vanilla-rails

| description | Shape a feature: scope it, apply vanilla-rails patterns, produce handoff for implementation planning |

Use when writing Rails controllers or implementing state changes - enforces resource extraction, thin controllers delegating to models, params.expect, and controller concerns for scoping

Use when designing database schema, writing migrations, or making data storage decisions - enforces UUIDs, account_id multi-tenancy, no foreign keys, and proper index patterns

Use when designing content systems where 5+ distinct types need to comingle in feeds, timelines, or searches with shared metadata and operations - NOT for simple polymorphic associations or 1-3 similar types

Use when writing Hotwire (Turbo/Stimulus) code in Rails - enforces dom_id helpers, morph updates, focused Stimulus controllers, and JavaScript private methods

Use when writing background jobs or async operations - enforces thin job wrappers (3-5 lines) that delegate to models using _later/_now naming pattern

Use when writing Rails models - enforces state-as-records not booleans, concerns as adjectives namespaced under model, and concern extraction triggers

Use when naming classes, methods, routes in vanilla Rails codebases - enforces concern adjectives (-able/-ible only), no bangs for state, resource naming cascade, and commit message format

Use when defining Rails routes, organizing controller directories, or adding resources - enforces resource extraction, shallow nesting, resolve helpers, and module scoping

Use after brainstorming to apply vanilla-rails patterns to a feature, producing structured handoff for implementation planning. Invoke with /shape.

Use when writing Ruby/Rails code - enforces expanded conditionals over guard clauses, private indentation, invocation-order methods, and bang method restrictions that contradict standard Ruby guides

Use when writing Rails tests - enforces fixtures-only, integration-style controller tests, Current.session setup, simple naming, and Minitest syntax (NO FactoryBot, NO RSpec)

Use when writing ERB templates, partials, or view helpers - covers partial organization, optional locals, CSS class patterns, and collection rendering with caching

Use when planning Rails features or breaking down work into PRs - enforces 2-5 file PRs, bug fix separation, and one-sentence scope test

Use when refactoring fat Rails models with repetitive prefixes like entropy_*, notification_*, or multi-association coordination. Extracts PORO wrappers that group operations around nouns/concepts.