The word “hallucination” has become overloaded, but it general means an LLM producing some output that isn’t plausible or grounded. When you have a very long context session where the context includes “minecraft.py” it’s not hard to extrapolate that Minecraft may have ended up in one of the reasoning traces and that distraction snowballed until it appeared in the output.

These effects are becoming more rare as the SOTA models are improving so much. If you spent a lot of time with earlier LLMs or you experiment with smaller, quantized local LLM models this type of thing happens very frequently. When you see it happen so much on a model you’re running on your own hardware it becomes a reflex to chuckle and reset the session with a clean context. When it happens from a hosted provider it can be scarier because it’s not the type of failure mode most people are used to seeing.

One of his tool results mentioned the word minecraft.py, and the response was about Minecraft.

It's a hallucination.