How did Louis XI learn about the Burgundian state during his exile?

During his exile, Louis XI lived as a guest of Philip the Good, the Duke of Burgundy. This position allowed him to acquaint himself thoroughly with the inner workings of the great Burgundian state, which he would later seek to dismantle.1

While he was a guest, his father, Charles VII, famously remarked that Philip was feeding the fox that would eventually eat his hens. During this same period, Louis also maintained a network of spies to keep himself informed about the details of his father's illness in France.1