Well, as a confirmed remainer and someone who will never forgive Johnson for stabbing us in the back, eh. The act required him to send a letter, which he did. Frankly, it's a silly and spurious requirement. It didn't require him to want an extension, or bar him for saying he didn't think it was a good idea.

Parliament can't directly negotiate treaties with foreign powers. It's just not possible, that's a function of the executive. Parliament can approve or disapprove of such treaties but can't determine what the executive wants to do. The same goes for the referendum and is why it was a stupid idea. No referendum can require parliament or the government to want to do something, or specify exactly and unambiguously how they should go about doing something they don't want to do.