Master Ruby and Rails Development

Provides Ruby expertise focused on clean, maintainable, and performant code, spanning metaprogramming, Rails conventions, gem development, performance optimization, and testing.

Use this skill when writing or refactoring Ruby code, building Rails applications with MVC architecture, developing and versioning gems, profiling and optimizing Ruby performance, or writing RSpec/Minitest test suites. Not a fit for tasks unrelated to Ruby or Rails development.

Focus areas span Ruby metaprogramming (modules, mixins, DSLs), Rails patterns across ActiveRecord, controllers, and views, gem development and dependency management, performance optimization and profiling, testing with RSpec and Minitest, and code quality enforcement with RuboCop and static analysis.

The approach favors Ruby's expressiveness and metaprogramming features, follows Ruby and Rails conventions and idioms rather than fighting them, uses blocks and enumerables idiomatically instead of manual loops, handles exceptions with proper rescue/ensure patterns, and optimizes for readability first and performance second - only reaching for performance-focused rewrites once correctness and clarity are established.

Output includes idiomatic Ruby code following community conventions, Rails applications structured with MVC architecture, RSpec or Minitest tests with fixtures and mocks, gem specifications with proper semantic versioning, performance benchmarks produced with benchmark-ips, and refactoring suggestions for legacy Ruby code. A Gemfile and .rubocop.yml are included when relevant to the task.

Built around the standard Ruby and Rails ecosystem: ActiveRecord for the Rails data layer, RSpec and Minitest for testing, RuboCop for static analysis and style enforcement, benchmark-ips for performance measurement, and Bundler-managed Gemfiles for dependency and gem version management. Following Rails conventions also means favoring generators and the framework's default MVC file layout over custom structure, so controllers stay thin and business logic lives in models or plain Ruby objects rather than spreading across the view layer.

Ruby and Rails developers who want idiomatic, convention-following code and tests rather than a direct port of patterns from another language, particularly when refactoring legacy Ruby or building out gem-based functionality. It's also useful for teams standardizing on RuboCop and a shared style guide, since suggested refactors are checked against static analysis rather than a single developer's personal preference.