GameMerging AI

WorldPrompt: Install and Build in Minecraft

WorldPrompt is a Fabric mod for Minecraft: Java Edition 26.3. It lets a signed-in Codex or Claude Code agent plan and build within a selected part of a Minecraft world. It has two downloads: the Mod JAR and the local Core app. It is a one-game AI building mod, not a mashup of two games. Original project (opens in a new tab).

Current author release at the October 20, 2026 check: Mod 1.0.0 and Core 1.0.0. The author provides Windows and Linux x86_64 Core archives; the README does not list a macOS Core download. The author says a ChatGPT or Claude subscription and its CLI are used rather than a separate API key. Usage counts against that subscription; the site has not tested the builds.

Get WorldPrompt Mod and Core (opens in a new tab)

Match your setup

Part Use the author's matching release
Game Minecraft: Java Edition 26.3, with Fabric Loader and Fabric API for 26.3.
Mod worldprompt-1.0.0.jar in the instance's mods folder.
Core Windows WorldPrompt-Core-1.0.0-windows-x86_64.zip or Linux WorldPrompt-Core-1.0.0-linux-x86_64.tar.gz; extract the whole archive.
Agent Codex CLI or Claude Code installed and signed in on the same computer and user account as Core.
Permissions Single-player cheats/operator privileges for /wp prompt; on a server, see the creator's permission and VPS notes.

First build, with a check at every step

  1. Install Fabric Loader for Minecraft 26.3, add the matching Fabric API and WorldPrompt JAR to that instance's mods folder, and remove an older WorldPrompt JAR. Expected: Minecraft starts with the mod. If not: compare game, loader, API and JAR versions before touching Core.
  2. In a terminal on the same user account, run codex login or claude auth login. Expected: the chosen CLI reports you are signed in. If not: finish the CLI's own sign-in; Core does not install the CLI for you.
  3. Extract the complete Core archive. Start WorldPrompt-Core.exe on Windows or ./WorldPrompt-Core on Linux, keeping its _internal folder beside it. Expected: a settings page opens in your browser. If not: check that the archive was fully extracted and that the OS matches its binary; the author lists Linux glibc 2.35+.
  4. In Core settings, choose Codex or Claude, select Check connection, then Save settings. Leave Core running. Expected: connection succeeds. If not: sign in to the CLI again and restart Core; a newly installed CLI may need a fresh Core process.
  5. Open a local Minecraft world with operator commands enabled. Look at safe ground and enter /wp select, then /wp prompt Build a small woodland cabin inside this area. Expected: a selection appears and the job begins; blocks are placed only within it. If not: check /wp info, operator permissions and the Mod–Core connection. Start with a small area rather than a huge build.

/wp pos1 and /wp pos2 let you set two corners. /wp jobs shows running jobs; /wp cancel stops a job. /wp undo restores blocks from the prior edit within the creator's documented history limit. Undo is useful but not a substitute for a world backup; save a copy before trying large changes.

Cost, privacy and multiplayer

The Core sends your prompt, selected-block description, position/view context and previews through your chosen CLI to that provider. It uses your subscription allowance. The author says the server alone needs the Mod for multiplayer, while Core runs on the server machine; users with permission can issue building commands. Do not give /wp prompt permission to people whose use of your subscription you cannot manage. The Windows Core is not code-signed; follow your own download verification policy and the author's SHA256SUMS.txt rather than treating a security warning as proof either way.

Sources checked October 20, 2026: WorldPrompt README (opens in a new tab), official releases (opens in a new tab). The author documents these steps; GameMerging AI has not run the mod.

Next: CRAFT AI vs WorldPrompt · AI mod safety · All AI mods