Shell auto-tmux behavior

Opening a new interactive terminal automatically attaches to a single shared tmux session named main (creating it if it doesn't exist yet), instead of spawning a new session per terminal window. See the tmux new-session -A -s main block at the end of .zshrc.

On a fresh server (no main yet), the first terminal first runs lazy-tmux bootstrap -session main, so a previously saved main (windows, panes, scrollback via the daemon and <prefix> C-s) is restored instead of starting blank. Restoring into an already-running session is a lazy-tmux no-op, so this only happens when main is first created; a missing or old lazy-tmux, or a restore failure, falls back to a plain empty session. tmux.conf.local also bootstraps on server start when no main session exists yet (covers servers started outside .zshrc that don't create main themselves, e.g. a bare tmux start-server); a server spawned directly as main skips it since the session already exists — use an ExecStartPre bootstrap in a systemd unit for that case.

It has to stay last in the file: that shell becomes the tmux server on the first terminal, so anything set after it never reaches the server's environment — including the ~/.local/bin entry that tmux.conf.local needs to find lazy-tmux.

Opting out

NO_AUTO_TMUX=1     # set in your environment

It's also skipped automatically in VS Code/Cursor integrated terminals, where auto-tmux breaks shell integration. If tmux fails to start, you're left at a normal shell rather than a closed window.