Doc Gen

Documentation Generator

Automatically generate clear, comprehensive documentation for code, APIs, and projects.

When to Activate

Explicit Triggers

• User says "generate documentation"
• User says "生成文档"
• User says "document this code"
• User says "write docs for this"

Implicit Triggers

• User completes a feature and mentions documentation
• User asks "how do I document this?"
• User needs API documentation

NOT Activated For

• Simple code comments (use inline comments instead)
• README updates (unless comprehensive rewrite needed)
• Changelog generation

Documentation Types

1. Code Documentation

• Function/Method Docs: Parameters, return values, exceptions
• Class Docs: Purpose, usage examples, properties
• Module Docs: Overview, exports, dependencies

2. API Documentation

• Endpoints: Method, path, parameters, responses
• Authentication: Auth methods, token formats
• Examples: Request/response samples
• Error Codes: All possible errors with descriptions

3. Project Documentation

• README: Overview, installation, quick start
• Architecture: System design, components, data flow
• Contributing: Development setup, guidelines
• Deployment: Build, test, deploy instructions

Documentation Standards

Function Documentation Template

/**
 * Retries a failed operation up to 3 times with exponential backoff.
 *
 * @param operation - The async function to retry
 * @param maxRetries - Maximum number of retry attempts (default: 3)
 * @param baseDelay - Initial delay in ms (default: 1000)
 * @returns The result of the successful operation
 * @throws {Error} If all retry attempts fail
 *
 * @example
 * ```typescript
 * const data = await retryOperation(
 *   () => fetchUserData(userId),
 *   3,
 *   1000
 * );
 * ```
 */
async function retryOperation<T>(
  operation: () => Promise<T>,
  maxRetries = 3,
  baseDelay = 1000
): Promise<T>

API Documentation Template

## POST /api/users

Create a new user account.

### Request

**Headers:**
- `Content-Type: application/json`
- `Authorization: Bearer <token>` (optional)

**Body:**
```json
{
  "email": "user@example.com",
  "name": "John Doe",
  "role": "user"
}

Response

Success (201 Created):

{
  "success": true,
  "data": {
    "id": "usr_123",
    "email": "user@example.com",
    "name": "John Doe",
    "role": "user",
    "createdAt": "2026-03-15T10:30:00Z"
  }
}

Error (400 Bad Request):

{
  "success": false,
  "error": "Invalid email format"
}

Error Codes

• 400 - Invalid input data
• 401 - Unauthorized (missing/invalid token)
• 409 - Email already exists
• 500 - Internal server error

## Best Practices

### 1. Clarity
- Use simple, clear language
- Avoid jargon unless necessary
- Define technical terms

### 2. Completeness
- Document all parameters and return values
- Include error conditions
- Provide usage examples

### 3. Accuracy
- Keep docs in sync with code
- Update docs when code changes
- Test all examples

### 4. Structure
- Use consistent formatting
- Organize logically (overview → details → examples)
- Include table of contents for long docs

### 5. Examples
- Provide realistic examples
- Show common use cases
- Include error handling examples

## Documentation Checklist

Before marking documentation complete:
- [ ] All public functions/classes documented
- [ ] Parameters and return values described
- [ ] Usage examples provided
- [ ] Error conditions documented
- [ ] Code examples tested and working
- [ ] Links to related documentation included
- [ ] Formatting consistent throughout

## Language-Specific Formats

### TypeScript/JavaScript
Use JSDoc format with TypeScript types

### Python
Use docstrings (Google or NumPy style)

### Go
Use godoc format with examples

### Java
Use Javadoc format

## Related Resources

- Keep documentation close to code
- Use automated doc generators (JSDoc, Sphinx, godoc)
- Version documentation with code