claude-code-skills

name	claude-code-skills
description	Comprehensive reference for creating Claude Code skills with progressive disclosure, SKILL.md structure, references/ organization, frontmatter specification, and best practices for modular capability development.

Claude Code Skills - Meta Reference

This skill provides the definitive reference for creating, organizing, and maintaining Claude Code skills. Use this when building new skills or improving existing skill architecture.

Quick Reference

Component	Purpose	Required
SKILL.md	Main reference file with frontmatter	Yes
scripts/	Executable code (runs, not loaded)	Optional
references/	Documentation (loaded on-demand)	Recommended
assets/	Output files (templates, icons)	Optional
data/sources.json	Curated external links	Recommended

Cross-Platform: Agent Skills standard adopted by Claude Code, Codex CLI, Gemini CLI, and VS Code Copilot. Skills are portable across platforms.

Skill Structure

skills/
└── skill-name/
    ├── SKILL.md           # Main reference (required)
    ├── scripts/           # Executable code (Python/Bash) - runs, not loaded
    │   └── validate.py
    ├── references/        # Documentation loaded into context on-demand
    │   ├── patterns.md
    │   └── examples.md
    ├── assets/            # Files for OUTPUT (templates, icons, fonts)
    │   └── template.html
    └── data/
        └── sources.json   # External references

Directory purposes:

• scripts/ - Executable code; output consumed, code never loads into context
• references/ - Documentation loaded into context when the agent needs it
• assets/ - Files used in generated output (not loaded into context)

SKILL.md Template

---
name: skill-name
description: One-line description of what this skill provides and when to use it
---

# Skill Name - Quick Reference

Brief overview of the skill's purpose and value.

## Quick Reference

| Task | Tool/Method | When to Use |
|------|-------------|-------------|
| Task 1 | Tool A | Context for usage |

## When to Use This Skill

The assistant should invoke this skill when a user requests:

- Use case 1
- Use case 2
- Use case 3

## Core Concepts

### Concept 1

Explanation with code example:

\`\`\`language
code example
\`\`\`

### Concept 2

Additional patterns...

## Navigation

**Resources**
- [references/skill-patterns.md](references/skill-patterns.md) - Common patterns
- [references/skill-validation.md](references/skill-validation.md) - Validation criteria

**Related Skills**
- [../claude-code-agents/SKILL.md](../claude-code-agents/SKILL.md) - Agent creation

Progressive Disclosure

Skills use progressive disclosure to optimize token usage:

Layer	Content	Token Cost
Discovery	Name + description only	~50 tokens
Activation	Full SKILL.md body	2K-5K tokens
Execution	scripts/, references/, assets/	On-demand

Pattern: SKILL.md provides overview -> Resources load only when needed

Limits: Keep SKILL.md under 500 lines (<5K tokens)

When to Split Content

Keep in SKILL.md	Move to references/
Decision trees	Full API references
Quick commands	Step-by-step tutorials
Common patterns	Edge case handling
1-2 code examples	Complete implementations

Frontmatter Specification

---
name: string                        # Required: lowercase-kebab-case, matches folder name
description: string                 # Required: PRIMARY trigger mechanism (50-300 chars)
disable-model-invocation: boolean   # Optional: Only user can invoke (for /deploy, /commit)
user-invocable: boolean             # Optional: false = background knowledge only
---

Name rules:

• Use kebab-case: ai-llm, not AI_LLM_Engineering
• Match folder name exactly
• Be specific: software-backend not backend

Description rules (PRIMARY TRIGGER):

• Description is the primary triggering mechanism - the runtime uses it to decide when to invoke
• Include "when to use" context HERE, not in the body
• Single line, 50-300 characters
• Include key technologies/concepts as trigger keywords

Optional frontmatter:

• disable-model-invocation: true - Only user can invoke (for workflows with side effects: /commit, /deploy, /send-slack)
• user-invocable: false - Not user-invocable (background knowledge only; runtime-dependent)

Skill Categories

Category	Prefix	Examples
AI/ML	ai-	ai-llm, ai-ml-data-science
Software	software-	software-backend, software-frontend
Operations	ops-	ops-devops-platform
Data	data-	data-lake-platform, data-sql-optimization
Quality	qa-	qa-debugging, qa-docs-coverage
Developer Tools	dev-, git-	dev-api-design, git-commit-message, dev-workflow-planning
Product	product-	product-management, docs-ai-prd
Document	document-	document-pdf, document-xlsx
Testing	testing-, qa-testing-	qa-testing-playwright, qa-testing-strategy
Marketing	marketing-	marketing-social-media, marketing-seo-complete
Claude Code	claude-code-	claude-code-agents, claude-code-skills

sources.json Schema

{
  "metadata": {
    "title": "Skill Name - Sources",
    "description": "Brief description",
    "last_updated": "YYYY-MM-DD",
    "skill": "skill-name"
  },
  "category_name": [
    {
      "name": "Resource Name",
      "url": "https://example.com/docs",
      "description": "What this covers",
      "add_as_web_search": true
    }
  ]
}

Categories should group logically:

• official_documentation
• tutorials
• community_resources
• tools_and_libraries

Quality Checklist

SKILL VALIDATION CHECKLIST

Frontmatter:
[ ] name matches folder name (kebab-case)
[ ] description is concise and actionable

Structure:
[ ] SKILL.md under 500 lines (split into references/ if needed)
[ ] references/ for detailed content
[ ] data/sources.json with curated links

Content:
[ ] Quick reference table at top
[ ] "When to Use" section present
[ ] Code examples are copy-paste ready
[ ] Related skills linked at bottom

Quality:
[ ] >40% operational content (code, tables, checklists)
[ ] <50% prose paragraphs
[ ] All URLs are live (no 404s)
[ ] Sources updated within 6 months

Multi-Tech vs Single-Tech Skills

Single-Tech Skill

software-backend/
├── SKILL.md              # Node.js focus
└── references/
    └── nodejs-patterns.md

Multi-Tech Skill

software-backend/
├── SKILL.md              # Overview + decision tree
├── references/
│   ├── nodejs-patterns.md
│   ├── go-patterns.md
│   ├── rust-patterns.md
│   └── python-patterns.md
└── assets/
    ├── nodejs/
    ├── go/
    ├── rust/
    └── python/

Navigation

Resources

• references/skill-patterns.md - Common skill patterns
• references/skill-validation.md - Validation criteria
• data/sources.json - Official documentation links

Related Skills

• ../claude-code-agents/SKILL.md - Agent creation
• ../claude-code-commands/SKILL.md - Command creation
• ../claude-code-hooks/SKILL.md - Hook automation