Slot Data

The Slot data structure is how Minecraft represents an item and its associated data in the Minecraft Protocol.

Slot

Name	Type	Meaning
Item ID	Short	The item ID. A value of -1 signifies that the slot is empty, and no further data follows. Item IDs are distinct from block IDs; see Data Generators for more information
Item Count	Optional Byte	Not present if Item ID is -1.
NBT	Optional NBT	Not present if Item ID is -1. If 0, there is no NBT data, and no further data follows. Otherwise the byte is the start of an NBT blob as shown below:

  COMPOUND ''
    LIST 'StoredEnchantments'
      COMPOUND
        SHORT 'id'
        SHORT 'lvl'
      END
      COMPOUND
        ...
      END
      ...
    END
    INT 'Unbreakable'
    ...
  END

See NBT for more information about the NBT format, and here for the contained information and its format. Note that tool durability is included in NBT, among other things.

Examples

  ff ff                      | empty slot
  01 16 01 00                | a diamond pickaxe
  01 16 01 01 04 CA FE BA BE | a diamond pickaxe with (made-up) NBT data