# GENESIS Agent Tools — API Response Contract Guard

> GENESIS Agent Tools — API Response Contract Guard is a paid API for AI agents from genesis-agent-tools.genesisagenttools.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-01).

Validates an API response object against a provided JSON schema, returning a boolean validity flag and a list of validation errors.

## Facts

- Endpoint: POST https://genesis-agent-tools.genesisagenttools.workers.dev/api/tools/api-response-contract-guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/genesis-agent-tools-api-response-contract-guard-3555499d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Yinc_WDOR6XimTSBOEa0y

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 genesis-agent-tools-api-response-contract-guard-3555499d -d '<json body>'
```

Example prompt: Check if this API response I just got back matches its expected JSON schema — here's the schema and the response object, tell me if it's valid and list any errors.

## When to prefer this

Choose this endpoint when an AI agent needs to programmatically verify that a live API response conforms to a known JSON schema contract before acting on the data — especially in multi-step agent pipelines where downstream steps depend on well-structured input. Ideal for catching schema drift, debugging integrations, or enforcing contracts in automated workflows where manual inspection is impractical.

## Known failure modes

- Missing required 'schema' or 'response' fields in request body — returns 400 or validation error
- Malformed or non-JSON-serializable schema object causes processing failure
- Empty or null response object may yield unexpected validation results
- Complex or deeply nested schemas may not fully validate depending on implementation
- Payment failure via x402 protocol prevents call from being processed

## How this service works

Pay-per-call x402 APIs for autonomous agents on Base USDC: API compatibility analysis, bounded HTTP/JSON workflows, URL evidence analysis, crypto price consensus, and agent/MCP readiness checks.

## Output

Returns a JSON object with a 'valid' boolean indicating whether the response conforms to the schema, and an 'errors' array listing any schema violations found.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "schema",
  "response"
 ],
 "properties": {
  "schema": {
   "type": "object"
  },
  "response": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "valid": {
   "type": "boolean"
  },
  "errors": {
   "type": "array"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/genesis-agent-tools-api-response-contract-guard-3555499d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from genesis-agent-tools.genesisagenttools.workers.dev](https://www.zero.xyz/host/genesis-agent-tools.genesisagenttools.workers.dev/llms.txt)