Add API Endpoint

Use this skill when adding or modifying service endpoints governed by schema-first contracts, structured RFC 9457 error handling, and sandbox isolation.

When to Use

• creating a new HTTP/RPC entrypoint anchored to OpenAPI 3.1 or JSON Schema
• evolving an existing endpoint's request/response shape with backward compatibility
• implementing RFC 9457 Problem Details error responses and boundary validators
• wiring default-deny auth/authz, idempotency keys, and rate limiting
• preparing endpoints and test suites for Level 0 air-gapped sandbox execution

Core Rules