When doing something, you can do a supplemental action, which increases the difficulty of the roll. Usually those are simple actions, like running to another zone or something like that.
But could you do a supplemental magic action?
Replacing a simple action with magic is mostly done by thaumaturgy, but sponsored magic allows you to do it at evocations speed, so it would probably work there, if not for evocation.
So how about spells that move you one zone (maybe the same way Harry's potion in SF does) as a supplemental action, instead of running the distance? A communication spell to shout a quiet warning to a friend while fighting off the horde of ghouls. There are a lot of simple things that probably won't require a full spell, because they just replace supplemental actions. Should they be able to be done as a supplemental magical action or should magic always be a full action by itself? Should they cost stress as any other spell does or would they just be a differently flavored supplemental action without additional cost?
Imagine someone exploding into thousands of tiny pieces that dart toward his target, set themselves together again in front of him and then lounge an attack. Would be quite a spectacle. Of course, you would also be able to go through a line of enemies that was supposed to cut you off, because you are not limited in the way you move as a cloud of dust. Maybe require stress taken only, if the supplemental magical action is more than adding flavor and actually creating an advantage.