how to use skills from Claude Code A.K.A Claudinho.

Source: Dev.to

Introduction

As a start to using Claude, I’ve been trying to make the most of its features. While talking with a friend, we started discussing skills.

What are Skills?

In the Claude documentation, skills are more personalized agents with additional context. For example, before asking the chat to create a new report, you can say:

“Act as a nutritionist with a cutting goal and create the best regimen for me.”

After that, the agent will be more accurate for this objective. If you want to reuse that context for future tasks, skills are your best option. You can create a single command to reuse the context across different objectives.

Creating a Code‑Review Skill

At work we often run into RuboCop issues because the project contains legacy code that needs to be refactored to follow RuboCop rules. This is tedious, so I created a skill to handle the review before we push the code to GitHub.

Skill Definition

# Create a /review-code skill to review Ruby and JavaScript code.
# The skill will:
# • Read the project's .rubocop.yml and .eslintrc.js files and extract the configured rules.
# • Identify files to review:
#     - If no argument is passed, run `git diff main...HEAD --name-only`
#       and read each relevant file before reviewing.
# • Produce a report with sections:
#     - Ruby rules grouped by category (Lint, Security, Metrics, Naming, Style, Layout)
#       – separating blocks that must be merged from warnings.
#     - JavaScript rules grouped (Errors, Warnings, Modern code in app/webpack/,
#       Vue, Legacy code in app/assets/javascripts/).
# • Report format:
#     🔴 Blockers
#     🟡 Warnings
#     🟢 Good practices observed
#     📋 Summary
# • Be direct and specific: quote the problematic snippet and show the corrected version.
#   Do not list rules that were not violated.

How It Works

1. Read configuration files – The skill parses .rubocop.yml and .eslintrc.js to understand which rules are active.

2. Select files – If you run the skill without arguments, it executes

   git diff main...HEAD --name-only

   and filters for Ruby (*.rb) and JavaScript (*.js, *.vue) files.

3. Analyze code – For each file, the skill checks the relevant rules and categorises findings as Blockers, Warnings, or Good practices.

4. Generate report – The output follows the emoji‑prefixed sections listed above, quoting the offending snippet and providing the corrected code.

Using the Skill

After defining the skill, it becomes available in your Claude project session. Invoke it by typing the slash command:

/review-code

You can also pass a specific file or directory as an argument if you only want to review a subset of the codebase. The skill will return a concise, actionable report ready for you to apply the suggested fixes before committing.