API Documentation Generator

API Documentation Generator

Overview

This skill automates the creation and maintenance of comprehensive API documentation with support for industry-standard formats and developer-friendly presentation. It intelligently analyzes source code to extract API contracts and generates complete, accurate documentation.

When to Use This Skill

• Generating OpenAPI/Swagger specifications from code
• Creating API documentation from existing endpoints
• Updating documentation to match API changes
• Producing developer guides and integration tutorials
• Analyzing API contracts and dependencies
• Converting API specifications between formats
• Reverse-engineering undocumented APIs
• Generating client SDK documentation
• Creating interactive API explorers

Supported Languages & Frameworks

REST APIs

• Express.js / Fastify (Node.js)
• Flask / Django (Python)
• Spring Boot (Java)
• ASP.NET Core (C#)
• Ruby on Rails
• Laravel (PHP)

GraphQL APIs

• Schema introspection
• Query/mutation/subscription documentation
• Type definitions and relationships

Other API Types

• gRPC services and protobuf definitions
• SOAP web services
• Webhook documentation

Supported Formats

• OpenAPI 3.0/3.1 (formerly Swagger)
• Swagger 2.0
• AsyncAPI 2.x (for event-driven APIs)
• RAML 1.0
• API Blueprint
• Postman Collections
• GraphQL Schema Definition Language (SDL)
• JSON Schema
• HAR (HTTP Archive format)

Documentation Components

API Information

• Title, description, and version
• Contact details and support information
• License information and terms of service
• External documentation links
• API lifecycle stage (development, beta, stable, deprecated)

Endpoints & Operations

• HTTP methods and paths
• Path, query, header, and cookie parameters
• Request body schemas with validation rules
• Response schemas for all status codes
• Example requests and responses
• Deprecation notices and migration guidance

Security Definitions

• API key authentication
• OAuth 2.0 flows (Authorization Code, Client Credentials, etc.)
• JWT/Token authentication
• Basic/Digest authentication
• Mutual TLS
• Custom authentication schemes
• Security requirement mappings per endpoint

Advanced Features

• Server definitions with variables
• Tags for logical grouping
• External documentation
• Callback definitions
• Link relations
• Webhooks and event documentation
• Discriminator objects for polymorphism

Analysis Capabilities

Code Analysis

• Framework-specific route detection
• Parameter and schema inference
• Authentication method identification
• Error response pattern recognition
• Validation rule extraction

Schema Detection

• Request/response schema analysis
• Type inference from code
• Validation constraints mapping
• Default value extraction
• Enum value detection

Security Analysis

• Authentication scheme identification
• Permission/role mapping
• Security requirement inference
• Credential location detection

Best Practices

Writing Effective Descriptions

• Use clear, concise language
• Explain purpose and behavior
• Document side effects
• Specify business context
• Include usage examples
• Define business terminology

Parameter Documentation

• Specify data types and constraints
• Indicate required vs optional
• Document default values
• Explain validation rules
• Include example values
• Describe inter-parameter relationships

Response Documentation

• Detail all possible status codes
• Document error response formats
• Specify success and failure cases
• Include example payloads
• Explain response headers
• Describe pagination patterns

Security Documentation

• Document authentication requirements
• Explain authorization scopes
• Specify rate limiting policies
• Detail security headers
• Provide security best practices

Generation Process

1. API Discovery

• Scan source code for API endpoints
• Extract route definitions and HTTP methods
• Identify API framework and patterns
• Map endpoint relationships

2. Schema Analysis

• Analyze request/response structures
• Infer data types and validation rules
• Extract example values
• Map relationships between entities

3. Security Mapping

• Identify authentication methods
• Map authorization requirements
• Document security schemes
• Extract API key locations

4. Specification Creation

• Generate OpenAPI specification
• Validate against standards
• Add descriptions and examples
• Organize endpoints by tags
• Include server definitions

5. Documentation Generation

• Create human-readable documentation
• Generate interactive API explorer
• Produce client SDK documentation
• Build integration guides
• Export in multiple formats

Quality Assurance

• Verify all endpoints are documented
• Check for consistent naming
• Validate example requests/responses
• Ensure security schemes are clear
• Confirm all parameters are documented
• Test generated documentation usability
• Validate against OpenAPI specification

Integration Guides

• Authentication setup
• Error handling patterns
• Rate limiting considerations
• Common use case examples
• Troubleshooting tips
• Migration guides for version changes
• Performance optimization recommendations

Scripts Available

• scripts/generate-openapi.js - Generate OpenAPI spec from code
• scripts/validate-spec.js - Validate API specification
• scripts/export-docs.js - Export documentation in various formats
• scripts/check-completeness.js - Verify documentation completeness
• scripts/analyze-endpoints.js - Deep endpoint analysis
• scripts/extract-schemas.js - Extract and document data schemas
• scripts/generate-sdk-docs.js - Generate client SDK documentation

References

• references/openapi-specification.md - Complete OpenAPI specification guidelines and best practices
• references/documentation-best-practices.md - API documentation best practices and writing guidelines
• references/framework-patterns.md - Framework-specific API patterns and conventions
• references/security-schemes.md - Comprehensive security scheme documentation
• references/error-handling.md - API error handling patterns and documentation