Steer sub-sessions from the sidebar
Fold a chat's sub-sessions away, stop or archive one from its menu, read what they said to each other, and see what the whole tree cost.
A tree you can fold
A chat with sub-sessions has a chevron. Folded, it shows how many it has and the most urgent state among them. Each state has its own shape as well as its colour, and the arrow keys move through the tree.
Each sub-session has a menu, on its row or with a right click: Open, Stop, Rename and Archive. Archive hides it from the sidebar and keeps its chat.
Cards where they were asked for
The Start and Not now card now sits under the message that asked for the sub-session, and becomes its live card once it runs. Thread on that card shows every message it sent and received. A sub-session's own chat opens with a link back to the chat that started it.
Cost and ownership
Hover a parent chat to see what the whole tree spent and how much of that its sub-sessions did. The Plan pane names the sub-session working on each step, with its live state and, on hover, the files it claimed.
Sub-sessions on a local model take turns, one at a time across all your chats, so the model is never asked for two at once.