Mind Piercer - the enchantment detecting rapier

I love the addition of flavor through a detection piece. It is likely that if it detects all enchantment magic it could be abused, and it could also lead to it being a headache for you keeping track of said enchantment magic. I think reacting to charmed people is a useful tool that isn't too powerful as it doesn't explicitly say which person it is in the area. You could also have it where the player needs to make a Will save or unsheathe the sword because there is a charmed person near them. Also, I'm trying to think if there are other spells you could toss in that would make sense so ti isn't a one trick pony, but can't seem to do so right this moment, haha. Either way, a great idea to make a mundane item in the leveling process potentially be something that the player keeps for their entire adventuring career.

Essentially the sword would compel the player to pull out the sword even if they didn't want to. So rather than cart blanch they pull it out whenever a charmed person is near, or they don't pull it out at all there is a chance that in the middle of town the player yanks out the sword. If I was the player and was walking through town I may happen to be near someone that is shapechanged the sword would try to be pulled by me as soon as possible. At this time I would roll against the established Will safe, and on a fail I would draw the scenario with complete disregard for other.