(a) In an action brought under Section 552.321 or 552.3215, the court shall assess costs of litigation and reasonable attorney fees incurred by a plaintiff who substantially prevails, except that the court may not assess those costs and fees against a governmental body if the court finds that the governmental body acted in reasonable reliance on:
(1) a judgment or an order of a court applicable to the governmental body;
(2) the published opinion of an appellate court; or
(3) a written decision of the attorney general, including a decision issued under Subchapter G or an opinion issued under Section 402.042.
(b) In an action brought under Section 552.324, the court may not assess costs of litigation or reasonable attorney's fees incurred by a plaintiff or defendant who substantially prevails unless the court finds the action or the defense of the action was groundless in fact or law. In exercising its discretion under this subsection, the court shall consider whether the conduct of the governmental body had a reasonable basis in law and whether the litigation was brought in good faith.