# Tidying

> Guide structural code improvements using Kent Beck's Tidy First methodology. Use when seeing messy code, before making behavioral changes, after completing features, or discussing when to clean up code. Use when this capability is needed.

- Skill: `tomevault-io/tidying` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/tidying`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/tidying/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/tidying

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# INSTRUCTIONS

Apply Kent Beck's "Tidy First?" philosophy: small, safe structural changes that improve code without changing behavior. Tidying is separate from feature work and gets its own commits.

- **Behavior Contract**: See `behavior-contract.md` for complete definition of "behavior" (inputs, validation, outputs, side effects, errors) and structural vs behavioral change examples
- **Context Boundaries**: See `context-boundaries.md` for what's safe to tidy in frontend/backend/CLI/library contexts (behavior boundary differs by context!)

## Core Principle

> "Tidying is a special kind of refactoring... tidying is small, and you never need to tidy."

Tidyings are:
- **Small**: Minutes, not hours
- **Safe**: Structure only, no behavior change
- **Optional**: You choose when (or if) to tidy
- **Separate**: Own commits, distinct from behavioral changes

## The Three Timings

| Timing | Trigger | Flow |
|--------|---------|------|
| **Tidy First** | Code is hard to change | `/tidy:first` → `refactor:` commit → behavioral change → `feat:/fix:` commit |
| **Tidy After** | Feature revealed better structure | behavioral change → `feat:/fix:` commit → `/tidy:after` → `refactor:` commit |
| **Tidy Later** | Tidying too big or off-focus | Note opportunity → backlog/TODO → continue current work |

## Decision Framework

```
1. Does this code need to change for my current task?
   No  → Tidy Later (or never)
   Yes ↓
2. Would tidying make my change easier/safer?
   No  → Make behavioral change, consider Tidy After
   Yes ↓
3. Is the tidying small (< 15 minutes)?
   No  → Tidy Later, make behavioral change anyway
   Yes → Tidy First, then make behavioral change
```

## When NOT to DRY

> "Duplication is far cheaper than the wrong abstraction." — Sandi Metz

Keep code inline when:
- Pattern is simple and self-explanatory (`vec![]`, `None`, error returns)
- Abstraction adds indirection without clarity
- Repetitions might evolve differently
- grep/search is easier with inline code

## Reference

Based on: *Tidy First?* by Kent Beck (2023)

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<!-- tomevault:4.0:skill_md:2026-04-11 -->