@JeremyECrawford Does the +1 from Improved Pact Weapon carry through when used as a spell focus?
— McGill (@RandomMagilla) December 19, 2017
The bonus to attack rolls conferred by Improve Pact Weapon applies to the weapon's attack rolls, not to a spell's attack rolls. #DnD https://t.co/t8HIFPxnwj
— Jeremy Crawford (@JeremyECrawford) December 19, 2017
does the +1 stack with say sun blade which already has a +2 to become a +3
no, it says, “In the case of Improved Pact Weapon, it adds a +1 Bonus to Attack and Damage Rolls made with the weapon unless it already has a +1 bonus or better”