5 In either case, we shouldn't be surprised to see Cai failing to fully represent its own inner workings. An agent cannot explicitly represent itself in its totality, since it would then need to represent itself representing itself representing itself ... ad infinitum. Environmental phenomena, too, must usually be compressed.

This is obviously false. An agent's model can most certainly include an exact description of itself by simple quining. That's not to say that quining is the most efficient way, but this shows that it certainly possible to have a complete representation of oneself.