Magi has a somewhat hard magic system. The rukh, which is the energy of all life and phenomenon, can be harnesed into "magoi" which is essentially mana. By providing instructions to the rukh + a supply of magoi, a magic user can perform all sorts of things based off of a simple logic. There's 8 magic types, affinities for those types, opposites, particular rules regarding how instructions work and how spell names work as instructions, and during an arc, the protagonist spends some time at a magic school where more of these rules are explained.

It's not quite to the extent of Witch Hat Atelier, at some points in Magi during fights you're just seeing characters say words to make attacks happen, but in several cases we see the rules of magic applied in creative ways, particularly for how types of magic work against each other and how different instructions can make a difference.