How about following the test-driven approach properly? Asking Claude Code to write tests first and implement the solution after?
Research -> Test Plan -> Write Tests -> Implementation Plan -> Write Implementation
I guess it is still useless in Ruby or Ruby on Rails.
Standard "find the method declaration" or "used here" do not work in Ruby on Rails. Still, huge companies maintain that Ruby on Rails mess, where you cannot properly investigate, so you just guess and use the search and find option.
Those codebases won't be replaced for a while, but good luck working on them. Such a headache!