Codebase Design
A shared vocabulary for designing deep modules — small interfaces, real seams, testable by construction
- What
- A shared vocabulary for designing deep modules — small interfaces, real seams, testable by construction
- Cost
- Free
- Needs
- a Muse account with skill installation enabled
- Install
- Copy the installer prompt below into your Muse — your agent does the rest.
Curated by Skill Harbor — a design-vocabulary skill that gives you exact words for designing deep modules: lots of behaviour behind a small interface. It defines module, interface (everything a caller must know — not just the type signature), implementation vs adapter, depth (leverage at the interface), seam (where the interface lives), adapter, leverage (what callers get) and locality (what maintainers get) — and bans the mushy substitutes: no "component," "service," "API," or "boundary." Principles included: the deletion test (delete the module — does complexity vanish or reappear across callers?), "the interface is the test surface," and "one adapter means a hypothetical seam, two means a real one." Testability falls out naturally: accept dependencies don't create them, return results don't produce side effects, keep the surface small. By @mattpocock, listed here with credit to its creator. Honest caveats: it's a reference to consult, not a session to run — it changes how the agent talks about design rather than doing the design for you; companion deep-dives (deepening a cluster, design-it-twice with parallel sub-agents) live in the repo's companion files. Skill Harbor never reviews the code, review it yourself before use.
Version:
Install
Prerequisites: a Muse account with skill installation enabled Install "Codebase Design" for me. A shared vocabulary for designing deep modules — small interfaces, real seams, testable by construction Repository: https://github.com/mattpocock/skills/blob/main/skills/engineering/codebase-design/SKILL.md 1. Fetch the SKILL.md file (and any helper files) from the repository path into a temporary folder and summarize what it does in one or two sentences. 2. Safety check: review the SKILL.md and scripts for anything suspicious (unexpected network calls, shell commands, credential harvesting). This repo should contain zero secrets in code, credentials only via the secure vault. Verify that holds here; STOP on any red flag and tell me. 3. Install it as a skill: copy SKILL.md and its helper files into the agent's skills directory, in a folder named "mattpocock-codebase-design". 4. Verify with no network calls: frontmatter valid, files in place. 5. Report what was installed, where, and what I still need to do myself (e.g. save my API key in the vault). GitHub is optional: if I have a GitHub account or the gh CLI, you may use it; otherwise public access is fine. Never require it unless it's in the prerequisites above. Rules: don't touch anything outside the temp folder and the install target. If anything looks off, stop and ask me.
Questions
How do I install a build?
Every product page includes a copy-paste install prompt. Paste it into your Muse and it sets the build up for you — no manual configuration.
Where does my money go?
Straight to the seller. Skill Harbor never processes payments: checkout happens on the seller’s own page, usually Stripe.
What does the ✓ next to a creator’s name mean?
It means we confirmed the identity of the person behind the listing. It says nothing about the code itself — always check a build before installing it.