Guide · Agent skill
How to use the Code Simplification agent skill
Updated · written with AI from the project's own documentation and checked against our catalogue data
The Code Simplification skill gives an AI coding agent a structured process for making working code easier to read and maintain while keeping its behavior exactly the same. This guide explains what the skill makes the agent do, how to install it, how to ask for it in plain language, and what to check before you trust the result. You do not need prior experience with agent skills to follow it.
Code Simplificationaddyosmani/agent-skills · MIT Download the skill Quick start
- 1Download the ZIP. Download the code-simplification ZIP from this page. It contains SKILL.md.
- 2Unzip into a skills folder. Unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder to limit it to that project.
- 3Or upload it in the Claude apps. In the Claude apps, go to Settings → Capabilities → Skills and upload the ZIP.
- 4Make sure tests exist. Confirm the code you want simplified has tests or other ways to check its behaviour, since the skill relies on tests passing after each change.
- 5Ask in plain language. Describe the job, for example asking to simplify one function without changing what it does.
- 6Review the changes. Read the diff, confirm behaviour is unchanged, and check it follows your project's conventions.
What the Code Simplification skill makes the agent do
When you ask the agent to simplify code, this skill tells it to work from a fixed process rather than just rewriting things. The goal is code that a new team member can understand faster than the original, not fewer lines. The skill says every change must preserve inputs, outputs, side effects, error behavior and edge cases.
Before changing anything, the agent is told to understand why the code was written that way, including checking git blame for the original context. It then looks for specific signals such as deep nesting (3+ levels), nested ternaries, generic names like data or temp, duplicated logic, dead code, and comments that explain what the code does rather than why.
- Checks that tests still pass without modification after each change
- Follows the project's conventions, starting with CLAUDE.md and neighbouring code
- Makes one simplification at a time and tests after each one
- Avoids over-simplifying, such as inlining helpers that name a concept, and avoids drive-by refactors outside the code you are working on
Install the code-simplification skill
You can install the skill in one of three ways. The skill is packaged as a ZIP and its only file is SKILL.md, so installation is a matter of putting that folder where your agent looks for skills.
For a personal setup, download the ZIP from this page and unzip it into ~/.claude/skills/. To limit the skill to one project, unzip it into that project's .claude/skills/ folder instead. In the Claude apps, you can also upload the ZIP under Settings → Capabilities → Skills.
- Personal install: unzip into ~/.claude/skills/
- Project install: unzip into the project's .claude/skills/
- Claude apps: upload the ZIP under Settings → Capabilities → Skills
Trigger the skill with natural requests
You do not need a special command. The skill's description tells the agent when to use it, so you trigger it by describing the job in ordinary words. Phrases the description covers include asking to simplify, clean up, or reduce the nesting of a function or module that already works, and refactoring for clarity without changing behavior.
The description also covers code that is pasted inline, so you can paste a function into the chat and ask for it to be tidied without a repository being involved.
- "Simplify this function, it works but the nesting is hard to follow."
- "Clean up this module without changing what it does."
- "Reduce the nesting in this handler. Don't change behaviour."
- "Review this file for unnecessary complexity and suggest simpler versions."
Example: what a simplification looks like
The skill's own examples show two common changes. The first replaces a dense nested ternary with a named function that uses early returns. The second replaces a chained reduce that builds objects inline with a plain loop over a Map that has a clear name.
Both versions produce the same result. The difference is that each step is easier to read and debug.
// UNCLEAR: Dense ternary chain
const label = isNew ? 'New' : isUpdated ? 'Updated' : isArchived ? 'Archived' : 'Active';
// CLEAR: Readable mapping
function getStatusLabel(item: Item): string {
if (item.isNew) return 'New';
if (item.isUpdated) return 'Updated';
if (item.isArchived) return 'Archived';
return 'Active';
}Know when not to use the skill
The skill is not a fit for every piece of code. The source says not to use it when the code is already clean, when you do not yet understand what it does, when the code is performance-critical and the simpler version would be measurably slower, or when the module is about to be rewritten entirely. In those cases, the skill tells the agent to stop or to read more context first.
If the code is still broken or its purpose is unclear, fix the understanding first. Changes made without understanding can introduce bugs.
- Code that is already clean: do not simplify for its own sake
- Code whose purpose nobody understands yet
- Performance-critical code where the simpler version is measurably slower
- Throwaway code that is about to be rewritten
Safety notes: scripts and network access
This skill runs no scripts and uses no network access, according to its listing. It requires nothing beyond the agent itself. Because it can change files, review every diff the agent produces, and run your existing tests before you merge.
The skill tells the agent to keep refactoring commits separate from feature or bug-fix commits, which makes review and rollback easier.
- Runs scripts: no
- Uses network: no
- Requires: nothing listed
- Review the diff and run your test suite before merging
What people use it for
- Reducing three or more levels of nesting in a working function so its control flow is easier to follow
- Replacing a nested ternary chain with a named function that uses early returns
- Renaming generic variables like data or temp to describe their contents
- Cleaning up a module during code review while keeping its behaviour intact
- Tidying one pasted function without touching the rest of the project
Frequently asked questions
How do I install the code-simplification skill?
Download the ZIP from this page and unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder for one project. In the Claude apps, you can upload the ZIP under Settings → Capabilities → Skills.
Does the code-simplification skill require anything else?
The listing says it requires nothing beyond the agent itself. It runs no scripts and uses no network access. You still need your code and, ideally, tests to check behaviour.
Is the code-simplification skill free?
The source material for this page does not state pricing. The skill is listed under the MIT licence on the source repository, which governs how you may use and share it.
Will the skill change how my code behaves?
The skill is designed to preserve exact behaviour, including outputs, error handling and side effects. It tells the agent to make a change only when it is confident behaviour is preserved, and to run tests after each step. You should still review every diff yourself.
What is the difference between this skill and asking an AI to just clean up my code?
This skill adds a fixed process: it checks why the code exists first, looks for specific patterns like deep nesting and nested ternaries, follows project conventions, and avoids over-simplifying. A general request may skip these checks and produce churn.
Why won't the agent simplify my code when it is broken?
The skill tells the agent to understand the code before changing it, and not to simplify code that is still broken or whose purpose is unknown. Fix the bug or clarify the intent first, then ask for simplification.
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Our verdict
This skill suits developers with working code that has become hard to read, teams who want review suggestions that keep behaviour intact, and anyone who wants an agent to tidy one function or module. It is a poor choice for broken or misunderstood code, performance-critical paths, or code about to be thrown away.
Download the skill