Creating Claude Code Skills

Skills are modular packages that extend Claude's capabilities with specialized knowledge, workflows, and tools.

Quick Start

my-skill/
├── SKILL.md              # Required: metadata + instructions
├── reference.md          # Optional: detailed docs
└── scripts/              # Optional: utility scripts
    └── helper.py

SKILL.md Structure

---
name: skill-name          # lowercase, hyphens, max 64 chars
description: What it does and when to use it. Max 1024 chars.
---

# Skill Name

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

## Examples
Concrete input/output examples.

Core Principles

1. Be Concise: Claude is smart. Only add context Claude doesn't already have.
2. Progressive Disclosure: SKILL.md is overview. Details go in separate files.
3. Match Freedom to Risk: Fragile operations need specific scripts; flexible tasks need general guidance.

Writing Effective Descriptions

The description field is critical for discovery. Include:

• What the skill does
• When to use it (triggers/contexts)
• Key terms users would mention

Good:

description: Extract text from PDF files, fill forms, merge documents. Use when working with PDF files, forms, or document extraction.

Bad:

description: Helps with documents

File Organization Patterns

Simple skill (single file):

commit-helper/
└── SKILL.md

Skill with references:

pdf-processing/
├── SKILL.md           # Quick start + navigation
├── FORMS.md           # Form-filling details
└── REFERENCE.md       # API reference

Skill with scripts:

data-analysis/
├── SKILL.md
├── scripts/
│   └── validate.py
└── references/
    └── schema.md

Key Guidelines

• Keep SKILL.md under 500 lines
• Use forward slashes in paths: scripts/helper.py
• Keep references one level deep from SKILL.md
• Use third person in descriptions
• Test with all models you plan to use

Skill Locations

• Personal: ~/.claude/skills/skill-name/
• Project: .claude/skills/skill-name/

For detailed patterns, see references/patterns.md. For anti-patterns to avoid, see references/anti-patterns.md.