Why OpenAI Reasoning Models Ignore Temperature

According to 2026 prompt engineering guides, reasoning models on OpenAI ignore the temperature parameter entirely. Instead of attempting to tune randomness via temperature or top_p on reasoning models, specify deterministic tie-breaking and formatting rules directly in the prompt brief.

Evaluate the candidate feature subsets and output the optimal selection. Deterministic Rule: Break any metric ties by selecting the feature subset with the lowest total column count.