LibCapableData (LibCD)

Data packs revolutionized how we customize Minecraft, but they often lack the finesse to adapt to a player's unique mod setup. That is where LibCapableData (LibCD) steps in. This lightweight Fabric library introduces a powerful conditional loading system, letting your data packs decide which recipes, advancements, or other resources should appear based on the mods and items present. Instead of cluttering your world with broken recipes or irrelevant content, LibCD gives you the hooks to build truly dynamic, context-aware packs.

What Exactly Does LibCapableData (LibCD) Do?

At its core, LibCD is a developer-friendly tool that extends the data pack framework. It was originally created to solve a simple but persistent problem: how do you load a recipe only when a specific mod is installed? Without LibCD, data packs would either load everything unconditionally or require complex workarounds. LibCD introduces a metadata-driven approach. By adding a .mcmeta file alongside any resource, you can define a set of conditions that must be met for that resource to load. This works for recipes, loot tables, advancements, and even custom resource types added by other mods.

One important note: you might see warnings about invalid entries in the LibCD mod JSON. Do not panic. These messages do not cause crashes, and they are not the reason your pack fails to load. Always dig deeper into the log to find the real culprit. The library is designed to fail silently on malformed conditions, returning false rather than breaking the game.

How Conditional Loading Works

The magic happens through a companion metadata file. For any resource you want to gate, create a file with the same name but append .mcmeta. For example, a recipe at data/mypack/recipes/diamond_sword.json would get a condition file at data/mypack/recipes/diamond_sword.json.mcmeta. Inside that JSON file, each key-value pair represents a condition that must evaluate to true. If all conditions pass, the resource loads; if any fail, it is silently skipped.

This system is intentionally simple and extensible. You do not need to be a Java coder to use it—just a basic understanding of JSON. And because LibCD hooks into the resource loading pipeline, it works seamlessly with any mod that adds custom resource types, making it a universal solution for conditional content.

Built-in Conditions You Can Use Right Away

LibCD ships with four ready-to-use conditions that cover the most common scenarios. You can combine them to create complex logic without writing a single line of Java.

• libcd:mod_loaded – Pass a mod ID string. Returns true if that mod is present. Perfect for cross-mod compatibility recipes.
• libcd:item_exists – Pass an item ID string. Returns true if that item is registered. Ideal for gating recipes behind specific items from other mods.
• libcd:not – Takes a single condition object. Returns true if that inner condition is false. Use it to disable a recipe when a certain mod is loaded.
• libcd:any_of – Takes a JSON object with multiple conditions. Returns true if at least one of them passes. Great for offering alternative recipes depending on which mods are available.

For instance, you could create a recipe that only loads if both "minecraft" and "techmod" are present, or a loot table that appears only when a specific item exists. The flexibility is immense, and because conditions are evaluated at resource load time, there is no runtime performance penalty.

Developer API: Extending LibCD with Custom Conditions

Mod developers can tap into LibCD's registry to add their own conditions, tying resource loading to config options, game stages, or any custom logic. The process is straightforward: call LibConditionalData.registerCondition() with an Identifier for your condition's name and a Predicate that receives the JSON value. The passed object can be a boxed primitive (Integer, Float, Boolean), a String, a List, a JsonObject, or null, so always use an instanceof check to handle it safely.

This API makes LibCD a cornerstone for modpack creators who want to build cohesive experiences. By registering a condition that checks a config setting, you can let players toggle entire content modules on or off without touching the data pack files. The library is available on the Cotton maven for easy integration into your own projects.

How to Install LibCapableData (LibCD) for Minecraft

Getting started with LibCD is quick. The mod requires the Fabric loader and works on Minecraft version 1.14 and above. Follow these steps to add it to your instance:

1. Ensure you have Fabric installed for your Minecraft launcher. If you are using a third-party launcher, many support Fabric out of the box.
2. Download LibCapableData (LibCD) from a trusted mod repository. Place the JAR file into your mods folder.
3. Launch the game. LibCD runs silently in the background; you will not see a new menu or button. Its power is unlocked through the data packs you create or install.

If you use the foxygame.net launcher, adding LibCapableData (LibCD) is even simpler: just browse the built-in add-on catalog, find the mod, and click install. The launcher automatically handles version compatibility and keeps the library updated, so you can focus on building your conditional data packs without worrying about manual downloads.

Once installed, you can start writing conditional metadata files immediately. Remember, the .mcmeta file must sit next to the resource it controls, and the JSON structure must be valid. A common pitfall is forgetting to nest conditions inside libcd:any_of or libcd:not correctly—always double-check your braces and quotation marks.

Why LibCapableData (LibCD) Is a Must-Have for Modpack Creators

Without LibCD, data pack authors are forced to either maintain multiple versions of a pack for different mod combinations or accept that some recipes will appear broken when required mods are missing. LibCD eliminates that headache. It empowers you to write a single, intelligent data pack that adapts to the player's environment. Whether you are building a massive modpack or a small quality-of-life tweak, conditional loading keeps the experience clean and professional.

Moreover, the library's lightweight design means it adds no noticeable overhead. It simply intercepts the resource loading process, checks your conditions, and moves on. The open API encourages community extensions, so you might find additional conditions provided by other mods that integrate with LibCD.

For anyone serious about data pack development on Fabric, LibCapableData (LibCD) is an essential tool. It bridges the gap between static JSON files and the dynamic, modded world players actually inhabit. Download LibCapableData (LibCD) today and start crafting smarter, more responsive content for Minecraft.