MOSFET Based Current Limiter
There are a number of things wrong here:





The opamp is being used open loop, therefore as a comparator.  Due to the offset voltage error, the output is indeterminate at 0 current.  All you know is that with enough current, the output of the opamp will go high.  However, in this case there is no guarantee it will ever go low.

A TL081 is inappropriate here.  It needs fairly high supply voltage, and then can't drive its output all that close to either rail.  You need to check, but the voltage on R1 might be high enough to be interpreted as high by the gate driver, even when the opamp is driving low.

The input common mode range of a TL081 doesn't extend to its positive supply.

I have no idea why you think a emitter follower is needed on the output of the opamp.  It makes no sense.

You didn't specify the gate driver, but most likely it inteprets its input as a digital signal.  It will either drive the gate fully high or fully low.

If so, this circuit will oscillate in over-current condition, even if the current detector worked as apparently intended.  When the current gets too high, the FET is turned off.  That makes the current 0, which causes the FET to be turned on again, etc.  This would be undesirable with many loads.

A 1 m&Omega; current sense resistor is silly, considering the Rdson of the FET is 30 m&Omega;.  Making R2 a bit bigger will give you higher signal to noise ratio of the current feedback, but not substantially add to the voltage drop as long as it remains small compared to the Rdson of the FET.