Add API Documentation (OpenAPI)

Use this skill when the user asks to add API docs, Swagger, OpenAPI spec, or generate endpoint documentation.

Steps

1. Detect the API framework — check for Express, Fastify, Next.js API routes, Hono, Django REST Framework, FastAPI, etc.

2. For Node.js/Express — install swagger-jsdoc and swagger-ui-express:

   npm install swagger-jsdoc swagger-ui-express
   npm install -D @types/swagger-jsdoc @types/swagger-ui-express
   

   Create the OpenAPI spec from JSDoc annotations on route handlers: