# Source: https://developers.openai.com/changelog/codex/2025-11-13.md

# Introducing GPT-5.1-Codex and GPT-5.1-Codex-Mini

- Date: 2025-11-13
- Products: Codex

Along with the [GPT-5.1 launch in the API](https://openai.com/index/gpt-5-1-for-developers/), 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](https://developers.openai.com/codex/local-config), you can instead try out `gpt-5.1-codex` for a new Codex CLI session using:

```bash
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](https://developers.openai.com/codex/local-config):

```toml
model = "gpt-5.1-codex”
```