An agent inside the browser you have
BrowserOS neovs the Codex Chrome extension
Both give Codex a real browser with your real logins. One borrows the browser you are using; the other gives agents their own.
OpenAI ships a Chrome extension that lets its agent drive your existing Chrome with the sessions you are signed into. You install it from the ChatGPT desktop app and call it from a ChatGPT Work or Codex chat. It handles real browser work — Gmail, Salesforce, internal tools — not just checking front-end code.
BrowserOS neo is a separate browser. Import your Chrome logins once, and any agent that speaks MCP works in its own tabs while your main browser stays yours.
The short version
Choose BrowserOS neo when
- You use more than one agent. neo works with anything that speaks MCP.
- You want agents out of your own window, in a browser of their own.
- You want more than one agent working at the same time.
- You want it free, open source and local, with no desktop app in the middle.
Choose the Codex Chrome extension when
- Codex is your agent and you are happy for it to stay that way.
- You do not want a second browser, full stop.
- The work is anchored to what you are already looking at — this page, this selection.
- You want per-site approvals with an allowlist and blocklist you manage.
Side by side
| Dimension | BrowserOS neo | the Codex Chrome extension |
|---|---|---|
| What you install | BrowserOS neoA browser, beside the one you already use. | the Codex Chrome extensionA Chrome extension, plus the ChatGPT desktop app that drives it. Chrome only — other Chromium browsers are not supported. |
| Which agents work with it | BrowserOS neoAny MCP agent — Codex, Claude Code, Cowork, Cursor, Zed, Copilot and more. | the Codex Chrome extensionOpenAI’s, documented for ChatGPT Work and Codex chats. |
| Whose window it uses | BrowserOS neoIts own. Agents open their own tabs in a separate application. | the Codex Chrome extensionYours. New tasks normally open in their own Chrome tab group, and it can also take over or continue in a tab you already have open. |
| Your logins | BrowserOS neoImported from Chrome in one click at setup. | the Codex Chrome extensionAlready there. It is your Chrome profile. |
| Several at once | BrowserOS neoYes. Each agent gets its own set of tabs, tracked separately. | the Codex Chrome extensionIt documents background work across task tab groups; equivalent per-agent isolation is not documented. |
| Permission model | BrowserOS neoThe browser itself is the boundary. You choose what you sign it into. | the Codex Chrome extensionFiner-grained than ours: allow once, allow for this site, allow for all sites or decline, plus an allowlist, a blocklist, and separate scoped approval for browser history. |
| Reviewing what happened | BrowserOS neoWatch live, and every session is saved automatically as a scrubbable video. | the Codex Chrome extensionYou watch it in your own browser. Page text, screenshots and tool calls become chat context. No automatic per-session browser replay is documented. |
| Price and source | BrowserOS neoFree, open source on GitHub under AGPL-3.0. Bring your own model keys. | the Codex Chrome extensionComes with ChatGPT rather than sold separately, though availability can vary. We could not find a public source repository. |
Three things get confused here. The Chrome extension drives the Chrome you already use, and its Web Store listing is titled simply “ChatGPT”. The built-in browser, invoked with @Browser, lives inside the ChatGPT app. Atlas was OpenAI’s standalone browser, now folding into ChatGPT. This page is about the first.
Credit where it is due: running each task in its own Chrome tab group is a good idea, and better than most of this category manages. It is a convention rather than a wall, though — OpenAI also documents the agent taking over a tab you already have open. neo draws the line at the application instead, so agent tabs cannot land among yours. The trade is that you run two browsers.
Where the Codex extension is better.
No second browser. That is the whole convenience argument and it wins it: your Chrome, your profile, your extensions, your logins, nothing to import. It is first-party, so there is nothing to wire up and no version drift.
Its permission model is more granular than ours — per-site prompts with allow-once as well as allow-always, an allowlist and blocklist, and browser history scoped separately with no always-allow. It also reaches context we cannot: the page you are on, your open tabs, your selected text, your extensions.
It is not narrow, either. Our own brief for this page assumed it was mainly for checking front-end code; current OpenAI documentation covers Gmail, Salesforce, LinkedIn, internal tools and research, so we corrected that rather than leave a convenient understatement in place.
Common questions
Is the Codex Chrome extension the same as ChatGPT Atlas?
No. Atlas was OpenAI’s standalone browser, being folded into ChatGPT’s browser-based agentic work. The Chrome extension drives the Chrome you already have. A third surface, the built-in browser invoked with @Browser, keeps browsing inside the ChatGPT app.
Does BrowserOS neo work with Codex?
Yes, through the same one-click MCP install as Claude Code, Cowork, Cursor and the rest. Picking neo does not mean giving up Codex, and you can use both.
Do I need a paid plan?
The extension comes with ChatGPT and needs the desktop app. OpenAI documents Codex across its plans, but we found no separate plan matrix for the extension and availability can vary — check their docs. BrowserOS neo is free and open source.
Does it work in browsers other than Chrome?
No. OpenAI’s documentation states that other Chromium-based browsers are not currently supported. BrowserOS neo is itself a Chromium browser you install, so this does not apply to it.
Check it yourself
Every claim about the Codex Chrome extension here was read off these pages on 4 August 2026. If something has gone stale, tell us.
- OpenAI documentation: Chrome extension
- ChatGPT on the Chrome Web Store
- Using the built-in browser in the ChatGPT desktop app
- OpenAI: evolving Atlas into ChatGPT for browser-based agentic work
What we could not confirm
- OpenAI documents Codex across ChatGPT plans, but we found no separate plan matrix for the extension, and availability can vary by plan, region and workspace role.
- We could not find a public source repository or licence, so we say that rather than calling it closed source.
- We found no automatic per-session browser replay in its docs, and no documented per-agent isolation. We claim neither absence as a limitation, only as undocumented.
Give your agent a browser it can sign into.
Free, open source, and it sits beside the browser you already use.