Documentation Skill
Create clear, useful documentation that helps people understand and use your code.
Core Principle
Write for the reader, not for yourself.
Name
han-core:document - Generate or update documentation for code, APIs, or systems
Synopsis
/document [arguments]Types of Documentation
1. README Files
Purpose: Help users understand what the project does and how to use it
Audience: New users, potential contributors
Key sections:
- What it does (one paragraph)
- Installation instructions
- Quick start example
- Common use cases
- Link to full documentation
- How to contribute
- License
2. API Documentation
Purpose: Help developers use your API correctly
Audience: Other developers integrating with your code
Key information:
- Endpoint/function signature
- Parameters and types
- Return values
- Error cases
- Authentication requirements
- Examples
3. Inline Comments
Purpose: Explain non-obvious decisions and complex logic
Audience: Future developers (including future you)
When to add:
- Non-obvious decisions ("why" not "what")
- Complex algorithms
- Workarounds
- Edge cases
- Performance considerations
- Security considerations
4. Technical Guides
Purpose: Teach how to accomplish specific tasks
Audience: Developers working with the system
Types:
- How-to guides (step-by-step)
- Architecture overviews (system structure)
- Integration guides (connecting systems)
- Troubleshooting guides (debugging help)
5. Architecture Decision Records (ADRs)
Purpose: Document important technical decisions and their rationale
Audience: Current and future team members
Key information:
- Context (what problem exists)
- Decision (what was chosen)
- Alternatives considered
- Consequences (trade-offs)
Documentation Principles
Good documentation:
- For the reader: Written for their level and needs
- Clear: No jargon unless necessary
- Concrete: Examples over abstract descriptions
- Complete: Answers the key questions
- Maintained: Updated when code changes
Bad documentation:
- Explains "what" instead of "why"
- Assumes too much knowledge
- No examples
- Out of date
- Too verbose or too terse
README Template
# Project Name
Brief description (one paragraph) of what this project does and why it exists.
## Features
- Feature 1
- Feature 2
- Feature 3
## Installation
npm install project-name
## Quick Start
import { Thing } from 'project-name'
const thing = new Thing() thing.doSomething() // Output: ...
## Usage
### Basic Usage
[Most common use case with complete example]
### Advanced Usage
[More complex scenarios]
## API Reference
### `functionName(param1, param2)`
Description of what the function does.
**Parameters:**
- `param1` (string, required): Description of parameter
- `param2` (number, optional): Description with default. Default: 42
**Returns:** `string` - Description of return value
**Throws:**
- `Error` - When parameter is invalid
**Example:**
const result = functionName('hello', 10) console.log(result) // "hello repeated 10 times"
## Configuration
[How to configure, if applicable]
## Troubleshooting
### Error: "Cannot find module"
**Cause:** Package not installed **Solution:**
npm install project-name
## Contributing
We welcome contributions! Please see [CONTRIBUTING.md](https://github.com/thebushidocollective/han/blob/HEAD/plugins/core/skills/document/CONTRIBUTING.md) for details.
## License
MIT License - see [LICENSE](https://github.com/thebushidocollective/han/blob/HEAD/plugins/core/skills/document/LICENSE) file for details.
API Documentation Template
REST API
## POST /api/users
Create a new user account.
### Authentication
Requires admin access token in Authorization header.
### Request
**Headers:**{ "Content-Type": "application/json", "Authorization": "Bearer <admin_token>" }
**Body:**
{ "email": "user@example.com", "name": "John Doe", "role": "user" }
**Body Parameters:**
- `email` (string, required): Valid email address. Must be unique.
- `name` (string, required): User's full name. 2-100 characters.
- `role` (string, optional): User role. One of: "user", "admin". Default: "user".
### Response
**Success (201 Created):**
{ "id": "abc123", "email": "user@example.com", "name": "John Doe", "role": "user", "createdAt": "2024-01-01T00:00:00Z" }
**Error Responses:**
**400 Bad Request:**
{ "error": "Invalid email format", "field": "email" }
**401 Unauthorized:**
{ "error": "Authentication required" }
**403 Forbidden:**
{ "error": "Admin access required" }
**409 Conflict:**
{ "error": "Email already exists", "field": "email" }
**429 Too Many Requests:**
{ "error": "Rate limit exceeded. Try again in 60 seconds.", "retryAfter": 60 }
### Example
**cURL:**
curl -X POST https://api.example.com/users \ -H "Content-Type: application/json" \ -H "Authorization: Bearer abc123..." \ -d '{ "email": "user@example.com", "name": "John Doe", "role": "user" }'
**JavaScript:**
const response = await fetch('https://api.example.com/users', { method: 'POST', headers: { 'Content-Type': 'application/json', 'Authorization': 'Bearer abc123...' }, body: JSON.stringify({ email: 'user@example.com', name: 'John Doe', role: 'user' }) })
const user = await response.json() console.log(user.id) // "abc123"
### Rate Limiting
- 100 requests per minute per API key
- Returns 429 when exceeded
- Check `X-RateLimit-Remaining` header
Function/Method Documentation
/**
* Calculate the total price including tax and shipping.
*
* Tax is calculated on the subtotal, not including shipping.
* Free shipping is applied for orders over $50.
*
* @param items - Array of cart items with price and quantity
* @param shippingAddress - Shipping address for tax calculation
* @returns Object containing subtotal, tax, shipping, and total
*
* @throws {Error} If items array is empty
* @throws {Error} If any item has invalid price or quantity
*
* @example
* ```typescript
* const total = calculateTotal([
* { price: 10, quantity: 2 },
* { price: 15, quantity: 1 }
* ], { state: 'CA' })
*
* console.log(total)
* // {
* // subtotal: 35,
* // tax: 2.80,
* // shipping: 0,
* // total: 37.80
* // }
* ```
*/
function calculateTotal(
items: CartItem[],
shippingAddress: Address
): OrderTotal {
// Implementation...
}Inline Comment Guidelines
When to Comment
DO comment:
- Why: Explains reasoning for non-obvious decisions
- Trade-offs: Documents deliberate choices
- Workarounds: Explains temporary solutions
- Complex logic: Clarifies difficult algorithms
- Edge cases: Documents special handling
- Performance: Explains optimization choices
- Security: Notes security considerations
DON'T comment:
- What: Code is self-explanatory
- Redundant: Comment repeats code
- Obvious: Anyone can see what it does
Good vs Bad Comments
// BAD: States the obvious
// Loop through users
for (const user of users) {
// Print user name
console.log(user.name)
}
// GOOD: Explains why
// Process in creation order to maintain referential integrity
// (newer records may reference older ones)
for (const user of users.sort((a, b) => a.createdAt - b.createdAt)) {
processUser(user)
}
// BAD: Redundant
// Add 1 to counter
counter = counter + 1
// GOOD: Explains non-obvious decision
// +1 offset because API uses 1-based indexing (not 0-based)
const pageNumber = index + 1
// BAD: Explains what (obvious)
function calculateTotal(price, quantity) {
// Multiply price by quantity
return price * quantity
}
// GOOD: Explains why (non-obvious)
function calculateTotal(price, quantity) {
// Use Number.toFixed(2) to prevent floating point errors
// (0.1 + 0.2 !== 0.3 in JavaScript)
return Number((price * quantity).toFixed(2))
}
// BAD: Commented-out code
function processOrder(order) {
// const tax = order.subtotal * 0.08
const tax = calculateTax(order)
return order.subtotal + tax
}
// GOOD: Explains temporary workaround
function processOrder(order) {
// TODO: Remove when new tax API is deployed (JIRA-123)
// Using hardcoded rate temporarily during migration
const tax = order.subtotal * 0.08
return order.subtotal + tax
}Comment Formats
Single-line comments:
// For brief explanations
const tax = subtotal * TAX_RATE // Updated quarterlyMulti-line comments:
/*
* For longer explanations that span multiple lines.
* Use when context requires more detail.
*/Doc comments (JSDoc/TSDoc):
/**
* For API documentation.
* Parsed by documentation generators.
* @param name - Parameter description
* @returns Return value description
*/TODO comments:
// TODO(username): Description of what needs to be done
// FIXME: Description of what's broken and needs fixing
// HACK: Description of temporary workaround
// NOTE: Important information to highlightTechnical Guide Template
# How to [Task Name]
Brief description of what this guide teaches and who should use it.
## Prerequisites
- Requirement 1
- Requirement 2
- Knowledge/tools needed
## Overview
High-level explanation of the process or concept.
## Step-by-Step Instructions
### Step 1: [First Action]
Detailed description of what to do.
Command to run
command --option value
**Expected result:** What you should see.
**If something goes wrong:** How to troubleshoot.
### Step 2: [Next Action]
[Continue with clear steps...]
## Example
Complete working example showing the entire process.
// Full code example
## Common Issues
### Issue: [Problem Description]
**Symptom:** What you see when this happens. **Cause:** Why it happens. **Solution:** How to fix it.
## Related Documentation
- [Link to related guide]
- [Link to API docs]
## Next Steps
- [What to do after completing this guide]
Architecture Decision Record Template
# ADR-###: [Decision Title]
**Status:** Proposed | Accepted | Deprecated | Superseded
**Date:** YYYY-MM-DD
**Deciders:** [Names of decision makers]
## Context
What is the issue we're trying to solve? What factors are at play?
What constraints exist?
## Decision
What did we decide to do?
## Alternatives Considered
### Alternative 1: [Name]
**Description:** Brief explanation
**Pros:**
- Advantage 1
- Advantage 2
**Cons:**
- Disadvantage 1
- Disadvantage 2
**Why not chosen:** Explanation
### Alternative 2: [Name]
[Same structure...]
## Consequences
### Positive
- Benefit 1
- Benefit 2
### Negative
- Drawback 1
- Drawback 2
### Neutral
- Trade-off 1
- Trade-off 2
## Implementation Notes
Any specific guidance for implementing this decision.
## References
- [Related documentation]
- [Discussion links]
- [Research sources]Documentation Best Practices
1. Write for Your Audience
Different audiences need different docs:
- New users: Quick start, common use cases
- API consumers: Complete reference, examples
- Contributors: Architecture, dev setup
- Maintainers: Design decisions, trade-offs
2. Show, Don't Just Tell
Bad:
The function accepts parameters and returns a result.Good:
function calculateTotal(items, tax) {
return items.reduce((sum, item) => sum + item.price, 0) * (1 + tax)
}
// Example usage:
const items = [{ price: 10 }, { price: 20 }]
const total = calculateTotal(items, 0.08) // 32.403. Keep Examples Runnable
Test your examples:
- Copy/paste should work
- Include all imports
- Show complete code, not fragments
- Verify examples actually run
4. Maintain Documentation
Documentation rots:
- Update docs when code changes
- Include doc updates in PRs
- Review docs periodically
- Mark outdated docs clearly
5. Use Clear Language
Avoid jargon:
- Bad: "Leverages polymorphic memoization"
- Good: "Caches results based on input type"
Be specific:
- Bad: "It's fast"
- Good: "Responds in < 100ms for 95% of requests"
Use active voice:
- Bad: "The request is processed by the server"
- Good: "The server processes the request"
Common Documentation Mistakes
No Examples
Bad: "Use the function to process data" Good: "Use processData(items) to validate and format user input"
Outdated Information
Bad: Docs say version 1.0, code is version 3.0 Good: Update docs with code changes
Assuming Knowledge
Bad: "Simply configure the flux capacitor" Good: "Add FLUX_CAPACITOR=true to your.env file"
Incomplete Examples
Bad:
const result = doSomething()Good:
import { doSomething } from 'my-package'
const result = doSomething({
option1: 'value',
option2: 42
})
console.log(result) // Expected outputToo Much Documentation
Bad: Document every single line Good: Document the "why" and non-obvious parts
Documentation Checklist
README
- Clear description of what project does
- Installation instructions
- Quick start example
- Link to full documentation
- How to contribute
- License information
API Docs
- All public APIs documented
- Parameters described with types
- Return values described
- Error cases documented
- Examples provided
- Authentication requirements stated
Inline Comments
- Complex logic explained
- Non-obvious decisions documented
- Workarounds noted
- No redundant comments
- No commented-out code
- TODOs have owner and context
Technical Guides
- Prerequisites listed
- Steps are clear and ordered
- Examples are complete and runnable
- Common issues addressed
- Related docs linked
Examples
When the user says:
- "Write a README for this project"
- "Document this API endpoint"
- "Add comments explaining this complex function"
- "Create a guide for setting up the development environment"
- "Update the docs to reflect the new authentication flow"
Integration with Other Skills
- Use explain skill for creating clear explanations
- Use proof-of-work skill to verify examples actually work
- Reference architect skill for architecture documentation
- Reference technical-planning skill for implementation guides
Notes
- Use TaskCreate to track documentation tasks
- Keep documentation close to code (inline comments, co-located READMEs)
- Update docs when code changes (include in PR reviews)
- Examples are worth a thousand words
- Test examples to ensure they work
- Consider using JSDoc/TSDoc for inline API documentation
Remember
- Write for the reader - What do they need to know?
- Show with examples - Working code is clearer than prose
- Keep it updated - Stale docs are worse than no docs
- Test examples - Verify they actually work
- Explain "why" - The "what" is in the code
Good documentation helps people use your code correctly and efficiently.