The engine is a command, sleds engine, and for the first month that was all it was. You started it in a terminal and you trusted it. If you wanted to know what it was doing you opened the board, or you attached to the tmux session and read.
That was fine for the people who wrote it and wrong for everyone else. An engine that runs agents on your machine, opens PRs under your name and spends your seat's window needs a place you can glance at. So it has one now: a mark in the menu bar, and a panel under it.
What the panel shows
The top line is the whole state: 2 running · 1 at PR, the sled's name, which machine the engine is on and what it opens sessions in (Adam-Mac-Studio · tmux), and a dot that is green when the engine has checked in recently. The foot carries the thing engineers ask about most: how much of the weekly window the seat has used, when it resets, and how old the numbers are.
Between them, the list. Filters along the top for the states that matter: Need (parked with a question for you), Running, PR, Waiting (nothing to start yet), Ready, Landed. Each item shows its key, its title, the node it is on, and a line that says plainly what the engine is doing or not doing about it: A at PR, not followed by this engine, armed, starts when a slot frees, parked · needs you.
Click the item and it opens on the route page. Click the icon beside it and the tmux session comes to the front, so watching the agent work is one click, not a command you have to remember.
The one switch
The segmented control under the title is the most important thing in the app: Approve or Auto.
In Approve, nothing starts until you press Start on it. Armed items wait in the list and the panel tells you so. This is the default, and for a lot of people it stays the setting: you decide what runs on your machine, one at a time, with the band in front of you.
In Auto, armed items start as they become ready, up to the number you allow at once. The engine runs the route, follows each PR, starts the next wave, and parks a node when it has to ask. You come back to a list of things at PR and, sometimes, one thing that needs you.
The switch is per person and per sled, and it can be flipped from the panel in a second. Nights and weekends on Auto, Approve during the day while you are in the code yourself, is the pattern we see most.
Why a menu bar app and not a tab
Because the engine is a thing on your Mac, and the honest place to show a thing on your Mac is next to the Wi-Fi icon. The board is for the team; it shows every sled. The panel is for you; it shows yours. The two agree, because they read the same record, but the panel can answer the question you actually have at 4 pm, which is "is anything about to run on my machine," without leaving whatever you were doing.