Here is some help from the Catechism of the Catholic Church
330 As pure spiritual creatures angels have intelligence and will: they are personal and immortal creatures, surpassing in perfection all visible creatures, as the splendor of their glory bears witness.
Angels cannot read our minds or know our heart, only God can.
So devils, being spiritual creatures
395 The power of Satan is, nontheless, not infinite. He is only a creature, powerful from the fact that he is pure spirit, but still a creature. He cannot prevent the building up of God’s reign. Although Satan may act in the world our of hatred for God and his kingdom in Christ Jesus, and although his actions may cause grave injuries–of a spiritual nature and, indirectly, even of a physical nature–to each man and to society, the action is permitted by divine providence which with strength and gentleness guides human and cosmic history. It is a great mystery that providence should permit diabolical activity, but we know that in everything God works for good with those how love him.
(Edwin 1961 brother)