Event catalogue

78 events are in the catalogue (ids 1-511 are stable ABI). Plugins can add their own events with ids from 512 (see Events).

Mutable fields can be changed by handlers and are read back by the code that fired the event; all others are readonly in C#. Engine says whether the engine fires the event in this release; an event marked “not yet” can be subscribed to, but nothing fires it until the gameplay code gets wired up.

Try the event explorer to filter this list.

Server and tick

ServerStartEvent

Fired once after the server finished starting, before the first tick. mc:server_start · id 1 · not cancellable · engine: fired · type reference

ServerStopEvent

Fired once when the server begins shutting down. mc:server_stop · id 2 · not cancellable · engine: fired · type reference

TickStartEvent

Fired at the start of every server tick. mc:tick_start · id 3 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Tick	ulong	no	The tick number.

TickEndEvent

Fired at the end of every server tick. mc:tick_end · id 4 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Tick	ulong	no	The tick number.
TickNanos	long	no	Wall time spent in this tick.

Other

ServerListPingEvent

A client asked for the server list status. Change the MOTD, the player counts or hide the player sample. mc:server_list_ping · id 100 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Connection	ulong	no	Connection id.
Address	Utf8String	no	Client address.
ProtocolVersion	int	no	Protocol version the client announced.
Motd	component	yes	The message of the day.
MaxPlayers	int	yes	Maximum player count shown.
OnlinePlayers	int	yes	Online player count shown.
HidePlayers	bool	yes	Do not send the player sample.

CommandsRegisteredEvent

The command tree changed (a plugin registered or removed commands, or a permission changed). Fired once per tick at most, before the trees are resent to the players. mc:commands_registered · id 101 · not cancellable · engine: fired · type reference

PluginEnableEvent

A plugin finished enabling. mc:plugin_enable · id 102 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
PluginId	Utf8String	no	The plugin id.
PluginName	Utf8String	no	The plugin name.
Version	Utf8String	no	The plugin version.

PluginDisableEvent

A plugin was disabled (unload or hot reload); its registrations are already released. mc:plugin_disable · id 103 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
PluginId	Utf8String	no	The plugin id.
PluginName	Utf8String	no	The plugin name.
Version	Utf8String	no	The plugin version.

PermissionChangedEvent

A permission entry of a player changed (or of a group or everything: AllPlayers is true). Fired after the change; the command trees of the players are resent in the same tick. mc:permission_changed · id 104 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	Uuid	no	The profile whose permissions changed (zero when AllPlayers).
AllPlayers	bool	no	A group, the default group or the whole backend changed.

PermissionsReloadedEvent

The permission backend was reloaded from disk (/perm reload or Permissions.Reload). mc:permissions_reloaded · id 105 · not cancellable · engine: fired · type reference

PrivateMessageEvent

A player sent a private message (/msg, /tell, /w) to one player. Cancel to drop the copy for that target. Changing the message sends it unsigned; a changed decoration keeps it signed. Console senders do not fire it. mc:player_private_message · id 305 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Sender	player	no	The player who typed the command.
Target	player	no	The recipient. A /msg with several targets fires once per target.
Message	Utf8String	yes	The typed text. Changing it sends the message unsigned.
Decoration	component	yes	The body as the line shows it (unsigned content). Equal to the typed text means none. Keeps the message signed.

InventoryOpenEvent

A player is about to open a container (chest, furnace, crafting table, …). Cancel to keep it closed. mc:inventory_open · id 260 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Kind	enum:InventoryKind	no	The container kind.
HasPos	bool	no	Whether the container is a block.
Pos	BlockPos	no	The block position.

InventoryCloseEvent

A player closed a container. mc:inventory_close · id 261 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Kind	enum:InventoryKind	no	The container kind.

InventoryClickEvent

A player clicked a slot of an open container (also the player inventory). Cancel to undo the click (the client is resynced). mc:inventory_click · id 262 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Kind	enum:InventoryKind	no	The container kind.
Slot	int	no	The clicked slot index of the container (-999 outside the window).
ClickType	enum:ClickType	no	How it was clicked.
Button	int	no	Raw button of the packet.
Clicked	item	no	The item in the clicked slot.
Cursor	item	no	The item on the cursor.

InventoryDragEvent

A player finished dragging a stack over several slots. Cancel to undo. mc:inventory_drag · id 263 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Kind	enum:InventoryKind	no	The container kind.
DragType	enum:DragType	no	The drag mode.
Slots	NativeBytes	no	The dragged slots as packed little-endian int32 values.
Cursor	item	no	The cursor stack being distributed.

CraftItemEvent

A player took the result of a crafting recipe (cancel the InventoryClick event of the result slot to prevent crafting). mc:craft_item · id 264 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Recipe	Utf8String	no	Recipe id.
Result	item	no	The crafted item.
ShiftClick	bool	no	Whether it is a quick-craft.

PrepareCraftEvent

The crafting grid matched a recipe. Cancel to show no result. mc:prepare_craft · id 265 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Recipe	Utf8String	no	Recipe id.
Result	item	no	The result that would be shown.

FurnaceSmeltEvent

A furnace, smoker or blast furnace finished smelting an item. Cancel to keep the input unsmelted. mc:furnace_smelt · id 266 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The furnace.
Source	item	no	The ingredient.
Result	item	no	The product.

FurnaceBurnEvent

A furnace is about to consume fuel. Cancel to not burn it; the burn time may be changed. mc:furnace_burn · id 267 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The furnace.
Fuel	item	no	The fuel.
BurnTicks	int	yes	Burn time in ticks.

EnchantItemEvent

A player is enchanting an item at an enchanting table. Cancel to refuse. mc:enchant_item · id 268 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Item	item	no	The item being enchanted.
Option	int	no	The chosen option (0-2).
Cost	int	no	Levels charged.

PrepareAnvilEvent

The anvil inputs changed and a result was computed. Cancel to show no result; the cost may be changed. mc:prepare_anvil · id 269 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
First	item	no	Left input.
Second	item	no	Right input.
Result	item	no	The computed result.
RepairCost	int	yes	Levels the player pays.
RenameText	Utf8String	no	The text typed in the rename field.

TimeSkipEvent

The day time jumped (sleeping through the night, /time set or /time add). mc:time_skip · id 300 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Reason	enum:TimeSkipReason	no	Why.
SkipAmount	long	no	Ticks the clock advanced.

WeatherChangeEvent

The rain started or stopped (overworld weather). mc:weather_change · id 301 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Raining	bool	no	Whether it will be raining.
Thundering	bool	no	Whether it will be thundering.

PortalCreateEvent

A nether portal frame is about to be filled or a destination portal built. Cancel to prevent it. mc:portal_create · id 303 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Reason	enum:PortalCreateReason	no	Why.
BlockCount	int	no	Portal blocks created.

MenuClickEvent

A player clicked in a custom GUI (Menu) of a plugin, after InventoryClick. Menus are locked: the click is denied (the client is resynced) unless a handler sets Allow, and a cancel always denies it. A click that could move items out of or into the menu (a slot of the menu, shift click, double click, drag, number key, off hand key) is delivered here with the slot of the menu’s own numbering (top slots first, then the player’s 27 + 9 slots). mc:menu_click · id 270 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Menu	int	no	The native id of the menu (what Menu uses to route the click).
Slot	int	no	The clicked slot, -999 outside the window.
ClickType	enum:ClickType	no	How it was clicked.
Button	int	no	Raw button of the packet.
Clicked	item	no	The item in the clicked slot.
Cursor	item	no	The item on the cursor.
Allow	bool	yes	Set by a handler to let the click change items like in a chest (default false: the menu is a display).

MenuCloseEvent

A plugin menu was closed for a player (for any reason). The player’s cursor stack has already been given back. mc:menu_close · id 271 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Menu	int	no	The native id of the menu.
Reason	enum:MenuCloseReason	no	Why it closed.

CustomItemUseEvent

A player used a custom item (right click in the air or on a block). Fired by the content layer after PlayerInteract. Cancel to stop the item’s own handler and the default action. mc:custom_item_use · id 272 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
CustomId	Utf8String	no	The id of the custom item, “myplugin:ruby”.
Hand	enum:Hand	no	The hand.
Item	item	no	The item stack.
HasBlock	bool	no	Whether the click was on a block.
Pos	BlockPos	no	The clicked block (only when has_block).
Face	enum:BlockFace	no	The clicked face (only when has_block).

CustomBlockPlaceEvent

A player is placing a custom block with a custom item. Cancel to refuse. mc:custom_block_place · id 273 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
CustomId	Utf8String	no	The id of the custom block.
World	world	no	The dimension.
Pos	BlockPos	no	Where it is placed.
Against	BlockPos	no	The block that was clicked.
Hand	enum:Hand	no	The hand.

CustomBlockBreakEvent

A player is breaking a custom block (fired by the content layer after BlockBreak). Cancel to keep the block. mc:custom_block_break · id 274 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
CustomId	Utf8String	no	The id of the custom block.
World	world	no	The dimension.
Pos	BlockPos	no	The block.
DropItems	bool	yes	Whether the block’s drops are spawned.

CustomBlockInteractEvent

A player right-clicked a custom block (fired by the content layer after PlayerInteractBlock). Cancel to stop the block handler and the item use. mc:custom_block_interact · id 275 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
CustomId	Utf8String	no	The id of the custom block.
World	world	no	The dimension.
Pos	BlockPos	no	The block.
Face	enum:BlockFace	no	The clicked face.
Hand	enum:Hand	no	The hand.
Item	item	no	The item in that hand.

NpcInteractEvent

A player clicked an NPC made with Npcs.Create (a left click is an attack, a right click an interaction). Observed only: the click has no other effect. mc:npc_interact · id 304 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Npc	ulong	no	The NPC’s handle.
Action	enum:NpcClick	no	The click.
Hand	enum:Hand	no	The hand (a left click is the main hand).
Sneaking	bool	no	Whether the player was sneaking.

Player

PlayerPreLoginEvent

A client finished authentication and is about to enter the configuration phase. Handlers run on the TICK thread: a blocking call (a database or web lookup) freezes the whole server, so do not look anything up here. Cancel to refuse the login (set the kick message first), or call Defer() and answer later from Scheduler.RunAsync: the login waits up to 30 seconds, continues when every deferral allowed it and is refused as soon as one denies. A plugin that unloads releases its pending deferrals (counted as allowed). mc:player_pre_login · id 10 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Connection	ulong	no	Connection id.
Uuid	Uuid	no	The authenticated profile id.
Username	Utf8String	no	The profile name.
Address	Utf8String	no	Client address.
KickMessage	component	yes	Shown to the client when the login is cancelled (default: a generic message).
Deferrals	int	no	How many plugins hold the login (each Defer() adds one): it continues when all of them allowed it, and any denial refuses it at once.

PlayerJoinEvent

A player entity entered the play state. The join message is broadcast after the handlers ran. mc:player_join · id 11 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Uuid	Uuid	no	The profile id.
Username	Utf8String	no	The profile name.
JoinMessage	component	yes	The message broadcast to everybody (set to an empty component to suppress it).

PlayerQuitEvent

A player disconnected (the entity is still alive during dispatch). mc:player_quit · id 12 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Uuid	Uuid	no	The profile id.
Username	Utf8String	no	The profile name.
Reason	Utf8String	no	Why the connection ended: disconnected, kicked, timeout, protocol_error, connection_lost or server_shutdown.
QuitMessage	component	yes	The message broadcast to everybody (set to an empty component to suppress it).

PlayerMoveEvent

A player moved or rotated. Cancel to teleport the player back; ‘to’, ‘yaw’ and ‘pitch’ may be rewritten. Fires for every accepted movement packet: keep handlers cheap. mc:player_move · id 13 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
From	Vec3d	no	Position before the move.
To	Vec3d	yes	Position after the move.
Yaw	float	yes	Yaw after the move.
Pitch	float	yes	Pitch after the move.
OnGround	bool	no	Whether the client reports being on the ground.

PlayerChatEvent

A player sent a chat message. Cancel to drop it. Changing Message or Rendered sends the line as an unsigned server message instead of the player’s signed one. SenderName, ChatType, Decoration and the filter fields restyle the signed line without unsigning it: the signature covers only the typed text. mc:player_chat · id 14 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The sender.
Message	Utf8String	yes	What the player typed. Changing it re-renders the line with the default format.
Rendered	component	yes	The complete line shown to everybody (default: message). Replace it to change the format; takes precedence over Message.
SenderName	component	yes	The sender name as the line shows it (hover, click and insertion included). Changing it keeps the message signed.
ChatType	enum:ChatKind	yes	The chat type of the line: Chat, EmoteCommand or SayCommand. The message kinds need a target and are refused here (Chat is used).
Decoration	component	yes	The body as the line shows it (unsigned content: colours, highlights, glyphs). Equal to the typed text means none. Keeps the message signed.
FilterKind	enum:ChatFilterKind	yes	How the recipients who filter text see the message (vanilla FilterMask). Any other value fully filters the message.
FilterBits	Utf8String	yes	For PartiallyFiltered: one 0 or 1 per UTF-16 unit of the typed text, 1 hides the unit. A different length or character fully filters the message.

PlayerCommandEvent

A player ran a command (without the leading slash). Cancel to suppress it; the command line may be rewritten. mc:player_command · id 15 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Command	Utf8String	yes	The command line without the slash.

PlayerInteractBlockEvent

A player right-clicked a block (fired after PlayerInteract). Cancel to stop the block interaction and item use. mc:player_interact_block · id 16 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Pos	BlockPos	no	The clicked block.
Face	byte	no	The clicked face (BlockFace).
Hand	byte	no	The hand (Hand).
Item	item	no	The item in that hand.

PlayerKickEvent

A player is about to be kicked by a command or plugin. Cancel to keep the player. Not fired for protocol errors or disconnects. mc:player_kick · id 110 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Reason	component	yes	The disconnect screen text.
LeaveMessage	component	yes	The message broadcast to everybody (empty = the default quit message).

PlayerRespawnEvent

A player is respawning. The destination may be changed. mc:player_respawn · id 111 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Reason	enum:RespawnReason	no	Why.
Position	Vec3d	yes	Where the player appears.
World	world	yes	The dimension the player appears in.
IsSpawnPoint	bool	no	True when a bed or respawn anchor of the player is used, false for the world spawn.

PlayerDeathEvent

A player died. The death message, inventory/experience drops and level keeping can be changed. mc:player_death · id 112 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Killer	Entity	no	The entity responsible (none if there is none).
Cause	enum:DamageCause	no	The damage cause.
DeathMessage	component	yes	Broadcast to everybody (empty = none).
DropInventory	bool	yes	Drop the items (false keeps them, like keepInventory). Only the items: the experience is controlled by the two fields below.
KeepLevel	bool	yes	Keep the experience level through the respawn (default: the keepInventory rule). True drops no experience orbs.
DropExperience	int	yes	Experience points dropped as orbs at the death position (default the vanilla amount min(level*7, 100), 0 with keepInventory); independent of drop_inventory.

PlayerCreativeSlotEvent

A creative-mode player put a stack into an inventory slot from the creative menu (slot -1: threw one out of the menu). Cancel to refuse; the client is resynced. mc:player_creative_slot · id 129 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Slot	int	no	The menu slot (1-45), or -1 for a drop.
Item	item	no	The stack the client wants.

PlayerItemHeldEvent

A player selected another hotbar slot. Cancel to revert the selection. mc:player_item_held · id 113 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
PreviousSlot	int	no	Hotbar slot before (0-8).
NewSlot	int	no	Hotbar slot selected (0-8).

PlayerSwapHandsEvent

A player swapped the main hand and off hand items (F key). Cancel to keep them. mc:player_swap_hands · id 114 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
MainHand	item	no	The item that moves to the off hand.
OffHand	item	no	The item that moves to the main hand.

PlayerDropItemEvent

A player drops an item from the hotbar or inventory (drop key). Cancel to keep it. mc:player_drop_item · id 115 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Item	item	no	The item (a single one, or the whole stack for the control-drop).
WholeStack	bool	no	Control-drop of the whole stack.

PlayerPickupItemEvent

A player is about to pick up an item entity. Cancel to leave it on the ground. mc:player_pickup_item · id 116 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
ItemEntity	Entity	no	The item entity.
Item	item	no	The stack on the ground.

PlayerConsumeEvent

A player finished eating or drinking. Cancel to prevent the effects and the item consumption. mc:player_consume · id 117 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Item	item	no	The consumed item.
Hand	enum:Hand	no	The hand.

PlayerInteractEvent

A player clicked (left or right, air or block). Cancel to stop the default action: block breaking start, block use, item use. mc:player_interact · id 118 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Action	enum:InteractAction	no	What was clicked.
Hand	enum:Hand	no	The hand.
Item	item	no	The item in that hand.
Pos	BlockPos	no	The clicked block (only for block actions).
Face	enum:BlockFace	no	The clicked face (only for block actions).
HasBlock	bool	no	Whether pos/face are valid.

PlayerInteractEntityEvent

A player right-clicked an entity. Cancel to stop the interaction. mc:player_interact_entity · id 119 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Target	Entity	no	The clicked entity.
Hand	enum:Hand	no	The hand.
Item	item	no	The item in that hand.

PlayerToggleSneakEvent

A player started or stopped sneaking. Cancel to ignore the change. mc:player_toggle_sneak · id 120 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Sneaking	bool	no	The new sneaking state.

PlayerToggleSprintEvent

A player started or stopped sprinting. Cancel to ignore the change. mc:player_toggle_sprint · id 121 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Sprinting	bool	no	The new sprinting state.

PlayerToggleFlightEvent

A player started or stopped flying (creative / may-fly). Cancel to ignore the change. mc:player_toggle_flight · id 122 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Flying	bool	no	The new flying state.

PlayerGameModeChangeEvent

A player’s game mode is about to change. Cancel to keep the old one. mc:player_game_mode_change · id 123 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
OldMode	enum:GameMode	no	The current mode.
NewMode	enum:GameMode	no	The new mode.
Cause	enum:GameModeChangeCause	no	Why.

PlayerTeleportEvent

A player is about to be teleported (command, plugin, ender pearl, …). Cancel to stay; the destination may be changed. mc:player_teleport · id 124 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
From	Vec3d	no	Current position.
To	Vec3d	yes	Destination position.
FromWorld	world	no	Current dimension.
ToWorld	world	no	Destination dimension.
Cause	enum:TeleportCause	no	Why.

PlayerPortalEvent

A player is about to travel through a portal (nether portal, end portal, end gateway). Cancel to stay. mc:player_portal · id 125 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
From	Vec3d	no	Current position.
FromWorld	world	no	Current dimension.
ToWorld	world	no	Destination dimension.
Cause	enum:TeleportCause	no	Which portal.

PlayerChangedWorldEvent

A player arrived in another dimension. mc:player_changed_world · id 126 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
FromWorld	world	no	The dimension left.
ToWorld	world	no	The dimension entered.

PlayerResourcePackStatusEvent

A client reported the state of a pushed resource pack. mc:player_resource_pack_status · id 127 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
PackId	Uuid	no	The pack id given in the push.
Status	enum:ResourcePackStatus	no	The reported state.

PlayerLevelChangeEvent

A player’s experience level changed. mc:player_level_change · id 128 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
OldLevel	int	no	Level before.
NewLevel	int	no	Level after.

Block

BlockBreakEvent

A player is about to break a block. Cancel to keep the block (the client is resynced). mc:block_break · id 20 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Pos	BlockPos	no	The block.
BlockState	blockstate	no	The block state about to be broken.
DropItems	bool	yes	Whether the block drops its loot (the experience is controlled by experience).
Experience	int	yes	The experience orbs dropped by the block, pre-filled with what vanilla would drop (ores, spawners, sculk; silk touch applied). Set 0 to drop none or any amount to drop that many; independent of drop_items.
Tool	item	no	The item in the main hand.

BlockPlaceEvent

A player is about to place a block. Cancel to refuse; ‘block_state’ may be rewritten. mc:block_place · id 21 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Pos	BlockPos	no	Where the block goes.
Against	BlockPos	no	The clicked block.
BlockState	blockstate	yes	The state that will be placed.
Hand	byte	no	The hand (Hand).
Item	item	no	The block item used.

BlockDamageEvent

A player started digging a block. Cancel to stop the dig. Set InstaBreak to break it at once. mc:block_damage · id 180 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Player	player	no	The player.
Pos	BlockPos	no	The block.
Face	enum:BlockFace	no	The face being dug.
Tool	item	no	The item in the main hand.
InstaBreak	bool	yes	Break the block immediately (as in creative mode).

BlockIgniteEvent

Fire is about to be placed in the world. Cancel to prevent it. mc:block_ignite · id 181 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	Where the fire goes.
Cause	enum:IgniteCause	no	What ignites it.
IgnitingEntity	Entity	no	The player or entity responsible, if any.

BlockBurnEvent

Fire is about to destroy a block. Cancel to keep it. mc:block_burn · id 182 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The burning block.
BlockState	blockstate	no	Its state.

BlockSpreadEvent

A block is spreading to a neighbour (grass, mycelium, vines, fire). Cancel to stop it. mc:block_spread · id 183 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The target position.
Source	BlockPos	no	The spreading block.
NewState	blockstate	no	The state that would be placed.

BlockFadeEvent

A block is melting, drying or fading (ice, snow, farmland, fire). Cancel to keep it. mc:block_fade · id 184 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The block.
BlockState	blockstate	no	The current state.
NewState	blockstate	no	The state it fades to.

BlockFormEvent

A block is forming through the environment (snow, ice, concrete, obsidian …). Cancel to stop it. mc:block_form · id 185 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The position.
BlockState	blockstate	no	The current state.
NewState	blockstate	no	The state that forms.

BlockGrowEvent

A plant is growing (crops, stems, cactus, sugar cane, …). Cancel to stop it. mc:block_grow · id 186 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The block.
BlockState	blockstate	no	The current state.
NewState	blockstate	no	The state after growth.

BlockPistonExtendEvent

A piston is about to extend. Cancel to keep it retracted. mc:block_piston_extend · id 187 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The piston.
Direction	enum:BlockFace	no	The push direction.
Sticky	bool	no	Whether it is a sticky piston.
MovedBlocks	int	no	Number of blocks that move.

BlockPistonRetractEvent

A piston is about to retract. Cancel to keep it extended. mc:block_piston_retract · id 188 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The piston.
Direction	enum:BlockFace	no	The push direction.
Sticky	bool	no	Whether it is a sticky piston.
MovedBlocks	int	no	Number of blocks that move.

BlockRedstoneEvent

A redstone component’s output power changes. The new power may be changed. mc:block_redstone · id 189 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
World	world	no	The dimension.
Pos	BlockPos	no	The block.
OldPower	int	no	Power before (0-15).
NewPower	int	yes	Power after (0-15).

Entity

EntitySpawnEvent

An entity is about to be added to the world. Cancel to prevent it. mc:entity_spawn · id 30 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Entity	Entity	no	The entity (already created).
EntityType	key.entity_type	no	The entity type key, e.g. minecraft:zombie.
Position	Vec3d	no	Where it appears.
Reason	enum:SpawnReason	no	Why it spawns.

EntityDamageEvent

A living entity is about to take damage. Cancel to negate it. ‘amount’ (the damage after armor and enchantments, before absorption) may be rewritten. mc:entity_damage · id 31 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Target	Entity	no	The damaged entity.
Attacker	Entity	no	The responsible entity, none when there is no attacking entity.
DamageType	key.damage_type	no	The damage type key, e.g. minecraft:fall.
Amount	float	yes	Final damage after armor and enchantments.
Cause	enum:DamageCause	no	The cause derived from the damage type.
RawAmount	float	no	Damage before armor and enchantments.
BlockSource	BlockPos	no	Position of the block that caused the damage.
HasBlockSource	bool	no	Whether block_source is valid (cactus, magma, fire, …).

EntityDeathEvent

A living entity died. mc:entity_death · id 32 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Entity	Entity	no	The entity.
Killer	Entity	no	The responsible entity (none if there is none).
DamageType	key.damage_type	no	The damage type key, e.g. minecraft:player_attack.
Cause	enum:DamageCause	no	The cause derived from the damage type.

EntityCombustEvent

An entity is about to be set on fire. Cancel to prevent it; the duration may be changed. mc:entity_combust · id 221 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Entity	Entity	no	The entity.
DurationTicks	int	yes	Burn time in ticks.
Source	Entity	no	The entity that ignites it, if any.

Network

PacketReceiveEvent

A decoded-frame packet arrived (payload excludes the packet id). Cancel to drop it. mc:packet_receive · id 40 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Connection	ulong	no	Connection id.
Player	player	no	The player entity (none before play).
State	byte	no	Connection state.
PacketId	int	no	Packet id.
Payload	NativeBytes	no	Packet body (borrowed).

PacketSendEvent

RESERVED: not fired yet (the per-connection send path encodes shared frames). A packet is about to be sent to one connection. mc:packet_send · id 41 · cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Connection	ulong	no	Connection id.
Player	player	no	The player entity (none before play).
State	byte	no	Connection state.
PacketId	int	no	Packet id.
Payload	NativeBytes	no	Packet body (borrowed).

World

ChunkLoadEvent

A chunk became loaded. mc:chunk_load · id 50 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Dimension	int	no	Dimension index.
X	int	no	Chunk x.
Z	int	no	Chunk z.
NewlyGenerated	bool	no	True when the chunk was generated, false when loaded from disk.

ChunkUnloadEvent

A chunk is about to be unloaded. mc:chunk_unload · id 51 · not cancellable · engine: fired · type reference

Field	Type	Mutable	Description
Dimension	int	no	Dimension index.
X	int	no	Chunk x.
Z	int	no	Chunk z.