Par3
Par3 is an "agent harness control surface" for teams. It lets you control the coding agents on your machines from a desktop app, a web app and a mobile app.
Works with your subscriptions on Claude Code, Codex, Cursor, GitHub Copilot, Grok Build, OpenCode, and Google Antigravity. If they're set up on your computer, Par3 can control them.
Why Par3 exists
Par3 is a fork of T3 Code, an excellent open-source project by T3 Tools. T3 Code is led directly by Theo, and its product decisions are his to make. That is a fair way to run a project, but some of those decisions don't fit how enterprise teams work.
The clearest example is plan mode. T3 Code removed it, while most engineers we work with, especially in enterprise, want to see and approve a plan before an agent touches their code. Par3 keeps plan mode as a first-class setting and makes product decisions around what enterprise teams need: reviewable plans, explicit permissions, and clear visibility into what agents do.
Two features build on that. Spec mode puts a requirements document that a person approves between a request and the code, and the server refuses implementation until it is approved. Sidekick pairs a thread's model with a cheaper one: the lead plans and reviews while the sidekick does most of the work. Sidekick follows the approach of Cognition's Devin Fusion.
We still merge T3 Code's improvements regularly and are grateful for the work behind it. T3 Code is MIT licensed, and so is Par3.
Installation
[!WARNING]
Par3 currently supports Codex, Claude, Cursor, GitHub Copilot, Grok Build, OpenCode, and Antigravity. Install and authenticate at least one provider before use:
- Codex: install Codex CLI and run
codex login
- Claude: install Claude Code and run
claude auth login
- Cursor: install Cursor CLI and run
agent login
- GitHub Copilot: install GitHub Copilot CLI and run
copilot login
- Grok Build: install Grok Build CLI and run
grok login
- OpenCode: install OpenCode and run
opencode auth login
- Antigravity: enable it in Settings, then use Install Antigravity and Sign in with Google. No CLI is required.
Command line
curl -fsSL https://par3.paritylabs.co.za/install.sh | sh
On Windows, in PowerShell:
irm https://par3.paritylabs.co.za/install.ps1 | iex
Then run par3 to start the server and open the local web app. par3 service install keeps it running in the background, par3 update moves to a newer release, and par3 --help has the full reference.
To try it once without installing, run npx @paritylabs/par3@latest instead.
Desktop app
Install the latest version of the desktop app from GitHub Releases.
Debian, Ubuntu (.deb)
Download the .deb from GitHub Releases, then:
sudo apt install ./Par3-*.deb
Some notes
We are very very early in this project. Expect bugs.
We are (mostly) not accepting contributions yet. Small fixes may be considered. Big features will not be.
Documentation
Full docs live in docs/. There's no docs site yet.
Building from source? Start at docs/internals/overview.md.
If you REALLY want to contribute still.... read this first
Install vp
Par3 uses Vite+ so you'll need to install the global vp command-line tool.
macOS / Linux
curl -fsSL https://vite.plus | bash
Windows
irm https://vite.plus/ps1 | iex
Checkout their getting started guide for more information: https://viteplus.dev/guide/
Install dependencies
vp i
Read CONTRIBUTING.md before reporting a bug or opening a PR.
Have a feature request? Start an Ideas discussion.
Need support? Join the Discord.
