What problem does it solve? Codebases accumulate shallow modules whose interfaces are nearly as complex as their implementations, causing scattered logic, disproportionate test wiring, and per-entity module proliferation. This Skill finds those modules and guides their consolidation into deep modules with small interfaces and high leverage. ## Core Features & Use Cases - Repo-wide shallow module detection: Spawns an Explore subagent with a structured brief to surface 5-10 strong refactoring candidates, each validated with the deletion test, knob test, and layer check. - Structured candidate review: Presents numbered candidates with per-file line counts, layer classification, preserve cross-checks against already-deep modules, and leverage/locality/test-surface analysis. - Parallel interface design: Optionally runs multiple subagents with different constraints (minimal interface, maximal flexibility, common-caller default) to compare seam designs before committing. - Use Case: When unit tests require excessive mocking and wiring relative to what they verify, run this Skill to find the misplaced seams, consolidate pass-through modules, and move tests to the deepened module's interface. ## Quick Start Ask the assistant to run the improve-codebase skill to find shallow modules in this repository that should be deepened.
