Codex

Codius runs Codex through the official codex CLI and its app-server interface.

Use Codius models automatically

Open Host Settings → Providers → Codius models, connect one organization API key, and keep automatic model access enabled. When Codius launches Codex, it supplies a session-scoped provider and the selected default model.

No provider file needs to be copied, and Codius does not overwrite Codex configuration. An explicit workspace provider or model takes precedence.

Use an existing provider account

Disable automatic Codius model access or choose an explicit workspace provider. You can then sign in to Codex with ChatGPT or an API key according to the official Codex setup.

Getting started

Install the Codex CLI on the machine running Codius:

npm install -g @openai/codex

Optional: sign in with ChatGPT for subscription access when you are not using the automatic Codius provider:

codex login

Or sign in with an API key for usage billed through your OpenAI Platform account:

# macOS or Linux
printenv OPENAI_API_KEY | codex login --with-api-key

# Windows PowerShell
$env:OPENAI_API_KEY | codex login --with-api-key

Then confirm the CLI starts:

codex

Codius uses this installation when you start a Codex agent.

Codex is missing in Codius

The ChatGPT desktop app and the Codex CLI are separate installs. Installing the desktop app does not make the codex command available to Codius.

Check whether the CLI is on your PATH:

# macOS or Linux
which -a codex

# Windows
where.exe codex

If the command is not found:

1. Install the Codex CLI.
2. Sign in with ChatGPT or an API key using the commands above. See Codex authentication.
3. Restart Codius if its daemon was already running when you installed the CLI.
4. In Codius, open Settings → Providers → Codex and select Refresh.

The provider should become available once Codius can find and start the codex command.

Use Codex in the Codius terminal

Codex also works inside the Codius terminal. Open a terminal in your workspace and run codex for the standard CLI experience while keeping access to your workspace, git changes, and other Codius tools.

See also

• Supported providers, for other agents you can run alongside Codex.
• Codius model access, for the one-key automatic setup.
• Custom providers, for custom binaries, third-party endpoints, or multiple Codex profiles.
• Codex integration, for the current Codius setup path.