The sleeper program was an initiative by Bureau 13 under the auspices of the Psi Corps to create specially-programmed sleeper agents. These agents were made by crafting a second personality, completely subservient to the Corps, submerged beneath the real one. This made them impervious to telepathic detection or interference, as the sleeper personality would be indistinguishable from the individual's own sub-conscious. However, upon receiving a telepathic codeword, the agent's original personality would be instantly erased - similar to a mindwipe - and the crafted persona would take over, armed with all of the knowledge and skills they were programmed with.