Wizardry

Wizardry is book magic, learned from tomes of wisdom and lore handed down through the generations. Spells of wizardry are all created by humans, so aren't a natural feature of the world.

Requirements

Anti-magic collars/handcuffs might be possible, but not available to everyone and I'd prefer to avoid anti-magic effects.

Gagging/binding is an option, but it's difficult to do long term. Do you keep a wizard permanently gagged and bound whilst they are in prison?

A focus of some kind (such as a staff) that a wizard has to have means it can be easily taken away. Disarming a wizard becomes possible.

If a new staff is too easy to make, it's not much of a deterrent. If it's too hard, then a character can be ruined by taking away their item.

Maybe a staff can be made in a few days. Maybe magic is a lot harder without it. Requires a certain type of wood, or certain enchantments to make a new staff. Good for short term disarmament, and in a controlled environment can be prevented from making a new one.

Possibly a wizard can invest part of their spirit into one to make it more powerful, but much weaker without it, and takes longer to construct again.