This guide can also be used for GPT-5.1-Codex and GPT-5.1-Codex-Mini, we recommend to keep the same prompts and harness for GPT-5.1-Codex and GPT-5.1-Codex-Mini as GPT-5-Codex Important details about GPT-5-Codex and this guide: This model is not a drop-in replacement for GPT-5, as it requires significantly different prompting. This model is only supported with the Responses API and does not suppor