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Guide · Open source

How to use T3 Code: install, connect agents and control them

Updated · written with AI from the project's own documentation and checked against our catalogue data

T3 Code is an open-source "agent harness control surface" that lets you control AI coding agents already installed on your computer, including Claude Code, Codex, Cursor, Grok Build, OpenCode and Google Antigravity. This guide shows you how to set up at least one agent, install T3 Code, and open it from a desktop app, web app or phone. By the end you will know what to install first and where to find the project's documentation.

T3 Codepingdotgg/t3code · ★ 39.7k · MIT

Quick start

  1. 1Install and sign in to an agent. Install at least one supported agent, such as Codex CLI or Claude Code, and log in with its command, for example codex login or claude auth login.
  2. 2Run the install command. On macOS or Linux, run the curl install script. On Windows, run the PowerShell irm command. You can also use a desktop package manager.
  3. 3Start T3 Code. Run t3 in your terminal to start the server and open the local web app.
  4. 4Keep it running (optional). Run t3 service install to keep T3 Code running in the background.
  5. 5Connect from a phone (optional). Install the iOS or Android app and follow the remote access guide in the docs folder.
  6. 6Read the docs. Check the permission modes and FAQ guides in the docs folder before you give agents broad access.

What you need before you install T3 Code

T3 Code does not replace your coding agents. It controls agents that are already set up on your machine, so you need at least one of them installed and signed in first. The README says T3 Code works with your existing subscriptions as long as the agents are set up on your computer.

  • Codex: install Codex CLI, then run codex login
  • Claude: install Claude Code, then run claude auth login
  • Cursor: install Cursor CLI, then run agent login
  • Grok Build: install Grok Build CLI, then run grok login
  • OpenCode: install OpenCode, then run opencode auth login
  • Antigravity: enable it in Settings, then use Install Antigravity and Sign in with Google. No CLI is required

Install T3 Code from the command line

On macOS or Linux, run the install script from the README in your terminal. On Windows, run the PowerShell command instead. Once installed, run t3 to start the server and open the local web app.

  • Run t3 service install to keep it running in the background
  • Run t3 update to move to a newer release
  • Run t3 --help for the full command reference
  • To try it once without installing, run npx t3@latest
curl -fsSL https://t3.codes/install.sh | sh

Install the desktop app with a package manager

The Electron-based desktop app is available from GitHub Releases or from a package registry. The README lists the following commands for each platform. Pick the one that matches your system.

  • Windows (winget): winget install T3Tools.T3Code
  • Windows (scoop): scoop install extras/t3code
  • macOS (Homebrew): brew install --cask t3-code
  • Debian or Ubuntu: download the .deb from GitHub Releases, then install it with apt
  • Arch Linux (AUR): t3code-bin for stable, t3code-nightly-bin for nightly
  • Nix: nix profile add github:NixOS/nixpkgs/nixos-unstable#t3code
brew install --cask t3-code

Use T3 Code from a phone or another machine

The README describes a mobile app for iOS and Android and a web app at app.t3.codes. The project includes a remote access guide for controlling agents from a phone or another machine. Check that guide before relying on remote control, since its setup details are in the docs rather than the README.

  • iOS and Android: the README links to the App Store and Google Play listings
  • Web app: available at app.t3.codes
  • Remote access setup: see docs/user/remote-access.md

Learn the main settings and where to look next

The README points to a set of guides in the docs folder rather than a docs website, because the project says there is no docs site yet. These cover permission modes, keyboard shortcuts, project settings, appearance, source control and running T3 Code as a background service.

  • Permission modes: docs/user/permission-modes.md
  • Keyboard shortcuts: docs/user/keybindings.md
  • Project settings: docs/user/project-settings.md
  • Source control integrations: docs/user/source-control.md
  • Run as a background service: docs/user/background-service.md
  • Connect outside agents over MCP: docs/user/outside-agents.md

Know the project's current limits

The README is direct about the state of the project. It says the project is very early, that you should expect bugs, and that it is mostly not accepting contributions yet. Small fixes may be considered, but big features will not be. Feature requests go to the Ideas discussions on GitHub, and support is offered through Discord.

  • Expect bugs, since the project is very early
  • Contributions: small fixes may be considered, large features will not
  • Feature requests: GitHub Ideas discussions
  • Support: Discord

What people use it for

  • Switch between Claude Code and Codex from one interface on your own computer
  • Check on a long-running coding agent from your phone while away from your desk
  • Run agents through the desktop app on Windows, macOS or Linux
  • Read and modify the MIT-licensed source to build your own editor or agent interface

Frequently asked questions

Is T3 Code free?

T3 Code is released under the MIT licence, which the project describes as an open-source licence you can read, fork and modify. The README says it works with your existing subscriptions to agents such as Claude Code or Codex. Those agents may have their own costs, which are not described in the README.

What do I need before installing T3 Code?

You need at least one supported agent installed and logged in on your computer. The README lists Codex, Claude, Cursor, Grok Build, OpenCode and Antigravity, with the login command for each. T3 Code controls these agents and does not work without one of them.

How do I install T3 Code on macOS?

The README gives two options. You can run the curl install script in your terminal, or install the desktop app with Homebrew using brew install --cask t3-code. Both methods are listed in the README.

How do I install T3 Code on Windows?

Use winget install T3Tools.T3Code for the desktop app, or scoop install extras/t3code. For the command line version, run the PowerShell command irm https://t3.codes/install.ps1 | iex.

Is T3 Code stable enough for daily work?

The README says the project is very early and that you should expect bugs. It is a reasonable choice for developers comfortable testing new software, but teams that need stable tools should wait.

How does T3 Code compare to Conductor or Cursor?

The README says the authors were inspired by Codex desktop app, Conductor, Claude Desktop and Cursor Glass but wanted something performant, remote-ready and truly open. Choose T3 Code if you want an MIT-licensed tool you can fork. Conductor, Cursor and Claude Desktop are the comparable projects listed for this directory.

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Our verdict

T3 Code suits developers who already use supported coding agents and want one interface for them, especially if they want MIT-licensed code or phone control. It is a poor fit if you use none of the listed agents, need stable software, or depend on full documentation, since the README says the project is very early and has no docs site yet.

Install options & downloads