OpenAPI Spec Generation skill: what it does and how to install it

What it does. Creates and maintains OpenAPI 3.1 specifications using design-first, code-first or hybrid approaches. Covers reusable schemas and references, examples, errors, security schemes, versioning and validation, with guidance for SDK generation and documentation portals.

When to use it. For documenting REST APIs, defining contracts before implementation, deriving specifications from existing code, checking implementations against contracts, or generating client SDKs. It also applies when setting up API documentation portals.