Detect scrying

Detect scrying is a divination spell that alerts one to magical eavesdropping.

Effect
You immediately become aware of any attempt to observe you by means of clairaudience/clairvoyance or scrying. The spell’s effect radiates from you moves as you move. The spell also reveals the use of crystal balls or other magic scrying devices. You know the location of every magical sensor within the spell's area.

If the scrying attempt originates within the area, you also know its location. If the attempt originates outside this range, you and the scrier immediately make opposed Scry skill checks. (A Scry check is the same as an Intelligence check for a creature without the Scry skill.) If you at least match the scrier's result, you get a visual image of the scrier and a sense of the scrier's direction and distance from you (accurate to within one-tenth the distance).

Material Components
A small piece of mirror and a miniature brass hearing trumpet.