codebase-design — Skills — getagentictools

What it does

Can I reduce the number of methods?

Can I simplify the parameters?

Can I hide more complexity inside?

The interface is the test surface. Callers and tests cross the same seam. If you want to test past the interface, the module is probably the wrong shape.

One adapter means a hypothetical seam. Two adapters means a real one. Don't introduce a seam unless something actually varies across it.

A Module has exactly one Interface (the surface it presents to callers and tests).

Depth is a property of a Module, measured against its Interface.

Source

Repository: https://github.com/mattpocock/skills

codebase-design FAQ

What does the codebase-design skill do?

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. Can I reduce the number of methods? Can I simplify the parameters?

How do I install codebase-design?

Run: npx -y skills add https://github.com/mattpocock/skills --skill codebase-design --agent claude-code — the source lives at github.com/mattpocock/skills.

Maintain codebase-design?

Let people know it's listed here — add the badge (live metrics, light/dark aware) or a plain link to your README or docs.

[![codebase-design on getagentictools](https://getagentictools.com/badge/skills/mattpocock-skills-codebase-design.svg)](https://getagentictools.com/skills/mattpocock-skills-codebase-design?ref=badge)

npx agentictools info skills/mattpocock-skills-codebase-design

The second line is the CLI lookup for this page — handy in READMEs and docs.