Agent Skills: action-controller-best-practices

Build or Refactor large Rails controller files into clean, maintainable code. Use when a controller action exceeds ~10 lines, a controller has custom non-RESTful actions, or when the user asks to refactor, slim down, clean up, or organize a Rails controller. Applies patterns: service objects, query objects, form objects, controller concerns, presenters/decorators, and RESTful resource extraction.