codex.mdx

---
title: Codex
---


## Install

Install the [Codex CLI](https://developers.openai.com/codex/cli/):

```
npm install -g @openai/codex
```

## Usage with Ollama

<Note>Codex requires a larger context window. It is recommended to use a context window of at least 32K tokens.</Note>

To use `codex` with Ollama, use the `--oss` flag:

```
codex --oss
```

### Changing Models

By default, codex will use the local `gpt-oss:20b` model. However, you can specify a different model with the `-m` flag:

```
codex --oss -m gpt-oss:120b
```

### Cloud Models

```
codex --oss -m gpt-oss:120b-cloud
```


## Connecting to ollama.com


Create an [API key](https://ollama.com/settings/keys) from ollama.com and export it as `OLLAMA_API_KEY`.

To use ollama.com directly, edit your `~/.codex/config.toml` file to point to ollama.com.

```toml
model = "gpt-oss:120b"
model_provider = "ollama"

[model_providers.ollama]
name = "Ollama"
base_url = "https://ollama.com/v1"
env_key = "OLLAMA_API_KEY"
```

Run `codex` in a new terminal to load the new settings.