Very seldom foxes bother cats.
Regardless if your sitting outside a fox still will get or make an attempt right in front of your face,I know from experience.
I recently am having the fox issue and this is what I do.
We spray wolf urine all around the perimeter,escpecially where the attacks are most frequently,I usually go into the woods a little and spray around,must be within 10-12 feet apart and applied after every rain and every ten days.I just started this and it even has My dogs intimidated,so I can only imagine what a fox thinks of it.
I also walk the perimeter of where attacks happen early in the mornings and late in the afternoon and occasionally try to walk it a during the day,but not everyone has a schedule to do so,but it’s summer and I have time.I have been letting the chickens free range and doing all this haven’t had one get caught,of course it’s only been four or three days.
On top of that I have two dogs,that means three different scents and three different canines that the fox has to compete with,foxes won’t fight a dog escpecially if they can get away,they cannot afford to get injured,best bet is to get a dog.