Claude Code Dual Boot Skill

Claude Code Dual Boot Skill

A Claude Code skill that helps you set up and manage dual-boot environments for Ruby and Rails applications using the [`next_rails`](https://github.com/fastruby/next_rails) gem.

What Does This Skill Do?

The Dual-Boot skill helps you:

• Set up dual-boot with the next_rails gem so your app runs with two dependency sets depending on one environment variable (ie. BUNDLE_GEMFILE)
• Write version-dependent code using NextRails.next? (the correct pattern — never respond_to?)
• Configure CI to test against both dependency sets (GitHub Actions, CircleCI, Jenkins)
• Clean up dual-boot code after the upgrade is complete

While most commonly used for **Rails version upgrades**, dual-boot works equally well for upgrading **Ruby versions** or any **core dependency** in your Gemfile (e.g., `sidekiq`, `devise`, `pg`).

Why Dual-Boot?

Dual-booting is a core part of the [FastRuby.io](https://fastruby.io) upgrade methodology:

• Quickly switch between dependency sets for debugging
• Run test suites against both versions
• Deploy backwards-compatible changes to production before the version bump
• Catch compatibility issues early in CI
• Allows you to gradually deploy versions of key dependencies (e.g. 10% of the traffic will now use the target version of Rails)

How to Use This Skill

Installation

**From inside the Claude Code CLI prompt (recommended):**

/plugin marketplace add ombulabs/claude-skills
/plugin install dual-boot@ombulabs-ai

**From your terminal:**

claude plugin marketplace add https://github.com/ombulabs/claude-skills.git
claude plugin install dual-boot@ombulabs-ai

**Manual install:**

git clone https://github.com/ombulabs/claude-code_dual-boot-skill.git
cp -r claude-code_dual-boot-skill/dual-boot ~/.claude/skills/

[!NOTE] This skill works standalone, but it is part of the full Rails upgrade toolkit. You may also want to install [rails-load-defaults](https://gi