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Using the Codex Desktop App

Codex is an AI coding agent that can inspect a project, edit files, run commands, review diffs, and help you iterate on a task while you stay in control of the final code. The Codex desktop app provides a standalone interface for working with Codex on local projects.

Unlike IDE plugins such as Copilot or Windsurf, the Codex desktop app works as a standalone app. The IDE you use does not matter; what matters is that Codex can access the project folder and the project can be built and tested locally.

For more details, refer to the official Codex app guide.

Installing Codex

1. Go to the official Codex app page.
2. Download the installer for your operating system.
3. After downloading, open the installer and follow the installation instructions for your operating system.

Signing in to Codex

1. Open the Codex app
2. Sign in to Codex
   • a)
     Sign in with ChatGPT if you are using a school-provided or subscription-based plan.
     Sign in with another way only if you are using an API key.
   • b)
     Follow the sign-in flow shown in the app.
   • c)
     Codex will now be ready to use on your computer.

Getting Started with Codex

Importing a Project

• Open the project picker
  • In the Codex app, start from the empty workspace screen and click Choose project.
  • Choose + New project, then select Use an existing folder to open a project that already exists on your computer.
  • Select the folder that contains your project.
    For a project using Git, it is important to select the repository root and not inner folders such as `src`.

Basic Usage Examples

Use Codex for small, reviewable tasks, such as tweaking a UI component or refactoring a code fragment.

• Start with a small change that you can easily verify.
• For example, you can ask something like add green borders for each contact card
• Codex will summarize the files it changed. Click Review to inspect the diff before accepting the change.
• In the review panel, check the file name and the red/green lines to understand exactly what Codex changed (shown below). Alternatively, you can use your IDE or Git tool to inspect the diff.

Where to Go Next

After you are comfortable with the basic workflow, feel free to explore the Codex app guides:

• Codex app overview: Start here for the official desktop app guide.
• Features: Learn about Local, Worktree, Git tools, the integrated terminal, approvals, and sandboxing.
• Commands: Learn app shortcuts and slash commands such as /plan, /goal, /review, and /status.
• Review: Learn how to inspect code changes before accepting or committing them.
• Worktrees: Learn how to try changes in an isolated Git worktree instead of your main project folder.
• Automations: Learn how Codex can run recurring checks or follow-up tasks.

Contributors: Hwang Jihun (@hwangjihun)