minecraft-modding
Minecraft Modding Skill
Overview
This skill guides Codex through developing open-source Minecraft mods. Target platforms:
| Platform | MC Version | Java | Build System |
|---|---|---|---|
| NeoForge | 1.21.x with 1.21.11 examples | Java 21 | Gradle + ModDevGradle |
| Fabric | 1.21.x with 1.21.11 examples | Java 21 | Gradle + Fabric Loom |
| Architectury (multiloader) | 1.21.x | Java 21 | Gradle + Architectury Loom |
Always confirm the platform and Minecraft version from gradle.properties or build.gradle
before writing any mod-specific code.
Routing Boundaries
Use when: the task is Java/Kotlin mod code, registry/event work, networking, datagen wiring, and loader APIs.Do not use when: the task is command-only vanilla logic (minecraft-commands-scripting) or pure datapacks (minecraft-datapack).
More from jahrome907/minecraft-agent-skills
minecraft-testing
Write automated tests for Minecraft mods and plugins for 1.21.x. Covers NeoForge GameTests (@GameTest annotation, GameTestHelper assertions, test structure placement), Fabric game tests (fabric-gametest-api-v1), unit testing non-Minecraft logic with JUnit 5, MockBukkit for Paper/Bukkit plugin testing (mock server, mock player, event dispatching, inventory checking), integration testing with a test server via Gradle, and GitHub Actions CI workflows that run GameTests headlessly. Includes patterns for mocking registries, testing event handlers, testing commands, and test-driven development for Minecraft projects. Use when the user asks about testing Minecraft mods or plugins, writing GameTests, setting up MockBukkit, or configuring CI for Minecraft projects.
9minecraft-multiloader
Build Minecraft mods targeting both NeoForge and Fabric simultaneously using the Architectury framework for Minecraft 1.21.x. Covers Architectury project structure (common/neoforge/fabric subprojects), ExpectPlatform annotation for platform-specific implementations, shared registry via Architectury's registration API, platform-specific entrypoints, architectury-loom Gradle plugin configuration, gradle.properties for both loaders, multi-jar publishing to Modrinth and CurseForge, and avoiding common pitfalls when sharing code. Use this skill when building a mod that must run on both NeoForge and Fabric with a single shared codebase.
9minecraft-datapack
Create, edit, and debug Minecraft vanilla datapacks for 1.21.x. Covers the full datapack format: pack.mcmeta, function files (.mcfunction), advancements, predicates, loot tables, item modifiers, recipe overrides, tags, damage types, dimension types, worldgen overrides, and structure sets. Handles function syntax, execute command chains, macro functions (1.20.2+), storage NBT, scoreboard operations, advancement triggers, pack format numbers, and /reload workflow. No Java or mod loader required — pure vanilla JSON and .mcfunction files. Use when creating or editing Minecraft datapacks, writing .mcfunction files, configuring loot tables or advancements, or any vanilla datapack development that does not need mod loaders.
9minecraft-world-generation
Create custom world generation content for Minecraft 1.21.x including custom biomes, dimensions, noise settings, surface rules, placed/configured features, carvers, structure sets, and biome modifiers. Covers both the datapack-only approach (JSON worldgen files) and the mod-code approach (NeoForge BiomeModifiers, Fabric BiomeModification API, code-driven worldgen registration with DeferredRegister). Includes JSON schemas for biome, noise_settings, placed_feature, configured_feature, structure, structure_set, and processor_list files. Targets Minecraft 1.21.x with official Mojang mappings. Use when the user asks about Minecraft worldgen, custom biomes, datapack JSON for dimensions or features, or mod-based biome modification with NeoForge or Fabric.
9minecraft-plugin-dev
Develop Minecraft server plugins using the Paper/Bukkit/Spigot API for Minecraft 1.21.x. Handles creating Paper plugins with JavaPlugin, event listeners with @EventHandler, commands, schedulers (sync/async/Folia-safe), Persistent Data Container (PDC), Adventure text components, Vault economy integration, BungeeCord/Velocity messaging, plugin.yml and paper-plugin.yml configuration, YAML config management, and Paper-specific enhancement APIs. Always targets Paper API 1.21.x (Java 21) with Gradle (Kotlin DSL). Plugins run server-side only and do not require client installation. Use when creating or modifying Minecraft server plugins, working with Paper/Bukkit/Spigot APIs, or developing server-side features involving event handlers, commands, or plugin.yml configuration.
7minecraft-server-admin
Set up, configure, and operate Minecraft Java Edition servers for 1.21.x across Paper, Purpur, Folia, Velocity networks, and modded (Fabric/NeoForge) deployments. Covers deployment selection, performance tuning playbooks, plugin operations, proxy/forwarding setup, backup and recovery runbooks, live incident troubleshooting, Docker/Pterodactyl patterns, and security hardening. Use for server infrastructure and operations, not plugin or mod feature development.
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