[xsamgreen]

You may be thinking of Indistinguishability Obfuscation. Current FHE algorithms (e.g. those undergoing standardization: https://homomorphicencryption.org/) don't provide IO. The compute provider knows the exact graph that is being computed, but, in the most secure scenario, they don't get to know the inputs and outputs of each node in the graph. The node operation (which can be only addition or multiplication) must be known to the compute provider so they can perform the correct mathematical transforms on the encrypted data.