Keen Hearing. The fox has advantage on Wisdom (Perception) checks that rely on hearing.

Telepathic Connection. While your familiar is within 100 feet of you, you can communicate with it telepathically. Additionally, as a your Bonus Action, you can see through the familiar’s eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses it has.

No Attacking: On each of this creature's turns it may take any action except attacking. See Combat Actions.

Assisted Casting: Whenever you cast a spell with the range of "Touch" you can have the effect come from this creature, this takes this creature's reaction and uses it's stats for any spell attack. (If there is one)