Events

Event handlers are registered using feature.on(event_name, handler). All events that support cancellation share a common cancelled property.

The Lua API definitions provide an overload for each event name, so the callback's event parameter is inferred automatically:

feature.on("player_jump", function(event)
    event.yaw = 90
    event.cancelled = true
end)

Cancellable event types inherit from types.cancellable_event, which declares cancelled. Core callbacks such as enabled, disabled, and game_tick receive no event parameter.

Common Properties

Property	Type	Description
cancelled	boolean	Set to true to block the event from proceeding.

Setting cancelled to false does not undo cancellation.

Game Events

packet

Event details for network packets.

• Property packet: net.minecraft.network.protocol.Packet - The raw Java packet object.
• Property type: string - The type of packet ("client" or "server").

The network functions network.send, network.send_no_event, network.is_server_packet, and network.process_packet accept Java packet instances, including packets created with java.new and the event.packet value received by this callback.

chat_message

Event details for outgoing chat messages.

• Property message: string - The message content.

key_press

Event details for keyboard input.

• Property key: enums.key_code - The key code.
• Property modifiers: number - The bitmask of active modifiers.

mouse_event

Event details for mouse input.

• Property position: types.vector2 - The scaled mouse position.
• Property button: number - The mouse button index.
• Property state: string - The mouse interaction state ("click", "released", "scroll").
• Property scroll_x: number - The scroll delta on X axis.
• Property scroll_y: number - The scroll delta on Y axis.

player_block_collision

Called when the client checks for player block collisions.

• Property voxel_shape: userdata - The voxel shape of the collision (Minecraft's Java VoxelShape object).
• Property position: userdata - The position of the block (Minecraft's Java BlockPos object).
• Property block_state: userdata - The state of the block (Minecraft's Java BlockState object).

player_attack_entity

Called when the player attacks an entity.

• Property entity: userdata - The entity being attacked (Minecraft's Java Entity object).
• Property type: string - The attack type ("pre" or "post").

player_attack_re_sprint

Called during attack slowdown and again before the attack resets sprinting.

• Property velocity: types.vector3 - The velocity multipliers during slowdown, or the current player velocity during sprint reset. Assign a new vector to change the slowdown multipliers, editing the returned copy does not update the event. Velocity changes during sprint reset are not applied.
• Property cancelled: boolean - Set to true to prevent the sprint reset. Cancellation does not prevent slowdown, change velocity to control it.

feature.on("player_attack_re_sprint", function(event)
    event.velocity = types.vector3.new(1, 1, 1)
    event.cancelled = true
end)

player_inventory_close

Called when a container is closed.

player_item_slow_down

Called when the player slows down when using items.

• Property modifier: number - The slow down modifier.

player_jump

Called when the player jumps.

• Property yaw: number - The jump yaw.
• Property delta_y: number - The jump delta Y.

player_move

Called when the player moves.

• Property delta_x: number - The movement delta X.
• Property delta_y: number - The movement delta Y.
• Property delta_z: number - The movement delta Z.

player_push

Called when another entities pushes the player.

player_send_update

Called when the player sends an update packet.

• Property x: number - The x position.
• Property y: number - The y position.
• Property z: number - The z position.
• Property yaw: number - The yaw rotation.
• Property pitch: number - The pitch rotation.
• Property on_ground: boolean - Whether the player is on the ground.
• Property type: string - The update type ("pre" or "post").

player_step

Called when the player wants to step up a block.

• Property height: number - The step height.

player_tick

Called when the player ticks.

post_player_tick

Called after the player ticks.

level_change

Called when the level changes.

• Property level: userdata - The new Level object.

toggle_feature

Called when a feature is toggled.

• Property feature_name: string - The name of the feature being toggled.
• Property state: boolean - The new state of the feature.

game_loop

Called when the game loop ticks.

client_rotation

Called when updating the player rotation.

• Property rotation: types.vector2 - The current rotations (x: yaw, y: pitch).
• Property tick_delta: number - The tick delta.
• Method set_rotation(yaw, pitch): Sets the new rotation, rotations will automatically be corrected (GCD applied, properly clamped & wrapped).

window_resize

Called when the client window is resized.

• Property width: number - The new window width.
• Property height: number - The new window height.

music_update

Called when the music data gets updated.

• Property data: types.music_data - The music data object.

play_sound

Called when a sound plays.

• Property sound: string - The sound id string.

anti_bot

Called to check whether an entity is a bot or not.

• Property entity: userdata - The entity to be checked (Minecraft's Java Entity object).
• Property is_bot: boolean - Whether the entity is a bot or not.

server_chat_message

Called when the server sends a chat message.

• Property message: string - The chat message.

detect_staff

Called when a staff is detected by the 'Staff Detector' feature.

• Property username: string - The username of the detected staff, can be nil.

sprint_key_press

Called when the sprint key press state is checked.

• Property pressed: boolean - Whether the sprint key is pressed.

Rendering Events

prepare_ui_canvas

Called when building the ui geometry.

• Property canvas: types.ui_canvas - The ui canvas.
• Property scaled_size: types.vector2 - The scaled window size.
• Property mouse_position: types.vector2 - The mouse position.
• Property tick_delta: number - The tick delta.

prepare_world_canvas

Called when building the world geometry.

• Property canvas: types.world_canvas - The world canvas.
• Property mouse_position: types.vector2 - The mouse position.
• Property tick_delta: number - The tick delta.

Core Events

Event	Handler Sig	Description
enabled	function()	Called when the feature is enabled
disabled	function()	Called when the feature is disabled
game_tick	function()	Called every game tick
on_interface_suffix	function(): string	Returns a suffix for the HUD enabled list