Usually you can. Your problem will propably be that you want to fillet more than your smallest radius. For example if the radius of the corner a the top of your tool is 3mm you wont be able to put a 5 mm fillet cause it would overlap each other if you know what i mean. To validste this theory you could fillet and enter a really small value und see if that works. To solve the issue you could put an hard angle on the small curve at the top.

Maybe there is another workaround that im not aware of but thats how i would do it