Apply Vanilla Rails (37signals/Basecamp) as the default architecture when writing or changing Rails code: thin controllers, rich models, no service/query/interactor layer unless genuinely justified. Load this skill when creating or editing controllers, models, jobs, concerns, mailers, routes, or form objects; when adding a custom action versus a nested resource; when extracting a service, form, query, or interactor; or when deciding where business logic lives. Also use for Rails reviews and simplification. Do not wait for the user to say "vanilla rails" or "service object". Skip migrations, gem/dependency bumps, CSS/JS/view-only work, credentials, and non-Rails tasks.

Apply Vanilla Rails (37signals/Basecamp) as the default architecture when writing or changing Rails code: thin controllers, rich models, no service/query/interactor layer unless genuinely justified. Load this skill when creating or editing controllers, models, jobs, concerns, mailers, routes, or form objects; when adding a custom action versus a nested resource; when extracting a service, form, query, or interactor; or when deciding where business logic lives. Also use for Rails reviews and simplification. Do not wait for the user to say "vanilla rails" or "service object". Skip migrations, gem/dependency bumps, CSS/JS/view-only work, credentials, and non-Rails tasks.