Hi,
I have idea about antibot mechanic
It will work with current experience system.
Lets say that every activity you do, cost some experience. In the normal state it will be really cheap.
When you repeat some action like "farming" you fill bar of "enjoy" until it change state to "boring" there will be activity more expensive and next will be level "furious" and so on.. something like hunger level bar.
If you do something different you will recieve some xp back.
If bot repeat action he will lost all xp and only way for him to continue is get some xp back by doing something else.
If it will be balanced right, it can work.