Akaasit Blade

You gain a +1 bonus to attack and damage rolls made with this magic weapon. This dagger is crafted from the arm blade of a defeated Akaasit (see Tome of Beasts 2). You can use an action to activate a small measure of prescience within the dagger for 1 minute. If you are attacked by a creature you can see within 5 feet of you while this effect is active, you can use your reaction to make one attack with this dagger against the attacker. If your attack hits, the dagger loses its prescience, and its prescience can't be activated again until the next dawn.