Rails Upgrades with AI: A Real-World Success Story
How a client's EMR application was moved from EOL Rails 7.1 to Rails 8 in days using the Rails Upgrade Skill for Anthropic's Claude.
A few weeks ago, I introduced the Rails Upgrade Skill for Anthropic’s Claude. You can check out the repository here: https://github.com/maquina-app/rails-upgrade-skill.
Yesterday, a client’s Ruby on Rails application—focused on EMR (Electronic Medical Records)—was successfully deployed to Rails 8 with only a minor, quickly resolved issue! Just a week prior, this same application was running on the End-of-Life (EOL) version, Rails 7.1.
Using the Rails Upgrade Skill, I was able to manage this rapid transition. The process involved first upgrading the application to Rails 7.2 and deploying it to production, and then, days later, performing the jump to Rails 8.
To be honest, the changes to the existing codebase were minor:
- A few broken specs.
- One gem that hadn’t been updated for recent Rails versions.
- Two small issues that were not caught by the test suite but were easily fixed before they became real-world problems.
Currently, I even have a Work-In-Progress (WIP) Pull Request for the Rails 8.1 version of this application. It’s blocked only because the Mongoid gem doesn’t yet support the latest released gems in Rails 8.1, but the core upgrade code is ready in the repository. Once again, the skill performed most of the work; we’re just waiting for the gem to be released to continue the upgrade.
The Real Power of the Skill 💡
The skill doesn’t just provide a high-level analysis; it gives clear, actionable guidance on the changes between versions. This includes:
- Step-by-step actions with a tailored script to check for breaking changes.
- Precise instructions for creating a branch and running necessary commands.
- Exactly what files to modify and the rationale behind each change.
Crucially, it makes merging configuration-specific changes much easier—a task that is often painful when using the rails app:update command.