Free Will

[Angrboda]

What is an agent?

It is no more a part of compatibilism than it is of the idea that free will and determinism are incompatible.  In all of the discussions of free will, there is something that is described as having free will, or not having free will, depending on the position taken.

If one takes the position that there is no self, no will, then there is nothing being discussed that can be said to be free, nor that can be said to be not free.

If you are not, then it would be incorrect to say that you are free, and equally incorrect to say that you are not free.  If there is no you, then neither "you are free" nor "you are not free" would be about anything.

You haven't actually answered the question. That there is a self involved does not involve any discontinuity between agent and circumstance until you postulate that the agent is free in a sense that the circumstance is not. It is then that you need to justify the difference. So long as agent and circumstance are playing by the same rules, there is no question.