Create Claude Code Skills

Guide for creating well-structured Claude Code skills that are discoverable and effective.

Skill Directory Structure

Skills can be placed in three locations:

# Personal skills (available across all projects)
~/.claude/skills/skill-name/SKILL.md

# Project skills (shared via git with team)
.claude/skills/skill-name/SKILL.md

# Plugin skills (distributed via marketplace)
plugin-name/skills/skill-name/SKILL.md

SKILL.md Format

Every skill requires a SKILL.md file with YAML frontmatter:

---
name: your-skill-name
description: Brief description of what this Skill does and when to use it
allowed-tools: Tool1, Tool2, Tool3  # Optional: restricts available tools
---

# Skill Title

## Instructions
Clear, step-by-step guidance for Claude.

## Examples
Concrete examples of using this skill.

Frontmatter Fields

Required Fields

Optional Fields

Writing Effective Descriptions

The description is critical for discoverability. Include:

1. What the skill does - the capability
2. When to use it - trigger phrases and contexts

Good Examples

description: Generate clear git commit messages from staged changes. Use when writing commits, reviewing diffs, or preparing code for push.

description: Analyze Excel spreadsheets, create pivot tables, and generate charts. Use when working with Excel files, .xlsx format, or tabular data analysis.

Bad Examples

# Too vague - Claude won't know when to use it
description: Helps with documents

# Missing trigger context
description: Processes PDF files

Tool Restrictions with allowed-tools

Use allowed-tools to limit Claude's capabilities when the skill is active:

---
name: code-reviewer
description: Review code for best practices. Use when reviewing PRs or analyzing code quality.
allowed-tools: Read, Grep, Glob
---

Common tool combinations:

Multi-File Skills

For complex skills, add supporting files:

my-skill/
├── SKILL.md           # Required: main instructions
├── reference.md       # Optional: detailed documentation
├── examples.md        # Optional: usage examples
├── scripts/
│   └── helper.py      # Optional: utility scripts
└── templates/
    └── template.txt   # Optional: templates

Reference files from SKILL.md:

For advanced usage, see [reference.md](reference.md).

Claude loads additional files only when needed (progressive disclosure).

Creating a Plugin Skill

For marketplace distribution, create this structure:

plugin-name/
├── .claude-plugin/
│   └── plugin.json
└── skills/
    └── skill-name/
        └── SKILL.md

plugin.json Format

{
  "name": "plugin-name",
  "description": "Brief plugin description",
  "version": "1.0.0",
  "author": {
    "name": "Your Name"
  }
}

Skill Creation Checklist

When creating a skill:

1. Choose a descriptive, hyphenated name
2. Write a specific description with trigger phrases
3. Decide on tool restrictions (if any)
4. Create clear, actionable instructions
5. Add examples for common use cases
6. List any requirements (CLI tools, packages)
7. Test by asking questions that match the description

Common Patterns

Simple Skill (Single File)

---
name: commit-message-generator
description: Generate clear commit messages from git diffs. Use when writing commits or reviewing staged changes.
---

# Commit Message Generator

## Instructions

1. Run `git diff --staged` to see changes
2. Generate a commit message with:
   - Summary under 50 characters
   - Detailed description of what and why
   - List affected components

## Format

- Use present tense ("Add feature" not "Added feature")
- First line is the subject, then blank line, then body

Script-Based Skill

---
name: api-tester
description: Test REST API endpoints with curl. Use when testing APIs or debugging HTTP requests.
allowed-tools: Bash, Read, Write
---

# API Tester

## Usage

Test an endpoint:

```bash
./scripts/test-api.sh GET https://api.example.com/users

Scripts

• scripts/test-api.sh - Main testing script
• scripts/format-json.sh - Pretty print JSON responses

### Read-Only Analysis Skill

```yaml
---
name: security-scanner
description: Scan code for security vulnerabilities. Use when reviewing code security or checking for OWASP issues.
allowed-tools: Read, Grep, Glob
---

# Security Scanner

This skill provides read-only security analysis.

## Checks

1. Hardcoded credentials
2. SQL injection vulnerabilities
3. XSS attack vectors
4. Insecure dependencies

Debugging Skills

If Claude doesn't use your skill:

1. Check description specificity - Add trigger phrases
2. Verify file path - Must be in correct location
3. Validate YAML - Check for syntax errors
4. Run with debug - claude --debug shows loading errors

Requirements

When creating skills for this marketplace:

• Follow the plugin structure with .claude-plugin/plugin.json
• Place skills in skills/skill-name/SKILL.md
• Update the root marketplace.json to register the plugin