Run Codex Code Reviews Inside Claude Code

// Before you start

What you need

Claude Code installed and working
Node.js 18.18 or later installed
A ChatGPT account (Free tier works) or an OpenAI API key
npm available in your terminal

Step 1 of 5

Add the OpenAI marketplace to Claude Code

1 min

Claude Code supports third-party plugin marketplaces. This command tells Claude Code where to find the Codex plugin. You type it directly into the Claude Code chat input, not a terminal.

Terminal · mac

$ /plugin marketplace add openai/codex-plugin-cc

What you should see

A confirmation message that the marketplace was added successfully.

This might happen

Command not recognised or Claude Code says plugins are disabled.

Make sure you are on a recent version of Claude Code. Run /help inside Claude Code and confirm plugin commands appear in the list.

Step 2 of 5

Install the Codex plugin

1 min

Now that Claude Code knows about the marketplace, this command downloads and registers the actual plugin. Still typed into the Claude Code chat input.

Terminal · mac

$ /plugin install codex@openai-codex

What you should see

A message confirming the plugin was installed.

This might happen

Install fails with a network or permission error.

Check your internet connection. If you see a permissions error, make sure your user account has write access to the Claude Code plugins directory.

Step 3 of 5

Reload plugins and run setup

2 min

Reloading makes Claude Code recognise the new plugin commands. Then /codex:setup checks whether the Codex CLI is present on your machine. If it is missing, the setup wizard will offer to install it for you automatically using npm.

Terminal · mac

$ /reload-plugins

$ /codex:setup

What you should see

After reload, the /codex: commands appear available. Setup reports either 'Codex is ready' or prompts you to install the Codex CLI.

This might happen

Setup says Codex CLI is missing and the automatic install fails.

Open a separate terminal and run: npm install -g @openai/codex — then return to Claude Code and run /codex:setup again.

Step 4 of 5

Log in to Codex

2 min

If setup reports that Codex is installed but you are not logged in, you need to authenticate. The exclamation mark prefix tells Claude Code to run this as a shell command rather than a plugin command. You will be prompted to sign in with your OpenAI or ChatGPT account in a browser window.

Terminal · mac

$ !codex login

What you should see

A browser window opens for authentication. After signing in, the terminal confirms you are logged in.

This might happen

Browser does not open or the login link expires.

Copy the URL printed in the terminal and paste it manually into your browser. Complete the login there.

Step 5 of 5

Run your first background code review

3 min

With everything set up, you can now ask Codex to review your uncommitted changes. The --background flag lets the review run without blocking your Claude Code session. Use /codex:status to check progress, then /codex:result to read the findings when it finishes.

Terminal · mac

$ /codex:review --background

$ /codex:status

$ /codex:result

What you should see

Review starts in the background. Status shows it running. Result prints the full Codex review once complete.

This might happen

Result shows nothing or an error after status says the job finished.

Wait a moment and run /codex:result again. Large multi-file reviews can take a few extra seconds to write their output.

// Status

cooked. baked. worked.

A working /codex:review command inside Claude Code that sends your current code changes to Codex and returns a written review, plus access to adversarial reviews, background task delegation, and session transfer between Claude Code and the Codex app.

// the honest bit

The honest part

This plugin requires an active Claude Code installation — it does not work as a standalone tool. Usage counts against your Codex usage limits even on a free ChatGPT account, so heavy use may hit rate limits. The /codex:rescue and /codex:transfer commands can take a long time on complex tasks; always use --background for anything non-trivial. The plugin cannot write or fix code on its own — review commands are read-only.