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mcMMO-SP

A port of mcMMO from a Bukkit/Spigot server plugin to a standalone Fabric mod, rebuilt around single-player.

RPG skills, levelling, sub-skills and active super abilities for vanilla Minecraft — no server, no database, no plugin platform.

Minecraft	1.21.11
Mod loader	Fabric Loader ≥ 0.19.3
Required dependency	Fabric API
Java	21+
License	GPL-3.0-only (inherited from upstream mcMMO)

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Start here

Page	What's on it
Installation	Getting the mod running, and where files land.
Commands	Every command the port actually has (it is a short list).
Skills	All 24 skills and every sub-skill, with what is and isn't implemented.
Super Abilities	The two-step gesture, and the item-triggered actives.
XP and Levelling	RetroMode, the XP curve, XP bars, and the speed-normalised movement model.
Configuration	Every config file and the knobs that matter.
Optional Integrations	Mod Menu, Cloth Config, Advancement Plaques.
Differences from mcMMO	What was cut, what was added, what behaves differently.
Troubleshooting	When something doesn't fire.
Building from Source	Gradle targets and the test suite.

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What's different in one paragraph

Everything multiplayer was removed, not disabled — parties, party chat, teleport, XP sharing, scoreboards, admin broadcasts, MySQL and the database conversion tooling are all gone, along with most of the command tree. What's left is the skill system itself, plus six skills upstream mcMMO does not have: Acrobatics was renamed Agility and restructured into a derived child skill of three new movement skills (Parkour, Swimming, Flying), and two brand-new skills were added (Stealth and Unarmored).

The mod runs on both sides ("environment": "*") and works in single-player, on LAN, and on a dedicated Fabric server — but with the multiplayer layer gone, a server install is just "everyone has their own skills."

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Status, honestly

The port is feature-complete against upstream mcMMO's single-player-relevant surface, boots clean, and carries a ~970-case JUnit suite that runs as part of ./gradlew build.

It is also young:

• The six new skills are code-complete but lightly play-tested. Their XP rates and reference speeds are starting estimates, not measured numbers — the tuning comments in experience.yml say so in as many words.
• The eight Limit Break sub-skills are dead enums. They show up in /mcstats and in the config files, they have ranks, and they do nothing at all. See Differences from mcMMO.
• Balance feedback and bug reports are genuinely useful right now. Please file issues.

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License

This is a fork of mcMMO, which is GPL-3.0. All original mcMMO code remains under GPL-3.0 and this fork's modifications are released under GPL-3.0 as well. mcMMO was created by nossr50 and maintained by the mcMMO team; the full contributor list is preserved in git history and on the upstream contributors page.