Claude Skills: What They Are and When to Use Them
Claude Code Skills package reusable instructions into folders Claude can load when relevant or invoke directly. SKILL.md is the required entry point, while supporting scripts, templates, examples and references are optional.
Quick answer
Use a Skill when Claude needs repeatable know-how: a workflow, checklist, domain procedure or bundled reference material. Use MCP when Claude needs external tools or data, and use CLAUDE.md for persistent project-level instructions.
What goes inside a Claude Skill?
Each skill is a directory with SKILL.md as its entry point. Supporting files are optional. Current Claude Code documentation says frontmatter fields are optional, with description recommended because Claude uses it to decide when a skill applies.
Where skills live
Project skills live under .claude/skills/<skill-name>/SKILL.md, personal skills under ~/.claude/skills/<skill-name>/SKILL.md, and plugins can ship skills in their own skills directories.
Why skills are useful
Skills keep procedures reusable without permanently loading every instruction into project context. The body loads when the skill is used, making them a better home for procedural material that would otherwise make CLAUDE.md too large.
Minimal SKILL.md example
---
name: release-check
description: Verify a web release before production deployment. Use when reviewing deployment readiness.
---
# Release check
1. Run tests.
2. Run the production build.
3. Review changed routes.
4. Report blockers before deployment.Official Claude documentation
Claude Code changes quickly. Use Anthropic’s documentation as the source of truth for current configuration fields and behavior.
Open Anthropic docs →Related Claude tools and guides
Frequently asked questions
What file does a Claude Skill use?
SKILL.md is the required entry point for a Claude Code skill.
Is description required?
Description is recommended rather than strictly required in current Claude Code docs. It helps Claude decide when the skill should load automatically.
Can a Skill include scripts?
Yes. Skills can include optional scripts, templates, examples and reference files.