+1 passive
+0.5 toggle
Please make it work if the conditions apply or default to a normal attack if the conditions no longer apply.
I wonder ...
Do you realize that such system would require you allways use your Sneak Attack Bonus first? O_o
Just imagine:
- 1hp Goblin is right next to you, if you move, you get AOO ...
- 15hp Bugbear is just few steppes far, it have Guiding Bolt effect on it > you could Sneak Attack it ...
Now ...
With toggle (or simply Off-Hand Sneak Attack button, that have litteraly the same effect) ...
You can kill the Goblin with regular Off-Hand attack, no reason to waste full action and stronger strike to them.
Then you can run towards the Bugbear and strike him down with Sneak Attack ... oh you missed, what a shame ... no matter, you still (if you are Thief ofc.) have second Off-Hand attack that will aply Sneak Attack bonus damage.
With passive ...
You have to trigger AOO ...
Since as long as it is there, you are threatened and have disadvantage for Ranged Attack > meaning no Sneak Attack for Bugbear ...
And in order to use that Sneak Attack you need to attack Bugbear first, otherwise you would just waste it to deal extra damage to 1hp Goblin.