Create the skill directory

mkdir -p ~/.claude/skills/explain-code

Write SKILL.md

---
name: explain-code
description: Explains code with visual diagrams and analogies. Use when explaining how code works, teaching about a codebase, or when the user asks "how does this work?"
---

When explaining code, always include:

1. **Start with an analogy**: Compare the code to something from everyday life
2. **Draw a diagram**: Use ASCII art to show the flow, structure, or relationships
3. **Walk through the code**: Explain step-by-step what happens
4. **Highlight a gotcha**: What's a common mistake or misconception?

Keep explanations conversational. For complex concepts, use multiple analogies.

Test the skill

How does this code work?

/explain-code src/auth/login.ts

my-skill/
├── SKILL.md           # Main instructions (required)
├── template.md        # Template for Claude to fill in
├── examples/
│   └── sample.md      # Example output showing expected format
└── scripts/
    └── validate.sh    # Script Claude can execute

---
name: api-conventions
description: API design patterns for this codebase
---

When writing API endpoints:
- Use RESTful naming conventions
- Return consistent error formats
- Include request validation

---
name: deploy
description: Deploy the application to production
context: fork
disable-model-invocation: true
---

Deploy the application:
1. Run the test suite
2. Build the application
3. Push to the deployment target

---
name: my-skill
description: What this skill does
disable-model-invocation: true
allowed-tools: Read, Grep
---

Your skill instructions here...

---
name: session-logger
description: Log activity for this session
---

Log the following to logs/${CLAUDE_SESSION_ID}.log:

$ARGUMENTS

my-skill/
├── SKILL.md (required - overview and navigation)
├── reference.md (detailed API docs - loaded when needed)
├── examples.md (usage examples - loaded when needed)
└── scripts/
    └── helper.py (utility script - executed, not loaded)

## Additional resources

- For complete API details, see [reference.md](reference.md)
- For usage examples, see [examples.md](examples.md)

---
name: deploy
description: Deploy the application to production
disable-model-invocation: true
---

Deploy $ARGUMENTS to production:

1. Run the test suite
2. Build the application
3. Push to the deployment target
4. Verify the deployment succeeded

---
name: safe-reader
description: Read files without making changes
allowed-tools: Read, Grep, Glob
---

---
name: fix-issue
description: Fix a GitHub issue
disable-model-invocation: true
---

Fix GitHub issue $ARGUMENTS following our coding standards.

1. Read the issue description
2. Understand the requirements
3. Implement the fix
4. Write tests
5. Create a commit

---
name: migrate-component
description: Migrate a component from one framework to another
---

Migrate the $ARGUMENTS[0] component from $ARGUMENTS[1] to $ARGUMENTS[2].
Preserve all existing behavior and tests.

---
name: migrate-component
description: Migrate a component from one framework to another
---

Migrate the $0 component from $1 to $2.
Preserve all existing behavior and tests.

---
name: pr-summary
description: Summarize changes in a pull request
context: fork
agent: Explore
allowed-tools: Bash(gh *)
---

## Pull request context
- PR diff: !`gh pr diff`
- PR comments: !`gh pr view --comments`
- Changed files: !`gh pr diff --name-only`

## Your task
Summarize this pull request...

---
name: deep-research
description: Research a topic thoroughly
context: fork
agent: Explore
---

Research $ARGUMENTS thoroughly:

1. Find relevant files using Glob and Grep
2. Read and analyze the code
3. Summarize findings with specific file references

# Add to deny rules:
Skill

# Allow only specific skills
Skill(commit)
Skill(review-pr *)

# Deny specific skills
Skill(deploy *)

mkdir -p ~/.claude/skills/codebase-visualizer/scripts

---
name: codebase-visualizer
description: Generate an interactive collapsible tree visualization of your codebase. Use when exploring a new repo, understanding project structure, or identifying large files.
allowed-tools: Bash(python *)
---

# Codebase Visualizer

Generate an interactive HTML tree view that shows your project's file structure with collapsible directories.

## Usage

Run the visualization script from your project root:

```bash
python ~/.claude/skills/codebase-visualizer/scripts/visualize.py .
```

This creates `codebase-map.html` in the current directory and opens it in your default browser.

## What the visualization shows

- **Collapsible directories**: Click folders to expand/collapse
- **File sizes**: Displayed next to each file
- **Colors**: Different colors for different file types
- **Directory totals**: Shows aggregate size of each folder

#!/usr/bin/env python3
"""Generate an interactive collapsible tree visualization of a codebase."""

import json
import sys
import webbrowser
from pathlib import Path
from collections import Counter

IGNORE = {'.git', 'node_modules', '__pycache__', '.venv', 'venv', 'dist', 'build'}

def scan(path: Path, stats: dict) -> dict:
    result = {"name": path.name, "children": [], "size": 0}
    try:
        for item in sorted(path.iterdir()):
            if item.name in IGNORE or item.name.startswith('.'):
                continue
            if item.is_file():
                size = item.stat().st_size
                ext = item.suffix.lower() or '(no ext)'
                result["children"].append({"name": item.name, "size": size, "ext": ext})
                result["size"] += size
                stats["files"] += 1
                stats["extensions"][ext] += 1
                stats["ext_sizes"][ext] += size
            elif item.is_dir():
                stats["dirs"] += 1
                child = scan(item, stats)
                if child["children"]:
                    result["children"].append(child)
                    result["size"] += child["size"]
    except PermissionError:
        pass
    return result

def generate_html(data: dict, stats: dict, output: Path) -> None:
    ext_sizes = stats["ext_sizes"]
    total_size = sum(ext_sizes.values()) or 1
    sorted_exts = sorted(ext_sizes.items(), key=lambda x: -x[1])[:8]
    colors = {
        '.js': '#f7df1e', '.ts': '#3178c6', '.py': '#3776ab', '.go': '#00add8',
        '.rs': '#dea584', '.rb': '#cc342d', '.css': '#264de4', '.html': '#e34c26',
        '.json': '#6b7280', '.md': '#083fa1', '.yaml': '#cb171e', '.yml': '#cb171e',
        '.mdx': '#083fa1', '.tsx': '#3178c6', '.jsx': '#61dafb', '.sh': '#4eaa25',
    }
    lang_bars = "".join(
        f'<div class="bar-row"><span class="bar-label">{ext}</span>'
        f'<div class="bar" style="width:{(size/total_size)*100}%;background:{colors.get(ext,"#6b7280")}"></div>'
        f'<span class="bar-pct">{(size/total_size)*100:.1f}%</span></div>'
        for ext, size in sorted_exts
    )
    def fmt(b):
        if b < 1024: return f"{b} B"
        if b < 1048576: return f"{b/1024:.1f} KB"
        return f"{b/1048576:.1f} MB"

    html = f'''<!DOCTYPE html>
<html><head>
  <meta charset="utf-8"><title>Codebase Explorer</title>
  <style>
    body {{ font: 14px/1.5 system-ui, sans-serif; margin: 0; background: #1a1a2e; color: #eee; }}
    .container {{ display: flex; height: 100vh; }}
    .sidebar {{ width: 280px; background: #252542; padding: 20px; border-right: 1px solid #3d3d5c; overflow-y: auto; flex-shrink: 0; }}
    .main {{ flex: 1; padding: 20px; overflow-y: auto; }}
    h1 {{ margin: 0 0 10px 0; font-size: 18px; }}
    h2 {{ margin: 20px 0 10px 0; font-size: 14px; color: #888; text-transform: uppercase; }}
    .stat {{ display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px solid #3d3d5c; }}
    .stat-value {{ font-weight: bold; }}
    .bar-row {{ display: flex; align-items: center; margin: 6px 0; }}
    .bar-label {{ width: 55px; font-size: 12px; color: #aaa; }}
    .bar {{ height: 18px; border-radius: 3px; }}
    .bar-pct {{ margin-left: 8px; font-size: 12px; color: #666; }}
    .tree {{ list-style: none; padding-left: 20px; }}
    details {{ cursor: pointer; }}
    summary {{ padding: 4px 8px; border-radius: 4px; }}
    summary:hover {{ background: #2d2d44; }}
    .folder {{ color: #ffd700; }}
    .file {{ display: flex; align-items: center; padding: 4px 8px; border-radius: 4px; }}
    .file:hover {{ background: #2d2d44; }}
    .size {{ color: #888; margin-left: auto; font-size: 12px; }}
    .dot {{ width: 8px; height: 8px; border-radius: 50%; margin-right: 8px; }}
  </style>
</head><body>
  <div class="container">
    <div class="sidebar">
      <h1>📊 Summary</h1>
      <div class="stat"><span>Files</span><span class="stat-value">{stats["files"]:,}</span></div>
      <div class="stat"><span>Directories</span><span class="stat-value">{stats["dirs"]:,}</span></div>
      <div class="stat"><span>Total size</span><span class="stat-value">{fmt(data["size"])}</span></div>
      <div class="stat"><span>File types</span><span class="stat-value">{len(stats["extensions"])}</span></div>
      <h2>By file type</h2>
      {lang_bars}
    </div>
    <div class="main">
      <h1>📁 {data["name"]}</h1>
      <ul class="tree" id="root"></ul>
    </div>
  </div>
  <script>
    const data = {json.dumps(data)};
    const colors = {json.dumps(colors)};
    function fmt(b) {{ if (b < 1024) return b + ' B'; if (b < 1048576) return (b/1024).toFixed(1) + ' KB'; return (b/1048576).toFixed(1) + ' MB'; }}
    function render(node, parent) {{
      if (node.children) {{
        const det = document.createElement('details');
        det.open = parent === document.getElementById('root');
        det.innerHTML = `<summary><span class="folder">📁 ${{node.name}}</span><span class="size">${{fmt(node.size)}}</span></summary>`;
        const ul = document.createElement('ul'); ul.className = 'tree';
        node.children.sort((a,b) => (b.children?1:0)-(a.children?1:0) || a.name.localeCompare(b.name));
        node.children.forEach(c => render(c, ul));
        det.appendChild(ul);
        const li = document.createElement('li'); li.appendChild(det); parent.appendChild(li);
      }} else {{
        const li = document.createElement('li'); li.className = 'file';
        li.innerHTML = `<span class="dot" style="background:${{colors[node.ext]||'#6b7280'}}"></span>${{node.name}}<span class="size">${{fmt(node.size)}}</span>`;
        parent.appendChild(li);
      }}
    }}
    data.children.forEach(c => render(c, document.getElementById('root')));
  </script>
</body></html>'''
    output.write_text(html)

if __name__ == '__main__':
    target = Path(sys.argv[1] if len(sys.argv) > 1 else '.').resolve()
    stats = {"files": 0, "dirs": 0, "extensions": Counter(), "ext_sizes": Counter()}
    data = scan(target, stats)
    out = Path('codebase-map.html')
    generate_html(data, stats, out)
    print(f'Generated {out.absolute()}')
    webbrowser.open(f'file://{out.absolute()}')