A question about Walt's plan cigarette plan, perhaps a flaw.

So Walt convinces Jesse that Gus took the cigarette with the ricin, with the intent to poison Brock and thus making it appear Walt did it for revenge, turning Jesse against Walt. We know, of course, this is a fabrication.

My question is, what if Jesse asked "How would Gus know about the ricin cigarette?"? How did Walt expect Jesse to believe Gus knew about it at all? This whole thing doesn't make sense to me.

If I'm Jesse, I'd say "Wtf are you talking about dude, we both know the ricin cigarette was 100% between us" Walter is so smart, but how did he expect this to go unnoticed?