Form Objects, Query Objects, Presenters

Three patterns for code that doesn't fit on the model and doesn't justify a service object. AI agents either over-extract (every form is a form object) or under-extract (1000-line model has its own form binding inline). This skill maps each pattern to the right trigger.

The opinion

Form objects when a single form spans multiple models or has non-AR validations. Query objects when a query is 10+ lines or reused across actions. Presenters / decorators when view helpers grow procedural and need state. None of these for simple cases — keep the logic on the model or in the controller.

Decision matrix