Developing on Mycel

For mod authors. If you just play the mods, you do not need this page.

Mycel ships as one universal jar for Fabric, Forge, and NeoForge alike, distributed through JitPack. Use a release tag (for example 1.1.0), a commit hash, or main-SNAPSHOT for bleeding edge. The pattern below is exactly how InstantXP and AutoBlockRefiller are built; both repos are small enough to read end to end.

Depending on Mycel

repositories {
    mavenCentral()
    maven { url 'https://jitpack.io' }
}

dependencies {
    // Fabric (loom)
    modImplementation 'com.github.MyCelium-GG:MyCel-Lib:1.1.0'
    // Forge (ForgeGradle userdev)
    // implementation 'com.github.MyCelium-GG:MyCel-Lib:1.1.0'
    // NeoForge (ModDev)
    // implementation 'com.github.MyCelium-GG:MyCel-Lib:1.1.0'
}

Minimal integration

Metadata, a config value, and an event subscription. File IO, loader events, and diagnostics come from Mycel:

public static final ModMetadata META =
        ModMetadata.builder("mymod", "My Mod", "1.0.0").build();

public static final ConfigValue<Boolean> ENABLED;
public static final MycelConfig CONFIG;

public static void init() {           // called from each loader entrypoint
    Mycel.initialize();
    Mycel.registerMod(META);

    ConfigBuilder builder = Mycel.config(META);
    ENABLED = builder.booleanValue("enabled", true, "Whether the feature runs.");
    CONFIG = builder.build();         // loads config/mymod.json

    MycelEvents.onPlayerJoin(event -> {
        if (Mycel.isEnabled("mymod") && ENABLED.get()) {
            PlayerUtil.sendMessage(event.player(), Component.literal("Hi!"));
        }
    });
}

More of the API

• More config types: intValue(key, def, min, max, desc), longValue, doubleValue, stringValue, enumValue, stringListValue. Group with builder.category("tweaks") / builder.root(), version with schemaVersion + migrate, reload with CONFIG.reload() or /mycel reload mymod.
• Scheduling: MycelScheduler.runLater / runEvery on the server thread, runAsync for background IO.
• Config screen: Mycel.openConfigScreen(parent, "mymod") is server-safe (returns null on dedicated servers). Register it for the mod-list entry on Forge/NeoForge; on Fabric add a one-line ModMenu integration.
• House rules: loader-independent code goes in common (vanilla imports only); loader quirks stay in thin per-loader entrypoints using each loader's native event bus. No per-tick scans without a reason, no sync HTTP, no required background threads.

Project layout

common/     loader-independent mod code (no loader imports)
fabric/     Fabric entrypoint + fabric.mod.json
forge/      Forge entrypoint + mods.toml
neoforge/   NeoForge entrypoint + neoforge.mods.toml
buildSrc/   shared Gradle conventions

Building

You need JDK 25. Then:

./gradlew build            # all loaders + tests
./gradlew :common:test     # unit tests only

First builds download and process Minecraft (caches around a gigabyte, decompile takes a few minutes, peaks around 6-8 GB RAM); later builds are incremental. Finished jars land in fabric/build/libs, forge/build/libs, and neoforge/build/libs.

Example repos

• InstantXP - tick-driven collection, int config
• AutoBlockRefiller - event-driven refill with deferred check
• MyCel-Lib - the library itself, plus a join-greeting example mod proving the whole API