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

# Codex CLI

> Use OpenAI's Codex CLI with Bifrost for powerful code generation with any provider.

[Codex CLI](https://developers.openai.com/codex/cli/) provides powerful code generation and completion capabilities directly in your terminal.

<Note>
  If your Allowed Headers are already set to `*`, you can skip this note. If not, and you face issues integrating Bifrost with Codex CLI, try switching to `*` or adding the specific headers required by your client. By default, Bifrost whitelists: `Content-Type`, `Authorization`, `X-Requested-With`, `X-Stainless-Timeout`, and `X-Api-Key`.
</Note>

## Installing Codex CLI

```bash theme={null}
npm install -g @openai/codex
```

## Configuring Codex CLI with Bifrost

<Warning>
  Codex CLI always prefers OAuth over custom API keys. Make sure you run `/logout` before configuring the Bifrost gateway with Codex.
</Warning>

### Update codex.toml

Add the Bifrost base URL and credentials to your global `~/.codex/config.toml` or project-specific `.codex/config.toml`:

```bash theme={null}
export OPENAI_API_KEY=<bifrost_virtual_key>
```

```toml theme={null}
openai_base_url="http://localhost:8080/openai/v1"
env_key="OPENAI_API_KEY"
model = "openai/gpt-5.4"
```

Always run `codex` from the same terminal session where you exported variables, or restart the terminal after changing your profile. GUI-launched terminals or IDEs may not pick up shell-profile exports unless the environment is configured there as well.

## Using Non-OpenAI models

Codex CLI defaults to [websocket mode](https://developers.openai.com/api/docs/guides/websocket-mode) for the Responses API and automatically falls back to HTTPS if the WebSocket connection fails. Non-OpenAI models are not supported in WebSocket mode, because in this mode, the server is expected to maintain the conversation context. If you are using non-OpenAI models, you must enable HTTPS mode.

To enable https for Codex CLI by default, add these settings in your `config.toml`:

```toml theme={null}

model_provider = "openai_http"

[model_providers.openai_http]
name = "OpenAI HTTP"
wire_api = "responses"
supports_websockets = false
base_url = "http://localhost:8080/openai/v1"
```

## Model Configuration

Use the `--model` flag to start Codex with a specific model:

```bash theme={null}
codex --model openai/gpt-5-codex
codex --model openai/gpt-5.4-pro
```

You can also switch models mid-session with the `/model` command:

```bash theme={null}
/model openai/gpt-5.4-pro
/model openai/gpt-5-codex
```

## Using Non-OpenAI Models with Codex CLI

Bifrost automatically translates OpenAI API requests to other providers, so you can use Codex CLI with models from Anthropic, Google, Mistral, and more. Use the `provider/model-name` format to specify any Bifrost-configured model:

```bash theme={null}
# Start with an Anthropic model
codex --model anthropic/claude-sonnet-4-5-20250929

# Start with a Google model
codex --model gemini/gemini-2.5-pro

# Switch mid-session
/model anthropic/claude-sonnet-4-5-20250929
/model mistral/mistral-large-latest
```

### Supported Providers

Bifrost supports the following providers with the `provider/model-name` format:

`openai`, `azure`, `gemini`, `vertex`, `bedrock`, `mistral`, `groq`, `cerebras`, `cohere`, `perplexity`, `xai`, `ollama`, `openrouter`, `huggingface`, `nebius`, `parasail`, `replicate`, `vllm`, `sgl`

<Warning>
  Non-OpenAI models **must support tool use** for Codex CLI to work properly. Codex CLI relies on tool calling for file operations, terminal commands, and code editing. Models without tool use support will fail on most operations.
</Warning>