Your Own Slash Commands

Working Code

Let's create a custom command for your project. Create a markdown file in the .claude/commands/ directory:

> Create .claude/commands/review.md with this content:
>
> Review the current git diff changes.
> Check from these perspectives:
> 1. Potential bugs
> 2. Security vulnerabilities
> 3. Performance issues
> 4. Coding convention violations
>
> For each item, say "Pass" if no issues, or explain the problem in detail.

Now use it in a Claude Code session:

> /project:review

The custom command runs and performs the code review automatically.

Try It Yourself

Create a more practical command:

Test generation command — .claude/commands/test.md:

Write unit tests for all public functions in $ARGUMENTS.

Requirements:

- Test framework: whatever the project uses
- Include normal cases, error cases, and edge cases
- Add clear descriptions for each test
- Filename: original-filename.test.{extension}

Usage:

> /project:test src/utils/validator.ts

$ARGUMENTS gets replaced with src/utils/validator.ts.

"Why?" — Turning Repetitive Tasks into Patterns

During development, you end up repeating the same types of requests: "review the code," "write tests," "add types." Instead of typing detailed prompts every time, it's more efficient to create a well-crafted command once and reuse it.

Command Storage Locations

| Location | Usage | Purpose | | --------------------- | ------------------ | ----------------------------------------- | | .claude/commands/ | /project:command | Shared with the team (included in Git) | | ~/.claude/commands/ | /user:command | Personal only (available in all projects) |

The $ARGUMENTS Variable

When you include $ARGUMENTS in a command file, the text after the slash command is substituted in:

/project:test src/utils/validator.ts
              ^^^^^^^^^^^^^^^^^^^^^^^^
              This part goes into $ARGUMENTS

What Makes a Good Custom Command

1. Specific instructions — use a checklist instead of "do it well"
2. Reusable — use $ARGUMENTS to dynamically specify the target
3. Defined output format — "organize as a table," "output as markdown"

Deep Dive