2015-06-22 : If there are additional costs to cast an instant or sorcery spell, apply those before applying cost reductions.

2015-06-22 : Jace’s Sanctum can reduce alternative costs such as miracle or overload costs.

2015-06-22 : Jace’s Sanctum’s scry ability will resolve before the instant or sorcery spell that caused it to trigger.

2015-06-22 : The first ability of Jace’s Sanctum can’t reduce the colored mana requirement of an instant or sorcery spell.