Architecture and boundaries

Domain

The domain declares Repository interfaces in business language. They may expose entities, immutable aggregate data, streams, and operations. They do not expose transport DTOs, database rows, storage clients, or DataSourceContainer.

Data

The Data layer owns typed DataSource contracts, technical implementations, mapping, cache policy, and the concrete Repository. It converts technical records into domain data before committing them.

Application

UseCases and application services depend on the domain Repository interface. An application-owned binding may turn a committed data change into a regular UseCase Forge Command; that mapping is application behavior.

Composition

The Composition Root constructs clients, DataSources, small repository-specific containers, repositories, UseCases, and bindings. It closes the object graph in reverse dependency order.