Schematic-Ai-Studio

The AI works on the schematic itself, not on a description of it. Everything it does is a normal editor action, so one request is one Ctrl+Z. It can also build a structure from nothing, which is how the project started. It reads and writes five kinds of schematic-type files and converts between all of them.

It is a desktop app: one installer and nothing else to set up. Download the latest version from the releases page.

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Two ways to use it

1. MCP server — recommended

The app can share its editor with another program over MCP. That other program can be Claude Code, Antigravity, Codex, LM Studio, or anything else that speaks MCP. It edits the schematic you already have open, using the same tools and the same undo history. You watch the build change on screen, and your Ctrl+Z still takes it back.

This is the recommended way, for a simple reason: it costs you nothing extra. It uses the AI subscription you already pay for, instead of buying API tokens on top of it. If you already have Claude Code or a similar tool, you have everything you need.

There is a second reason. The AI on the other side is usually stronger than what you reach through an API key. But it cannot do the parts this app is for. It cannot read and write the file formats. It cannot place a block with the right state and the right connections to its neighbours. And it cannot draw the result so you can see it. That is the work the app does for it.

Turn it on in Settings → MCP server. It only listens on your own computer, and it asks for a token.

Default port	4571. Use 0 to let the system pick any free port, which is what a second copy of the app needs.
Authentication	A token. It is hidden by default, and you can copy it or create a new one.
Folder it may touch	The server cannot open, save or delete anything outside this folder. Empty means the output folder.
Deleting files	Off by default. Even when it is on, files go to the recycle bin.
Tools	36 in total: 11 shared with the in-app chat, and 25 that only MCP has.

The settings page shows two ready-to-paste commands. This one is for a client that speaks MCP over HTTP:

claude mcp add --transport http schematic <url> --header "Authorization: Bearer <token>"

And this one is for a client that only speaks stdio. A small bridge ships with the app for that case:

claude mcp add schematic -- node "<path to resources/mcp-bridge.mjs>"

The bridge needs no arguments and no setup. It finds the running app by itself, which is also why the port can be 0. It exists because stdio works the other way round: the client starts the server, and a server that has just started has no schematic open. The whole point here is the file you are looking at right now, so the bridge simply passes everything to the app that already has it.

2. Standard mode — the built-in chat

This is much better than it was in BuilderGPT. It no longer only generates. It edits the schematic you have open: it looks at the build through tools and changes it directly. It streams while it thinks, shows every tool call as it happens, and keeps a separate conversation for each schematic. One request is one undo step. If nothing is open, your message goes to the generator instead, and that is how you build a schematic from a single sentence.

This mode needs an API model that you pay for per token. That is exactly why MCP is recommended above.

Provider	Notes
OpenAI	API key required
Google Gemini	API key required
OpenCode	Many of its models are free and need no key at all. The rest are paid.
Custom (OpenAI Compatible)	Any endpoint that follows the OpenAI API

That last row is the interesting one, because it is how you run models on your own computer. Point the base URL at LM Studio, at Ollama's OpenAI-compatible server, or at anything else that offers /v1/chat/completions. Everything then runs locally, at no cost, and nothing leaves your machine.

API keys are encrypted by your operating system's keychain. There is no .env file and no plain text on disk, and the keys are never sent back to the window. The window itself cannot open any network connection at all: its security policy sets connect-src 'none', and every HTTP request is made by the main process.

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Formats & compatibility

Five kinds of file, all read and all written. The converter turns any of them into any other, without opening either file.

	MCEdit .schematic	Sponge v2 .schem	Sponge v3 .schem	Litematica .litematic	Function .mcfunction
Game versions	✅ 1.8.8 – 1.12.2. 🚧 Works above 1.13, but loses detail.	✅ 1.13+	✅ 1.13+	✅ 1.13.2+. One release later than the others, see below.	✅ 1.13+
BlockData (1.13+ states)	🚧 Approximate. The base block is written, and the loss is listed by name.	✅ Full	✅ Full	✅ Full	✅ Written as id[state=value]
MaterialData (old ID:DATA)	✅ This is the format's own model	❌ Uses 1.13+ block names, which did not exist before	❌ Same	❌ Same	❌ Same
ItemData (chest contents, sign text, NBT)	✅ Kept as it was	✅ Kept as it was	✅ Kept as it was	✅ Kept as it was	✅ Written inside the setblock command
Entities	✅	✅	✅	✅	❌ Not written. summon is a different command, so the count is reported instead.
WorldEdit paste anchor	✅ WEOffsetX/Y/Z	✅ Metadata.WEOffsetX/Y/Z	✅ Offset	❌ The format has no such idea. The loss is reported.	✅ Kept for free by ~ ~ ~
World origin	✅ WEOriginX/Y/Z	✅ Offset	✅ Metadata.WorldEdit.Origin	❌ Reported as lost	🚧 Read from absolute coordinates, but not written
DataVersion	❌ The format has no such tag	🚧 Optional. Left out when there is none.	🚧 Optional	✅ Required. The file cannot be written without one.	❌ Commands carry no version
Other metadata	❌ The format has nowhere to keep it	✅ Kept as it was	✅ Kept as it was	✅ Kept, with five fields recalculated	❌ Nothing to keep
Unknown blocks	❌ The save fails and names the blocks	✅	✅	✅	✅

Legend — ✅ supported · 🚧 partly supported, with a limit · ❌ the format cannot store it

Three things the table cannot show

The two newest formats start at different game versions. A .mcfunction needs setblock <pos> <block> with modern block names, and that is 1.13. A .litematic needs the Litematica mod not to convert it when it opens, and the mod converts every file below DataVersion 1631. So its first version is 1.13.2. A .litematic marked as 1.13 does not fail. It opens in the mod with the wrong blocks, which is worse. The app refuses to write one and explains why.

A .mcfunction is not really a schematic file. It has no metadata, no anchor tag, no version and no NBT. It is only a list of commands, and setblock and fill happen to be enough to describe a build. When you open one, you get a Sponge v3 document with no file path, so Save asks you where to put it instead of writing a Sponge file over your commands. Rows of identical blocks become one fill, and that is what makes the format usable: a real build of 259,072 cells came out as 10,877 commands instead of 259,072. This matters, because the game stops reading a function after 65,536 commands and does not tell you.

"Changed" and "missing" are different answers. A degraded block is still in the file, just approximate. A dropped item is simply not there. Both are listed by name after every save and every conversion. A loss that nobody tells you about is the exact problem this project tries to avoid.

Converting

Converting is its own action, not a trick. It never touches the file you have open, so you do not lose your work. It never overwrites: if a file with that name already exists, it is renamed with a timestamp first. And it never crops the build, because a conversion should describe the same schematic, only in another format.

One thing is worth knowing before it surprises you. A .mcfunction cannot become a .litematic unless you choose a Minecraft version, because commands carry no version and Litematica always needs one. The converter says so and offers you the list.

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Running from source

You need Node.js 20 or newer. Dependencies install themselves the first time you run it.

	Windows	Linux / macOS
Start (dev, hot reload)	scripts\start.ps1	scripts/start.sh
Build	scripts\build.ps1	scripts/build.sh
Build an installer	scripts\build.ps1 -Package win	scripts/build.sh --package linux
Run all checks	scripts\check.ps1	scripts/check.sh

Builds go to out/, and installers to release/. The npm scripts (npm run dev, npm run build, npm run package:win, and so on) work directly too. check.sh runs the type checker and all seventeen test suites, and it does not stop at the first failure, because that would hide how much else is broken.

There are no native dependencies. The sandbox is QuickJS compiled to WebAssembly, so the same build runs everywhere and there is nothing to compile.

Which editor

This project was written with IntelliJ IDEA, and the .run/ folder holds its run configurations. You do not need it. Everything here is plain Node, TypeScript and Svelte, so Visual Studio Code, WebStorm, Neovim or any other editor works just as well. Nothing in the build depends on the editor you use.

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A note on benchmarking AI models

Schematic AI Studio is not only a tool for building. It also turns out to be a very honest test of how well a model understands 3D space, because the result is a building you can walk around and look at. Text can sound correct while being wrong; a structure cannot. A model with no real picture of the space in its head cannot hide it here. The roof floats, the stairs face a wall, or the second floor has no way to reach it.

I have tested several models myself, both free and paid, and the differences are large. They show up in the finished build, but also in the way each model thinks about the problem. Gemini 3.1 Pro with high thinking, used through Antigravity over MCP, stood out at once for both speed and quality.

Try it yourself. Open the app fresh, connect your AI tool over MCP, and give it exactly this:

Using the connected schematic-ai-studio MCP server, generate a Minecraft schematic within the Schematic AI Studio editor. Create a Sponge v3 schematic with dimensions 16x32x16 for Minecraft 26.2 and save the file as benchmark.schem.

Build a two-story birch wood village house with a cobblestone floor and transparent glass block windows. The cobblestone floor should be slightly elevated. Place birch wood stairs in front of the double entrance doors. On the ground floor, include a bed, a chest, and a fireplace with a chimney extending through the roof. On the second floor, add another chest and colorful mosaic carpets. Connect the two floors using a ladder. Add an open balcony on the second floor. Ensure there is both interior and exterior lighting (exterior lights should be attached to the exterior walls).

It asks for a lot at the same time. Two floors have to line up. A chimney has to pass through a roof that the model is also building. A ladder has to connect two spaces at once. And the lights have to go on the outside of the walls. Very few models get all of it right.

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Contributing

Contributions are welcome. Please follow these steps.

1. Open an issue first. Describe the feature you want or the bug you found, before you write any code. This avoids work that goes in the wrong direction, and it gives us a place to agree on what the change should do.
2. Work on your own fork. Create a branch there and commit your work to it.
3. Open a pull request and link it to the issue.
4. I will review it as quickly as I can.

A few rules that make review easier:

• Write in English, everywhere: issues, pull requests, commit messages, code comments and any documentation you touch.
• Using AI is fine, and even encouraged. Claude Code is the recommended tool, and this project is built to work well with it: the CLAUDE.md file in the repository explains the rules the code follows and why.
• Check the work yourself before you send it. Read every line you are asking someone else to accept, run scripts/check.sh, and make sure the app still starts. You are responsible for your pull request, whether or not an AI wrote part of it.

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Credits

This project is built on the work of other people.

• CyniaAI/BuilderGPT — the original Python/Streamlit version that this desktop app comes from. The generation approach and the prompt design come from that project.
• MCBench — BuilderGPT's JavaScript way of describing a build, and parts of its prompting approach, are inspired by MCBench. The JavaScript parsing and integration code here was written separately.
• Faithful — the 64x resource pack included to texture the 3D view, used under its own licence.
• PrismarineJS/minecraft-data (MIT) — the table of old block ids used to read legacy MCEdit files.
• misode/mcmeta — the block registry behind the block list, the block states and the placement defaults.
• minecraft.wiki — command syntax, block models, block state meanings and DataVersion history. All of it is copied into this repository by hand, never downloaded while the app runs.
• maruohon/litematica and litemapy — the sources for the .litematic version history and its data packing.
• models.dev — the OpenCode model catalogue that provides pricing and capability data.
• ChatGPT — the application icon was generated with it.

And the libraries it is made of: Electron, Svelte, Three.js, prismarine-nbt, quickjs-emscripten, the Vercel AI SDK, @modelcontextprotocol/sdk, marked, DOMPurify, pngjs and adm-zip.

Minecraft is a trademark of Mojang Studios. This project is not affiliated with, endorsed by, or connected to Mojang Studios or Microsoft.

License

Apache License 2.0. See LICENSE.