ADR 0001: Enforce layered dependency direction

• Status: Accepted
• Date: 2026-07-21

Context

The provider spans byte transport, PostgreSQL protocol semantics, ADO.NET, replication, EF Core, and optional extensions. Mixing these concerns would make wire behaviour hard to test and force low-level packages to inherit volatile dependencies.

Decision

Use the dependency direction in docs/architecture/overview.md. Protocol code cannot expose ADO.NET concepts; Data cannot expose EF Core concepts. Optional extensions integrate through BlueTusk.Extensions.Abstractions.

Consequences

Some operations require orchestration types in BlueTusk.Client even when most of their implementation is lower-level. Cross-layer convenience APIs belong in the highest applicable layer.