Agent Skill Creator

Skill Creator

Overview

This skill helps you create well-structured Claude Agent Skills. A skill is a modular capability that extends Claude's functionality with domain-specific expertise, workflows, and best practices.

Skill Structure Requirements

Every skill must have:

• SKILL.md: Main instruction file with YAML frontmatter (required)
• Optional files: Additional markdown files, scripts, templates, or resources

Creating a New Skill

Step 1: Define the Skill

1. Name:

   • Maximum 64 characters
   • Only lowercase letters, numbers, and hyphens
   • No XML tags
   • Cannot contain "anthropic" or "claude"
   • Example: pdf-processor, api-documenter, code-reviewer

2. Description:

   • Maximum 1024 characters
   • Must describe what the skill does AND when Claude should use it
   • No XML tags
   • Be specific about triggers (e.g., "Use when working with PDF files")

Step 2: Create SKILL.md Template

---
name: [skill-name]
description: [What it does and when to use it]
---

# [Skill Name]

## Overview
[Brief description of the skill's purpose]

## Quick Start
[Simple example showing basic usage]

## Detailed Instructions
[Step-by-step guidance]

## Examples
[Concrete examples with code or workflows]

## Advanced Usage
[Optional: advanced patterns and edge cases]

## References
[Optional: links to additional resources]

Step 3: Organize Additional Files

Structure additional files logically:

• Use subdirectories for scripts, templates, or resources
• Reference external files in SKILL.md using relative paths
• Keep files focused and purposeful

Best Practices

Writing Effective Descriptions

• Start with what the skill does (verb phrase)
• Include triggers: "Use when..."
• Be specific about use cases
• Mention key capabilities

Good examples:

• "Create presentations, edit slides, analyze presentation content. Use when working with PowerPoint files or when the user mentions presentations, slides, or PPTX files."
• "Extract text and tables from PDF files, fill forms, merge documents. Use when working with PDF files or when the user mentions PDFs, forms, or document extraction."

Progressive Disclosure

• Level 1 (Metadata): Keep descriptions concise (~100 tokens)
• Level 2 (SKILL.md): Main instructions (~5k tokens)
• Level 3 (Resources): Bundle comprehensive guides and scripts

Instruction Writing

• Use clear, actionable language
• Provide step-by-step workflows
• Include code examples when relevant
• Reference additional files for complex topics
• Use markdown for formatting (code blocks, lists, headers)

Code and Scripts

• Store reusable code in .py, .js, or .sh files
• Keep scripts focused and executable
• Document script parameters and usage
• Reference scripts in SKILL.md instructions

Common Patterns

Pattern 1: Single-Purpose Skill

my-skill/
└── SKILL.md

Pattern 2: Skill with Additional Resources

my-skill/
├── SKILL.md
├── ADVANCED.md
└── REFERENCE.md

Pattern 3: Skill with Scripts

my-skill/
├── SKILL.md
└── scripts/
    ├── process.py
    └── validate.sh

Pattern 4: Comprehensive Skill

my-skill/
├── SKILL.md
├── GETTING_STARTED.md
├── EXAMPLES.md
├── REFERENCE.md
├── scripts/
│   ├── helper.py
│   └── utilities.sh
└── templates/
    └── template.json

Validation Checklist

Before finalizing a skill, verify:

• SKILL.md has valid YAML frontmatter with name and description
• Name follows naming conventions (lowercase, hyphens, < 64 chars)
• Description clearly states what it does and when to use it
• Description is < 1024 characters and contains no XML tags
• Instructions are clear and actionable
• Examples are included
• Additional files are properly referenced in SKILL.md
• Scripts are executable and documented

Examples of Skill Creation

Example 1: Simple Skill

When creating a simple skill for formatting code:

1. Create directory: code-formatter/
2. Create SKILL.md with name, description, and formatting instructions
3. That's it! Simple skills may only need SKILL.md

Example 2: Complex Skill

When creating a skill with multiple components:

1. Create directory: api-tester/
2. Create SKILL.md with main instructions
3. Add SCRIPTS.md for script documentation
4. Add scripts in scripts/ directory
5. Reference scripts in SKILL.md

When to Use This Skill

• User wants to create a new Claude skill
• User needs help structuring a skill directory
• User wants templates or examples
• User needs guidance on skill best practices
• User is validating or reviewing an existing skill