MMCP

MMCP is a Fabric mod that exposes your Minecraft world to AI assistants through the Model Context Protocol (MCP). It runs a local MCP server inside Minecraft, allowing AI tools like Claude, Codex, or any MCP-compatible client to read and interact with your game in real time.

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What it does

The mod starts an HTTP-based MCP server at http://127.0.0.1:47355/mcp while Minecraft is running. A lightweight stdio proxy (mmcp.jar) bridges your AI client to this server. Once connected, the AI can call tools to observe the world around your player.

Available tools:

Tool	Description
get_player_position	Player coordinates, rotation, dimension, and server address.
get_player_health_hunger	Health, absorption, hunger, and saturation values.
get_inventory	All non-empty inventory slots including armor and offhand.
get_nearby_blocks	Blocks around the player within a configurable radius.
get_nearby_entities	Nearby entities sorted by distance, with type and position.
get_biome	Current biome at the player's position.
get_time_weather	World time, day index, daytime state, rain, and thunder.

All tools are read-only in this release. Control tools are planned for future versions.

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Why you'd want this

If you use AI assistants in your workflow, this mod gives them real context about your Minecraft world. Instead of describing your situation in chat, your AI can see your inventory, health, surroundings, and more and help you accordingly.

It also opens the door for autonomous AI gameplay. Future control tools will allow an AI to move, mine, build, and navigate on its own.

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Requirements

• Minecraft 1.21.1
• Fabric Loader 0.18.4+
• Java 21
• Fabric Language Kotlin 1.13.9+kotlin.2.3.10

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Quick Setup

1. Drop minecraft-mcp-<version>.jar into your mods folder.
2. Launch Minecraft. The MCP server starts automatically.
3. Point your MCP client to mmcp.jar:

java -jar mmcp.jar

For Codex CLI:

codex mcp add mmcp -- java -jar path/to/mmcp.jar

1. Keep Minecraft running while using MCP tools.

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Important Notes

• The MCP server only listens on 127.0.0.1 (localhost). No data is sent to any remote server.
• This mod is intended for singleplayer use or servers you own and control.