Source: Psionics Handbook
You can raise a fortified defense against psionic attacks.
Benefit: You gain +1 mental hardness against a foe's successful psionic attack when you pay the cost of 3 power points. You decide whether or not to pay the cost after determining the failure or success of the psionic attack to breach your Will save.
Special: You can gain this feat multiple times, each time gaining bonus mental hardness equal to the previous bonus +1, but you must pay a cost equal to the previous cost + 8.