Focus-follows-mouse for tmux panes in Ghostty.

Hover your mouse over a tmux pane and it automatically gets focus — no clicking required. Just like Ghostty's native focus-follows-mouse, but for tmux panes.

Split your terminal into panes with tmux, then just move your mouse between them. The active pane follows your cursor.

Requires macOS 13+ and Ghostty terminal.

git clone https://github.com/julian0xff/tmux-focus.git
cd tmux-focus
swift build -c release
cp .build/release/tmux-focus /usr/local/bin/

Or with Homebrew (coming soon):

brew install julian0xff/tap/tmux-focus

tmux-focus          # Start the daemon (run in background with &)
tmux-focus --stop   # Stop the daemon
tmux-focus --help   # Show all options

Start it in the background:

tmux-focus &

1. Monitors mouse movement via macOS global event monitor
2. Detects the Ghostty window under the cursor
3. Maps pixel coordinates to tmux cell coordinates using your Ghostty padding config
4. Runs tmux select-pane when you hover over a different pane

The daemon reads your Ghostty config (~/.config/ghostty/config) to get the correct padding values. No manual configuration needed for most setups.

• Only activates when Ghostty is the frontmost app
• Only runs when tmux has 2+ panes (single pane = no-op)
• Only calls tmux select-pane when the pane actually changes (not on every mouse move)
• Throttled to 20Hz — negligible CPU usage (~0.1%)
• Does nothing when tmux is not running

Add to your shell config (.zshrc / .bashrc):

# Start tmux-focus if tmux is running and daemon isn't
if command -v tmux-focus >/dev/null 2>&1 && tmux list-sessions &>/dev/null && ! pgrep -qf 'tmux-focus$'; then
    tmux-focus &>/dev/null &
    disown
fi

• macOS 13.0+
• Ghostty terminal
• tmux
• Accessibility permissions (System Settings → Privacy & Security → Accessibility → Ghostty)

MIT