Pattern developed on top of rails_event_store: a form object behaving like an ActiveModel form that wraps nested dry-struct types and defines multiple atomic commands. Only commands whose fields actually changed are dispatched, enabling intention-revealing updates even from a single large form. Data-input validations live on the command form, not on business commands. Also supports 'weak' fields (e.g. references) that don't trigger command dispatch on their own. First version took the team ~2–3 days; a fully ActiveModel-compatible second version took ~1.5 days of pair programming driven by RSpec use cases.