Codex Client Control
by JiuWu
Codex Client Control opens a local HTTP and WebSocket interface so AI tools running on the same machine can read and operate a running Minecraft client.
What it does
A token-guarded connection listens only on the loopback address 127.0.0.1, letting an AI tool running on that same computer both read the state of the client and issue genuine in-game commands to it. Reading covers player state, chat history, the crosshair target, container contents, the current screen and the player list. Acting covers movement keys, camera look, hotbar selection, chat sending, command execution, GUI clicks, scrolling, key input, text entry and widget targeting.
The mod was written because most AI tools can explain or write Minecraft code but cannot operate a running client. Through the same interface, external scripts, desktop tools and agents can run short action sequences, take screenshots and inspect or debug the client. The HTTP design was chosen so any agent can make an ordinary local request without a special plugin host, and an embedded scripting environment is part of the project.
Codex Client Control is client-side only, so only the client needs it and servers run without it. It is published for Fabric and NeoForge with files for 1.21.8 and 1.21.11, and the latest build, 1.1.0+1.21.11, is dated 2026-03-18. It is open source under the GNU Lesser General Public License v3.0 or later, and its source code and wiki are public.
Key features
Local token-protected API
An HTTP and WebSocket interface listens only on the local address, and every request must carry a token.
Client state reading
Agents can query chat history, the crosshair target, container contents, the current screen and the player list.
In-game input
Movement keys, camera turns, hotbar slot changes and chat or command input are sent as real actions.
GUI interaction
Clicks, scrolling, key presses, text fields and widget targeting work on open screens, and screenshots can be taken.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
APIBlock is a Fabric mod for 1.21 – 1.21.11 that runs on client and server, with a GNU General Public License v3.0 only license. MCPFabric covers Fabric and NeoForge for 1.21.1 – 26.3 on client and server under the MIT License. Codex Client Control differs by being client-side only and by its scope, which is driving the client through a local API rather than adding server-side functions.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Codex Client Control | Fabric and NeoForge | 1.21.8 – 1.21.11 | Client-side only | 2026-03-18 |
| APIBlock | Fabric | 1.21 – 1.21.11 | Client and server | 2026-06-10 |
| MCPFabric | Fabric and NeoForge | 1.21.1 – 26.3 | Client and server | 2026-10-15 |
Questions
Does Codex Client Control need to be installed on the server?
Which loader should be used with Codex Client Control?
Can the interface be reached from another computer?
In the catalog
Codex Client Control is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 19,862 mods support Minecraft 1.21.11.
Similar mods
What the author says
Codex Client Control started from a simple problem: most AI tools can explain Minecraft, talk about Minecraft, and write code for Minecraft, but they still cannot actually operate a running Minecraft client. That gap is what this mod is meant to close. It opens a token-protected local HTTP and WebSocket interface on…
Official listing
- Modrinth page
- modrinth.com/mod/codex-client-control
- Owner
- JiuWu
- Published
- 2026-03-18
- Updated on Modrinth
- 2026-03-18
- Facts verified
- 2026-10-15