The Command Deck is a new feature that was introduced in Kingdom Hearts Birth by Sleep and appeared later in Kingdom Hearts Birth by Sleep Final Mix, Kingdom Hearts Re:coded, and Kingdom Hearts 3D: Dream Drop Distance. It is here that Deck Commands can be equiped for use. The player can save up to three deck commands to choose from later on, and Command Melding is accessible from this menu as well.
At the start of the game, the player has three slots for battle commands, with that number increasing to five in Critical mode, and can unlock more as the story progresses, to a maximum of eight.
The number of slots for Action Commands, however, varies from character to character, with Terra having the least number, and Aqua the most.
Lastly, there's only one slot for Shotlock commands, regardless of the character.