The Memory of Earth

Wikipedia contains spoilers

The Memory of Earth is the first novel of the Homecoming saga of Orson Scott Card. Humanity has lived for 40 million years in the planet Harmony, after making Earth uninhabitable. In order not to repeat the mistakes that led to the destruction of civilization on Earth, a computer was left as guardian of this planet. Its main mission was to prevent humans from developing technologies that could make wars a global affair. For that, humans were genetically modified so they could communicate with the Oversoul, as the computer is known. However, after this long time the Oversoul is beginning to fail, and he choses a group of human to go to Earth and update his programing.