usecase

Define exported InputSchema and OutputSchema with z.object, extend the Handler base class, and wrap all database operations in this.withTransaction inside the handle method. Pass the transaction to every repository call and persist domain events via domainEventRepository.save in the same transaction.

Define a struct implementing types.Handler with Name and Execute methods, inject dependencies through a constructor, and wrap all database mutations in uow.Execute. Register the handler with fx.Provide in module.go and persist domain events inside the transaction closure.

In TypeScript, format validation belongs only in controllers; use case schemas carry shape without refinements. In Go, validate tags are required on both the controller request struct and the use case Input struct because Go use cases are also invoked from non-HTTP paths like webhook handlers and workers.

Direct publishing breaks atomicity: if the transaction rolls back, a published event cannot be undone. Instead, save events to the domain event repository inside the same transaction, and let the outbox dispatcher deliver them asynchronously after commit.

Do not use it for read queries serving the UI, which belong in query use cases with direct ORM access, or for reacting to events, which belongs in event handlers. Single-entity business rules belong in entity methods rather than use case orchestration.