# code-simplifier

A skill that gives AI agents 47 rules for cleaning up recently changed code without altering what it does.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1600 installs · ★ 218
- Author: pproenca
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/pproenca/dot-skills/tree/HEAD/skills/.curated/code-simplifier/SKILL.md
- Updated: 2026-08-15
- HTML: https://affpapa.org/en/nevibecode/skills/pproenca-code-simplifier

## What it does

\`code-simplifier` is a rule set an AI agent follows when simplifying code. It ships 47 rules in 8 categories, ordered by impact: context discovery and behavior preservation come first, language idioms last. Each rule carries an explanation, a wrong-vs-right example, and impact notes.

The core idea is restraint. The agent reads project conventions before touching anything, then changes how code is written, never what it does. Diffs stay small and scoped to recently modified files. Return values, error messages, public signatures and side effects are left alone. Rules include `flow-early-return` for cutting nesting, `name-intention-revealing` for names that say what they mean, and `dead-delete-not-comment` for removing dead code instead of commenting it out.

It installs into Claude, Codex, Cursor, GitHub Copilot, Gemini CLI and OpenCode. On Claude the file lands at `~/.claude/skills/code-simplifier/SKILL.md`. Worth checking before you install: if your project has no `CLAUDE.md` and no lint config, the agent has nothing to match, so the Context Discovery rules have little to work with.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill code-simplifier -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/code-simplifier/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/code-simplifier/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill code-simplifier -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/code-simplifier/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill code-simplifier -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/code-simplifier/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install pproenca/dot-skills code-simplifier
```

2. **Manually: put the files in place**
- File: `.github/skills/code-simplifier/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill code-simplifier -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/pproenca/dot-skills --path skills/.curated/code-simplifier
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/code-simplifier/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill code-simplifier -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/pproenca/dot-skills/tree/HEAD/skills/.curated/code-simplifier/SKILL.md

## When to use it
- flatten deep nesting in a function you just edited
- pull repeated conditionals into one branch
- rename variables so the name explains the intent
- delete dead code instead of commenting it out
- match edits to project style rather than generic advice

## Example prompts
- Simplify the code in `src/parser.ts` I just changed, keep behavior identical
- Run code-simplifier over my last commit and show the diff
- Reduce nesting in this function using early returns

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 982e52e3b834cad9.

BEGIN THIRD-PARTY FILE 982e52e3b834cad9
```text
---
name: code-simplifier
description: Code simplification skill for improving clarity, consistency, and maintainability while preserving exact behavior. Use when simplifying code, reducing complexity, cleaning up recent changes, applying refactoring patterns, or improving readability. Triggers on tasks involving code cleanup, simplification, refactoring, or readability improvements.
---

# Community Code Simplification Best Practices

Comprehensive code simplification guide for AI agents and LLMs. Contains 47 rules across 8 categories, prioritized by impact from critical (context discovery, behavior preservation) to incremental (language idioms). Each rule includes detailed explanations, real-world examples comparing incorrect vs. correct implementations, and specific impact metrics.

## Core Principles

1. **Context First**: Understand project conventions before making any changes
2. **Behavior Preservation**: Change how code is written, never what it does
3. **Scope Discipline**: Focus on recently modified code, keep diffs small
4. **Clarity Over Brevity**: Explicit, readable code beats clever one-liners

## When to Apply

Reference these guidelines when:
- Simplifying or cleaning up recently modified code
- Reducing nesting, complexity, or duplication
- Improving naming and readability
- Applying language-specific idiomatic patterns
- Reviewing code for maintainability issues

## Rule Categories by Priority

| Priority | Category | Impact | Prefix | Rules |
|----------|----------|--------|--------|-------|
| 1 | Context Discovery | CRITICAL | `ctx-` | 4 |
| 2 | Behavior Preservation | CRITICAL | `behave-` | 6 |
| 3 | Scope Management | HIGH | `scope-` | 5 |
| 4 | Control Flow Simplification | HIGH | `flow-` | 9 |
| 5 | Naming and Clarity | MEDIUM-HIGH | `name-` | 6 |
| 6 | Duplication Reduction | MEDIUM | `dup-` | 5 |
| 7 | Dead Code Elimination | MEDIUM | `dead-` | 5 |
| 8 | Language Idioms | LOW-MEDIUM | `idiom-` | 7 |

## Quick Reference

### 1. Context Discovery (CRITICAL)

- [`ctx-read-claude-md`](references/ctx-read-claude-md.md) - Always read CLAUDE.md before simplifying
- [`ctx-detect-lint-config`](references/ctx-detect-lint-config.md) - Check for linting and formatting configs
- [`ctx-follow-existing-patterns`](references/ctx-follow-existing-patterns.md) - Match existing code style in file and project
- [`ctx-project-over-generic`](references/ctx-project-over-generic.md) - Project conventions override generic best practices

### 2. Behavior Preservation (CRITICAL)

- [`behave-preserve-outputs`](references/behave-preserve-outputs.md) - Preserve all return values and outputs
```
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