A Workshop Witch (工房の魔女 Koubou no Majo?, lit. "Studio Witch") is an offical term that refers to witches educated in witchcraft "Workshops", trained to stop the evil events performed by Tower Witches in any major city, anywhere in the world.
The Workshop Witches build workshops in cities where many people gather and reside and keep watch to make sure that no magic users are using their magic for evil. There are workshops in every major city that do the monitoring of the witches activities. Every city of workshops has a commander and it's a custom to get the permission of the commander when a student witch decides to take an apprentice.
Despite being absolutely honorable, the Workshop Witches' mission is no more than preventing actions from Tower Witches against ordinary people and property. Workshop Witches are not allowed to interfere with normal human problems, such as a fight with gangsters.