NeoForge mod generator for 1.21.1 and 26.x

NeoForge is a full-featured mod loader that grew out of the Forge community in 2023. It provides a large event system and registries for adding blocks, items, entities and more, and it powers a big share of the modpack scene.

Where Fabric keeps its core small and relies on Fabric API, NeoForge ships more features in the loader itself. A NeoForge mod reacts to game events, such as a block being broken, a player logging in or the HUD being drawn, by registering listeners, and it adds content through registries.

Our AI writes mods in that style: listeners registered in code, content registered through NeoForge registries, and the conventions of the version you choose.

The NeoForge generator offers four Minecraft versions. 26.2 and 26.1.2 use stable NeoForge releases. 26.3 is offered as a beta because NeoForge has only published beta builds for it so far, so expect loader updates while that version matures.

The API changed a lot between 1.21.1 and 26.x. ResourceLocation became Identifier, the block break event was renamed, and key mappings now declare their category as an object instead of a plain string. The generator applies the rules of the family you pick, so a 1.21.1 mod never borrows 26.x names, and the reverse.

ModDevGradle is the Gradle plugin the NeoForged team maintains for building mods. It sets up Minecraft and NeoForge for the chosen version, compiles your code against them and packages the .jar.

The first build on a version has to download and prepare Minecraft for it, which takes a few minutes. That preparation is kept, so the next builds on the same version are much quicker.

When the compiler reports an error, the exact message goes back to the AI. It fixes the code and the build runs again until the .jar is ready to download.

A NeoForge mod describes itself in META-INF/neoforge.mods.toml: mod ID, display name, version, description, and the NeoForge and Minecraft versions it needs. Older Forge-style mods used mods.toml; NeoForge now expects the neoforge.mods.toml name.

Template projects often leave placeholders such as ${mod_version} for Gradle to fill in. The generator writes final values into the file, pins the Minecraft version you built for and sets the minimum NeoForge version to the build the mod was compiled against.

The result is a mod that NeoForge either loads or rejects with a clear dependency message, instead of starting on the wrong version and failing later.

Many NeoForge modpacks stay on 1.21.1 for a long time, because moving a large pack to a new release means waiting for dozens of mods to update. A small custom mod is often what a pack is missing: a server tweak, a quest item, a message on a specific event.

Generate the mod for 1.21.1, make sure the NeoForge version in your pack is at least as recent as the one the mod was built with, then drop the .jar into the pack's mods folder. If the mod adds content, the server and every player need the same .jar.

The generator writes a standalone mod, so describe what it should do on its own rather than how it plugs into another mod of the pack.