# SignalHarness NFT Duplicate Media Hash Detector

> SignalHarness NFT Duplicate Media Hash Detector 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).

Detects duplicate media hashes across a supplied set of NFT media data, identifying NFTs that share identical underlying media content.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/nft_duplicate_media_hashes/invoke
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-nft-duplicate-media-hash-detector-b648ef61
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_yfZsOgObsfvqUiotxpvne

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-nft-duplicate-media-hash-detector-b648ef61 -d '<json body>'
```

Example prompt: Can you check this list of NFT media hashes for duplicates and tell me which ones share the same underlying media content?

## When to prefer this

Choose this endpoint when you need to programmatically detect whether multiple NFTs share identical underlying media content based on their hashes — particularly useful for NFT marketplace integrity checks, collection audits, anti-plagiarism workflows, or collector due diligence. It is purpose-built for the NFT media deduplication use case and returns structured evidence with a verifiable result hash, making it suitable for agent pipelines that require auditable outputs.

## Known failure modes

- Malformed or empty nft_media_hash_request string returns validation error
- Input exceeding 65536 characters is rejected
- No duplicates found returns an empty duplicate_media_hashes result (not an error)
- Invalid JSON structure in the request body causes a parse failure
- Payment not received results in HTTP 402 response before execution

## 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 a 'duplicate_media_hashes' field listing any detected duplicates, a list of warnings, an evidence scope indicating the data was caller-supplied, and a full receipt with payment and execution metadata including the service version, network, and a SHA-256 hash of the result.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "nft_media_hash_request": {
   "type": "string",
   "maxLength": 65536,
   "minLength": 2
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Hashes are not computed from remote media and are trusted as supplied."
   ],
   "service_id": "nft_duplicate_media_hashes",
   "evidence_scope": "caller_supplied_data",
   "duplicate_media_hashes": "{\"duplicate_groups\":[{\"media_hash\":\"0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\",\"token_ids\":[\"1\",\"2\"]}],\"unique_hash_count\":1}"
  },
  "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_duplicate_media_hashes",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "5000",
   "resultSha256": "2d64d044a6323f0e8de9ef4a5398a43609383184545fc96e0ec93c5efe107f46",
   "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-nft-duplicate-media-hash-detector-b648ef61/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)