Cobble

A modern, Python-like language for creating Minecraft Data Packs

Cobble web demo preview

Cobble transpiles .cbl source into Minecraft Java Edition data packs. It lets you write functions, events, resources, and command-heavy logic with a Python-like syntax while still emitting plain .mcfunction, pack.mcmeta, tag, and JSON resource files.

Cobble 0.6.3 targets Minecraft Java Edition 26.1.2 and pack format 101.1.

Website And Web Demo

Website: https://deveworld.github.io/cobble/ Browser compiler: https://deveworld.github.io/cobble/try/

The website introduces Cobble with short examples and links to the browser compiler at /try. The compiler runs Cobble's Rust parser and transpiler through WebAssembly, so you can inspect generated functions, resources, metadata, diagnostics, and data pack ZIP output without installing the CLI.

[!WARNING] Cobble is pre-1.0 software in active development. Bugs and API changes are still possible. Please report issues at https://github.com/deveworld/cobble/issues.

Features

Python-like syntax for functions, indentation, imports, and control flow
Static type inference for variables, constants, and expressions
Data pack output for functions, event tags, predicates, advancements, loot tables, recipes, item modifiers, and dialogs
Minecraft command handling with JSON safety, macro parameters, and command validation
Standard library helpers for events, text, scoreboards, storage, schedules, bossbars, teams, and entities
CLI workflow for project templates, build, check, watch, validation, and ZIP output
Browser playground powered by Rust and WebAssembly

Installation

cargo install cobble-lang
cobble --help

The crates.io package is named cobble-lang; the installed command is cobble.

To build from source:

git clone https://github.com/deveworld/cobble.git
cd cobble
cargo build --release

Quick Start

cobble init --name my-datapack
cd my-datapack

Edit src/main.cbl:

import stdlib
from stdlib import event

def on_load():
    /tellraw @a {"text":"Cobble loaded","color":"green"}

def reward(player, amount):
    /give {player} minecraft:diamond {amount}

stdlib.addEventListener(event.LOAD, on_load)

Build the data pack:

cobble build --validate --zip

Copy the generated output to your world's datapacks directory:

.minecraft/saves/YourWorld/datapacks/

Commands

Command	Purpose
`cobble init`	Create a new project
`cobble build`	Build source files into a data pack
`cobble check`	Check Cobble syntax without building
`cobble doctor`	Inspect project and validation environment status
`cobble inspect`	Summarize generated build metadata
`cobble validate`	Validate generated `.mcfunction` files
`cobble watch`	Rebuild when source files change

Use cobble build --dry-run to compile and inspect the output plan without writing the final data pack. Each build writes .cobble/build_manifest.json with the Cobble version, Minecraft target, pack format, source inputs, generated resource entries, validation summary when available, and generated file counts. Use cobble inspect output/ to summarize that metadata after a build. Use cobble build --quiet when a script only needs the exit code.

cobble build --validate and cobble validate check generated .mcfunction files against Minecraft Java Edition 26.1.2 commands. The default data/commands.json file is generated automatically on first validation when missing; this requires curl and Java.

Configuration

cobble.toml controls the project namespace, pack metadata, source directory, output directory, and entry points.

[project]
name = "my-datapack"
namespace = "my_namespace"
version = "1.0.0"
pack_format = "101.1"

[build]
source = "src"
output = "output"
entry_points = []

Development

cargo test --locked

cd web
npm install
npm run dev

cobble-lang 0.6.3