Custom Commands and Skills

The Problem This Solves

Imagine every time you finish a feature, you type something like this:

review this diff for security issues, check test coverage, and check
for any leftover console.log statements

This works fine the first time. But typing it every single time is slow, and you might word it slightly differently each time — sometimes forgetting to mention test coverage, sometimes forgetting console.log statements. A custom command solves this: you write the instruction once, save it under a short name, and reuse the exact same instruction every time after that.

Creating a Custom Command

Save a markdown file under .claude/commands/ in your project folder:

Review the current diff for:
- security issues
- missing test coverage
- leftover console.log or debug statements
 
Report findings as a checklist.

The file name becomes the command name. Now, instead of typing the whole instruction again, you just run:

/pre-merge

Claude Code reads the saved file and follows those exact instructions — same wording, same checklist, every single time you use it.

Skills: The Same Idea, With More Power

A Skill does the same job as a custom command, but with a few extra abilities:

• It can carry more instructions and even load extra reference files
• It can restrict which tools it is allowed to use — for example, a review skill that can only read files, never edit them
• Claude Code can sometimes trigger it automatically when the task fits, even if you never typed its name

Skills live in a slightly different location: .claude/skills/NAME/SKILL.md (a folder per skill, not just a single file).

Choosing Between Them

Next → Hooks