Can God read minds, and if so - to what extent?
It seems clear that God can read minds or else prayer, for instance, would be meaningless... It seems absurd to assert that God would require thoughts to be spoken aloud, or written down.
And if this was so, there would be the usual problem of uncertain interpretation of such indirect and symbolic media God might misunderstand!
Yet, if free will or agency is real (which, for Christians it must be), then there must be something inaccessible to God.
Yet again, it makes little sense to suppose that we could conceal our plans from God, and successfully lie to God.
Did Satan do this, at first - did he conceal his real nature and plans from God?
My conclusion is that God knows our conscious thinking, but neither God nor our consciousness has direct knowledge of our ultimate selves.
Thus God cannot read-off our ultimate nature, cannot know by observation and fully and for-sure - how we really are - and neither can we do so.
In other words, God can know our thinking, but our thinking is not our-self.
Both God and our thinking only know ourselves by inference, by observing what our-self does, including what thoughts emerge from our-self.
God could only know Satan by observation and inference.. Albeit that observation included Satan's thinking.
But this model can't be complete (no model can be complete!), especially because it has only one-way traffic from the self to consciousness, which would mean the self could not learn.
Since the self can learn, the self can't be divided from consciousness...
Indeed, this is another of those "polar logic" situations where self and thinking may be distinguished but not divided, since they are not separate in origin or nature...
Both thinking and self are attributes of All Beings, but the self stands for that individual unknowability which enables agency...
That "bit" of us which God cannot read.
Thus it was that Satan deceived God as to his nature and plans. It was possible because Satan was also deceiving himself.
Satan did not even Know himself, except by observation and inference.
And neither do we.