On May 29 I was doing my rounds — scanning a wall of tmux panes, each one running a separate Claude agent, to figure out who was busy and who was sitting idle so I could hand out the next piece of work. If you’ve never seen this: tmux is a terminal multiplexer, which is a fancy way of saying it splits one screen into a grid of little labeled boxes, and each box was a coding agent chewing on its own task.
One box was titled “Debug QUIC error.” So I nudged that agent: hey, how’s the QUIC bug coming?
It corrected me, politely. It had shipped that fix three days earlier. It was now deep in something completely different, and my nudge cost it a full turn — it had to stop, re-read my message, explain that I was wrong, and get back to what it was doing. In agent time that’s the whole cycle wasted.
Here’s what I’d gotten backwards. The window title wasn’t telling me what the agent was doing. It was telling me what the agent was named when the session started. Those are different facts, and one of them goes stale the instant work ships.
Think of a whiteboard on someone’s office door that says “WORKING ON: Q2 budget.” Useful the morning they wrote it. Useless a week later when they’ve moved on and never wiped it. Nobody updates the door. The title is a label, not a live readout.
The reliable signal was sitting right there the whole time — in the last 30 or 40 lines of the agent’s own transcript. That’s where the state lives. Three things I should have read instead of the title:
The agent’s recap — its own summary of what it thinks it’s doing right now. Its end-of-turn verdict — did it finish, get stuck, or ask a question? And its visible task checklist, the little list of subtasks with boxes ticked off.
A title is set once and forgotten. A transcript is the agent narrating itself in real time. If you want to know what someone’s doing, read what they just said, not the sign on the door.
A last-N-lines classifier beats a title read give me the detail
The fix was to stop reading pane titles entirely and classify from the tail of each pane’s live buffer. tmux hands you the visible scrollback directly:
# grab the last 40 lines of a pane's actual output
tmux capture-pane -p -t "$pane" -S -40Then a cheap classifier over that text, checked in priority order:
asking -> ends with a question / "waiting for" / a prompt cursor
working -> a spinner, "Running…", or an unchecked task box (- [ ])
done -> "shipped" / "committed" / all boxes checked (- [x])
idle -> no output delta across two polls, no pending promptPoll twice a few seconds apart so idle means actually not moving, not just paused mid-thought. Only route new work to idle and done. Never derive any of this from #{window_name} — that string was frozen at session start and will lie to you the moment a task ships.
So: treat the title as a nametag, never as status. When you’re triaging a fleet of agents, the truth is always in the last few lines they wrote — read those, and you’ll stop interrupting agents who already moved on.