Singleplayer Anticheat

Singleplayer Anticheat: Commandlock

Regarding further updates

No further updates after 26.2 will be made, as Mojang has _patched_ using commands via “OPEN TO LAN”, hence this mod is no longer of any use. Nevertheless, being one of my first mods, I’m quite glad the way it turned out and that I got over 200 downloads!

Overview

A self-enforcing anticheat mod for singleplayer hardcore and survival worlds. Permanently locks your world against cheating by detecting and eliminating command usage, creative mode, and mod tampering.

The Problem

In singleplayer, there’s no way to verify if a hardcore or survival world was played legitimately. Open to LAN allows enabling cheats, and even if you remove this mod, the blocks remain — creating an undetectable loophole.

The Solution

Commandlock generates a hidden self-healing structure at world spawn containing 6 repeating command blocks and a unique verification block. If the mod is removed:

• The verification block disappears
• Command blocks instantly detect this
• You are killed, ending the run

Even if cheats are enabled through mods like Axiom, the kill command executes and your world ends.

How It Works

• Removes the “Open to LAN” button entirely
• Intercepts all command attempts on the client side
• Auto-kills players in creative mode
• Self-healing barrier structure that regenerates constantly
• Force-loads its chunk to always monitor your world

⚠️ Important

Do not open worlds created with this mod without it installed. The verification block won’t exist and you will be killed instantly.

Works on Minecraft 1.21.11 and 26.2