gmx

gmx is a terminal multiplexer for ghostty, built on zmx and Ghostty's recently exposed Applescript capabilities. Native Ghostty splits + persistent sessions in plain old Ghostty.

It aims to be vaguely tmux compatible but does not aim to be 100% tmux compatible.

Install

brew install nicosuave/tap/gmx
gmx completions install
gmx keybinds install

Usage

gmx - Ghostty Multiplexer with zmx session persistence

Usage: gmx <command> [args]

Commands:
  [n]ew [name] [--tab] [--remote R] [--dir D]   Create a new session (name defaults to cwd)
  [a]ttach <name> [--tab]                       Reattach to a session
  [d]etach                                      Detach from current session (ctrl+\ also works)
  [k]ill [name]                                 Kill a session (defaults to current)
  [l]s                                          List sessions
  [s]plit [right|down]                           Add a split to the current session
  [r]ename <old> <new>                           Rename a session
  [c]onfig remote <name> <host>                  Configure a remote host
  key[b]inds install|uninstall|show              Manage Ghostty keybindings
  completions install|uninstall|show <shell>     Shell tab completions

By default, new and attach work in the current terminal.
Use --tab to open in a new Ghostty tab instead.

Create a session and start working:

gmx n myproject              # creates zmx session, attaches in current terminal
gmx s right                  # split right, new zmx pane
gmx s down                   # split down, another pane

Close the tab. Sessions persist. Come back later:

gmx l                        # list sessions
gmx a myproject              # reattach in current terminal
gmx a myproject --tab        # or recreate full layout in new Ghostty tab

Keybindings

gmx can install Ghostty keybindings for you:

gmx b install                # ctrl+shift+d/e/t/a/x/s
gmx b install --prefix ctrl+b   # tmux-style: ctrl+b then d/e/c/a/x/s
gmx b uninstall              # remove them
gmx b show                   # dry run

The text: keybindings send commands to your shell, so they work at a prompt but not inside vim/htop. For that, use Hammerspoon global hotkeys:

-- ~/.hammerspoon/init.lua
hs.hotkey.bind({'ctrl','shift'}, 'd', function()
  hs.execute('/opt/homebrew/bin/gmx split right', true)
end)

Remote sessions

Configure a remote host, then create sessions that SSH in and run zmx on the remote:

gmx c remote nicbook nicbook --transport ssh
gmx n backend --remote nicbook --dir ~/Code/backend
gmx s right                  # splits also SSH to remote

Mosh is supported too: gmx c remote myhost myhost.local --transport mosh

Sessions persist on the remote via zmx. Close the tab, reattach later, the remote shell state is still there.

How it works

gmx uses Ghostty's AppleScript API to create tabs and splits with explicit surface configurations (environment variables, working directory). Each pane runs zmx attach <session> for persistence. Sessions are named <name>.1, <name>.2, etc.