codebase-design

Deep modules hide complex implementation behind a simple interface to improve codebase maintainability. This software design approach reduces tight coupling, establishes clear architectural boundaries, and provides high functional leverage for easier code navigation and testing.

To design testable modules, place architectural seams at dependency boundaries and apply dependency injection. Establishing clear guidelines for seam placement ensures code is naturally testable, while adapter implementation manages external coupling during refactoring.

Refactor shallow code into high-leverage modules by evaluating module depth and restructuring interfaces to hide implementation complexity. Transform pass-through code by defining clear ports and adapters, ensuring the new interface design maximizes functional leverage and boundary clarity.

The best way to explore interface designs before implementation is using a parallel sub-agent pattern. This architectural process allows you to systematically compare multiple interface designs, ensuring the selected module structure optimizes testability and hides implementation complexity.

Yes, this architectural design approach specifically targets tightly coupled codebases by applying a structured process to deepen shallow modules. It provides a shared architectural vocabulary for seam placement and dependency management to successfully restructure complex services.