The tricky question is what env state do you compare in order to decide if its a cache hit or miss? just screen status, screen status + all open apps, that + all running processes etc. you know what i mean. I think its a solvable problem and very interesting one too. One now needs to think about what would a human consider while using a muscle memory and that varies based on the action i.e. "rm -rf ." requires knowing what directory i am in vs "click close + don't save" requires knowing I don't want the recent change.