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_objective("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 (advancement-based detection):

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

@on_login

Runs when a player logs in (joins) the server:

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

@on_advancement

Runs when a player earns a specific advancement:

@on_advancement("story/mine_diamond")
fn got_diamonds() {
    tellraw(@s, "You found diamonds!");
}

@on_craft

Runs when a player crafts a specific item:

@on_craft("minecraft:diamond_sword")
fn crafted_sword() {
    tellraw(@s, "You crafted a diamond sword!");
}

@on_join_team

Runs when a player joins a specific team:

@on_join_team("red")
fn joined_red() {
    title(@s, "Red Team");
    effect(@s, "speed", 200, 1);
}

@on(EventType)

Handles a static event. The supported event types are:

Event	Description
PlayerDeath	A player dies
PlayerJoin	A player joins the server
BlockBreak	A player breaks a block
EntityKill	A player kills an entity
ItemUse	A player uses an item

@on(PlayerDeath)
fn handle_death(player: selector) {
    say("A player has died!");
}

@on(PlayerJoin)
fn handle_join() {
    title(@s, "Welcome!");
}

@keep

Prevents the dead code elimination (DCE) optimizer from removing a function. By default, functions whose names start with _ are treated as private/internal and may be removed if unreachable. Use @keep to force them to be retained:

@keep
fn _internal_helper() {
    // Won't be removed even though it starts with _
}

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");
}

DCE and Private Functions

RedScript's dead code elimination (DCE) optimizer automatically removes unreachable functions. The visibility rules are:

• Functions not starting with _ are public — always emitted as callable via /function
• Functions starting with _ are private — only kept if called from somewhere or decorated with @keep
• Decorated functions (@tick, @load, @on_*, etc.) are always kept regardless of name

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("x")	Trigger scoreboard detection
@on_death	Advancement-based death detection
@on_login	Tag-based join detection
@on_advancement("id")	Advancement reward function
@on_craft("item")	Advancement inventory_changed detection
@on_join_team("team")	Team join detection
@on(EventType)	Event tag polling per tick

Next Steps

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