Minecraft MCP

Java-only Minecraft 1.21.1 client mod exposing a local MCP-style JSON-RPC endpoint for AI agents.

Supported loaders:

• Fabric 1.21.1
• NeoForge 1.21.1

Default transport is local HTTP JSON-RPC at /mcp. The mod writes discovery data to mcp/server.json under the game directory. It binds to 127.0.0.1 by default and requires a bearer token.

Build:

./gradlew build

Example MCP call:

curl -s -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' \
  http://127.0.0.1:$PORT/mcp

For MCP clients that connect over stdio, such as Claude Code, use the stdio bridge. It stays up while the game is restarted and can launch, stop and read the logs of the client itself.