What are the costs and fees of a plaintiff who prevails on a special motion to strike?

The court shall award attorney fees to a plaintiff who prevails on a special motion to strike if the court finds that the defendants' motion was frivolous or solely intended to cause unnecessary delay. ( 128.5.) In such case, the court is required to award costs and reasonable attorney fees to the plaintiff pursuant to section 128.5 as a sanction. ( 425.16, subd. (c)(1) ; Ketchum v. Moses (2001) 24 Cal.4th 1122, 1131, [104 Cal.Rptr.2d 377, 17 P.3d 735].)⁷