Glossary
This page collects terms that appear often in the Plexus Mod Loader docs. Terms are in alphabetical order. Each entry lists the page that explains the term in detail.
| Term | Meaning | Details |
|---|---|---|
| Blocked / Experimental (compatibility status) | A status showing how well Plexus Mod Loader can run a mod from another loader: Verified, Partial, Experimental, Blocked, Untested. Experimental means only some experiments passed; no loader has this status today, since Fabric, Forge, NeoForge and Quilt mods are all Verified. Blocked means the mod cannot run because of a known problem. If a bridge reports even one finding that blocks, the mod is not loaded. A jar that merely loaded is never labeled Verified. | Compatibility |
| Bridge (loader bridge) | An SPI (ModLoaderBridge) that evaluates and runs mods from other loaders (Fabric, Quilt, NeoForge, and MinecraftForge). It is diagnostics-first: each feature Plexus Mod Loader cannot provide is reported as one finding. A jar from a loader with no bridge is blocked with PLEXUS-COMPAT-001. | Compatibility |
Capabilities (capabilities) | Permissions you declare in capabilities in plexus.mod.json before using risky or deep features. A missing required permission gives PLEXUS-METADATA-012. Today only replacesSystems (system.provider.replace) and transforms (internal.bytecode.transform) are checked. | plexus.mod.json schema |
| Data version | A version number for the data a mod saves (world storage, block entity data, entity data). It is written under the reserved key plexus_version. If the stored data is older, DataMigration runs. If it is newer, the data is left untouched and PLEXUS-STORAGE-001 is logged. | Stored data and versions |
| Entrypoint | A class that Plexus Mod Loader calls when it initializes a mod, listed in entrypoints in plexus.mod.json. common implements CommonModInitializer, client implements ClientModInitializer, and server implements DedicatedServerModInitializer. Plexus Mod Loader calls the common entrypoints of all mods first, then the side-specific ones. All declarations must finish inside the common entrypoint. | Entrypoints, Lifecycle and threads |
| Game layer | The per-version module plexus-game-v<id>. It is compiled compileOnly against the downloaded Minecraft jar and implements the Native API with that version's game classes. It is the only Plexus Mod Loader package defined by the game class loader. It turns a mod's declarations into real game objects once the game is ready. | — |
| Game test | A mod test that runs against the real game on Mojang's game test server. You register it in the common entrypoint, and its ID is <mod id>:<name>. A test passes only when it calls succeed(). No window opens, so it also runs in CI. | In-game tests |
| Generated pack | The data pack that Plexus Mod Loader creates and uses (.plexus/generated-pack). It writes biomes, placed features, structures, and game test area structures defined in code into the game's file format. It is a known pack, and its version is determined by the generated file contents. | World generation |
Known pack (KnownPack) | The known-pack information that Plexus Mod Loader attaches to the packs in mod jars (KnownPack("plexus", <mod id>, <version>)). The generated pack is also a known pack. Minecraft 26.2 registers only registry entries that come from known packs as stable. This is why a mod's world generation, dimension, and damage type data do not mark the world as "experimental settings". | World generation |
| Native API | The API that Plexus Mods use. Its packages are under dev.plexusmodloader.api. It exposes no Minecraft types, so you compile against plexus-lifecycle-api alone. All of it is at the PREVIEW level. | Native API overview |
| Plexus Mod | A mod built with Plexus Mod Loader's Native API that runs only on Plexus Mod Loader. Like Fabric mods and Forge mods, it is named after its loader. Its jar contains plexus.mod.json (or poly.mod.json). At startup, Plexus Mod Loader classifies each mod by the metadata files in its jar as Plexus Mod, Fabric, NeoForge, Forge, or unknown. A loader bridge judges the mods that are not Plexus Mods. | Create your first Plexus Mod |
| Stability level | The level that @ApiStability puts on a public type: STABLE, PREVIEW, VERSION_BOUND, INTERNAL, UNSAFE. The 0.1 series has no STABLE API. All Native APIs are PREVIEW and can change between versions. | API stability |
System and provider (SystemProvider) | A system is a unit of Plexus Mod Loader functionality that a mod can replace as a whole. Its ID is namespace:path, and the primary system is plexus:game_brand (with plexus:game_brand supported as a compatibility alias). A provider (SystemProvider) creates the implementation of a system. A mod declares replacements in replacesSystems in plexus.mod.json (or poly.mod.json), and conflicts are resolved before any mod code runs. | System replacement, plexus.mod.json schema |
| Transform rule and failure policy | A transform rule (TransformRuleDefinition) is data that holds a rule ID, the owning mod, the game version and side, the target (owner internal name, method name, JVM descriptor), the action, and a failure policy. There are two failure policies: ABORT_STARTUP (stop startup) and DISABLE_RULE (turn off only that rule). A failure is never recorded as "applied". A mod declares transforms in transforms in plexus.mod.json (or poly.mod.json), and the default policy is disable_rule. | plexus.mod.json schema |
| Version adapter | The per-version module plexus-version-adapter-v<id>. It holds the run target (game entry point) and the built-in transform rules for that Minecraft version. At startup, Plexus Mod Loader reads version.json from the game jar and picks the matching GameVersionAdapter with ServiceLoader. If none exists, the result is PLEXUS-BOOTSTRAP-002. | — |