Messages can contain up to 120,000 characters. If a draft is longer, T3 Code keeps it in the composer and shows how many characters need to be removed. Shorten the draft or split it into multiple messages, then send again in the same thread.
When a turn ends while work is still running, a banner sits above the composer and names that work: the agents still going, or the watch loops and background shells waiting on something.
Open Details on the banner for the full list, with each item's latest progress line and when it last reported. A watch loop that is waiting and one that has stopped making progress look the same in the banner, and the progress line is what tells them apart.
Stop ends every item in that list at once and interrupts the session. Items cannot be stopped one at a time.