Proposed Canon
An agreement between sides that contains terms each side must follow. Terms of a contract appear extremely difficult, or impossible to disobey.
 Known Contracts
Parson formed a contract with Charlie, trading calculations from his bracer in exchange for Charlescomm leaving the RCC.
Ansom signed Charlie's contract, forming an alliance.
Slately attempted to form a contract with Don King in order to procure enough shmuckers to promote his son to heir.
Archons have mentioned fulfilling contracts for Charlie.
Contracts apparently manifest as glowing paper with writing upon it, floating in the air.
It is expected that some of the resident barbarians in the Magic Kingdom survive by working for various sides by contract (as mercenaries, or selling spells as a service).