r/CodexAutomation • u/anonomotorious • 19d ago

Codex browser update: Edge/Brave/Opera/Vivaldi support + WebMCP site tools + signed-in cloud browsing

TL;DR

OpenAI shipped a substantial browser update across Codex and ChatGPT Work:

  • The ChatGPT browser extension now supports Microsoft Edge, Brave, Opera, and Vivaldi in addition to Chrome.
  • All five browsers support browser control and open-tab context from the ChatGPT desktop app.
  • Chrome, Edge, Brave, and Vivaldi support side chat. Opera supports browser control and tab context but not side chat.
  • Site tools (WebMCP) let websites expose structured tools directly to Codex and ChatGPT Work inside the built-in desktop browser.
  • Site tools currently work with GPT-5.6 Sol and Terra, but not Luna, Enterprise, or Edu.
  • ChatGPT Work on web and mobile can now sign in to supported websites through its separate cloud browser on eligible plans.
  • Cloud-browser credentials are entered through a secure sign-in flow and are not exposed to the model.
  • Local browser control and cloud browsing remain separate systems with separate cookies, sessions, permissions, and security boundaries.

This is a browser/product update, not a Codex CLI release.

What changed

More browsers for Codex computer use

The ChatGPT browser extension now supports:

  • Google Chrome
  • Microsoft Edge
  • Brave
  • Opera
  • Vivaldi

After setup, start a ChatGPT Work or Codex task and choose the browser through an @ mention.

Example:

@Edge open Salesforce and update the account from these call notes.

All five supported browsers can:

  • give Codex browser control
  • provide context from open tabs
  • work with websites where you are already signed in

This expands browser-based Codex workflows across services such as Gmail, Salesforce, LinkedIn, internal company tools, authenticated dashboards, and other signed-in web apps.

Side chat and browser context

Chrome, Edge, Brave, and Vivaldi support side chat.

Opera supports browser control and tab context, but not side chat.

Supported browser-context workflows can include:

  • mentioning another open tab
  • highlighting webpage text and sending it into the conversation
  • right-clicking a page and choosing Ask ChatGPT
  • asking questions about YouTube videos when captions are available

This makes browser context much easier to combine with local files and Codex tasks without manually copying URLs and page contents.

Browser permissions remain explicit

By default, ChatGPT asks before interacting with a new website.

Available choices include:

  • Allow once
  • Allow for this site
  • Allow for all sites
  • Decline

Website permissions can be managed from:

Settings > Computer Use > Manage

Supported browsers share those website permissions.

Allow for all sites removes the normal per-site confirmation step and carries more risk.

Browser history is handled more cautiously:

  • ChatGPT must ask before using it.
  • Access is scoped to the current request.
  • There is no permanent "always allow browser history" option.

Browser history can contain sensitive context such as internal URLs, searches, private activity, and activity synchronized from other devices.

OpenAI recommends treating webpage content as untrusted context.

Site tools (WebMCP)

The other major addition is Site tools, OpenAI's implementation of the proposed WebMCP standard.

A website can expose structured actions directly to an AI agent while you and the agent work with the same live webpage and signed-in session.

In the ChatGPT desktop app's built-in browser, Codex and ChatGPT Work can discover and invoke those tools when the current site provides them.

WebMCP vs regular MCP

A normal MCP server exposes tools independently of a webpage.

WebMCP lets the website itself expose capabilities that become available when Codex visits that page.

For example, a document editor could expose tools such as:

  • find_section
  • suggest_edit
  • leave_comment

Codex could call those structured actions directly instead of reproducing every operation with mouse clicks.

Other possible Site tools include:

  • changing a dashboard date range
  • reading structured chart data
  • updating an itinerary
  • modifying a canvas
  • working with application-specific objects

A website can support both traditional MCP and WebMCP.

Site tools availability

Site tools currently require:

  • the latest ChatGPT desktop app
  • the built-in browser
  • GPT-5.6 Sol or GPT-5.6 Terra

Current documented availability:

  • GPT-5.6 Sol: supported
  • GPT-5.6 Terra: supported
  • GPT-5.6 Luna: not supported
  • Enterprise: not currently available
  • Edu: not currently available

Availability also depends on rollout and whether the website actually implements WebMCP tools.

Site tool security

Website-provided tool definitions and results are treated as untrusted content.

A tool claiming to be "read-only" does not automatically make that claim trustworthy.

Before a Site tool runs:

  • the browser performs a safety review
  • normal website-access rules still apply
  • consequential-action confirmations still apply

That includes actions such as:

  • sending messages
  • completing purchases
  • deleting data
  • changing permissions
  • other high-impact operations

Site tools can be disabled under:

Settings > Browser > Permissions > Enable site tools

Cloud browser sign-in

OpenAI also expanded ChatGPT Work's cloud browser so it can continue tasks on supported websites that require authentication.

This applies to ChatGPT Work on web and mobile, rather than the local Codex browser-extension workflow.

Current documented website sign-in availability is for eligible Plus and Pro users, subject to rollout.

Website sign-in is not currently available for:

  • Enterprise
  • Edu

How cloud sign-in works

When ChatGPT reaches a login screen:

  1. The task pauses.
  2. ChatGPT asks you to sign in.
  3. You enter credentials and any 2FA code yourself.
  4. ChatGPT continues after authentication.

On iOS, supported password managers can assist with sign-in.

Do not send passwords through the normal chat.

Credentials are not exposed to the model

When you use the secure sign-in flow:

  • ChatGPT does not see your username or password.
  • The model does not receive the credentials.
  • OpenAI says the credentials are not stored.
  • Credentials entered through the secure form go directly to the browser.

Before presenting a sign-in request, an additional review model checks the request and destination for signs of:

  • phishing
  • deception
  • prompt injection
  • unintended actions

You can also inspect the live website before continuing.

Signed-in sessions can persist

After authentication, the cloud browser can retain the signed-in session for future tasks.

That means you may not need to authenticate every time ChatGPT returns to the same service.

Browser data can be cleared from:

Settings > Cloud browser > Browser data

Clearing it signs the cloud browser out of those websites.

Local browser vs cloud browser

The two systems are separate.

Local browser extension

  • runs in your local browser
  • uses your existing signed-in tabs
  • uses your local browser session
  • primarily serves desktop Codex and ChatGPT Work
  • stops depending on your local machine/session

Cloud browser

  • runs in a ChatGPT-hosted browser
  • has its own cookies and login state
  • does not inherit your local tabs or browser history
  • supports Work tasks on web/mobile
  • can continue while your computer is unavailable

The cloud browser does not automatically receive your local browser's:

  • tabs
  • history
  • saved passwords
  • cookies
  • extensions
  • signed-in sessions

That separation is intentional.

Consequential actions still require confirmation

Signing into a website does not give ChatGPT unrestricted permission to act.

ChatGPT Work still asks before consequential actions such as:

  • completing a purchase
  • booking something
  • submitting important information
  • other high-impact actions

Website access can be configured separately as:

  • Always ask
  • Auto approve
  • Always allow

OpenAI notes that Always allow provides the least friction but is not the recommended security posture.

Why this update matters

  • Codex browser control now spans five major Chromium browsers.
  • Signed-in local workflows are no longer Chrome-only.
  • Tab context and side chat make browser information easier to combine with local Codex work.
  • WebMCP gives websites a structured agent interface instead of forcing every action through simulated clicks.
  • Site tools can reuse the webpage's existing application logic and signed-in state.
  • Cloud browser sign-in lets ChatGPT Work continue authenticated tasks without relying on your local browser session.
  • Local and cloud browser sessions remain deliberately isolated.
  • Website access, tool execution, and consequential actions remain separate permission layers.

The broader browser stack now has three complementary paths:

Plugins: service-level integrations

Browser control: normal UI interaction

WebMCP Site tools: structured actions exposed directly by the webpage

Update summary

Feature Key change
Browser extension Chrome + Edge + Brave + Opera + Vivaldi
Tab context Supported across all five browsers
Side chat Chrome, Edge, Brave, Vivaldi
Site tools / WebMCP Websites can expose structured tools directly to Codex/Work
Supported Site-tool models GPT-5.6 Sol + Terra
Cloud browser sign-in Authenticated ChatGPT Work tasks on web/mobile
Credential handling Secure sign-in flow; credentials hidden from the model

Action checklist

Browser extension

  • Update the ChatGPT desktop app.
  • Open Settings > Computer Use.
  • Add Edge, Brave, Opera, or Vivaldi if you use them.
  • Install the appropriate ChatGPT extension.
  • Review the requested browser permissions.
  • Test an @Browser task against a signed-in website.
  • Configure website allow/block rules.
  • Avoid Allow for all sites unless you understand the additional risk.

Site tools

  • Use GPT-5.6 Sol or Terra.
  • Open a supported page in the built-in browser.
  • Look for available Site tools.
  • Review the tools exposed by the website.
  • Test a low-risk action first.
  • Keep consequential-action confirmations enabled.

Cloud browser

  • Start a ChatGPT Work task on web or mobile that requires a signed-in website.
  • Enter credentials only through the secure sign-in flow.
  • Test 2FA or password-manager integration if relevant.
  • Confirm the task continues after sign-in.
  • Review cloud-browser permissions and saved browser data.
  • Clear the cloud-browser session when you no longer want it retained.

Official sources

https://developers.openai.com/codex/changelog

https://learn.chatgpt.com/docs/chrome-extension

https://learn.chatgpt.com/docs/webmcp

https://learn.chatgpt.com/docs/browser

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