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Claude CodeSkillsBeginner4 min

Create and Test a Custom Claude Code Skill

A useful review prompt becomes tedious and inconsistent when you paste it into every session. A skill turns that repeated workflow into a named command that lives with the project or follows you across projects.

When to use

  • Standardize a review, release or debugging workflow.
  • Give teammates the same reusable instructions through Git.
  • Restrict a sensitive workflow to a small, explicit tool set.

Example

Your team runs the same diff review before every PR. Store it as review-diff so anyone can invoke the same checks and output format.

TL;DR

A skill is a folder with a SKILL.md. Put it in .claude/skills/<name>/ and call /<name>.

bash
mkdir -p .claude/skills/review-diff
$EDITOR .claude/skills/review-diff/SKILL.md

Steps

  1. 1

    Write SKILL.md

    Create the file with a precise name and description, then define the exact review and output you want. The description helps Claude decide when the skill is relevant.

    .claude/skills/review-diff/SKILL.md
    ---
name: review-diff
description: Review the current git diff for bugs, security issues and missing tests.
disable-model-invocation: true
allowed-tools: Bash(git diff:*), Read, Grep
---

Review the output of `git diff main...HEAD`.

For each issue report: file, line, severity (Critical, Required, Optional, Nit), problem, suggested fix.
End with a verdict: Approve or Request changes.
  2. 2

    Choose the scope

    Project skills are shared through git. Personal skills work in every repo.

    paths
    .claude/skills/<name>/SKILL.md     # this project
~/.claude/skills/<name>/SKILL.md   # all your projects
  3. 3

    Run it

    Invoke the skill by its name from Claude Code after your branch contains the changes you want reviewed.

    Claude Code
    /review-diff
  4. 4

    Iterate

    Edit SKILL.md and run it again on the same diff until the output is stable.

Gotchas

  • disable-model-invocation: true means only you trigger it; remove it to let Claude pick it automatically.
  • Keep SKILL.md short; move long references into extra files in the same folder and link them.
  • A vague description means Claude never selects the skill.
  • Restrict allowed-tools for review skills so they stay read-only.

Cheat sheet

.claude/skills/<name>/SKILL.mdProject skill
~/.claude/skills/<name>/SKILL.mdPersonal skill
/<name> [args]Run a skill
disable-model-invocation: trueManual only
allowed-tools:Limit tools

Related

Sources

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