KoperLib Fullpack APIs

KoperLib Fullpack APIs is the content side of KoperLib. Items, blocks, mobs, recipes, menus, quests and dialogue are defined in JSON packs called Fullpack and Lua or Java adds behaviour where JSON is not enough. Models, animation aneffects come with it.
Requires KoperLib Core.

What is inside

The jar holds three nested Fabric mods. Addons depend on the module id they use.

• Fullpack (koperlib_fullpack): JSON, Lua and Java content packs, KUI menus and HUD, quests and dialogue, Bedrock addon conversion.
• Kodel (koperlib_kodel): models and animation for blocks, mobs, armour, items and the player, with bone hitboxes and anchors.
• Effects (koperlib_effects): KFX, composable effect graphs authored in JSON, Lua or Java.

Fullpacks

A Fullpack is a folder or ZIP in koperlib/fullpacks/ with a pack.kopermeta manifest. A working item takes two files. Scripts bind by file name, so scripts/flame_sword.lua attaches to items/flame_sword.json with no extra
wiring.

• /koperlib reload applies changes in a running game: textures, models, stats, recipes, loot, menus, scripts, pack Java, and even new items, blocks and entities.
• Removing a pack does not destroy what it added. Its blocks and items stay in the world as missing content, keeping their data, and work again when the pack returns.
• Three tiers that build on each other: JSON for content, Lua for behaviour, Java for anything deeper.

Bedrock addons (experimental)

Bedrock addon support is very experimental and a work in progress. .mcaddon, .mcpack, .mctemplate and unpacked Bedrock packs are converted into Fullpacks, and addon scripts run on KoperLib's own implementation of the Bedrock scripting API.

Expect bugs. Many APIs, components and events are missing or incomplete, and addons often conflict with each other. Using many addons at once, or large and advanced addons, is not recommended. Simple addons with a few items, blocks or mobs have the best chance of working. The converter writes every warning to the converted pack, which helps when reporting an issue.

Requirements

• KoperLib Core
• Minecraft 26.3
• Fabric Loader 0.19.5 or newer
• Fabric API 0.161.0+26.3 or newer
• Java 25
• Linux x86_64 or Windows x86_64
  Works with or without KoperLib Khysics. Installed together, they use eachother's features, for example physics shapes taken from Kodel models.

Status

KoperLib is in alpha. Features work in the scenarios they were tested in, and the Java API can still change between versions, so addons should pin theKoperLib version they build against. Entities are not yet kept as missing content when their pack is removed. The full list of known gaps is in the README on GitHub.

Documentation and source

• Fullpack guide: https://github.com/ministerkoperku/koperlib/blob/main/docs/KOPERLIB.md
• Lua API: https://github.com/ministerkoperku/koperlib/blob/main/docs/LUA_API.md
• Bedrock addons: https://github.com/ministerkoperku/koperlib/blob/main/docs/BEDROCK.md
• Source: https://github.com/ministerkoperku/koperlib
• Issues: https://github.com/ministerkoperku/koperlib/issues

Credits

• The Fullpack system is inspired by JSON Things and similar data driven content mods.
• Kodel's Bedrock model and animation math is a clean reimplementation derived from GeckoLib (MIT). No GeckoLib files are shipped.
• Bedrock scripts run on QuickJS (MIT).

None of these projects are affiliated with KoperLib.

How this project is made

Code and documentation were written with help from AI coding tools, mainly Claude and ChatGPT (Codex). Design and release decisions are made by a person, and the project is not fully vibe coded. Every release is tested in game by people from the project's Discord, and AI written code goes through the same tests as the rest.

License

LGPL-3.0-only. Forks and modified versions must stay under the same license. Mods and packs that only use KoperLib as a dependency can use any license. KoperLib is an unofficial Minecraft mod and is not approved by or associated with Mojang or Microsoft.