code-quality
Improve the quality and type-safety of TypeScript/JavaScript being written or refactored — parse-don't-validate, make-illegal-states-irrepresentable, exhaustive matching, pure-function/IO separation, and public-API hygiene. Use when asked to refactor, clean up, improve, harden, or review the design/quality of code or an API. NOT for hunting bugs (that's /code-review) and NOT for vigiles's own spec/lint rules.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/zernie/vigiles --skill code-quality- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads code-quality automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Apply a small set of type-driven quality techniques when writing or refactoring code. Each technique has its own reference — the principle, a real before/after from this repo, and the smells to grep for. Read the reference(s) that match the code in front of you; don't apply all five blindly.
When this fires
A request to refactor / clean up / improve / harden / tighten code or an API — or when you're about to write a new module/type/public export and want it right the first time. Not a bug hunt (use /code-review).
The techniques — read the matching reference
| Smell in front of you | Technique | Reference |
|---|---|---|
a magic 0 / "" / -1; the same primitive re-validated at many sites; "x" in obj repeated | Parse, don't validate | references/parse-dont-validate.md |
a field that's always ""; boolean-flag soup; a sentinel standing in for "absent"; an impossible combo that still compiles | Make illegal states irrepresentable | references/make-illegal-states-irrepresentable.md |
a switch/if-chain on a union with no exhaustiveness guard | Exhaustive matching | references/exhaustive-matching.md |
logic tangled with IO (spawn/fetch/fs); a function that's hard to test | Pure functions + injected seams | references/pure-functions.md |
a public export with a fuzzy shape; a string that means an enum; a leaked internal helper | Public-API quality | references/public-api-quality.md |
How to apply
- Name the decision out loud before you change the shape — what illegal state it forbids, where the parse boundary sits (the
surface-architecture-decisionsreflex). A quality change the reviewer can't see is churn. - One technique at a time, tests stay green. Change the type, let
tscshow you every call site, fix them, run the tests. Never batch five refactors into one unreviewable diff. - Don't over-abstract (rule-of-three / YAGNI). A tagged union for 3 real variants is good; an abstraction for a difference that doesn't exist yet is the bug this skill is supposed to prevent.
- Prefer the strongest option the DECIDABILITY allows — a type that can't express the bad state beats a runtime check that hopes to catch it; but a runtime guard at a boundary beats nothing when the input is genuinely dynamic.
Guardrails
- Quality only, not correctness. This skill improves shape/design; it does not hunt for bugs — that's
/code-review. - Every change removes a real failure mode. If you can't name the bug the new shape prevents, don't make the change.
- Keep the public surface small. A new
exportis a contract (see the public-API reference); don't widen it to make a refactor convenient.
FAQ
What does the code-quality skill do?
Improve the quality and type-safety of TypeScript/JavaScript being written or refactored — parse-don't-validate, make-illegal-states-irrepresentable, exhaustive matching, pure-function/IO separation, and public-API hygiene. Use when asked to refactor, clean up, improve, harden, or review the design/quality of code or an API. NOT for hunting bugs (that's /code-review) and NOT for vigiles's own spec/lint rules.
How do I install code-quality?
Run npx skills add https://github.com/zernie/vigiles --skill code-quality in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/code-quality/ (personal) or .claude/skills/code-quality/ (project).
Which AI agents can use code-quality?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is code-quality safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains code-quality?
It is published by zernie in zernie/vigiles. It has 391 recorded installs.
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