Lab

Mod Lab

Running at home

My kid types an idea and a local model turns it into a Minecraft Bedrock add-on that installs in the game.

Mod Lab

Attempt 2 of 3

a pickaxe that mines faster

Specreply matches the schemapassed
Checksitems exist, ids are freepassed
Type-checkscript against the game typingspassed
Compilepacks and texturesbuilt

Attempt 1 failed the type-check. The error went back to the model, and attempt 2 passed.

Your Quick Pickaxe is ready. Download it and open the file to install it in Minecraft.

The builder thread for one idea: the first attempt fails the script type-check, the error goes back to the model, and the second attempt passes. Mockup with sample data.

Quick Pickaxe

A pickaxe that digs much faster than a normal one.

pickaxe2 attempts

9Mining speed

800Durability

1Stack size

Recipe

Give commands

/quick_pickaxeone

/quick_pickaxe 8eight

Copied

The mod card: stats from the spec, the crafting recipe, the texture the compiler drew, and a copy button for each give command. Mockup with sample data.

$ build "a pickaxe that mines faster"

attempt 1 safety passed

attempt 1 spec passed

attempt 1 cross-check passed

attempt 1 type-check 1 error

9:18 Property 'mineFaster' does not exist on type 'ItemStack'.

attempt 2 spec passed

attempt 2 cross-check passed

attempt 2 type-check passed

texture quick_pickaxe 16x16

packs Quick Pickaxe BP and RP

wrote Quick Pickaxe.mcaddon

The compile log for the same build: a failed type-check on attempt 1, a pass on attempt 2, then textures and the zip. Mockup with sample data.

How it works

He types an idea and it gets read first. A word filter runs on the text, then the local model judges whether the idea is appropriate. The build prompt itself never asks for a last name, age, school, address or phone number.
The model answers with a spec, not a finished mod. The reply has to match a zod schema: items, blocks, recipes, a script and a short explanation. Then code cross-checks it. Item references that are not real Minecraft items are rejected, and so is a command name that clashes with a built-in one.
The script is type-checked, not trusted. The model’s JavaScript is checked in memory against the official @minecraft/server typings, so a call to something that does not exist in the game fails before it ever reaches Minecraft.
The compiler writes the add-on. It generates the behavior pack and the resource pack, draws each 16x16 texture in code from a template and three colors, and zips everything into a single .mcaddon he can open to install.
A failure gets another attempt. The error list goes back to the model for up to 3 attempts. If they run out, a plain-language explanation tells him what to try instead. The parent page keeps the log: every idea, the attempts it took, and anything that was blocked.

Built with

Node and ExpressOne process serves the builder, the parent page and the download.
OllamaRuns the local model. Builds can also go to my GPU job queue, where a faster node wins.
zodThe schema for the spec, and the error messages sent back to the model.
TypeScriptIts compiler API type-checks the model’s scripts against the @minecraft/server typings.
fflateZips the two packs into the .mcaddon.
pngjsWrites the generated 16x16 textures and pack icons as PNG files.
vitestTests for the spec checks, the compiler and the prompt examples.

Decisions

Type-check model code instead of trusting it. Small local models invent API calls that look right. Running the real typings over every script catches those before they reach a child’s game, where the only symptom would be an add-on that silently does nothing.
Repair with the failure explained. A bare “try again” wastes an attempt. Each retry gets the exact error lines, so attempt 2 is a fix and not a reroll. When the attempts run out, the child gets a plain reason, because retyping the same idea would fail the same way.
Draw textures in code. Each texture comes from a template, three colors and a 16x16 grid, rendered by the compiler. Nothing copyrighted ships in an add-on, and the model only has to name colors, not draw pixels.