It's a challenge if he's ever heard one, but John has long since lost the need to prove himself to anyone and so he shakes his head easily.

"At the moment, nothing. I don't know nearly enough to be trusted not to make things worse." Then he smiles and says, "Besides, I told you, I'm a grunt. I execute plans, I don't create them." Finch is the one with the mind for that, not him.