(A drug conspiracy requires no "act in furtherance.")

So if you are "just joking" with your team and one of them takes your joke seriously and purchases bank robbery supplies or puts an SD card into a sandwich you are liable.

I think the most solid proof thats its not a geuine conspiracy would be

A) if you lied to the person giving you the money, about owning a gun or something else relevant, showing your intentions weren't genuine

B) showing the conspiracy is not credible, i.e. you are conspiring ro use a sniper rifle but you don't k ow how to shoot.

Also conspiracy doesn't require you to be proficient at executing your plan but rather the intention and motivation and opportunity to do so. You can still shoot a gun and cause harm even if you don't know how to shoot, and there's no way to really prove you don't either.