OpenAI Says Its New Codex-Max Model Is Better, Faster and Cheaper

OpenAI today launched GPT-5.1-Codex-Max, a new variant of its GPT-5.1-Codex foundation model that was specifically trained to excel at coding tasks and which powers OpenAI’s Codex agent.

The original Codex model launched about two months ago and, at the time, it was extremely competitive — and often led the competition — on most benchmarks. But nobody in this field is standing still. OpenAI itself launched the 5.1 versions of its GPT models, including Codex, just a few days ago, and Google’s Gemini 3, which launched earlier this week,…