a 10k NFT collection and want to make sure the metadata template is solid — can you validate this sample metadata entry and list any warnings: '{"name":"AstroApe #1","description":"Space-faring ape","external_url":"https://astroapes.io","image":"ipfs://QmAbc...","attributes":[]}'?”
Marketplace listing compliance check
“I need to list an NFT on a major marketplace and want to make sure the metadata passes validation — please check this and tell me what's wrong: '{"name":"SkyDragon","image":"https://cdn.example.com/dragon.png","attributes":[{"trait_type":"Rarity","value":"Legendary"}]}'?”
Technical details
Endpoint
POSThttps://signalharness.ai/api/agent/services/nft_metadata_validate/invokeWhen to prefer
Choose this endpoint when you need a quick, programmatic, per-call NFT metadata validation with a structured warning list and evidence scope — especially useful for pre-mint checks, marketplace submission pipelines, or automated collection auditing. At $0.005 USDC per call it is cost-effective for single-item or batch-level spot checks. Prefer this over generic JSON schema validators when you need NFT-domain-aware validation logic and a tamper-evident receipt.
Side effects
- Invalid or malformed JSON string input — returns error status
- Input string too short (below minLength of 2) or too large (above maxLength of 65536)
- Payment failure or insufficient USDC balance — request blocked before execution
- Network or service unavailability — returns non-success status
- Metadata content that cannot be parsed as NFT metadata — may return empty or minimal validation result
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| nft_metadata_request | string |
Output
Schema · Response
{
"type": "json",
"example": {
"replay": false,
"result": {
"warnings": [
"Validation does not fetch media or authenticate the collection."
],
"service_id": "nft_metadata_validate",
"evidence_scope": "caller_supplied_data",
"nft_metadata_validation": "{\"errors\":[],\"supplied_fields\":[\"attributes\",\"image\",\"name\"],\"valid\":true}"
},
"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": "nft_metadata_validate",
"executionId": "example-execution",
"startedAtMs": 0,
"amountAtomic": "5000",
"resultSha256": "529b9d3a8492c95115b1036cbe8feccc4890670969cbf582db02d8f0c2e0a01d",
"serviceVersion": "1.0.0",
"settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
},
"artifacts": [],
"requestId": "example-request",
"executionId": "example-execution"
}
}Tags
x402
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