Create Skill From Source Code

Create Skill from Source Code

This skill guides you through the process of analyzing an existing source code implementation and transforming it into comprehensive educational documentation in the form of a skill file.

Overview

When you have a reference implementation and need to create teaching materials or reusable documentation from it, follow this systematic workflow to extract patterns, analyze architecture, and generate well-structured educational content.

Prerequisites

• Access to the source code file(s) you want to document
• Understanding of the target audience for the skill
• Knowledge of the programming language/framework used

Workflow Steps

1. Read and Parse the Source Code

First, read the complete source file to understand its full scope:

# Read the source file
cat /path/to/source/file.ext

Or use file reading tools to access the content programmatically.

2. Identify Key Architectural Patterns

Analyze the code to identify:

• Core architectural patterns: What design patterns are used? (e.g., Observer, Factory, MVC)
• Key implementation techniques: How are specific challenges solved?
• Important data structures: What structures enable the functionality?
• Critical algorithms: What are the main algorithmic approaches?
• Integration points: How does the code interact with external systems?

Take notes on 3-5 major patterns that define the implementation.

3. Create the Skill Directory Structure

# Create skill directory
mkdir -p skills/skill-name

# If you need auxiliary files (examples, scripts, etc.)
mkdir -p skills/skill-name/examples
mkdir -p skills/skill-name/templates

4. Generate Comprehensive SKILL.md

Create a SKILL.md file with the following structure:

Required YAML Frontmatter

---
name: descriptive-skill-name
description: Brief one-sentence description of what the skill teaches
---

Frontmatter rules:

• Must be enclosed in --- fences
• name: lowercase, use hyphens for spaces
• description: concise but informative (1-2 sentences max)

Document Body Structure

Organize the content into clear sections:

# [Skill Title]

## Overview
Brief introduction to what pattern/technique is being taught.

## Key Patterns Identified

### Pattern 1: [Name]
**Purpose**: What problem does it solve?
**Implementation**: How is it implemented in the reference code?
**Key Code Elements**: 
- Relevant classes/functions
- Important variables/structures

### Pattern 2: [Name]
[Same structure as Pattern 1]

[Continue for 3-5 main patterns]

## Complete Code Template

Provide a minimal but complete implementation:

\`\`\`[language]
// Simplified, well-commented version of the key code
// Include only essential elements
// Add explanatory comments
\`\`\`

## Usage Examples

### Example 1: Basic Usage
\`\`\`[language]
// Practical example showing how to use the pattern
\`\`\`

### Example 2: Advanced Usage
\`\`\`[language]
// More complex scenario
\`\`\`

## Best Practices

- List key recommendations
- Common pitfalls to avoid
- Performance considerations
- Testing strategies

## When to Use This Pattern

Explain scenarios where this pattern is appropriate and where it might not be the best choice.

## Related Patterns

Reference related techniques or alternative approaches.

## References

- Link to original source (if applicable)
- Related documentation
- Further reading

5. Verify File Creation and Frontmatter

After creating the skill file, verify:

# Check file exists
ls -la skills/skill-name/SKILL.md

# Verify frontmatter format
head -n 5 skills/skill-name/SKILL.md

# Should show:
# ---
# name: skill-name
# description: Description here
# ---

Ensure:

• File starts with --- on line 1
• YAML contains at least name and description fields
• Frontmatter closes with ---
• Content follows immediately after

6. Add Auxiliary Files (Optional)

If the pattern benefits from additional resources:

Example script (examples/demo.sh):

#!/bin/bash
# Demonstration script showing the pattern in action

Template file (templates/starter.template):

# Ready-to-use template that users can copy

Configuration example (examples/config.example):

# Sample configuration demonstrating best practices

Tips for Creating Effective Skills

Make It Generalizable

• Abstract away specific variable names, file paths, or domain-specific details
• Focus on the pattern, not the specific implementation
• Use placeholders like [your-project], [input-file] for context-specific values

Keep It Actionable

• Use imperative language: "Create...", "Implement...", "Configure..."
• Provide concrete code examples
• Include expected outputs or results
• Add verification steps

Structure for Clarity

• Use hierarchical headings (##, ###, ####)
• Break complex steps into numbered sub-steps
• Use code blocks with appropriate syntax highlighting
• Add tables or lists for comparing options

Balance Detail and Brevity

• Be comprehensive but concise
• Focus on the "what" and "why", not just the "how"
• Link to external resources for deep dives
• Include only code essential to understanding the pattern

Example: Transforming a Virtual List Component

Given a VirtualList.ts source file implementing virtual scrolling:

1. Read: Load the complete TypeScript source
2. Identify patterns:
   • Chunk-based rendering for performance
   • Scroll event listeners for viewport tracking
   • DOM manipulation for dynamic updates
   • State management for visible items
3. Create structure: skills/virtual-scrolling-pattern/
4. Generate SKILL.md:
   • Frontmatter with name: virtual-scrolling-pattern
   • Sections explaining each of the 4 patterns
   • Simplified code template showing core logic
   • Examples of basic and advanced usage
5. Verify: Check file format and frontmatter validity

Common Pitfalls to Avoid

• Too specific: Don't tie the skill to one particular codebase
• Missing frontmatter: Always include valid YAML frontmatter
• No examples: Abstract patterns need concrete examples
• Incomplete templates: Code templates should be runnable or near-runnable
• Poor organization: Use clear sections with descriptive headings

Validation Checklist

Before finalizing the skill:

• YAML frontmatter is present and valid
• Name is lowercase with hyphens
• Description is concise (1-2 sentences)
• Key patterns are clearly identified (3-5 patterns)
• Code examples are provided and well-commented
• Usage examples demonstrate practical application
• Content is generalized beyond the specific source
• File structure follows conventions
• No task-specific details remain
• Instructions are actionable and clear