moai-lang-ruby

name	moai-lang-ruby
description	Ruby 3.3+ development specialist covering Rails 7.2, ActiveRecord, Hotwire/Turbo, and modern Ruby patterns. Use when developing Ruby APIs, web applications, or Rails projects.
license	Apache-2.0
compatibility	Designed for Claude Code
allowed-tools	Read Grep Glob Bash(ruby:*) Bash(gem:*) Bash(bundle:*) Bash(rake:*) Bash(rspec:*) Bash(rubocop:*) Bash(rails:*) mcp__context7__resolve-library-id mcp__context7__get-library-docs
user-invocable	false
metadata	{"version":"1.1.0","category":"language","status":"active","updated":"2026-01-11","modularized":"true","tags":"language, ruby, rails, activerecord, hotwire, turbo, rspec"}
progressive_disclosure	{"enabled":true,"level1_tokens":100,"level2_tokens":5000}
triggers	{"keywords":["Ruby","Rails","ActiveRecord","Hotwire","Turbo","RSpec",".rb","Gemfile","Rakefile","config.ru"],"languages":["ruby"]}

Quick Reference (30 seconds)

Ruby 3.3+ Development Specialist - Rails 7.2, ActiveRecord, Hotwire/Turbo, RSpec, and modern Ruby patterns.

Auto-Triggers: Files with .rb extension, Gemfile, Rakefile, config.ru, Rails or Ruby discussions

Core Capabilities:

• Ruby 3.3 Features: YJIT production-ready, pattern matching, Data class, endless methods
• Web Framework: Rails 7.2 with Turbo, Stimulus, and ActiveRecord
• Frontend: Hotwire including Turbo and Stimulus for SPA-like experiences
• Testing: RSpec with factories, request specs, and system specs
• Background Jobs: Sidekiq with ActiveJob
• Package Management: Bundler with Gemfile
• Code Quality: RuboCop with Rails cops
• Database: ActiveRecord with migrations, associations, and scopes

Quick Patterns

Rails Controller Pattern:

Create UsersController inheriting from ApplicationController. Add before_action for set_user calling only on show, edit, update, and destroy actions. Define index method assigning User.all to instance variable. Define create method creating new User with user_params. Use respond_to block with format.html redirecting on success or rendering new with unprocessable_entity status, and format.turbo_stream for Turbo responses. Add private set_user method finding by params id. Add user_params method requiring user and permitting name and email.

ActiveRecord Model Pattern:

Create User model inheriting from ApplicationRecord. Define has_many for posts with dependent destroy and has_one for profile with dependent destroy. Add validates for email with presence, uniqueness, and format using URI::MailTo::EMAIL_REGEXP. Add validates for name with presence and length minimum 2 maximum 100. Define active scope filtering where active is true. Define recent scope ordering by created_at descending. Create full_name method returning first_name and last_name joined with space and stripped.

RSpec Test Pattern:

Create RSpec.describe for User model type. In describe validations block, add expectations for validate_presence_of and validate_uniqueness_of for email. In describe full_name block, use let to build user with first_name John and last_name Doe. Add it block expecting user.full_name to eq John Doe.

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Implementation Guide (5 minutes)

Ruby 3.3 New Features

YJIT Production-Ready:

YJIT is enabled by default in Ruby 3.3 providing 15 to 20 percent performance improvement for Rails applications. Enable by running ruby with yjit flag or setting RUBY_YJIT_ENABLE environment variable to 1. Check status by calling RubyVM::YJIT.enabled? method.

Pattern Matching with case/in:

Create process_response method taking response parameter. Use case with response and in for pattern matching. Match status ok with data extracting data variable and puts success message. Match status error with message extracting msg variable. Match status with guard condition checking pending or processing. Use else for unknown response.