tmux or herdr — pick per connection.

The short answer

• Already living in tmux? Pick tmux. Moshpit attaches to the sessions you already have and never restyles them.
• Mostly running coding agents? Pick herdr. Agent status works with nothing installed, panes render full width, and you can start an isolated task from the phone.
• Neither installed and not sure? Pick None. Moshpit is a perfectly good plain SSH client; add a multiplexer when you miss one.

Side by side

	tmux	herdr
Where it is	On nearly every server already	Install it yourself (one binary)
Agent status	Hook install, then accurate	Protocol field — nothing to install
What it calls things	session · window · pane	workspace · tab · pane
Rendering on the phone	Full layout, panes and splits	One pane, full width
Your laptop’s window size	Shared — the smallest client wins	Untouched — your phone resizes only its own pane
Isolated task from the phone	—	git worktree, workspace and agent in one sheet
Maturity	Twenty years of it	New, and moving fast

Where each one is genuinely worse

tmux shares one window size across every attached client, so a phone joining your session can squeeze the layout on your laptop. Moshpit pins the window to work around it, but the constraint is real. Agent status also needs the hook installed on the host, and without it Moshpit falls back to reading output, which is a guess.

herdr is young. Its direct attach is exclusive per pane, so two clients on the same pane fight over it; the app backs off and tells you rather than flickering silently. Its tree is polled, so somebody else’s change on the laptop can take a few seconds to show up. And on 0.7.3 it reports no foreground command, so the pane crumb falls back to pane N.

Changing your mind

The multiplexer lives on the connection, in Edit → Advanced. Change it and reconnect. Nothing is lost — the other multiplexer’s sessions are still on the host, exactly as you left them, because Moshpit never killed anything to make the switch.

Over Mosh, both fall back

Mosh transmits rendered screen differences, which cannot carry tmux’s control-mode protocol or herdr’s frame protocol. Over Mosh you get the multiplexer’s own text UI inside the terminal instead of native rendering — still useful, still roaming, just not the native lists. See Mosh and roaming.