BBMCP

BBMCP is an internal development tool for Minecraft 1.21.1 on NeoForge. It embeds a local HTTP Model Context Protocol (MCP) server inside the Minecraft client JVM, allowing AI coding agents and automation tools to inspect and interact with a running game.

Agents can query the local player's position and health, inspect blocks, block entities, item data components, nearby entities, registries, loaded mods, loot tables, and the latest game logs. They can also execute Minecraft commands, capture screenshots, inspect FTB Quests chapters, export complete quest canvases, and register custom MCP tools through KubeJS scripts.

FTB Quests and KubeJS are optional integrations. BBMCP detects whether they are loaded and only enables their tools when the corresponding mod is available. KubeJS tools are rebuilt automatically after server-script reloads, so modpack developers can expose custom pack mechanics to their AI workflow.

Installation

1. Install NeoForge for Minecraft 1.21.1.
2. Download the BBMCP .jar and place it in the instance's mods folder.
3. Launch the NeoForge client and load or create a single-player world.
4. Configure your MCP-capable coding agent to use:

   http://localhost:8080/mcp

The HTTP server is enabled by default and binds only to localhost. The generated configuration file is config/bbmcp-client.toml; use it to change the port, request limits, timeouts, or privileged tool switches. Restart the Minecraft client after changing the port or server settings.

Usage

Register bbmcp as an HTTP MCP server in Codex, Claude Code, GitHub Copilot, Antigravity/Agy, or another MCP-compatible client. Once Minecraft is running, the agent can discover the available tools with MCP tools/list and invoke them with tools/call.

Useful starting tools include:

• list_mods to see which compatibility integrations are available.
• get_player_info to confirm that the client is connected to a world.
• read_latest_logs to inspect recent startup or runtime errors.
• get_player_info, get_nearby_entities, and get_block_entity_data for game-state inspection.
• execute_command for controlled development commands. Commands are sent without the leading /.
• FTB Quests tools for chapter layouts, quest GUIs, screenshots, and full canvas exports when FTB Quests is installed.

The endpoint is intentionally local and has no authentication layer. Do not forward the port, expose it to a network, or enable it in an environment where untrusted local processes can access the machine. Command execution and KubeJS script injection can change the world or execute pack logic, so disable allowCommandExecution or allowKubejsScriptInjection when those capabilities are not needed.