rails-kit

A fast, compiled CLI for inspecting Rails projects. Most commands read project files directly without loading Rails, making them useful for developers, scripts, editors, and AI agents.

Installation

brew install --cask janstol/tap/rails-kit

Homebrew is macOS/Linux only. On Windows, download the windows_amd64.zip asset from the releases page (works well with Rails-on-WSL2 setups too).

Or install with Go:

go install github.com/janstol/rails-kit@latest

Quick start

Run rails-kit anywhere inside a Rails project. It finds the Rails root automatically; use --root to override it.

rails-kit about
rails-kit schema users
rails-kit routes users
rails-kit related user
rails-kit model user
rails-kit skeleton app/services

Most inspection commands accept --json for structured output:

rails-kit model user --json
rails-kit --root /path/to/app schema users --json

schema and model accept --color=auto|always|never (default auto) for terminal accents. auto disables color when stdout isn't a terminal; NO_COLOR (any non-empty value) disables color even under --color=always; --json output is never colored.

Commands

Command	Description
rails-kit about	Summarize application, dependency, runtime, and database metadata
rails-kit schema [table...]	Inspect db/schema.rb or db/structure.sql
rails-kit routes [pattern...]	Cached Rails routes, offline --static parsing, or --watch re-render
rails-kit related <name>	Find files related to a model
rails-kit fixtures [name]	Inspect test fixtures
rails-kit locales [scope]	Browse locale keys and values
rails-kit model <name>	Summarize an Active Record model
rails-kit skeleton <input...>	Generate compact Ruby AST skeletons through Prism
rails-kit gem [name]	Inspect Gemfile.lock
rails-kit concerns [name]	Inspect model and controller concerns
rails-kit controllers [name]	Summarize a Rails controller's filters, rescue_from, and actions
rails-kit mailers [name]	Summarize a Rails mailer's defaults, layout, and attachments
rails-kit jobs [name]	Summarize a Rails ActiveJob's queue, retry/discard, and methods
rails-kit services [name]	Summarize a Rails service's constants, concerns, and methods
rails-kit datagrids [name]	Summarize a Rails datagrid's filters, columns, scope, and decorator
rails-kit skill install|uninstall	Manage the bundled Claude Code or Codex skill
rails-kit completion bash|zsh|fish	Generate shell completions
rails-kit version	Print version information

See the command reference for examples, JSON shapes, requirements, and limitations.

rails-kit completion bash|zsh|fish emits a shell completion script. Once sourced, commands also dynamically complete positional arguments — model names, table names, gem, concern, controller, mailer, job, service, and datagrid names, and locale keys (drilling down one dotted segment at a time for locales).

Documentation

• Command reference
• --json output contract
• Static routes parser
• Configuration
• Agent skill installation
• Development and releases
• Changelog

Runtime behavior

Most commands are pure Go and do not boot Rails. The main exceptions are:

• routes runs bundle exec rails routes; use routes --static for a fast offline approximation, or routes --watch to re-render on file change.
• about --runtime boots Rails to obtain active runtime values; plain about is static.

skeleton parses Ruby through an embedded in-process Prism parser (pure-Go WASM) — no Ruby install required, and it does not load the Rails application.

Static parsing is intentionally conservative. Consult the relevant reference page before using its output as a source of truth in CI or production audits.