---

name: write-skill description: Create effective Claude Code SKILL.md files following Anthropic's official patterns. Use when writing new skills, improving existing skills, or learning skill best practices.

Skill Creator

Create skills that extend Claude's capabilities with specialized knowledge and workflows.

Core Principles

1. Concise is key - Context window is shared; only add what Claude doesn't know
2. < 200 lines - Split to references/ if approaching limit
3. Description triggers - Include "Use when..." in YAML description, not body
4. Scripts for precision - Create .py scripts for tasks requiring exact format or validation; for templates, prefer Python scripts over raw markdown to ensure stable formatting

Skill Structure

Copy.claude/
└── skills/
    └── skill-name/
        ├── SKILL.md           # Required: instructions (<200 lines)
        ├── scripts/           # Optional: executable code
        ├── references/        # Optional: docs loaded on-demand
        └── assets/            # Optional: templates, images

Creation Process

1. Initialize

Run the init script to create proper structure:

Copypython3 scripts/init_skill.py <skill-name>

Options:

• --path, -p: Output directory (default: .claude/skills)

2. Write SKILL.md

Frontmatter (required):

Copy---
name: my-skill
description: [What it does]. Use when [specific triggers].
---

Body: Instructions only. Keep lean—move details to references/.

3. Validate

Copypython3 scripts/validate_skill.py <path/to/skill>

4. Test

Restart Claude Code, trigger naturally (don't mention skill name).

Degrees of Freedom

Progressive Disclosure

Split content when SKILL.md grows:

Copy## Quick start
[Essential usage]

## Advanced
- **Forms**: See [forms.md](references/forms.md)
- **API**: See [api.md](references/api.md)

Claude loads references only when needed.

What NOT to Include

• README.md, CHANGELOG.md, INSTALLATION_GUIDE.md
• Explanations Claude already knows
• "When to use" sections in body (put in description)
• Shared conventions - if multiple skills use the same convention, extract to .claude/rules/

Relationship with Rules

Rules = conventions shared across skills.

If you find yourself repeating the same guideline in multiple skills:

1. Extract to .claude/rules/ using write-rules skill
2. Skills automatically inherit rules (auto-injected)
3. Keep skill-specific details in the skill

References

• spec.md - YAML frontmatter specification
• patterns.md - Common skill patterns
• examples.md - Before/after examples