Events

Handle server events with mc.on(eventName, handler). All events are wired through Fabric API callbacks in the mod lifecycle — no mixins are used for events.

Event handlers do not receive a ctx argument — unlike command handlers, they receive the event-specific arguments directly.

mc.on("player_join", function(player)
    mc.broadcast(player.name .. " joined the server!")
end)

Event Reference

Event	Handler Args	Cancellable
`server_start`	`()`	❌
`server_stop`	`()`	❌
`init`	`()`	❌
`uninit`	`()`	❌
`player_join_init`	`(player)`	✅
`player_join`	`(player)`	❌
`player_respawn`	`(player, alive)`	❌
`player_leave`	`(player)`	❌
`player_death`	`(player, damageType)`	❌
`player_chat`	`(player, message)`	✅
`player_block_break`	`(player, pos, blockId)`	✅
`player_block_place`	`(player, pos, blockId)`	✅
`player_use_item`	`(player, hand, item, itemId)`	✅
`player_attack_entity`	`(player, entity)`	✅
`player_interact_entity`	`(player, entity, hand)`	✅
`player_hurt`	`(player, damageType, amount)`	✅
`entity_hurt`	`(entity, damageType, amount, source)`	✅
`player_damage`	`(player, damageType, amount, blocked)`	❌
`entity_damage`	`(entity, damageType, amount, source, blocked)`	❌
`player_kill`	`(player, target, damageSource)`	❌
`entity_spawn`	`(entity)`	❌
`entity_despawn`	`(entity)`	❌
`entity_death`	`(entity, damageType, amount)`	✅

Cancellable Events

For cancellable events, return false to cancel:

mc.on("player_block_break", function(player, pos, blockId)
    if not player:hasPermission("build") then
        player:sendMessage("You cannot break blocks!")
        return false  -- cancels the block break
    end
end)

Notes

damageType is the last segment after . in the damage type registry ID (e.g. "player_attack", "fall", "in_fire", "on_fire").
blocked is a boolean indicating whether the damage was blocked by a shield. Available on player_damage and entity_damage only (not on the cancellable hurt events).
source on entity_hurt / entity_damage is the entity that caused the damage (or nil).
pos is a {x, y, z} table.
alive on player_respawn is true if the player respawned alive, false if they died and respawned.
player_block_place only fires when the held item is a BlockItem — right-clicking with a non-block item (food, tool, etc.) does not trigger it.
Async (mc.sleep, mc.fetch) is not available in event handlers — they run on the main thread, not inside a coroutine. Use mc.schedule(0, function() ... end) to defer async work from an event.