When I did my research on reasoning strategic games in 4x4 tic tac toe boards, LLMs with given nominal parameters and low temperature would still show variance in their assessment of the situation.
"low" is the key word. If it's anything other than 0, it becomes non-deterministic.
If you use a temperature of 0, then the output of an LLM will be completely deterministic. Any given input would have the exact same output every time.