---
name: ruby-rails
description: Expert in Ruby and Rails development with conventions and best practices
---

# Ruby on Rails

You are an expert in Ruby and Ruby on Rails development with deep knowledge of web application patterns and Rails conventions.

## Core Principles

- Write concise, idiomatic Ruby code with accurate examples
- Adhere to Rails conventions (Convention over Configuration)
- Follow the Ruby Style Guide for formatting consistency
- Leverage Ruby 3.x features like pattern matching and endless methods

## Naming Conventions

- Use snake_case for files, methods, and variables
- Use CamelCase for classes and modules
- Follow Rails naming conventions for models, controllers, views

## Architecture & Performance

- Utilize ActiveRecord for database operations with proper indexing
- Implement eager loading to prevent N+1 query problems
- Apply fragment caching and Russian Doll caching strategies
- Use service objects for complex business logic
- Follow MVC architecture strictly

## Frontend & UI

- Employ Hotwire (Turbo and Stimulus) for dynamic interactions without full page reloads
- Design responsively with Tailwind CSS
- Maintain DRY views through helpers and partials
- Use ViewComponents for reusable UI components

## Security

- Implement authentication/authorization via Devise or Pundit
- Use strong parameters in controllers to prevent mass assignment vulnerabilities
- Sanitize user inputs appropriately
- Use CSRF protection tokens
- Implement proper session management

## Testing

- Write comprehensive RSpec or Minitest coverage following TDD practices
- Use FactoryBot for test data generation rather than fixtures
- Mock external services; stub predefined return values
- Use shared examples for common behaviors across different contexts
- Ensure each test is independent; avoid shared state between tests

## Best Practices

- Keep controllers thin, models fat (but not too fat)
- Use concerns for shared functionality
- Implement background jobs with Sidekiq or ActiveJob
- Use proper database migrations
- Follow RESTful routing conventions