Slot Data

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

Slot

Name	Type	Meaning
Present	Boolean	True if there is an item in this position; false if it is empty.
Item ID	Optional VarInt	The item ID. Not present if present is false. Item IDs are distinct from block IDs; see Data Generators for more information
Item Count	Optional Byte	Not present if present is false.
NBT	Optional NBT	Not present if present is false. If 0 (TAG_End), 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

  00                      | empty slot
  01 01 01 00             | a stone block
  01 01 01 04 CA FE BA BE | a stone block with (made-up) NBT data