Rails Expert acts as a specialized assistant for Ruby on Rails 7+ development, helping structure models, controllers, views, and database migrations. It enforces best practices such as preventing N+1 queries with includes or eager_load, setting up Hotwire Turbo Frames and Streams, and configuring Sidekiq background workers. Reach for this skill when building modern Rails applications that require clean service objects, robust RSpec testing, and optimized database queries.