API Documentation Generator

What this skill does

This skill reads REST API route handlers (Express, FastAPI, Go net/http, Rails, Django, or any framework) and generates complete OpenAPI 3.0 YAML documentation. It extracts paths, HTTP methods, path/query/body parameters, response shapes, and error codes, then writes properly structured YAML with example request and response bodies. The output can be loaded directly into Swagger UI, Redoc, or any OpenAPI-compatible tool.

Use this when you have undocumented API code and need to produce accurate, usable API documentation quickly.

How to use

Claude Code / Cline

Copy this file to .agents/skills/api-docs-generator/SKILL.md in your project root.

Then point the agent at your routes file and ask:

• "Use the API Documentation Generator skill on server/routes.ts."
• "Generate OpenAPI docs for all routes in src/api/ using the API Documentation Generator skill."

The agent will read the route files and any referenced handler functions to extract parameter and response shapes.