McCarthy is pleased the stopper is still at the club after a number of bids over the summer from Chelsea.
He said: “From day one, the chairman and gaffer said John wasn't for sale and that remained the case.
“It just shows that we want to build. It's a measure of the ambition here at Everton.
“We have got a good squad and we want to continue to build and strengthen and get better – you can see that."