github-actions
Create, evaluate, and optimize GitHub Actions workflows and custom actions. Use when building CI/CD pipelines, creating workflow files, developing custom actions, troubleshooting workflow failures, performing security analysis, optimizing performance, or reviewing GitHub Actions best practices. Covers Ruby/Rails, TypeScript/Node.js, Heroku and Fly.io deployments.
kamal
Deploy containerized web applications to any Linux server using Kamal 2. Use when users need to deploy, configure, debug, or manage Kamal deployments including initial setup, configuration of deploy.yml, deployment workflows, rollbacks, managing accessories (databases, Redis, Litestream), troubleshooting deployment issues, CI/CD integration, multi-environment setups, or understanding Kamal commands and best practices. Also use when working with Kamal Proxy, Docker-based deployments, zero-downtime deploys, or 37signals deployment tooling.
tailscale
Comprehensive Tailscale VPN setup, configuration, and management for mesh networking, secure access, and zero-trust infrastructure. Covers installation, CLI commands, subnet routers, exit nodes, Tailscale SSH, ACL/grants configuration, MagicDNS, Tailscale Serve/Funnel, API automation, and production deployment best practices. Use when setting up Tailscale, configuring tailnet access controls, deploying subnet routers or exit nodes, enabling Tailscale SSH, exposing services with Serve/Funnel, automating via the Tailscale API, troubleshooting connectivity, or planning production Tailscale deployments.
rubocop
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ruby
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mermaid-diagrams
Comprehensive guide for creating software diagrams using Mermaid syntax. Use when users need to create, visualize, or document software through diagrams including class diagrams (domain modeling, object-oriented design), sequence diagrams (application flows, API interactions, code execution), flowcharts (processes, algorithms, user journeys), entity relationship diagrams (database schemas), C4 architecture diagrams (system context, containers, components), state diagrams, git graphs, pie charts, gantt charts, or any other diagram type. Triggers include requests to "diagram", "visualize", "model", "map out", "show the flow", or when explaining system architecture, database design, code structure, or user/application flows.
eslint
Comprehensive ESLint agent for JavaScript/TypeScript code quality. Use when setting up ESLint, configuring linting rules, analyzing code for issues, fixing violations, or integrating ESLint into development workflows. Triggers on requests involving code quality, linting, static analysis, or ESLint configuration for JavaScript, TypeScript, React, or Node.js projects.
javascript-unit-testing
Writing high-quality unit tests for JavaScript and TypeScript using Jest. Covers test structure (AAA pattern, USE naming), breaking dependencies (stubs, mocks, dependency injection), testing async code (promises, callbacks, timers), avoiding flaky tests, and test-driven development. Use when writing tests, debugging test failures, refactoring tests for maintainability, or questions about Jest, TDD, mocks, stubs, or test best practices.
vitest
Comprehensive Vitest testing framework guide with strong emphasis on Jest-to-Vitest migration. Covers automated migration using codemods, configuration setup, API differences, best practices, and troubleshooting. Use when migrating from Jest, setting up Vitest, writing tests, configuring test environments, or resolving migration issues. Primary focus is seamless Jest migration with minimal code changes.
brakeman
Static analysis security vulnerability scanner for Ruby on Rails applications. Use when analyzing Rails code for security issues, running security audits, reviewing code for vulnerabilities, setting up security scanning in CI/CD, managing security warnings, or investigating specific vulnerability types (SQL injection, XSS, command injection, etc.). Also use when configuring Brakeman, reducing false positives, or integrating with automated workflows.
cucumber-gherkin
BDD testing with Cucumber and Gherkin for Ruby and Rails applications. Use when writing feature files (.feature), step definitions, hooks, or implementing Behaviour-Driven Development in Ruby/Rails projects. Covers Gherkin keywords (Feature, Scenario, Given/When/Then, Background, Scenario Outline, Rule), Ruby step definition patterns, Cucumber Expressions, hooks (Before/After/BeforeAll/AfterAll), tags, data tables, doc strings, World modules, and Capybara integration. Triggers on cucumber, gherkin, BDD, feature files, step definitions, acceptance testing, executable specifications.
design-patterns-ruby
Comprehensive Ruby implementations of Gang of Four (GoF) design patterns. Use when implementing object-oriented design solutions, refactoring to reduce coupling, solving architecture problems, or when user mentions specific patterns (Factory, Singleton, Observer, Strategy, etc.) in Ruby context.
postgresql-rails-analyzer
Comprehensive PostgreSQL configuration and usage analysis for Rails applications. Use when Claude Code needs to analyze a Rails codebase for database performance issues, optimization opportunities, or best practice violations. Detects N+1 queries, missing indexes, suboptimal database configurations, anti-patterns, and provides actionable recommendations. Ideal for performance audits, optimization tasks, or when users ask to "analyze the database", "check for N+1 queries", "optimize PostgreSQL", "review database performance", or "suggest database improvements".
rails-generators
Create expert-level Ruby on Rails generators for models, services, controllers, and full-stack features. Use when building custom generators, scaffolds, or code generation tools for Rails applications, or when the user mentions Rails generators, Thor DSL, or automated code generation.
rails
Comprehensive Ruby on Rails v8.1 development guide with detailed documentation for Active Record, controllers, views, routing, testing, jobs, mailers, and more. Use when working on Rails applications, building Rails features, debugging Rails code, writing migrations, setting up associations, configuring Rails apps, or answering questions about Rails best practices and patterns.
review-ruby-code
Comprehensive Ruby and Rails code review using Sandi Metz rules and SOLID principles. Analyzes changed files in current branch vs base branch, runs rubycritic and simplecov, identifies OOP violations, Rails anti-patterns, security issues, code smells, and test coverage gaps. Outputs REVIEW.md with VSCode-compatible file links. Use when reviewing Ruby/Rails code, conducting code reviews, checking for design issues, pull request review, code quality analysis, or when user mentions Sandi Metz, POODR, 99 Bottles, SOLID, Law of Demeter, or "Tell Don't Ask".
rspec
Comprehensive RSpec testing for Ruby and Rails applications. Covers model specs, request specs, system specs, factories, mocks, and TDD workflow. Automatically triggers on RSpec-related keywords and testing scenarios.
rubycritic
Integrate RubyCritic to analyze Ruby code quality and maintain high standards throughout development. Use when working on Ruby projects to check code smells, complexity, and duplication. Triggers include creating/editing Ruby files, refactoring code, reviewing code quality, or when user requests code analysis or quality checks.
simplecov
Comprehensive test coverage analysis and improvement for Ruby and Rails applications using SimpleCov and SimpleCov Console formatter. Automatically runs coverage reports, identifies gaps, suggests tests, and enforces coverage standards. Integrates with RubyCritic for holistic code quality. Use when running tests, analyzing coverage, improving test suites, or setting up coverage tracking in Ruby/Rails projects.