Create Agent Skills in Simple Steps

Agent skills extend Claude Code and Codex with custom capabilities through simple markdown files and scripts.

Claude Code

Install the skills marketplace

/plugin marketplace add anthropics/skills

Install skill-creator

/plugin install skill-creator@anthropic-agent-skills

Create a new skill

Ask Claude to create a skill:

Create a new skill called "slug-generator" that converts text to URL-friendly slugs

Or manually initialize:

python scripts/init_skill.py my-skill --path ./skills

Skill structure

my-skill/
├── SKILL.md (required)
├── scripts/ (optional)
├── references/ (optional)
└── assets/ (optional)

SKILL.md format

---
name: slug-generator
description: |
  Convert text to URL-friendly slugs with customizable
  separators. Use when you need to: (1) Generate URL
  slugs from titles, (2) Create file-safe names.
---

# Slug Generator

## Usage

Input: "My Blog Post Title!"
Output: "my-blog-post-title"

## Implementation

See [slug_transform.py](scripts/slug_transform.py)

Example script

scripts/slug_transform.py:

import re

def generate_slug(text: str, separator: str = '-') -> str:
    slug = text.lower().strip()
    slug = re.sub(r'[^a-z0-9]+', separator, slug)
    slug = re.sub(f'{separator}+', separator, slug)
    return slug.strip(separator)

if __name__ == '__main__':
    import sys
    text = sys.argv[1] if len(sys.argv) > 1 else "Example Text"
    print(generate_slug(text))

Package the skill

python scripts/package_skill.py ./skills/my-skill

Creates my-skill.skill file.

Install your skill

/plugin install ./my-skill.skill

Use your skill

Use the slug-generator skill to convert: "My Amazing Title"

Codex (OpenAI)

Create skill with skill-creator

$skill-creator

With context:

$skill-creator
Create a skill that generates commit messages from git diff.

Manual creation

Create in either location:

# User-scoped
~/.codex/skills/my-skill/

# Repo-scoped
.codex/skills/my-skill/

Codex SKILL.md format

---
name: commit-msg-generator
description: Generate conventional commit messages from git diff. Use when committing changes.
---

# Commit Message Generator

Review git diff and generate a conventional commit message.

## Steps

1. Run `git diff --staged`
2. Analyze changes
3. Generate message with format: `type(scope): subject`
4. Suggest conventional types: feat, fix, refactor, docs

Restart Codex

# Restart to load new skills
codex restart

Activation

Skills activate automatically when mentioned or via:

/skills

Or explicitly:

$my-skill

Key Differences

Resources

• Claude Skills Repository
• Codex Skills Documentation
• Creating Custom Skills