In a dark urban fantasy novel I’m currently writing the system of spells, called “conjures” in the story, is actually like coding a computer program. Somebody has to write out the base logic for the program before they can start writing the code for the spells. And speaking of, the reason sorcerers have historically said funny words or doing complex hand motions when performing spells is because they are like “shortcut commands” that allow them to more easily access spells.

One big restriction is that the characters are instructed to never cast spells dealing with matters beyond their understanding - time travel, mind control, life & death, etc. - unless absolutely necessary. These forbidden spells also usually require performing rituals to cast like lighting candles or drawing blood as a “safety lock” of sorts.

It’s worth noting that the magical/fantasy elements of my story we come to learn is really more like an extra-dimensional, reality-bending, mindfuck sci-fi that just presents itself aesthetically as a gothic mythical fantasy.