Construction with 'gratias agere' and a verb clause
Gratias tibi ago pro munere.
Gratias tibi ago quod munus mihi dedisti.
Is "quod" the correct conjunction in the second sentence, if I want to thank someone for an action expressed by a verb? And is "dedisti" in the right mood, or should it be subjunctive? Cicero has "Tibi ago gratias quod me omni molestia liberas." Is this the only construction, or are there others?