API Documentation Writer

API documentation is the most common reason developers abandon an integration. Outdated docs, missing endpoints, incorrect examples, and no error documentation cost teams hours of debugging. Most API docs are either: - Hand-written and stale — drift from the actual implementation within days - Auto-generated and unusable — Swagger UI output that repeats function names without context - Incomplete — no error codes, no rate limits, no authentication walkthroughs - Not agent-friendly — AI agents can't parse them reliably, making them useless for AI-assisted development This skill solves all of these by generating complete, multi-format documentation from a single input source, with quality gates that catch drift, missing endpoints, and broken examples.

What It Does

• OpenAPI Spec to Multi-Format Docs — Converts OpenAPI 3.0/3.1 YAML/JSON into Markdown, HTML, Postman collections, and llms.txt
• Source Code Scanning — Scans Python (FastAPI, Flask, Django REST), Node.js (Express, Next.js, Hono, Koa), and Go (Gin, Echo, Chi) codebases to extract route definitions and generate OpenAPI specs
• Natural Language to API Docs — Describe your API in plain English and get structured documentation
• Quality Auditing — Checks for missing endpoints, undocumented error codes, missing auth schemes, incomplete examples, and broken links
• Agent-Friendly Output — Generates llms.txt and llms-full.txt files following the llmstxt.org standard for AI agent consumption
• Postman Collection Generation — Creates importable Postman collections with environment variables and example requests
• Changelog Integration — Compares current docs against previous versions and generates changelog entries
• Multi-Framework Support — Detects framework-specific patterns (FastAPI decorators, Express routers, Gin handlers) for accurate route extraction

Use Cases

• Startup API Launch — Generate complete documentation for a new API before public release, including Postman collections for early access partners
• API Migration — Document an existing undocumented API by scanning source code, then generate migration guides comparing old and new endpoints
• Open Source Project — Generate and maintain documentation for an open-source API, with CI/CD integration for automatic updates on every release
• Enterprise API Catalog — Generate consistent documentation across dozens of microservices with standardized branding and format
• AI Agent Integration — Generate llms.txt files so AI agents can discover and use your API without human intervention
• API Audit for Acquisition — Audit a target company's API documentation quality as part of technical due diligence