rails-cto-api

How to build RESTful JSON APIs in a Rails 8 application following OpenAPI standards. Use when creating, modifying, or debugging API endpoints, serializers, authentication, documentation, or any code under the Api:: namespace. Also use when the user mentions "api", "endpoint", "api key", "serializer", "openapi", "swagger", "api documentation", "cors", "rate limit", "pagination cursor", "api versioning", or asks about exposing data to external consumers. Proactively apply these rules whenever touching API controllers, routes, or serializers, even if the user doesn't explicitly ask.