---
title: How do I install OpenAI Codex for codus?
question: install OpenAI Codex on Mac or Windows
area: getting-started
surface: desktop
audience: beginner
keywords: [Codex CLI, ChatGPT login, Windows PowerShell, Mac Terminal, not installed, PATH]
related: [what-do-i-need-before-i-start, how-do-i-install-codus, how-do-i-start-working-on-a-project]
updated: 2026-09-09
visibility: public
---

# How do I install OpenAI Codex for codus?

Install the Codex command-line app for your operating system, run `codex`, and complete its sign-in. Codus can then use it in a project quadrant or the Brain. You do not need Claude Code to use a Codex-powered Brain.

## Before you start

Use an OpenAI sign-in method available to your account. Your Codus subscription does not include OpenAI usage. The [official Codex CLI guide](https://learn.chatgpt.com/docs/codex/cli) is the authority for installation and authentication options.

## Install and sign in

1. On Mac, open **Terminal** and run:

   ```sh
   curl -fsSL https://chatgpt.com/codex/install.sh | sh
   ```

2. On Windows, open **PowerShell** instead and run:

   ```powershell
   powershell -ExecutionPolicy ByPass -c "irm https://chatgpt.com/codex/install.ps1 | iex"
   ```

These are OpenAI's platform-specific installers. Use only the command for your operating system; review organisation restrictions before running downloaded installers.

3. Open a new terminal window and run `codex --version`. It should print a version.
4. Run `codex`, choose **Sign in with ChatGPT** or another offered method, and finish the browser approval.

If the command is not found, follow the installer's PATH instructions. PATH is the list of locations your computer searches for programs. On Windows, installing only inside WSL does not make Codex available in native PowerShell.

## Start it in Codus

1. Finish active work and reopen Codus if it was running during installation.
2. Assign a project folder.
3. Click **start → Codex → boot project**, or choose **Codex** in the Brain.
4. Read any first-folder trust or permission prompt. Approve only a folder and tools you recognise.

## How do I know it worked?

The Codex session starts in the intended project or Brain and answers. Its own version is separate from the Codus app version shown in **Settings → Updates**.