Model page

GPT-5.1 codex

GPT-5.1 optimized for agentic coding in Codex. 400K context, 128K max output.

Key dates

We use concrete dates and keep them consistent across the site.

ChatGPT

OpenAI is retiring GPT‑4o inside ChatGPT on February 13, 2026. This does not automatically imply API removal.