You're brushing up real close to the framework of CS Friedmans' Coldfire Trilogy.
No, I don't think so, though that's my own fault for inclarity of presentation.
I'm not envisioning anything like the bits in the Coldfire books where Vryce's own nightmares come to life and he has to hack them up.
Because we none of us have the completeness of knowledge required to affirm belief in the technology we use each day, and the most momentary lack of belief or faith cripples said tech.
Nor am I proposing the operation of technology being inherently faith-based. Though faith-affected is an interesting question without an obvious answer; it would seem to make sense that technology should be notably hard to effect with magic, and the more sophisticated, the harder to effect.
One of the difficult bits comes in when you attempt to sort out what exactly is responding to the subject's belief. Here is a bit of recursion for you: Does the subject believe that an embodied actor is casting the magic, and, if so, will an embodied actor be created or an existing one be compelled to act?
I definitely did not specify things clearly enough then.
What I have in mind for the operation of magic is that there exist spells and spell-casters. And that the spells must be initiated by someone casting them. The subject's belief governs the
efficacy of the magic rather than its
existence, is I think the distinction for which I am looking; magic cannot be generated
ex nihilo by the belief of a subject. The belief effect is reactive rather than proactive.