Teaching Claude Code to Upgrade Rails at Blue Ridge Ruby '26

This is a lightning talk for Blue Ridge Ruby '26.

What if Claude could just upgrade Rails for me?

Out of the box, Claude Code happily bumps the Rails version in your Gemfile, but it skips the practices that make upgrades safe: dual booting, gradual deployments, smaller upgrade branches, and fixing the test suite to work against both the current and target Rails versions.

This talk introduces an opinionated Claude Code skill that strong-arms Claude into doing Rails upgrades the right way: dual boot locally, in CI, and in production, from Rails 2.3 to Rails 8.1 and beyond. The result: experience + LLMs = speed (and fewer tokens).

Try the skill and report issues here: https://github.com/ombulabs/claude-code_rails-upgrade-skill

Transcript

1. Teaching Claude Code to Upgrade Rails Blue Ridge Ruby May 1st, 2026
2. What if… Claude could upgrade Rails for me?
5. Why you no dual boot, Claude?
9. Too many conditionals ¯\_(π)_/¯
10. I think it’s still worth all the conditionals…
11. Gradual deployments, easier debugging, smaller upgrade branches…
12. Maybe you should write a Claude skill…
13. Say less
15. What’s a Claude skill?
16. Can you combine skills? Yes! Rails Upgrade Skill depends on Load Defaults Skill and Dual Boot Skill
17. /rails_upgrade Upgrade from Rails 2.3 to Rails 3.0
18. https://github.com/ ombulabs/ claude-code_rails-upgrade-skill
19. An opinionated Code Code skill to upgrade Rails*
20. * Upgrade Rails the FastRuby.io way
21. Experience + LLMs = Speed
22. Experience + LLMs = Speed (and fewer tokens)
26. UPGRADE RAILS
27. Why do I need a skill?
28. Process 1 bundle exec rake test 2 Track Deprecation Warnings 3 Address Deprecation Warnings 4 next bundle install 5 next bundle exec rake test 6 Fix Errors & Failures 7 Deploy to Staging 8 QA / Rework 9 Gradually Deploy to Production 10 Monitor
29. Strong Opinions, Strongly Held
30. No test suite? “NO UPGRADE FOR YOU”
31. Strong arm Claude into dual booting
32. Dual boot locally, in CI, and in production
33. Fix the test suite to work with current and target Rails versions
34. From Rails 2.3 to Rails 8.1 and beyond…
35. Give it a try and report back any issues you find on GitHub ♥ 35
36. https://github.com/ ombulabs/ claude-code_rails-upgrade-skill
37. 37 Thank you! Thank You!