Container Blocker

A lightweight Minecraft Fabric mod that prevents configured items from being placed into containers. By default, it blocks the Ender Dragon Egg, but can be configured to block any item.

Features

Configurable blocked items: Customize which items cannot enter containers via config/blocked_items.json
Blocks manual placement: Prevents players from clicking blocked items into container slots (chests, barrels, hoppers, etc.)
Blocks shift-clicking: Prevents players from shift-clicking blocked items from their inventory into containers
Blocks hoppers: Prevents hoppers from transferring blocked items between containers
Works with all containers: Applies to all container types including chests, barrels, shulker boxes, hoppers, and modded containers
Player inventory allowed: Blocked items can still be moved within the player's own inventory and hotbar

Configuration

The mod creates a config/blocked_items.json file on first run. You can edit this file to customize which items are blocked:

{
  "blockedItems": [
    "minecraft:dragon_egg"
  ]
}

How it works

The mod uses Mixins to intercept item transfer methods

Technical Details

Platform: Fabric
Language: Java
Minecraft Version: 1.21.2 and higher

Installation

Ensure you have Fabric Loader and Fabric API installed
Place the mod JAR file in your .minecraft/mods folder
Launch Minecraft
Edit config/blocked_items.json to configure blocked items (optional)