4B model mines an iron pickaxe in Minecraft in 23 decisions, generating zero tokens
Top-Evidence174 · reddit · 2026-09-26
The open-source decision model Mica v0.1 4B went from an empty inventory to an iron pickaxe on a real Minecraft 1.20.4 server in just 23 decisions — without generating a single token.
How it works:
- Each step, the bot's live game state (inventory, nearby blocks, entities, last result) is written out as text;
- Mica scores candidate commands and picks one by reading answer-label token probabilities — output tokens are 0;
- The chosen command runs via Mindcraft's skill library (Mineflayer bot).
The full chain covers logs, planks, crafting table, wooden pickaxe, stone, stone pickaxe, furnace, iron ore, smelting, and the iron pickaxe. Decisions take 90–150ms, running Q5KM via llama.cpp on an RTX 3090. The video shows each decision's candidates, probabilities, and outcomes; weights and code are open-sourced.
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