How to Answer
“I split it into two numbers, because they are not the same problem. There is total time, and there is time to first signal. People tolerate forty seconds far better than they tolerate eight seconds of a blank spinner. So the target isn’t ‘make it fast’, it’s ‘never be silent for more than about a second’.
Concretely: stream tokens as they come, and emit a progress event for every tool call — ‘searching four knowledge bases’, ‘reading the Q3 contract’. That is real work, and showing it is honest rather than decorative.
Then I ask whether they should be waiting at all. Past about thirty seconds, make it a job: return a handle immediately, do the work in the background, notify on completion. That is a product decision more than an engineering one.
And let them out. Cancel has to actually cancel — propagate the abort into the in-flight tool call. Hiding the spinner is not cancelling.”