I am looking for a metaphorical phrase which would mean the opposite of "set the bar". Like "set the upper limit", but not that straightforward.
When you set the bar, you are defining the lower level of standard for something. It is OK if you do better than the bar they set.
When you do the opposite, you are defining the upper level. It is OK to do at this level or worse, but not better.
Listen, man, we need our jobs. If this new guy keeps going at this pace, they will lower the rates and fire our asses. Take Tim and Rob with you, meet him behind the warehouse and explain to him that he should ________ (do the opposite of setting the bar) at five thousand pounds of cargo per day.
When I am saying "fifty cold calls a day", I am setting the bar, not _______ (doing the opposite of setting the bar). No one will be mad at you if you call more. You don't have to call it a day the moment you've made your fiftieth call".