What is a Skill?
Concept
A Skill is a specialized capability module in Claude Code. Each Skill is deeply optimized for a specific task domain, with built-in best practices, workflows, and domain expertise.
Think of it this way:
- Claude Code itself = a full-stack software engineer
- Skill = a "professional certification" in a specific domain — when activated, Claude works to the highest standards of that domain
What Problem Do Skills Solve?
In daily development, many tasks follow fixed workflows and require domain knowledge:
- Bug debugging follows a "reproduce → narrow → hypothesize → verify → fix" loop
- TDD follows a "red → green → refactor" loop
- Issue triage requires a state-machine-driven process
Without Skills, you'd need to manually describe these workflows every time. With Skills, a single /diagnose command switches Claude Code into professional debugging mode.
Types of Skills
1. Built-in Skills
Claude Code ships with 20+ official Skills:
| Category | Skills | Description |
|---|---|---|
| Dev Workflow | diagnose, tdd, prototype | Debugging, test-driven development, prototyping |
| Project Mgmt | triage, to-issues, to-prd | Issue triage, task breakdown, PRD generation |
| Code Quality | review, simplify, security-review | Code review, simplification, security audit |
| Docs & Knowledge | grill-with-docs, init, improve-codebase-architecture | Doc review, project init, architecture improvement |
| Dev Tools | write-a-skill, claude-api, update-config | Skill authoring, API development, config management |
| Productivity | caveman, loop, handoff | Compact mode, recurring tasks, session handoff |
2. Custom Skills
You can create your own Skills using the write-a-skill Skill. Custom Skills can:
- Encapsulate team-specific workflows
- Integrate internal tools and APIs
- Codify project-specific best practices
Skill vs. Normal Conversation
| Normal Chat | With Skill | |
|---|---|---|
| Workflow | Must describe each time | Auto-loaded |
| Domain Knowledge | Relies on general model knowledge | Built-in expert guidance |
| Consistency | May vary each time | Standardized output |
| Efficiency | Needs multiple clarification rounds | One-shot precision |
Next Steps
- How to Use Skills — Learn triggering and interaction
- Quick Start — Hands-on in 5 minutes