Creating Your First Command

Registering custom commands in Pumpkin using Kotlin is concise, idiomatic, and strongly typed.

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1. Quick Example

Here is a complete Kotlin plugin (Plugin.kt) that registers a /hello command with permission checks and sends a response back to the player.

package plugin

import pumpkin.plugin.context.Context
import pumpkin.plugin.command.Command
import pumpkin.plugin.permission.Permission
import pumpkin.plugin.permission.PermissionDefault

class MyPlugin {
    fun onLoad(ctx: Context) {
        // 1. Register permission node
        ctx.registerPermission(
            Permission(
                node = "my_kotlin_plugin:hello",
                description = "Allows executing the /hello command",
                default = PermissionDefault.ALLOW,
                children = emptyList()
            )
        )

        // 2. Build and register command tree
        val cmd = Command(
            names = listOf("hello", "hi"),
            description = "Greets the player"
        )
        ctx.registerCommand(cmd, "my_kotlin_plugin:hello")
    }

    fun handleCommand(sender: pumpkin.plugin.command.CommandSender): Int {
        sender.sendMessage("Hello from Kotlin Plugin!")
        return 1
    }
}

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2. In-Game Preview

Once registered, your command automatically gains client-side autocompletion, syntax validation, and color highlighting in Minecraft:

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3. How It Works

Step-by-Step Breakdown

Step 1: Define the Permission Node

Construct a Permission object and pass it to ctx.registerPermission:

ctx.registerPermission(
    Permission(
        node = "my_kotlin_plugin:hello",
        description = "Allows executing the /hello command",
        default = PermissionDefault.ALLOW,
        children = emptyList()
    )
)

Step 2: Build the Command Tree

Instantiate Command with primary names and aliases:

val cmd = Command(
    names = listOf("hello", "hi"),
    description = "Greets the player"
)

Step 3: Register with Context

Register the command with ctx.registerCommand and handle calls inside handleCommand:

ctx.registerCommand(cmd, "my_kotlin_plugin:hello")

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Next Steps

• Follow the Kotlin Quick Start Guide to configure your Makefile and Kotlin/Wasm build tools.