mr-propper

name: mr-propper description: Improve code readability, maintainability, SRP, naming, typing, and testability. Use when asked to make code cleaner/clearer, improve maintainability/readability/testability, refactor, split modules, improve DX, or when creating new functionality with an eye toward future growth and user’s code style.

Mr Propper — Code Cleanliness & Maintainability

Apply this skill when creating or refactoring code to improve readability, structure, naming, typing, and testability. Respect the existing project style and conventions.

Core Goals

• Clear intent in names and structure
• Single responsibility per module
• Strong, explicit typing
• Testable, modular design
• Future‑ready without over‑engineering

Workflow

1. Scan current structure and style (naming, folder layout, file size, typing, tests).
2. Identify the smallest set of changes that improves clarity and SRP.
3. Propose a minimal, structured refactor plan.
4. Implement with consistent style and explicit types.
5. Add/update tests for new or changed behavior.

Heuristics

Naming

• Use domain terms, avoid abbreviations.
• Functions are verbs, types are nouns.
• Prefer explicit names over clever ones.

Structure

• One responsibility per file/module.
• Keep files under 300 lines; split by domain or sub‑area.
• Co‑locate types with the logic they describe.
• If a registry/definition file grows large, split registrations into per‑domain files and keep a thin index that aggregates them.

Typing

• Prefer explicit input/output types.
• Avoid any, prefer union/enum for states.
• If a type is shared, export it from the closest module boundary.
• Derive literal unions from source objects (keyof typeof) instead of manually maintaining unions.

Testability

• Add tests for new behavior and edge cases.
• Avoid testing implementation details.
• Keep dependencies injectable where possible.

Future‑proofing

• Anticipate likely extensions and design for adding new variants.
• Prefer composition over branching by type/status.
• Avoid global/shared mutable state.

Coordination With Other Skills

• If a domain‑specific architecture skill is active, follow its rules first.
• This skill focuses on cleanliness, naming, structure, and testability.