codebase-design
Shared vocabulary for designing deep modules. Use when the user wants to design or improve a module's interface, find deepening opportunities, decide where a seam goes, make code more testable or AI-navigable, or when another skill needs the deep-module vocabulary.
- Kind
- Skill
- Works with
- Claude Code
- Source
- mattpocock/skills @ 24fe0ef7737e
- Path
- skills/engineering/codebase-design/SKILL.md
- License
- MIT
- Jobs
- Planning, Implementation
InstallCopy it from the source repository, or sign in and let the assistant adapt it for your project.
# Codebase Design Design **deep modules**: a lot of behaviour behind a small interface, placed at a clean seam, testable through that interface. Use this language and these principles wherever code is being designed or restructured. The aim is leverage for callers, locality for maintainers, and testability for everyone. ## Glossary Use these terms exactly: don't substitute "component," "service," "API," or "boundary." Consistent language is the whole point. **Module**: anything with an interface and an implementation. Deliberately scale-agnostic: a function, class, package, or tier-spanning slice. _Avoid_: unit, component, service. **Interface**: everything a caller must know to use the module correctly: the type signature, but also invariants, ordering constraints, error modes, required configuration, and performance characteristics. _Avoid_: API, signature (too narrow, they refer only to the type-level surface). …