Inventory and items

inventory is game.inventory() — the 36 main slots plus the four armor slots and the off-hand. Reads are free; every mutation is queued onto the client's move queue and needs the client thread.

on<PrePlayerTickEvent> {
    val slot = inventory.find("golden_apple")
    if (!slot.found() || inventory.busy()) return@on
    val stack = inventory.item(slot)
    chat.print("${stack.count()} x ${stack.name()}")
    inventory.shiftClick(slot)
}

#Addressing a slot

#Slot.Kind

#ArmorSlot

#Reading

Item ids default to the minecraft: namespace, so "mace" and "minecraft:mace" are the same id. No read returns null: an absent stack comes back as an item whose empty() is true.

#Searching

#Moving things

#Inventory.Batch

Every mutation needs an open screen handler, and with a non-player screen open the ARMOR and OFFHAND slots throw ScriptStateException; a batch does not block, its queue drains over the following ticks. Slots of an open chest or server menu are addressed by Containers; switching the held hotbar slot is Slots and armor.

#The stack

#What it can do

#AttributeModifier

#Cooldowns

A cooldown belongs to the item's cooldown group, not to the stack, so every stack of that item reports the same value. setCooldown and removeCooldown write only the client's copy; the server keeps its own, and the next cooldown packet for that group overwrites yours.

#Names, lore, components

Text values are styled text.

#Rarity

#Hands

#Hand

#Arm

Arm is nursultan.item.Arm, the main-arm side reported by RenderItemEvent.arm() and the client-settings packets.