A fuel injector assembly includes a fuel injector and an annular filter coupled with the fuel injector, the annular filter being snap-fitted with one of a nozzle case or an injector body of the fuel injector and slip-fitted with the other of the nozzle case or the injector body. The annular filter has a perforated wall forming a filtration screen covering an actuation fluid inlet formed in the nozzle case and positioned upstream of the actuation fluid inlet to trap particulates in incoming actuation fluid.