Your First Datapack

Let's build a complete Kill Counter datapack step by step. Players earn points for killing mobs, see their score on the sidebar, and get rewards at milestones.

Step 1: Create the Project

Create a new file called killcount.mcrs:

mkdir kill-counter
cd kill-counter
touch killcount.mcrs

Step 2: Define Variables

const REWARD_THRESHOLD: int = 10;

Step 3: Setup on Load

Use @load to initialize scoreboards when the datapack loads:

@load
fn init() {
    scoreboard_add("kills", "playerKillCount");
    scoreboard_add("level", "dummy");
    scoreboard_display("sidebar", "kills");
    say("Kill Counter datapack loaded!");
}

Step 4: Track Kills

Use @tick to check scores and give rewards:

@tick(rate=20)
fn check_rewards() {
    // Check if any player reached the threshold
    foreach (player in @a) {
        if (scoreboard_get(player, "kills") >= REWARD_THRESHOLD) {
            grant_reward(player);
        }
    }
}

fn grant_reward(player: selector) {
    // Give rewards
    give(player, "diamond", 1);
    effect(player, "regeneration", 10, 2);
    title(player, "Level Up!");

    // Increment level and reset kills
    scoreboard_add_score(player, "level", 1);
    scoreboard_set(player, "kills", 0);

    // Announce
    tellraw(@a, "${player} leveled up!");
}

Step 5: Welcome New Players

@on_join
fn welcome(player: selector) {
    title(player, "Kill Counter");
    subtitle(player, "Kill mobs to earn rewards!");
    scoreboard_set(player, "kills", 0);
    scoreboard_set(player, "level", 0);
}

Step 6: Death Messages

@on_death
fn on_death() {
    scoreboard_set(@s, "kills", 0);
    tellraw(@s, "You died! Kill count reset.");
}

Complete Code

Here's the full killcount.mcrs:

const REWARD_THRESHOLD: int = 10;

@load
fn init() {
    scoreboard_add("kills", "playerKillCount");
    scoreboard_add("level", "dummy");
    scoreboard_display("sidebar", "kills");
    say("Kill Counter datapack loaded!");
}

@tick(rate=20)
fn check_rewards() {
    foreach (player in @a) {
        if (scoreboard_get(player, "kills") >= REWARD_THRESHOLD) {
            grant_reward(player);
        }
    }
}

fn grant_reward(player: selector) {
    give(player, "diamond", 1);
    effect(player, "regeneration", 10, 2);
    title(player, "Level Up!");
    scoreboard_add_score(player, "level", 1);
    scoreboard_set(player, "kills", 0);
    tellraw(@a, "${player} leveled up!");
}

@on_join
fn welcome(player: selector) {
    title(player, "Kill Counter");
    subtitle(player, "Kill mobs to earn rewards!");
    scoreboard_set(player, "kills", 0);
    scoreboard_set(player, "level", 0);
}

@on_death
fn on_death() {
    scoreboard_set(@s, "kills", 0);
    tellraw(@s, "You died! Kill count reset.");
}

Step 7: Compile

redscript compile killcount.mcrs -o ./kill-counter-pack

Step 8: Install

1. Copy kill-counter-pack to your Minecraft world's datapacks/ folder
2. In-game, run /reload
3. You should see "Kill Counter datapack loaded!" in chat

Step 9: Test

1. Switch to survival mode: /gamemode survival
2. Spawn some mobs: /summon zombie ~ ~ ~
3. Kill mobs and watch your score on the sidebar
4. After 10 kills, you'll receive diamonds and a level up!

What You Learned

• @load — Run code when the datapack loads
• @tick(rate=N) — Run code periodically
• @on_join / @on_death — React to player events
• Scoreboard functions — Track and display data
• give / effect / title — Interact with players

Next Steps

• Variables & Types — Deep dive into the type system
• Decorators — All available decorators
• Built-in Functions — Complete function reference