Shi'te signals what attack he wants, where he wants it, and uke delivers it as ordered. These are not real attacks - they are overextended punches or dagger thrusts, ritualized tegetana strikes, scripted grab attempts, etc.
I believe in and do cooperative training. But I do NOT, even with newbies, purposedly deliver overextended attacks.
I am always giving the best attack I can; with newbies I may deliver it in slo-mo and make sure if he cannot make a connection to my center, then I will via my ukemi try to make a connection to his center so we can work together on the technique.