<objective A response that adds a nullable field or quietly drops one slips past spot-checks and silently breaks the frontend in production. Schema-as-contract tests catch that drift in CI, not prod. This skill produces REST and GraphQL API tests that assert response shape, status codes, headers, auth boundaries, and timing — against a real test environment, not a mocked stand-in. </objective Discovery Questions Check first — if it exists, use it and skip anything already answered there. Then: 1. REST, GraphQL, or both? REST-only suites use standard HTTP assertions. GraphQL needs query/mutati…