What problem does it solve? Writing the application (usecase) layer in Go DDD projects often leads to inconsistent transaction boundaries, business logic leaking out of the domain, and unclear handling of multi-aggregate coordination. This Skill enforces a single convention for implementing usecases so every command and query follows the same structure. ## Core Features & Use Cases - Command implementation: Writes one type per business event with a single Execute method following the fixed pipeline: resolve inputs, open a transaction via tx.Manager.Run, restore or generate the aggregate, narrow state, operate, and save. - Query implementation: Defines read ports and DTO read models owned by the usecase side, with no aggregate restoration, no writes, and no transactions. - Cross-aggregate coordination: Decides between same-transaction operations and event-driven separate usecases based on the consistency rules in domain-model documents. - Use Case: Given a domain-model document describing a room reservation aggregate, generate the HoldReservation and ConfirmReservation usecases with correct ID generation, time handling via Input At, sentinel error wrapping, and overlap invariant checks. ## Quick Start Implement the reservation confirm usecase in Go following the implement-usecase conventions from this domain-model document.
