What Are Claude Skills
Claude Skills are a mechanism for giving Claude domain expertise and custom workflows. By writing structured SKILL.md files, you can inject:
- Domain-specific knowledge (e.g., code review standards, writing style)
- Step-by-step workflows (e.g., TDD, meeting notes organization)
- Tool usage instructions (e.g., API calls, MCP integration)
Why Skills Matter
1. Improve Task Consistency
General-purpose Claude may produce varied outputs across conversations. By defining "how to do it" and "to what extent" in a Skill, results become more stable and predictable.
2. Reuse Best Practices
Turn team or personal best practices into Skills. New members or projects can reuse them directly, reducing repeated communication and trial-and-error.
3. Extend Claude's Capabilities
Claude does not natively know all tools and APIs. By describing tool usage, parameters, and examples in a Skill, Claude can correctly invoke external capabilities.
Basic Usage Flow
Create a Skill
Create a new folder under the Skills directory, e.g. my-skill/, and add SKILL.md:
my-skill/
└── SKILL.mdWrite SKILL.md
SKILL.md typically includes:
Trigger in Conversation
When your question or instruction matches the Skill's trigger conditions, Claude will automatically load and apply it. For example, if the Skill says "Use when user requests code review," saying "help me review this code" will trigger it.
Common Skill Types
- Domain knowledge: Resume optimization, e-commerce copywriting, meeting notes
- Process-oriented: TDD development, systematic debugging, PR review checks
- Tool-oriented: Figma design-to-code, Notion integration, API calls
Summary
Claude Skills inject domain knowledge and workflows into Claude via SKILL.md, making it more professional and consistent on specific tasks. Understanding the basics of Skills is the first step to leveraging Claude's customization capabilities.