Minecraft Server ScriptAPI

Workflow

1. Scope: Identify task (events, entities, components, commands, timing). Default to latest stable version unless beta/preview requested.
2. Docs: Navigate from module index to specific class/interface/event. Use Microsoft Learn as source of truth. Search via MCP when details missing.
3. Output: Quote exact API names. Provide minimal working example with required imports. Verify no official equivalent exists before creating custom helpers.
   • For enums like CustomCommandParamType, always check Microsoft Learn to confirm availability.
   • @minecraft/vanilla-data is not on Microsoft Learn, so skip MCP searches for those enums.

Common patterns

Events

• Subscribe/unsubscribe on world/system events. Guard logic for performance.

Dimensions

• Use world.getDimension(MinecraftDimensionTypes.<Dimension>) and pick the appropriate dimension for the task.

Components

• Check existence before access.
• Use typed IDs: EntityComponentTypes, BlockComponentTypes, ItemComponentTypes.

Scheduling

• Use system.run, system.runTimeout, system.runInterval, system.runJob.

Identifiers

• MUST use @minecraft/vanilla-data enums: MinecraftBlockTypes, MinecraftEntityTypes, MinecraftItemTypes, MinecraftDimensionTypes, MinecraftEffectTypes, potionEffect, potionDelivery, feature, enchantment, cooldownCategory, cameraPresets, biome.
• Custom IDs: Must include namespace prefix (e.g., example:cmd). One consistent prefix per addon.

Example:

import { world, system } from "@minecraft/server";
import { MinecraftDimensionTypes, MinecraftBlockTypes } from "@minecraft/vanilla-data";

system.runInterval(() => {
  const dimensions = [MinecraftDimensionTypes.Overworld, MinecraftDimensionTypes.Nether];
  const blocks = [MinecraftBlockTypes.Stone, MinecraftBlockTypes.Sand, MinecraftBlockTypes.GrassBlock];
  for (const dimension of dimensions) {
    for (const block of blocks) {
      world.getDimension(dimension).setBlockType({ x: 0, y: 0, z: 0 }, block);
    }
  }
});

Permission modes

Read-only

• Before simulation/events/tick start. No world mutations.
• Fix: defer to system.run/runTimeout/runJob.

Doc verification

• When using any method/property, always check Microsoft Learn to confirm whether it is read-only safe or early-execution safe.
• Look for explicit notes in the API reference (read-only / early-execution) and follow them strictly.
• For arrow-function callbacks only, also check for restricted-execution notes like:
  • “This closure is called with restricted-execution privilege.”
  • “This function can’t be called in restricted-execution mode.”
• If a restricted-execution note applies, review the arrow-function body to ensure no read-only or early-execution violations; defer with system.run if needed.

Example (read-only deferral):

world.beforeEvents.playerInteractWithBlock.subscribe((event) => {
  const player = event.player;
  system.run(() => {
    player.runCommand("say ok");
  });
});

Early-execution

• Before world loads. Many APIs unavailable.
• Fix: defer to world.afterEvents.worldLoad or system.run.
• Subscribe at root to avoid missing events.

Safe in early-execution:

• Event subscriptions (world/system beforeEvents/afterEvents)
• system.clearJob, clearRun, run, runInterval, runJob, runTimeout, waitTicks
• BlockComponentRegistry.registerCustomComponent, ItemComponentRegistry.registerCustomComponent

Custom commands

• Interface: CustomCommand (name, description, permissionLevel, mandatoryParameters, optionalParameters).
• Parameters: CustomCommandParameter (name, type, optional enumName).
• Param types and arrow-function argument types:
  • String -> String
  • PlayerSelector -> Player
  • Location -> Vector3
  • ItemType -> ItemType
  • Integer -> Number
  • Float -> Number
  • Enum -> String
  • EntityType -> EntityType
  • EntitySelector -> Entity
  • Boolean -> Bool
  • BlockType -> BlockType
• Register enums: CustomCommandRegistry.registerEnum(name, values).
• Register cmd: CustomCommandRegistry.registerCommand(customCommand, callback).
• Callback: (origin, ...args) => CustomCommandResult.
• Custom command callbacks run with restricted-execution privileges, so do not call read-only-restricted methods directly; defer with system.run if needed.
• When using an arrow function, align parameter names and order with the CustomCommandParameter.name list; avoid mismatched names or generic args when parameters are defined.

Example:

import {
  system,
  StartupEvent,
  CommandPermissionLevel,
  CustomCommandParamType,
  CustomCommandStatus,
} from "@minecraft/server";

system.beforeEvents.startup.subscribe((init: StartupEvent) => {
  init.customCommandRegistry.registerEnum("example:mode", ["on", "off"]);

  init.customCommandRegistry.registerCommand(
    {
      name: "example:demo",
      description: "Command demo",
      permissionLevel: CommandPermissionLevel.GameDirectors,
      cheatsRequired: true,
      mandatoryParameters: [
        {  type: CustomCommandParamType.String, name: "msg", },
        {  type: CustomCommandParamType.Enum, name: "example:mode"},
      ],
      optionalParameters: [
        { type: CustomCommandParamType.Boolean, name: "silent" },
        { type: CustomCommandParamType.Integer, name: "count" },
      ],
    },
    (origin, msg, mode, silent, count) => {
      const msgValue = String(msg ?? "ok");
      const modeValue = String(mode ?? "off");
      const silentValue = Boolean(silent ?? false);
      const countValue = Number(count ?? 1);

      return {
        status: CustomCommandStatus.Success,
        message: silentValue
          ? undefined
          : `[${origin.sourceType}] ${msgValue} mode=${modeValue} count=${countValue}`,
      };
    }
  );
});

Script events

• Send: system.sendScriptEvent(id, message) (namespaced ID, payload string).
• Receive: system.afterEvents.scriptEventReceive.subscribe(callback, options?).
• Event: ScriptEventCommandMessageAfterEvent (id, message, sourceType, optional sourceEntity/sourceBlock/initiator).
• Filter: ScriptEventMessageFilterOptions.namespaces.

Example:

import { system, world, ScriptEventSource } from "@minecraft/server";

system.afterEvents.scriptEventReceive.subscribe((event) => {
  const { id, message, sourceType, initiator, sourceEntity, sourceBlock } = event;
  if (id !== "example:say") return;

  switch (sourceType) {
    case ScriptEventSource.Block:
      world.sendMessage(`sendBy:${sourceBlock?.typeId ?? "unknown"} ${message}`);
      break;
    case ScriptEventSource.Entity:
      world.sendMessage(`sendBy:${sourceEntity?.typeId ?? "unknown"} ${message}`);
      break;
    case ScriptEventSource.NPCDialogue:
      world.sendMessage(`sendBy:${initiator?.typeId ?? "unknown"} ${message}`);
      break;
    case ScriptEventSource.Server:
      world.sendMessage(`sendBy:server ${message}`);
      break;
  }
});

Performance

• Expensive work in events: use system.runJob(generator) to spread across ticks.
• Short-circuit before iterating large sets.

system.run variants

• run: next tick.
• runTimeout(cb, ticks): delay N ticks. 0 can cause tight loops if misused.
• runInterval(cb, ticks): repeat every N ticks until clearRun.
• runJob(generator): long-running work. Keep iterations small.

Type safety

• Use typeId checks and verify component existence.
• instanceof only for documented @minecraft/server classes.

Minimal templates

Event subscription:

world.afterEvents.playerJoin.subscribe((event) => {
  const player = event.player;
});

Tick loop:

system.runInterval(() => {
  // tick logic
}, 1);

Get dimension:

const overworld = world.getDimension(MinecraftDimensionTypes.Overworld);

Spawn entity:

const overworld = world.getDimension(MinecraftDimensionTypes.Overworld);
overworld.spawnEntity(MinecraftEntityTypes.Zombie, { x: 0, y: 80, z: 0 });

Give item:

const item = new ItemStack(MinecraftItemTypes.Diamond, 1);
player.getComponent("inventory")?.container?.addItem(item);

Apply effect:

player.addEffect(MinecraftEffectTypes.Speed, 200, { amplifier: 1 });

Get component (typed):

const health = entity.getComponent(EntityComponentTypes.Health);

Pitfalls

• Null components: Check existence before access.
• Heavy events: Use system.runJob.
• Permissions: Avoid read-only/early-execution violations.
• Raw IDs: Use typed enums.
• Namespaces: One consistent prefix per addon.

MCP tools

• Endpoint: https://learn.microsoft.com/api/mcp
• Search: microsoft_docs_search (module + class + task).
• Fetch: microsoft_docs_fetch (full signatures/details).