> ## Documentation Index
> Fetch the complete documentation index at: https://radiusbrowser.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Codex

> Choose CLI or API-key authentication for Codex in Radius.

| Method      | Use it for                                                                           | How it works                                               |
| ----------- | ------------------------------------------------------------------------------------ | ---------------------------------------------------------- |
| **CLI**     | ChatGPT/Codex login, Azure, Amazon Bedrock, gateways, or compatible custom providers | Codex uses your normal `CODEX_HOME` and shell environment. |
| **API Key** | An OpenAI key managed by Radius                                                      | Radius supplies the key to an isolated Codex home.         |

## What belongs where

| Part                  | Behavior                                                                                               |
| --------------------- | ------------------------------------------------------------------------------------------------------ |
| Codex runtime         | Radius bundles and versions it. You don't need to install Codex.                                       |
| User configuration    | Codex reads `$CODEX_HOME/config.toml`, normally `~/.codex/config.toml`.                                |
| Authentication        | **CLI** uses the native Codex account or provider environment. **API Key** uses Radius's secure store. |
| Project configuration | Codex loads applicable settings for the current project.                                               |
| Model selection       | Codex reports availability; Radius applies the selection for the conversation.                         |

Both methods use Radius's bundled Codex app-server. Radius asks the app-server
for available models and displays the returned names and capabilities.

The native configuration supplies the initial model when that model is
available. A model that you select in Radius overrides it for the conversation.