Documentation

Automated documentation generation for READMEs, APIs, changelogs, runbooks, and SDK clients.

Quick Start

Generate README:

Generate a README for this project based on its structure and dependencies

Generate API docs:

Generate API documentation for the endpoints in src/routes/

Create changelog:

Generate a changelog from git commits since the last release tag

Generate runbook:

Create an operational runbook for deploying and monitoring this service

Capabilities

1. README Generation

Generate comprehensive README files from project analysis.

Analysis Process

1. Detect project type from config files
2. Extract name, description from package.json/pyproject.toml
3. Identify technologies and dependencies
4. Find existing documentation
5. Detect build/test commands
6. Generate structured README

README Template

# {Project Name}

{Brief description from package.json or generated}

## Features

- {Auto-detected from code structure}
- {Key exports and capabilities}

## Installation

```bash
{Detected package manager install command}

Quick Start

{Basic usage example from tests or docs}

Documentation

• API Reference
• Contributing
• Changelog

Development

Prerequisites

• {Detected runtime}: {version from config}
• {Other requirements from docker-compose, etc.}

Setup

{Clone, install, configure steps}

Testing

{Detected test command}

License

{Detected from LICENSE file or package.json}

See [references/readme-templates.md](references/readme-templates.md) for project-specific templates.

---

### 2. API Documentation

Generate comprehensive API documentation from code.

#### OpenAPI/Swagger Generation

**From Express routes:**
```javascript
/**
 * @openapi
 * /users/{id}:
 *   get:
 *     summary: Get user by ID
 *     parameters:
 *       - in: path
 *         name: id
 *         required: true
 *         schema:
 *           type: integer
 *     responses:
 *       200:
 *         description: User found
 */
router.get('/users/:id', getUser);

Generation workflow:

1. Scan route files for endpoint definitions
2. Extract HTTP methods, paths, parameters
3. Identify request/response schemas
4. Document authentication requirements
5. Generate OpenAPI YAML or markdown

REST API Documentation Template

# API Reference

## Base URL
`https://api.example.com/v1`

## Authentication

Authorization: Bearer <token>

## Endpoints

### Users

#### Get User
`GET /users/{id}`

**Parameters**
| Name | Type | In | Required | Description |
|------|------|-------|----------|-------------|
| id | integer | path | Yes | User ID |

**Response 200**
```json
{
  "id": 1,
  "email": "user@example.com",
  "name": "John Doe"
}

See [references/api-doc-patterns.md](references/api-doc-patterns.md) for framework-specific patterns.

---

### 3. TypeDoc/JSDoc Generation

Generate documentation from TypeScript/JavaScript comments.

#### JSDoc Comment Patterns

```javascript
/**
 * Creates a new user in the system.
 *
 * @param {Object} userData - The user data
 * @param {string} userData.email - User's email address
 * @param {string} userData.name - User's full name
 * @param {string} [userData.role='user'] - User's role (optional)
 * @returns {Promise<User>} The created user object
 * @throws {ValidationError} If email is invalid
 * @example
 * const user = await createUser({
 *   email: 'john@example.com',
 *   name: 'John Doe'
 * });
 */
async function createUser(userData) {
  // ...
}

TypeDoc Configuration

{
  "entryPoints": ["src/index.ts"],
  "out": "docs/api",
  "excludePrivate": true,
  "excludeInternal": true,
  "readme": "README.md",
  "plugin": ["typedoc-plugin-markdown"]
}

npx typedoc --options typedoc.json

---

4. Changelog Generation

Generate changelogs from git history following Keep a Changelog format.

Git History Analysis

# Get commits since last tag
git log $(git describe --tags --abbrev=0)..HEAD --pretty=format:"%h %s"

# Get commits with conventional commit parsing
git log --pretty=format:"%s" | grep -E "^(feat|fix|docs):"

Conventional Commits Mapping

Prefix	Changelog Section
feat:	Added
fix:	Fixed
docs:	Documentation
perf:	Performance
BREAKING CHANGE:	Breaking Changes

Changelog Template

# Changelog

## [Unreleased]

### Added
- New user authentication flow (#123)

### Changed
- Updated dependencies to latest versions

### Fixed
- Fixed race condition in queue processing (#124)

## [1.2.0] - 2024-01-15

### Added
- Initial release features...

[Unreleased]: https://github.com/owner/repo/compare/v1.2.0...HEAD
[1.2.0]: https://github.com/owner/repo/releases/tag/v1.2.0

---

5. Database Schema Documentation

Document database tables, relationships, and migrations.

Schema Documentation Template

# Database Schema

## Tables

### users

| Column | Type | Nullable | Default | Description |
|--------|------|----------|---------|-------------|
| id | uuid | No | gen_random_uuid() | Primary key |
| email | varchar(255) | No | | User's email |
| name | varchar(255) | Yes | | Display name |
| created_at | timestamp | No | now() | Creation time |

**Indexes:**
- `users_pkey` - PRIMARY KEY (id)
- `users_email_key` - UNIQUE (email)

**Foreign Keys:**
- None

### orders

| Column | Type | Nullable | Default | Description |
|--------|------|----------|---------|-------------|
| id | uuid | No | gen_random_uuid() | Primary key |
| user_id | uuid | No | | FK to users |
| total | decimal(10,2) | No | | Order total |

**Foreign Keys:**
- `orders_user_id_fkey` - REFERENCES users(id)

## Entity Relationship Diagram

┌─────────┐ ┌─────────┐ │ users │───<───│ orders │ └─────────┘ └─────────┘

Generation from ORM

# Prisma
npx prisma generate --generator erd

# TypeORM
npx typeorm-uml ormconfig.json

# Django
python manage.py graph_models -a -o schema.png

---

6. Runbook Generation

Create operational runbooks for deployment and incident response.

Runbook Template

# {Service Name} Runbook

## Overview
- **Service:** {name}
- **Team:** {owning team}
- **On-call:** {PagerDuty/OpsGenie link}
- **Repository:** {git repo URL}

## Architecture

{Brief architecture description with diagram}

## Dependencies
| Service | Purpose | Criticality |
|---------|---------|-------------|
| PostgreSQL | Primary data store | Critical |
| Redis | Session cache | High |
| Stripe API | Payment processing | Critical |

## Deployment

### Prerequisites
- [ ] Access to {deployment system}
- [ ] VPN connected
- [ ] Latest code on main branch

### Standard Deployment
```bash
{deployment commands}

Rollback Procedure

{rollback commands}

Monitoring

Key Metrics

Metric	Normal Range	Alert Threshold
Response time (p99)	< 200ms	> 500ms
Error rate	< 0.1%	> 1%
CPU usage	< 60%	> 80%

Dashboards

• Grafana Dashboard
• Application Logs

Common Issues

Issue: High response times

Symptoms: p99 latency > 500ms Possible causes:

1. Database connection pool exhausted
2. External API degradation
3. Memory pressure

Resolution:

1. Check database connection count
2. Verify external service status
3. Review memory usage and restart if needed

Issue: Authentication failures

Symptoms: 401 errors increasing Resolution:

1. Verify JWT signing key is correct
2. Check token expiration settings
3. Review auth service logs

Escalation

Severity	Response Time	Contact
P1 - Critical	15 min	On-call + Manager
P2 - High	1 hour	On-call
P3 - Medium	4 hours	Team queue

See [references/runbook-patterns.md](references/runbook-patterns.md) for more templates.

---

### 7. API Client/SDK Generation

Generate client SDKs from OpenAPI specifications.

#### Generator Tools

```bash
# OpenAPI Generator (multi-language)
npx @openapitools/openapi-generator-cli generate \
  -i openapi.yaml \
  -g typescript-fetch \
  -o src/api-client

# Available generators: typescript-fetch, python, go, java, ruby, etc.

# Orval (TypeScript focused)
npx orval --config orval.config.ts

# openapi-typescript (types only)
npx openapi-typescript openapi.yaml -o types.ts

Generated Client Example

// Generated from OpenAPI spec
export class UsersApi {
  constructor(private config: Configuration) {}

  async getUser(id: string): Promise<User> {
    const response = await fetch(
      `${this.config.basePath}/users/${id}`,
      {
        headers: this.config.headers,
      }
    );
    return response.json();
  }

  async createUser(data: CreateUserRequest): Promise<User> {
    const response = await fetch(
      `${this.config.basePath}/users`,
      {
        method: 'POST',
        headers: this.config.headers,
        body: JSON.stringify(data),
      }
    );
    return response.json();
  }
}

---

8. Migration Guide Generation

Generate migration guides for breaking changes.

Migration Guide Template

# Migration Guide: v1.x to v2.0

## Overview

This guide covers breaking changes in v2.0 and how to migrate your code.

## Breaking Changes

### 1. API Response Format Change

**Before (v1.x):**
```json
[
  {"id": 1, "name": "Item 1"},
  {"id": 2, "name": "Item 2"}
]

After (v2.0):

{
  "data": [
    {"id": 1, "name": "Item 1"},
    {"id": 2, "name": "Item 2"}
  ],
  "pagination": {
    "page": 1,
    "totalPages": 5
  }
}

Migration:

// Before
const items = await api.getItems();
items.forEach(item => console.log(item.name));

// After
const response = await api.getItems();
response.data.forEach(item => console.log(item.name));

2. Removed Deprecated Methods

Removed Method	Replacement
getUser(id)	users.get(id)
deleteUser(id)	users.delete(id)

Migration Checklist

• Update API response handling
• Replace deprecated method calls
• Update TypeScript types
• Run test suite
• Test in staging environment

---

### 9. Troubleshooting Documentation

Generate troubleshooting guides from common issues.

#### Troubleshooting Template

```markdown
# Troubleshooting Guide

## Common Issues

### Connection refused errors

**Symptoms:**
- Error: `ECONNREFUSED 127.0.0.1:5432`
- Application fails to start

**Causes:**
1. Database not running
2. Wrong connection string
3. Firewall blocking connection

**Solutions:**

1. **Check database status:**
   ```bash
   docker-compose ps
   # or
   systemctl status postgresql

2. Verify connection string:

   echo $DATABASE_URL
   # Should be: postgres://user:pass@localhost:5432/dbname
   

3. Test connection manually:

   psql $DATABASE_URL -c "SELECT 1"
   

Out of memory errors

Symptoms:

• JavaScript heap out of memory
• Process killed by OOM killer

Solutions:

1. Increase Node.js memory:

   NODE_OPTIONS="--max-old-space-size=4096" npm start
   

2. Check for memory leaks:

   node --inspect app.js
   # Use Chrome DevTools Memory tab
   

---

### 10. FAQ Generation

Generate FAQ from code comments, issues, and documentation.

#### FAQ Template

```markdown
# Frequently Asked Questions

## General

### What is {Project Name}?
{Brief description extracted from README}

### What are the system requirements?
- Node.js {version}+
- npm or yarn
- {Other requirements}

## Installation

### How do I install {Project Name}?
```bash
npm install {package-name}

I'm getting installation errors. What should I do?

1. Clear npm cache: npm cache clean --force
2. Delete node_modules and reinstall
3. Check Node.js version compatibility

Usage

How do I configure {feature}?

{Configuration example}

Can I use this with {technology}?

{Compatibility information}

Troubleshooting

Why am I getting {common error}?

{Error explanation and solution}

---

## Environment Variable Documentation

Generate documentation for all environment variables.

```markdown
# Environment Variables

## Required

| Variable | Description | Example |
|----------|-------------|---------|
| `DATABASE_URL` | PostgreSQL connection string | `postgres://user:pass@host:5432/db` |
| `JWT_SECRET` | Secret for JWT signing | `your-256-bit-secret` |

## Optional

| Variable | Description | Default |
|----------|-------------|---------|
| `PORT` | Server port | `3000` |
| `LOG_LEVEL` | Logging verbosity | `info` |

---

Architecture Decision Records (ADRs)

ADR Template

# ADR-{number}: {Title}

**Date:** {YYYY-MM-DD}
**Status:** {Proposed | Accepted | Deprecated}

## Context
{Describe the issue motivating this decision}

## Decision
We will use **{chosen option}** because {justification}.

## Consequences
- {positive consequence}
- {negative consequence}

---

Hook Integration

PostToolUse Hook - Auto-Document Changes

After code changes, suggest documentation updates:

{
  "hooks": {
    "PostToolUse": [{
      "matcher": "Edit",
      "command": "check-doc-updates.sh"
    }]
  }
}

Script example:

#!/bin/bash
# check-doc-updates.sh

# Check if API routes changed
if echo "$CHANGED_FILES" | grep -q "routes/"; then
  echo "SUGGEST: API routes changed - consider updating API docs"
fi

# Check if README needs update
if echo "$CHANGED_FILES" | grep -q "package.json"; then
  echo "SUGGEST: Dependencies changed - consider updating README"
fi

# Check if environment variables added
if grep -r "process.env\." "$CHANGED_FILES" 2>/dev/null; then
  echo "SUGGEST: New environment variables detected - update .env.example"
fi

Hook response pattern:

interface DocUpdateSuggestion {
  type: 'readme' | 'api' | 'changelog' | 'env';
  reason: string;
  files: string[];
  priority: 'high' | 'medium' | 'low';
}

SessionEnd Hook - Changelog Update

At session end, summarize changes for changelog:

{
  "hooks": {
    "SessionEnd": [{
      "matcher": "",
      "command": "summarize-changes.sh"
    }]
  }
}

CI/CD Integration

GitHub Actions - Documentation Generation

name: Documentation
on:
  push:
    branches: [main]

jobs:
  docs:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Generate API docs
        run: |
          npx typedoc --out docs/api src/

      - name: Generate OpenAPI spec
        run: |
          npx swagger-jsdoc -d swaggerDef.js -o openapi.yaml src/routes/*.ts

      - name: Update changelog
        if: startsWith(github.ref, 'refs/tags/')
        run: |
          npx conventional-changelog-cli -p angular -i CHANGELOG.md -s

      - name: Deploy docs
        uses: peaceiris/actions-gh-pages@v3
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: ./docs

Pre-commit Hook - Doc Sync

#!/bin/bash
# .git/hooks/pre-commit

# Check if .env.example is in sync
if [ -f ".env" ] && [ -f ".env.example" ]; then
  env_vars=$(grep -E "^[A-Z_]+=" .env | cut -d= -f1 | sort)
  example_vars=$(grep -E "^[A-Z_]+=" .env.example | cut -d= -f1 | sort)

  if [ "$env_vars" != "$example_vars" ]; then
    echo "Warning: .env and .env.example are out of sync"
    diff <(echo "$env_vars") <(echo "$example_vars")
  fi
fi

Templates

• templates/adr-template.md - Architecture Decision Record
• templates/api-endpoint.md - API endpoint documentation
• templates/env-vars.md - Environment variables template

Reference Files

• references/api-doc-patterns.md - Framework-specific API documentation
• references/changelog-conventions.md - Changelog format guidelines
• references/readme-templates.md - README templates by project type
• references/runbook-patterns.md - Operational runbook templates