ombulabs/claude-code_rails-upgrade-skill

What it solves

This project provides a specialized skill for Claude Code that automates the analysis and planning of Ruby on Rails upgrades (from version 2.3 to 8.1). It eliminates the guesswork and risk associated with upgrading legacy Rails applications by enforcing a sequential, version-by-version upgrade strategy and providing codebase-specific migration guides.

How it works

The skill analyzes the user's actual codebase to generate comprehensive upgrade reports and previews of configuration changes (via app:update). It implements the FastRuby.io upgrade methodology, which utilizes a "dual-boot" strategy—running two versions of Rails simultaneously using the next_rails gem to test and deploy backwards-compatible changes before the final version bump.

It works in tandem with three other companion skills: rails-load-defaults, dual-boot, and upgrade-cleanup (which handles the removal of dual-boot scaffolding after a version hop is completed).

Who it’s for

Ruby on Rails developers and teams maintaining legacy applications who need to upgrade their framework version while minimizing downtime and risk.

Highlights

• Sequential Upgrade Path: Enforces a strict no-skip policy (e.g., 6.0 $\rightarrow$ 6.1 $\rightarrow$ 7.0) to avoid compound bugs.
• Codebase-Specific Reports: Generates migration guides with "OLD vs NEW" code examples pulled directly from the user's project.
• Dual-Boot Integration: Supports running two Rails versions in parallel for safer transitions.
• Deprecation-First Approach: Encourages fixing all deprecation warnings in the current version before bumping the version.
• Automated Cleanup: Includes a dedicated plugin to tear down dual-boot scaffolding and retire old-version code once an upgrade hop is finished.