Like I said several times.Okay, I think I'm tracking you with these last two. You're saying some kind of story of how magic works has to exist in order for the ruleset for magic to work or make sense? I don't agree. I don't bother to explain how magic works in my games and it seems to go just fine. Anytime you can swap in different things and nothing else changes it's a good sign that that thing isn't important to the overall operation. It might do something else, like tell a story you like, but it's not essential to the ruleset.
You do not need to use an interface to explain the connection of magic and spells. You don't have to explain anything.
But if you don't explain things, you can't explain thing nor enter discussion about explanations. if someone says "it doesnt make sense" and you lack explanations, you can't display how it makes sense.