synthesis.work

Download and install

Install the synthesis work system.

One command sets it up on a Mac for Claude Code, Codex and Muse. If the Mac lacks Apple’s Command Line Tools, it installs them first.

Install

Install on a Mac

Run this in Terminal. It installs the synthesis plugin in each of Claude Code, Codex and Muse that it finds, the runtime the plugin uses, and the synthesis command.

curl -fsSL https://raw.githubusercontent.com/synthesisengineering/synthesis-skills/stable/onboard.sh | sh

It needs git, python3 and at least one of Claude Code (the desktop app or the command line), Codex or Muse. Setup asks whether to turn on the commit check, and on a first install asks two questions for a starting configuration. Every step is safe to rerun, and running it again updates. Read the installer · What setup changes

After setup

Quit and reopen each app: a restart is what loads new skills and hooks. In Codex, approve the synthesis hooks with /hooks; in Muse, run muse plugins approve synthesis-skills. Then synthesis doctor checks every part.

Other ways to install

With Homebrew

The formula adds a launcher that runs the same setup.

brew install synthesisengineering/tap/synthesis && synthesis-onboard

Only the plugin, with your app's own commands

These install the skills and hooks, and the runtime arrives with the first session. They skip the rest of setup: Codex's settings, the commit check and the synthesis command.

# Claude Code
claude plugin marketplace add synthesisengineering/synthesis-skills@stable
claude plugin install synthesis-skills@synthesis-engineering

# Codex
codex plugin marketplace add synthesisengineering/synthesis-skills --ref stable
codex plugin add synthesis-skills@synthesis-engineering

Source and licensing. Provider data handling and costs depend on the app and model service you choose.

What setup changes on your Mac

In each app it finds
The synthesis plugin, installed with that app’s own commands: Claude Code, Codex and Muse.
In your home folder
The runtime under ~/.synthesis/v5, and the synthesis command in ~/.local/bin when that name is free.
Codex settings
Turns on hooks, raises the instruction limit and lets the sandbox write the synthesis board, after backing up ~/.codex/config.toml.
Claude Code settings
Keeps conversation transcripts for ten years, unless you already chose a period.
Only if you say yes
The commit check in every repository, which refuses a commit that carries a credential, a flagged disclosure or another session’s claimed files.
On a first install
A starting configuration from two questions: where your knowledge repositories are, and words never to send.

Every step is safe to rerun, and running the command again updates. Setup schedules nothing unless you ask for its day-end reminder, and it approves no hooks for you. Every option is in the README.

To remove what it installed:

curl -fsSL https://raw.githubusercontent.com/synthesisengineering/synthesis-skills/stable/onboard.sh | sh -s -- uninstall

Standalone tools

Each tool installs on its own and does not need the full work system.

Synthesis SlopCheck

Reviews writing quality from your terminal. A hosted version runs in the browser.

Installation and source

Questions before you install

Which apps does it work with?

Claude Code (the desktop app or the command line), Codex and Muse. Other apps that read Agent Skills can use the skill files, but the hooks, guards and coordination run only in those three.

What does my Mac need?

One of those apps, plus git and python3 3.9 or newer, which come with Apple’s Command Line Tools. If they are missing, the installer opens Apple’s installer for them and carries on when it finishes. With no supported app on the Mac, setup stops before changing anything and says which one to install.

Will it update without asking?

Setup schedules nothing. Run the same command again to update; your app may also update the plugin through its own plugin settings.

Does installing Synthesis replace my coding agent?

No. It adds skills, hooks and a few commands to the apps you already use. Each app keeps its own permissions, model access and features, and you approve its hooks yourself.