What it does · Install · Blueprint · Undo · Datapacks · FAQ

Vibe-build in Minecraft. Type it, see the blueprint, place it.

A watchtower on the hill you're standing on. A bridge over the river. A speed boost when you eat a golden carrot. Type it in your terminal and Trowel builds it in your world. It reads the blocks around you, shows the build as a blueprint first, places it when you say yes, and takes it back with one /undo.

Trowel is free and open source. Out of the box it runs on a free local model through Ollama. A Claude, GPT or Gemini key is optional, if you already have one. No account, no limits, nothing to buy.

What it does

Blueprint first. Walk around it before a single block is placed	Datapacks. It runs /reload, reads the log and fixes what broke
Survival-ready. The exact shopping list, or a Litematica file to build it by hand	One-step undo. Every block the turn touched, back as it was

Install

Download	For
Windows 10 and 11	Trowel-1.4.0-portable-x64.exe

1. Start Trowel-1.4.0-portable-x64.exe. No installer, no admin rights.
2. Add the companion. Drop the Fabric jar into your mods folder next to Fabric API. On a Paper server, put the plugin in plugins and run /trowel connect in game. On Minecraft on Rust, turn on Agent Control in Horizon instead. No mod needed.
3. Start the game, then run trowel. It finds the running game on its own.

It sees where you're standing

Trowel doesn't build blind. Before it plans, the companion reads the blocks around you, the biome and what you're looking at. It matches the palette of the builds nearby, so a new tower next to your spruce house comes out in spruce and stone, not quartz.

Blueprint first

Every build shows up in your world as a blueprint before it's real: white outlines you can walk through and look at from every side. Only you can see it. Too far left? Say "move it 3 blocks east" or pick Move or rotate. Happy? Say yes and it fills in.

One-step undo

Every turn is a transaction. Trowel snapshots the region, places the build in batches that stay under the max_block_modifications game rule, and keeps an undo journal of every block it replaced. /undo puts all of them back, grass and path blocks included. Nothing outside the build is touched.

Datapacks too

Ask for game rules, not just buildings: recipes, advancements, loot tables and functions. Trowel writes the pack with the right pack.mcmeta for your version (data pack format 121 on 26.3), runs /reload and reads the log. One bad line makes Minecraft drop the whole function file, so Trowel checks every reload and fixes what failed before it calls the turn done.

Also

• Survival-ready. /materials lists every block you'd need. /export writes .litematic, .nbt or .schem.
• Your world, your rules. Put limits in TROWEL.md: no building below y 64, no concrete, never touch the farm. See examples/TROWEL.md.
• Any model. A free local model through Ollama by default. Claude, GPT or Gemini if you add your own key.
• Only where you're allowed. Singleplayer, LAN worlds you host, and servers where you're an operator.

Where it works

Game	How Trowel connects	Preview
Java Edition 26.1 to 26.3, singleplayer or LAN	Fabric companion	Blueprint in your world
Paper 26.3 servers	Paper plugin, operators only	Blueprint shown only to you
Minecraft on Rust (Horizon)	Horizon's built-in Agent Control (horizon-ctl mcp)	In Trowel's preview window, since Horizon has no preview hook yet

Undo works everywhere, because the journal lives in Trowel, not in the game.

Build from source

You need Rust 1.85 or newer for the terminal app, and Java 25 for the companions.

git clone https://github.com/Straitbrashadow/minecraft-ai-mod-builder.git
cd minecraft-ai-mod-builder
cargo build --release                  # the trowel command
cargo test --workspace
cd companion/fabric && gradle build    # the Fabric companion
cd ../paper && gradle build            # the Paper plugin

Path	What's inside
crates/trowel-core	Ghost previews, block batches, the undo journal
crates/trowel-cli	The trowel command
companion/fabric	The Fabric companion mod
companion/paper	The Paper server plugin
examples/	A sample TROWEL.md

FAQ

Is it free?

Yes, completely. Trowel is free and open source under the MIT license. It runs on a free local model through Ollama out of the box. If you already have a Claude, GPT or Gemini key you can use it, but you never need one.

Can I use it on a server I don't run?

Only if you're an operator there. The Paper plugin refuses everyone else, and the Fabric companion only builds in worlds running on your own PC.

Does it work in survival?

Yes. In creative it places the build for you. In survival, use /materials for the shopping list and /export litematic to build it yourself, block by block.

Does it work with Minecraft on Rust?

Yes. Turn on Agent Control in Horizon and run trowel --horizon. Building and undo work the same. The blueprint shows in Trowel's own preview window until Horizon adds a way to draw it in game.

Is this made by Mojang?

No. Trowel is an independent open-source project.

Is Trowel like WorldEdit or Litematica?

It plays well with both. WorldEdit is for people who know the commands, Litematica for schematics that already exist. Trowel draws the build from a sentence, shows the blueprint where it'll stand and exports .schem and .litematic files.

License

Trowel is MIT licensed. The README images were made with Inter and Geist Mono, both under the SIL Open Font License 1.1 (see assets/fonts). Block textures in the images are original pixel art.

Minecraft is a trademark of Mojang Synergies AB. Trowel isn't an official Minecraft product and isn't approved by or associated with Mojang or Microsoft.

WorldEdit, Litematica and Claude Code are named for comparison only. Trowel isn't affiliated with their authors or with Anthropic.