| Field Name | Field Type | Field Constraints | Field Notes |
|---|
| Id |
short |
|
Send fixed Id of 0 for invalid item |
| Stack size |
unsigned short |
<div style="padding-left: 0px;">Minimum = 0<br>Maximum = 64</div> |
The number of items in the stack. Must be within the item's allowed stack size range. |
| Aux value |
unsigned varint |
<div style="padding-left: 0px;">Minimum = 0<br>Maximum = 32767</div> |
Item auxiliary/metadata value. Used to distinguish item variants. Ignored for block items where aux is always 0. |
| Net Id Variant |
ItemStackNetIdVariant |
|
Optional network ID variant used to track item stack identity across client and server. |
| Block Runtime Id |
unsigned varint |
<div style="padding-left: 0px;">Minimum = 0</div> |
Runtime block state ID associated with this item when it represents a block. Used to identify the exact block state placed when the item is used. |
| User Data Buffer |
string |
|
The ItemInstanceUserData binary blob encoded as a String, so it's unsigned varint length prefixed. Get all your nbt+property bytes, calculate the length, write that length, THEN write the data. |
