deep-codebase-auditlisted

# Deep Codebase Audit Surface architectural friction and propose **deepening opportunities** — refactors that turn shallow modules into deep ones. The aim is testability, AI-navigability, and leverage. References for this skill are in the `references/` folder: - [GLOSSARY.md](references/GLOSSARY.md) — vocabulary to use in every suggestion - [DEPTH-GUIDE.md](references/DEPTH-GUIDE.md) — how to classify dependencies and test across seams - [INTERFACES.md](references/INTERFACES.md) — how to explore alternative interfaces ## When to Use Use this skill when: - The user says the codebase feels messy, hard to change, or "not ready for AI". - You want to improve testability and make future TDD or autonomous agent work more effective. - You're about to invest heavily in AI-driven changes and want to reduce risk first. Do **not** use this skill when the user just wants to ship a small feature — use `/incremental-tdd` instead. ## Glossary Use these terms exactly in every suggestion. Consistent language is the point — don't drift into "component," "service," "API," or "boundary." Full definitions in [GLOSSARY.md](references/GLOSSARY.md). - **Module** — anything with an interface and an implementation (function, class, package, slice). - **Interface** — everything a caller must know to use the module: types, invariants, error modes, ordering, config. Not just the type signature. - **Implementation** — the code inside. - **Depth** — leverage at the interface: a lot of behaviour b