Big Three

Guide

Install Big Three on Windows

Download, unzip, double-click. The first run takes a few minutes; after that the app opens right away. You need Node.js and at least one model CLI already signed in.

Updated November 4, 2026

What you need first

  • Windows 10 or 11. Developed and used on Windows 11. macOS and Linux have not been tried yet.
  • Node.js 20 or newer.
  • At least one of these CLIs, signed in with your own account: Claude Code (claude, with a Claude subscription), the Antigravity CLI (agy, for Gemini, with a Google account) or the Codex CLI (codex, with a ChatGPT account).

Install Claude Code and the Antigravity CLI the way their own documentation describes. Codex installs with:

npm i -g @openai/codex

The easy way: the ZIP

  1. Download the ZIP (or use the green Code button on GitHub) and unzip it anywhere.
  2. Double-click Big-Three.cmd. The first run installs what it needs, including a one-time download of the Electron runtime (about 110 MB).
  3. Next time, double-click it again. It opens right away.

From a terminal

git clone https://github.com/marcj19/Big-Three.git
cd Big-Three
npm install
npm start

Check which CLIs are ready

Not sure which of the three CLIs are installed and signed in? Run this in the project folder. It lists each one, its version and whether it is signed in.

npm run doctor

You can also sign in from inside the app: the sidebar shows each model's status and an Enter button when one is signed out.

Your first conversation

  1. Click New conversation (Ctrl+N) and choose the folder the models may work in. They can see that folder and its subfolders, so start with the smallest one that does the job.
  2. Under the text field, pick who you talk to, what it may do (read, edit or full) and the team.
  3. Write. Enter sends, Shift+Enter adds a new line.
  4. Ask for help in plain words whenever you like: "ask Gemini to review this".

Good to know

The interface is in Brazilian Portuguese for now. Models start read-only; anything more asks you in a native dialog first. Read how the team works together and how database access stays read-only.

Install questions

Is there an installer?

Not yet. Big Three runs from the folder you unzip or clone. The first run installs what it needs, and a packaged installer is planned.

Why does the first run take a few minutes?

It installs the app's dependencies and downloads the Electron runtime once, about 110 MB. After that the app opens right away.

How do I update?

If you cloned the repository, run git pull and then npm install in the folder. If you downloaded the ZIP, download the new ZIP and unzip it over a fresh folder.

Does it work with only one model signed in?

Yes. One signed-in CLI is enough to start a conversation. The more CLIs you sign in to, the more colleagues the lead can consult.

Keep reading