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Parker Rex DailyJanuary 9, 2025

Claude Code Just Open-Sourced Their Simplifier Agent

Boris released the source code for Claude Code's Simplifier plugin. Here's what's inside and what it teaches you about building your own skills.

Show Notes

Boris (creator of Claude Code) just open-sourced the Simplifier agent. Here's what I found digging through the source, and what it teaches you about building your own plugins.

How to Install It

In a Claude Code session, follow Boris's instructions to add the plugin. Once it's running, you can read the source yourself.

Where to Find the Source

Navigate to your Claude Code directory:

~/.claude/plugins/

Inside plugins/, you'll see all the official ones. The Simplifier agent lives under agents/.

What's in the Plugin

The structure is pretty revealing if you're trying to build your own:

Front matter:

  • Name
  • Description
  • Model (you can tweak this)

Sections:

  1. Preserve the functionality — Important because sometimes the AI will delete stuff. This tells it not to.
  2. Apply the project standards — References your CLAUDE.md for coding style preferences.
  3. Enhancing clarity — General cleanup rules.

The length of this plugin is a good reference point. Now you know how detailed Anthropic thinks these should be.

My First Run

I gave it two simple pages — one static, one dynamic. It ran for about 5 minutes.

What I liked: It refactored a Promise.all pattern for fetching repository info on my website. Clean improvement.

What felt like overkill: Some changes felt like code golf — looking for stuff to simplify when there wasn't much to do. That's probably because I gave it simple code.

How I'd Use This

This makes sense as a hook in your workflow. After a batch of changes, run the Simplifier to clean things up before committing. Think of it as automated code review for clarity.