"gpt-5-chat-latest is described by OpenAI as a non-reasoning GPT-5 variant—meaning it doesn’t engage in the extended “thinking token” process at all.

  gpt-5 with reasoning_effort="minimal" still uses some internal reasoning tokens—just very few—so it’s not truly zero-reasoning.

  The difference: "minimal" is lightweight reasoning, while non-reasoning is essentially no structured chain-of-thought beyond the basic generation loop."