This is very fine provided you know which part of the AI's code contains the utility function, and are certain it's not going to be modified. But it seems to me that if you were able to calculate the utility of world-outcomes modularly, then you wouldn't need an AI in the first place; you would instead build an Oracle, give it your possible actions as input, and select the action with the greatest utility. Consequently, if you have an AI, it is because your utility calculation is not a separable piece of code, but some sort of global function of a huge number of inputs and internal calculations. How can you apply a filter to that?

You've assumed away the major difficulty, that of knowing what the AI's utility function is in the first place! If you can simply inspect the utility function like this, there's no need for a filter; you just check whether the utility of outcomes you want is higher than that of outcomes you don't want.

If you know the utility function, you have no need to filter it. If you don't know it, you can't filter it.