# Hermes Data Contract Check

> Hermes Data Contract Check is a paid API for AI agents from hermes-counterparty-api.onrender.com, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-15).

Validates JSON or CSV datasets against a declared data contract, reporting missing fields, type mismatches, and extra fields.

## Facts

- Endpoint: POST https://hermes-counterparty-api.onrender.com/v1/data-contract-check
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hermes-data-contract-check-18e758b6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_spw5GTdd7aN_yr9P8lMVj

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 hermes-data-contract-check-18e758b6 -d '<json body>'
```

Example prompt: Can you check whether this JSON dataset meets our data contract — the contract requires 'user_id' (string), 'timestamp' (string), and 'amount' (number) as required fields, no extra fields allowed, and here are the records: [{"user_id":"abc","timestamp":"2024-01-01","amount":9.99}]?

## When to prefer this

Choose this endpoint when you need a deterministic, structured report of schema conformance for JSON or CSV data against a formal contract — especially in agentic pipelines where you need machine-readable pass/fail results with field-level detail. Prefer it over ad-hoc LLM-based validation when auditability and a stable schema fingerprint matter, or when you need to catch type mismatches and missing fields reliably at low cost ($0.015 per call).

## Known failure modes

- Invalid or malformed JSON/CSV input returns an error before validation runs
- Contract specifying field types that don't match any supported type descriptor may produce unexpected results
- Very large record arrays may time out on the hosted Render instance
- Missing 'format' field in dataset object causes request rejection
- Payment not fulfilled (x402) results in a 402 response before any validation occurs

## How this service works

Agent utilities for company research, package maintenance intelligence, dependency vulnerability checks, counterparty availability, SEC company snapshots, OFAC sanctions screening, and deterministic JSON/CSV data-quality work. Company domain intelligence includes a free preview before the paid enrichment call.

## Output

Returns a JSON object indicating whether the dataset is compatible with the contract (true/false), plus lists of missing required fields, type mismatches, extra fields, and human-readable failure reasons. Also includes a schema version string and a SHA-256 schema fingerprint for audit traceability.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "dataset": {
   "oneOf": [
    {
     "type": "object",
     "required": [
      "format",
      "records"
     ],
     "properties": {
      "format": {
       "type": "string",
       "const": "json"
      },
      "records": {
       "type": "array",
       "items": {
        "type": "object"
       }
      }
     }
    },
    {
     "type": "object",
     "required": [
      "format",
      "data"
     ],
     "properties": {
      "data": {
       "type": "string"
      },
      "format": {
       "type": "string",
       "const": "csv"
      }
     }
    }
   ]
  },
  "contract": {
   "type": "object",
   "properties": {
    "field_types": {
     "type": "object"
    },
    "required_fields": {
     "type": "array",
     "items": {
      "type": "string"
     }
    },
    "allow_extra_fields": {
     "type": "boolean"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "reasons": [],
  "compatible": true,
  "extra_fields": [],
  "schema_version": "1.0",
  "type_mismatches": [],
  "schema_fingerprint": "sha256:example",
  "missing_required_fields": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hermes-data-contract-check-18e758b6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hermes-counterparty-api.onrender.com](https://www.zero.xyz/host/hermes-counterparty-api.onrender.com/llms.txt)