How to Use OpenAI Codex in Your Browser with the New Chrome Extension

Introduction

OpenAI's Codex has taken a significant leap forward with its new Chrome extension, allowing AI agents to operate directly within your live browser session. This means you can automate tasks in Gmail, Salesforce, LinkedIn, and other web apps without the clunky screenshot-and-click loop. Here's a step-by-step guide to get started.

What You Need

• OpenAI Codex app installed on Windows or macOS (version with computer-use capabilities from April 2025 or later)
• Google Chrome browser (latest version recommended)
• An active internet connection
• Access to the Chrome Web Store for extension installation
• Logged-in sessions for any web apps you want the agent to interact with (e.g., Gmail, Salesforce)

Step-by-Step Guide

Step 1: Install the Codex Chrome Extension

Open your Chrome browser and navigate to the Chrome Web Store. Search for "OpenAI Codex" and locate the official extension (published by OpenAI). Click Add to Chrome, then confirm by clicking Add Extension in the pop-up. A small Codex icon will appear in your browser's toolbar once installation is complete.

Step 2: Launch and Connect the Codex Desktop App

If you haven't already, download and install the Codex desktop app from OpenAI's official website. Open the app on your Windows or macOS machine. Ensure it's running and signed in with your OpenAI account. The extension will automatically detect the app on your local network, but you may need to allow firewall permissions if prompted.

Step 3: Open the Extension and Authorize Connection

Click the Codex icon in your Chrome toolbar. A popup will appear asking to connect to the Codex app. Click Connect. The extension may ask for permission to read and modify data on all websites you visit. This is necessary for the agent to interact with your browser sessions. Grant the permissions to proceed.

Step 4: Log into Your Target Web Apps

Before giving the agent tasks, make sure you are already signed into the web applications you want it to use. For example, open Gmail in one tab and log in. The extension leverages your existing cookies and sessions, so the agent won't need to handle authentication manually. Repeat for any other tools (Salesforce, LinkedIn, internal dashboards) in separate tabs.

Step 5: Define Your Task in Codex

Switch to the Codex desktop app. In the input field, clearly describe the task you want the agent to perform. For instance: "Find the latest email from Client X in Gmail, then create a new contact in Salesforce with their details." Be specific about the sequence and the apps involved. The extension allows the agent to work across multiple tabs simultaneously.

Step 6: Execute and Monitor the Agent's Actions

Press Enter or click the run button. The agent will begin operating in your live browser session. You'll see it open new tabs, scroll, click buttons, type in forms, and navigate pages – all using your existing logged-in state. Unlike older systems, it doesn't rely on screenshot analysis; it works directly within Chrome. Monitor the process in real-time from the Codex app or by watching your browser. You can intervene at any point by closing tabs or pausing the task.

Step 7: Review and Confirm Results

Once the agent completes the workflow, review the outputs in the relevant apps. Check that the email was correctly read or that the new contact was created in Salesforce. If something goes wrong, you can provide feedback to Codex for refinement. The extension maintains a log of actions in the Codex app for debugging.

Tips for Best Results

• Keep tabs organized: The agent works best when target applications are already open in separate tabs. Avoid unnamed or duplicate tabs that may confuse the agent.
• Use clear, step-by-step instructions: Break down complex workflows into smaller sub-tasks. For example, "Step 1: Open Gmail. Step 2: Search for invoice. Step 3: Click the first result."
• Limit the number of active tabs: While the extension supports multiple tabs, too many open tabs can slow down performance. Stick to 3–5 essential tabs.
• Secure sensitive actions: For critical tasks like financial transactions, consider supervising the agent closely or using a test environment first.
• Update regularly: Both the Chrome extension and the Codex app receive updates. Enable automatic updates to get the latest features and bug fixes.
• Understand limitations: The agent works within your browser's context but may struggle with sites that use heavy JavaScript, iframes, or complex pop-ups. Test on simpler workflows initially.
• Use plugins as a complement: For tasks that require direct API access (e.g., fetching data from GitHub), consider using Codex's plugin system alongside the extension for best results.

By following these steps, you can harness OpenAI Codex's new browser-native capabilities to automate repetitive web tasks efficiently. The extension transforms your browser into a powerful automation hub, freeing you to focus on higher-level work.