Scry Ambush — Open RPG Guide

Casting Time: 1 reaction, which you take when an enemy tries to make a surprise attack against you
Range: Self
Components: V, S
Duration: Instantaneous

You foresee your foe’s strike a split second before it occurs. When you cast this spell successfully, you also designate a number of your allies that can see or hear you equal to your spellcasting ability modifier + your proficiency bonus. Those allies are also not surprised by the attack and can act normally in the first round of combat.

If you would be surprised, you must make a check using your spellcasting ability at the moment your reaction would be triggered. The check DC is equal to the current initiative count. On a failed check, you are surprised and can’t use your reaction to cast this spell until after your next turn. On a successful check, you can use your reaction to cast this spell immediately.