Middle-Codes are a series of communications between Middlemen and their comrades or headquarters. The total number of Middle-Codes is unknown (even by The Middleman), but there are at least eighty-six.
Known codes are:
- Code 7: A trusted Middleman ally is in jeopardy. (introduced in "The Doomsday Armageddon Apocalypse")
- Code 47: A brief, prerecorded message sent from the Middleman to his or her trainee (or vice versa) via the Middle-Watch if the wearer dies on a mission. The Middleman records a Code 47 for Wendy before every mission, but she resisted the idea, calling it "planning for failure", until the end of "The Clotharian Contamination Protocol".
- Code 86: Shuts down the Real-Time Situation Recording Archive if a Middleman or Middle-trainee requires privacy of a personal nature, such as an intimate encounter. Wendy repeatedly fails to engage Code 86 while hooking up with Tyler Ford in "The Obsolescent Cryogenic Meltdown", which means Ida is allowed to watch every intimate encounter between them.
Nothing has been revealed about the remaining eighty-three codes, and, as stated above, there may also be more beyond Code 86.