name: skill-developer description: Meta-skill for creating and managing Claude Code skills. Activated when creating skills, modifying skill rules, or working with the skill system.

Skill developer

Purpose

Guide for creating and managing Claude Code skills. Covers skill structure, triggers, rules configuration, and best practices.

When to use

This skill activates when:

• Creating new skills
• Modifying existing skills
• Configuring skill triggers
• Understanding the skill system
• Debugging skill activation

Skill structure

Directory layout

.claude/skills/
├── skill-rules.json          # Skill activation rules
└── my-skill/
    └── SKILL.md              # Skill content

SKILL.md format

---
name: my-skill
description: Brief description for skill activation. Keywords here help trigger the skill.
---

# Skill title

## Purpose

What this skill is for and when to use it.

## When to use

This skill activates when:

- Condition 1
- Condition 2

## Core content

[Skill-specific guidance]

## Checklist

- [ ] Verification item 1
- [ ] Verification item 2

skill-rules.json

Basic structure

{
  "version": "1.0.0",
  "skills": {
    "my-skill": {
      "type": "domain",
      "enforcement": "suggest",
      "priority": "high",
      "description": "What this skill does",
      "promptTriggers": {
        "keywords": ["keyword1", "keyword2"],
        "intentPatterns": ["pattern.*match"]
      }
    }
  }
}

Fields

Prompt triggers

"promptTriggers": {
  "keywords": [
    "exact match word",
    "another keyword"
  ],
  "intentPatterns": [
    "(create|write).*?test",
    "how.*?implement"
  ]
}

File triggers

"fileTriggers": {
  "paths": [
    "**/*.py",
    "**/tests/**",
    "**/pyproject.toml"
  ]
}

Content triggers

"contentTriggers": {
  "patterns": [
    "@dataclass",
    "from typing import",
    "def test_"
  ]
}

Creating a new skill

1. Create directory

mkdir -p .claude/skills/my-skill

2. Create SKILL.md

Write the skill content with frontmatter.

3. Add to skill-rules.json

Add entry with appropriate triggers.

4. Test activation

Try prompts that should trigger the skill.

Best practices

Skill scope

• One skill per domain/concept
• Clear, focused purpose
• Not too broad, not too narrow

Keywords

• Include common terms users would use
• Include technical terms
• Include synonyms

Intent patterns

• Use regex for flexible matching
• Match user intent, not specific phrasing
• Test with various phrasings

Content

• Actionable guidance
• Code examples
• Checklists for verification
• Links to external resources

Example skill

SKILL.md

---
name: api-design
description: API design patterns and best practices for Python APIs.
---

# API design

## Purpose

Guide for designing clean, type-safe Python APIs.

## When to use

This skill activates when:

- Designing public interfaces
- Creating function signatures
- Building class APIs

## Core principles

### Type-safe signatures

\`\`\`python
def process(
    data: list[str],
    *,
    strict: bool = False,
) -> Result:
    ...
\`\`\`

## Checklist

- [ ] All parameters typed
- [ ] Return type specified
- [ ] Keyword-only args for options

skill-rules.json entry

"api-design": {
  "type": "domain",
  "enforcement": "suggest",
  "priority": "high",
  "description": "API design patterns and best practices",
  "promptTriggers": {
    "keywords": ["api design", "function signature", "public interface"],
    "intentPatterns": ["(design|create).*?api", "how.*?signature"]
  },
  "fileTriggers": {
    "paths": ["**/src/**/__init__.py"]
  }
}

Debugging

Check if skill triggers

1. Look for skill activation message in output
2. Verify keywords match your prompt
3. Test intent patterns with regex tester

Common issues

• Keywords too specific (not matching)
• Patterns too broad (matching everything)
• Priority too low (not shown)

Checklist

• SKILL.md has proper frontmatter
• Description includes trigger keywords
• skill-rules.json entry added
• Triggers tested with sample prompts
• Content is actionable and complete

Related files:

• .claude/skills/skill-rules.json - Activation rules
• .claude/hooks/skill_activation_prompt.py - Activation hook