Giving a 'Brain' to Minecraft NPCs with a Local LLM — Nemotron + Mineflayer Implementation Notes

What We Want to Achieve Traditional Minecraft bots primarily relied on command-based operations, but natural conversation with players and situation-aware decision-making remained a challenge. This article focuses on implementing a system where a locally running LLM is integrated into an NPC to automatically generate situation awareness → decision-making → actions. We will locally execute NVIDIA's Nemotron 9B model with vLLM, integrate it with the Minecraft world via Mineflayer, and achieve flexible responses to player utterances. System Architecture This system consists of four layers. Minecraft Server ↓ Mineflayer (Minecraft operation with Node.js) ↓ IPC (WebSocket/stdin) brain.py (LLM integration with Python) ↓ vLLM (Local execution of Nemotron 9B) Role of Each Component Mineflayer: A Node.js library that connects to the Minecraft server and controls block operations and chat events. brain.py: Collects situation awareness data (player position, inventory, etc.) and sends the context