WHAT SHIPPED
● A Chromium browser inside Claude Cowork, on the desktop app for Mac, Windows and Linux. Announced 26 August.
● Nothing to install. No extension, no setup. It opens in the side panel when a task needs a website.
● The key property: a clean profile with none of your logins — nothing shared from your own browser unless you choose to.
● Rolling out over the following week to all paid plans.
What it does
When a Cowork task needs a website, a browser opens in the side panel and Claude navigates it — reading pages, clicking, typing. Anthropic's examples: filling in a form, pulling numbers from a dashboard, or working through a portal that has no connector.
That last case is the useful one. Connectors cover the major services. Everything else — a supplier portal, an internal tool, a booking system, a government form — has no integration and never will. A browser is the universal fallback.
Three browsers, and the difference that matters
| Which |
Uses your logins? |
Use it when |
Cowork browser
new, 26 Aug |
No — clean profile |
General tasks needing a site with no connector |
Claude Code browser
shipped July |
No — clean profile |
Development work. Docs, issue trackers, testing your own app |
Claude in Chrome
extension |
Yes — your real sessions |
The work is on a page you already have open and signed into |
THE ONE QUESTION THAT DECIDES IT
Does the task need you to be logged in?
If yes, the Chrome extension is the only option — Anthropic says so itself. If no, the built-in browser is better, because a clean profile means a compromised page cannot reach your authenticated sessions.
That separation is a security property, not a limitation. The whole risk of a browsing agent is that a malicious page injects instructions and the agent acts on them with your credentials attached. A profile with no credentials removes the second half of that.
The Claude Code browser shipped in July with additional controls: classifier review of write actions, a domain allowlist outside the permissive modes, explicit approval required for purchases and account creation, and organisation-level ability to restrict or disable browser tools entirely. Worth confirming which of those carry over to Cowork before pointing it at anything consequential.
Two companies, same conclusion, opposite methods
Three weeks ago Cloudflare shipped Kitesurf — a browser written from scratch in Rust, running in V8 isolates with no Chromium underneath, using 3 to 7 times less CPU and memory. Its argument was that Chromium was built for humans and agents need none of it: no tabs, no extensions, no 60fps rendering.
Anthropic reached the same conclusion — agents need their own browser — and did the opposite thing. It embedded Chromium.
|
Cloudflare Kitesurf |
Claude Cowork browser |
| Approach |
Rebuilt without Chromium |
Embedded Chromium |
| Runs |
In the cloud, at fleet scale |
On your machine, one session |
| Optimises for |
Cost per session |
Site compatibility |
| Trade-off |
Subset of browser behaviour |
Full Chromium resource cost |
Both are defensible because they serve different jobs. Running a thousand agents needs cheap sessions. Running one agent through a bank portal that breaks outside real Chromium needs compatibility. The convergence is what matters: two companies independently deciding agents should not use your browser.
OpenAI landed in the same place from a third direction, discontinuing its standalone Atlas browser in favour of one inside the ChatGPT desktop app.
The pattern in Anthropic's year
Read the release order and the direction is unambiguous. Cowork launched as a desktop-only agent. Claude Design added canvas editing. Cowork went mobile and web. The Code tab got a browser in July. The Chrome extension became a full Cowork session. Chat and Cowork merged their memory yesterday. Now a dedicated browser.
Each release removes a reason to leave the application. This is not a chatbot that opens a browser — it is a workspace that contains a chatbot, a code editor, a file manager, a scheduler and now a browser.
What to do with it
| If you are... |
Do this |
| On a paid plan with the desktop app |
Wait for the rollout. Nothing to install |
| Using the Chrome extension for everything |
Move anything that does not need your logins to the built-in browser. Smaller blast radius |
| In an organisation |
Check whether the Code-tab controls — allowlists, disabling browser tools — apply here too |
| Worried about prompt injection |
The clean profile is the mitigation. A page cannot reach sessions that are not there |
| On Claude Free |
Not available. Cowork requires a paid plan |
FAQ
What is the Claude Cowork browser?
A Chromium browser built into Claude Cowork on the desktop app for Mac, Windows and Linux, announced 26 August 2026. It opens in the side panel when a task needs a website, and Claude reads, clicks and types in it.
Do I need to install anything?
No. No extension and no setup — it is part of the desktop app, rolling out to all paid plans over the week following announcement.
Does it use my logins?
No. It runs a clean profile with none of your sessions, and nothing is shared from your own browser unless you choose to. That is the main difference from the Claude in Chrome extension.
When should I use the Chrome extension instead?
When the task needs you to be signed in, or when the work is on a page you already have open. Anthropic says the extension is still the right choice in that case.
Is this the same as the Claude Code browser?
No. That shipped in July inside the Code tab, aimed at development work — documentation, issue trackers, testing your own application. Both use clean profiles; this one is for general Cowork tasks.
Is it safe against malicious pages?
The clean profile is the main mitigation — a page cannot reach credentials that are not loaded. The Code-tab browser also shipped with classifier review of write actions and organisation-level controls; confirm which apply to Cowork before pointing it at anything sensitive.
Can I use it on the free plan?
No. Cowork requires a paid plan, and the rollout covers paid plans only.