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 that hide complexity behind small interfaces. ## Core Features & Use Cases - Deep module vocabulary: Precise definitions of module, interface, seam, adapter, depth, leverage, and locality so teams and agents name architectural concepts consistently. - Dependency-aware deepening: Classifies dependencies as in-process, local-substitutable, remote-but-owned, or true external, and prescribes ports-and-adapters strategies for each. - Parallel interface exploration: Spawns multiple sub-agents to design radically different interfaces for a candidate module, then compares them on depth, locality, and seam placement. - Use Case: When refactoring a cluster of shallow service classes, use this Skill to identify the right seam, merge the cluster into one deep module, and write tests at the new interface instead of the old internals. ## Quick Start Ask the agent to review a module or package in your codebase and propose a deeper interface using the codebase-design vocabulary.
