Originally Posted by qhristoff
How will counterspell work in single player turn based? will the game stop and prompt each time?


On your turn, you set your reactions, likely through some kind of "Reactions" panel. A mage would turn off "Attack of Opportunity", and turn on "Cast Shield Spell" and/or "Counterspell", and if the condition which triggers Counterspell occurs, it goes off automatically. No prompt required.