# Simplify Code

Reduces complexity and nesting while keeping behavior exactly the same.

- Repository: https://github.com/addyosmani/agent-skills (112533 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add addyosmani/agent-skills --skill code-simplification -g -a claude-code -y`
Codex: `npx skills add addyosmani/agent-skills --skill code-simplification -g -a codex -y`
Cursor: `npx skills add addyosmani/agent-skills --skill code-simplification -g -a cursor -y`
Gemini CLI: `npx skills add addyosmani/agent-skills --skill code-simplification -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add addyosmani/agent-skills`

## Description

Simplifies code for clarity. Use when refactoring code for clarity without changing behavior. Use when code works but is harder to read, maintain, or extend than it should be. Use when reviewing code that has accumulated unnecessary complexity. Use when asked to simplify, clean up, or reduce the nesting of a function or module that already works, even when the code is pasted inline and nothing else needs to change.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Code Simplification

> Inspired by the [Claude Code Simplifier plugin](https://github.com/anthropics/claude-plugins-official/blob/main/plugins/code-simplifier/agents/code-simplifier.md). Adapted here as a model-agnostic, process-driven skill for any AI coding agent.

## Overview

Simplify code by reducing complexity while preserving exact behavior. The goal is not fewer lines, it's code that is easier to read, understand, modify, and debug. Every simplification must pass a simple test: "Would a new team member understand this faster than the original?"

## When to Use

- After a feature is working and tests pass, but the implementation feels heavier than it needs to be
- During code review when readability or complexity issues are flagged
- When you encounter deeply nested logic, long functions, or unclear names
- When refactoring code written under time pressure
- When consolidating related logic scattered across files
- After merging changes that introduced duplication or inconsistency

**When NOT to use:**

- Code is already clean and readable, don't simplify for the sake of it
- You don't understand what the code does yet, comprehend before you simplify
- The code is performance-critical and the "simpler" version would be measurably slower
- You're about to rewrite the module entirely, simplifying throwaway code wastes effort

## The Five Principles

### 1. Preserve Behavior Exactly

Don't change what the code does, only how it expresses it. All inputs, outputs, side effects, error behavior, and edge cases must remain identical. If you're not sure a simplification preserves behavior, don't make it.

```
ASK BEFORE EVERY CHANGE:
→ Does this produce the same output for every input?
→ Does this maintain the same error behavior?
→ Does this preserve the same side effects and ordering?
→ Do all existing tests still pass without modification?
```

### 2. Follow Project Conventions

The rest: https://github.com/addyosmani/agent-skills/blob/HEAD/skills/code-simplification/SKILL.md