Decorators

Decorators attach behavior to functions. They control when and how functions are called.

@load

Runs once when the datapack loads (or on /reload):

@load
fn init() {
    say("Datapack loaded!");
    scoreboard_add("kills", "playerKillCount");
}

@tick

Runs every game tick (20 times per second):

@tick
fn check_health() {
    foreach (player in @a) {
        if (scoreboard_get(player, "health") <= 5) {
            effect(player, "glowing", 1, 1);
        }
    }
}

@tick(rate=N)

Runs every N ticks instead of every tick:

@tick(rate=20)
fn every_second() {
    say("One second passed");
}

@tick(rate=100)
fn every_five_seconds() {
    actionbar(@a, "Server running");
}

@on_trigger

Runs when a player triggers a scoreboard trigger:

@on_trigger("shop")
fn open_shop() {
    tellraw(@s, "Welcome to the shop!");
}

Players trigger it in-game with:

/trigger shop

@on_death

Runs when an entity dies:

@on_death
fn on_player_death() {
    say("A player has fallen!");
    scoreboard_add_score(@s, "deaths", 1);
}

@on_join

Runs when a player joins the server:

@on_join
fn welcome() {
    title(@s, "Welcome!");
    tellraw(@s, "Type /trigger help for commands");
}

@on_respawn

Runs when a player respawns:

@on_respawn
fn on_respawn() {
    effect(@s, "regeneration", 5, 2);
    tellraw(@s, "You have respawned!");
}

Combining Decorators

A function can have multiple decorators:

@load
@tick(rate=200)
fn scoreboard_display() {
    // Runs on load AND every 10 seconds
    sidebar_set("Kills", @a, "kills");
}

How Decorators Work

Decorators compile to Minecraft's function tag system:

Decorator	Compiles To
@load	#minecraft:load tag
@tick	#minecraft:tick tag
@tick(rate=N)	Schedule command with interval
@on_trigger	Trigger scoreboard detection
@on_death	Advancement-based detection

Next Steps

• Structs & Enums — Custom data types
• Decorator Reference — Complete decorator list