Compukters

Getting started

This guide takes you from a clean installation to a Kotlin program running inside a Minecraft computer. The primary authoring path is the project-based client IDE; a small editor and compiler inside each computer provide an autonomous terminal workflow. Both produce the same verified Compukter executable format.

Requirements

Component Supported baseline
Minecraft: Java Edition Exactly 26.1.2 or 1.21.1
NeoForge 26.1.2.97+ for Minecraft 26.1.2; 21.1.250+ for Minecraft 1.21.1
Java JDK 25 for 26.1.2; Java 21 for 1.21.1
Packaged native runtime Linux x86_64 or Windows x86_64

Create 6.0.10 through 6.0.x is an optional dependency on Minecraft 1.21.1. Install it on both client and server only when using the Create kinetics Guest API.

The mod is required on both the client and server. macOS and ARM builds are not part of the current published artifacts.

Install Compukters

  1. Install the Java, Minecraft, and NeoForge versions from one matching baseline above.
  2. Download the matching compukters-<minecraft>-neoforge-<version>.jar asset from the latest Compukters release.
  3. Put the JAR in the mods directory of the client and, for multiplayer, the server.
  4. Start the game with the matching NeoForge profile. Compukters has no Architectury runtime dependency.

Use a disposable world while learning the current development release. Back up worlds before moving them between mod versions.

Place and open a computer

Compukters does not currently provide a survival recipe. In a creative world, open the Compukters creative tab and take a Compukter, or run:

/give @s compukters:compukter

Place the block and use it with an empty hand. Its terminal opens and the built-in shell displays a > prompt after the computer boots. Run help to see the currently available shell commands.

Path 1: build and run a project in the IDE

The IDE stores projects on the client under <game directory>/compukters/ide/projects. A project can contain multiple Kotlin files and can be deployed to the computer you opened it from.

  1. Click IDE in the computer terminal or press Ctrl+I. Opening the IDE from the terminal automatically attaches that computer as the target. You can also look directly at a computer and press Ctrl+I.
  2. Choose Create project, enter hello, and confirm. The IDE creates compukter.toml and opens src/main.kt.
  3. Enter this program:
fun main() {
    println("Hello from Compukters!")
}
  1. Press Ctrl+S, then use Build or press Ctrl+F9. Wait for the status line to report a successful build.
  2. Use Deploy to install /home/hello on the attached computer. Confirm the overwrite dialog if that path already exists.
  3. Open the Terminal tool on the right and run hello at the shell prompt.

The triangular Run action is the shortcut for the final sequence: it saves, builds, deploys the manifest program, and submits its installed path to the attached computer.

Path 2: write directly inside the computer

The computer also carries a compact terminal editor and compiler. At the shell prompt, open a source file with edit hello.kt, enter the program above, press Ctrl+S, and then Ctrl+X. Compile it with:

kotlinc hello.kt

Without -o, kotlinc writes an extensionless executable with the source basename. Run it from the shell:

hello

The terminal should print:

Hello from Compukters!

The source and executable live in this computer’s writable /home filesystem. The built-in edit, kotlinc, and shell programs live in the read-only /rom filesystem. /home survives ordinary saves and world reloads; breaking a computer removes its active filesystem and moves the data to a recoverable tombstone rather than treating the dropped block as a portable disk.

Useful IDE shortcuts

Shortcut Action
Ctrl+I Open the IDE
Ctrl+S Save the active source
Ctrl+F9 Build the project
Ctrl+Space Request completion
Ctrl+P Show parameters for the call at the caret
Ctrl+B Go to declaration
Ctrl+Alt+L Reformat the active Kotlin source
Alt+Left / Alt+Right Navigate backward / forward

Current boundaries

Compukters intentionally supports a focused Kotlin subset. Do not assume that arbitrary Kotlin/JVM libraries, Java interop, reflection, threads, ordinary coroutines, collections, or exceptions are available. The Guest Kotlin support matrix is the compatibility contract for language features, standard-library operations, Guest APIs, and IDE behavior.

Programs execute in a deterministic managed VM rather than a general JVM. CPU work, memory, filesystem access, terminal I/O, processes, and redstone are admitted through bounded runtime contracts.

Next steps