What problem does it solve? Codebases accumulate shallow modules whose interfaces are nearly as complex as their implementations, making code hard to test, navigate, and change. This Skill provides a shared vocabulary and decision framework for designing deep modules, choosing where seams go, and safely deepening clusters of coupled code. ## Core Features & Use Cases - Deep-module vocabulary: Precise definitions of module, interface, seam, adapter, depth, leverage, and locality so teams and AI agents use consistent design language. - Dependency-aware deepening: Classifies dependencies as in-process, local-substitutable, remote-but-owned, or true external, and prescribes ports-and-adapters or mock strategies per category. - Parallel interface exploration: Dispatches isolated designer agents to produce radically different interface designs, then compares them on depth, locality, testability, and seam placement. - Use Case: When refactoring a tangle of small service classes, use this Skill to identify a deepening candidate, define a port at the seam with HTTP and in-memory adapters, and rewrite tests against the new interface. ## Quick Start Ask the agent to review a module in your codebase and propose a deeper interface using the codebase-design vocabulary.
