Rails

Rails CLI In-Depth Reference

Complete reference for the Rails CLI surface — commands, generators, database tasks, rake tasks, flags, positional arguments, and shell completion targets. Built for creating a carapace completer.

Data Flow

bin/rails COMMAND [args] [options]
  ├── rails new          → AppGenerator (Thor)
  ├── rails generate     → GenerateCommand → Generator subclasses
  ├── rails server       → ServerCommand (Rack/Puma)
  ├── rails console      → ConsoleCommand (IRB)
  ├── rails dbconsole    → DbconsoleCommand (psql/mysql/sqlite3)
  ├── rails runner       → RunnerCommand (eval code)
  ├── rails test         → TestCommand → Minitest
  ├── rails routes       → RoutesCommand (router inspection)
  ├── rails db:          → Rake tasks (Active Record)
  ├── rails credentials  → CredentialsCommand (encrypted YAML)
  ├── rails encrypted    → EncryptedCommand (generic encrypted files)
  ├── rails notes        → NotesCommand (annotation grep)
  ├── rails query        → QueryCommand (Active Record REPL)
  └── rails <task>       → Rake fallback (Thor delegate)

Sub-Resources

Load the reference that matches your task. When in doubt, load multiple references.

Quick Guide

• How do I complete rails new flags? → references/rails-new.md
• How do I complete rails generate <thing>? → references/generators.md
• What flags does rails server accept? → references/cli-commands.md
• What are all the db:* subcommands? → references/database.md
• How do I complete test paths and subcommands? → references/testing.md
• What --environment values are valid? → The string environment — value can be any string, typically development, test, production, or staging. Not enum-limited.
• How does --database work in rails new? → references/rails-new.md
• What field types does generate model accept? → references/generators.md
• How does multi-db completion work for db:* tasks? → references/database.md
• What are the rails credentials:* subcommands? → references/cli-commands.md
• How does db:system:change --to= work? → references/database.md
• What are the aliases for rails commands? → references/cli-commands.md
• How do I complete rails encrypted:edit/show? → references/cli-commands.md
• What does config.load_defaults do? → references/configuration.md
• How does the Rails boot sequence work? → references/configuration.md
• What are the config/environments/*.rb settings? → references/configuration.md
• How does config/database.yml work with multi-db? → references/configuration.md
• What environment variables does Rails recognize? → references/environment.md
• How does DATABASE_URL interact with config/database.yml? → references/environment.md
• What is RAILS_MASTER_KEY used for? → references/environment.md
• How do RAILS_ENV and RACK_ENV relate? → references/environment.md

Cross-Project References

• For Ruby language fundamentals (classes, blocks, gems, Bundler), consult Ruby's official documentation — Rails is a Ruby framework and its configuration DSLs are Ruby-based.
• For Bundler (bundle, Gemfile, BUNDLE_GEMFILE), consult Bundler's official documentation — this skill covers only how Rails uses Bundler in config/boot.rb.
• For Puma server internals (puma.rb, threads, workers, RAILS_MAX_THREADS), consult Puma's official documentation — this skill documents only the Rails-side conventions in config/puma.rb.
• For carapace completion integration (the rails completer in carapace-bin, specs, actions, macros), see the carapace skill.
• For Thor (the CLI framework Rails uses for generators and commands), consult Thor's official documentation.