Changelog Update

Along with the GPT-5.1 launch in the API, we are introducing new gpt-5.1-codex-mini and gpt-5.1-codex model options in Codex, a version of GPT-5.1 optimized for long-running, agentic coding tasks and use in coding agent harnesses in Codex or Codex-like harnesses.

Starting today, the CLI and IDE Extension will default to gpt-5.1-codex on macOS and Linux and gpt-5.1 on Windows.

If you have a model specified in your config.toml configuration file, you can instead try out gpt-5.1-codex for a new Codex CLI session using:

codex --model gpt-5.1-codex

You can also use the /model slash command in the CLI. In the Codex IDE Extension you can select GPT-5.1-Codex from the dropdown menu.

If you want to switch for all sessions, you can change your default model to gpt-5.1-codex by updating your config.toml configuration file:

model = "gpt-5.1-codex”