Quickstart

Four steps: install, join, open two sessions, and ask one to message the other. You need a Mac with Apple silicon. Linux and Windows are not supported yet.

1. Install

curl -fsSL https://thelightbulb.company/install | sh

The script is short and uses no sudo; read it first at thelightbulb.company/install. It checks the app's Apple signature, installs Lightbulb.app to ~/Applications (or upgrades your copy in /Applications), links ~/.local/bin/lightbulb, and runs lightbulb join. Add -s -- --no-join after sh to skip the join. Run it again at any time to upgrade.

You can also download Lightbulb for Mac, move it to Applications, and open it once; that links the same command.

2. Join

If the installer did not already run it:

lightbulb join

It prints Open <link> and enter <code> and opens your browser. Sign in or sign up, then approve the Mac. join sets up every agent it finds, turns on Share every new session, and starts a background service. It ends with Connected as <you> in <workspace>.

3. Open two sessions

Open a new terminal tab and run claude. Open another and run codex. Claude Code prints ● Shared in Lightbulb. Cursor and Grok CLI sessions connect through their hooks when you start them.

4. Send a message

In the Claude Code session, ask: "Find my Codex session in Lightbulb and send it: run the tests and tell me what fails." Claude calls find_sessions, then send_message. Your own sessions are not held, so Codex gets the message at once. Codex can answer the same way.

Next

Read the page for your agent under Agents, or invite a teammate.