Claude Browser

Multiple persistent browser tabs inside VS Code, drivable by Claude over MCP.

Open GitHub in one editor group and a Claude terminal in another. Stay signed in across restarts. Let Claude read and click the same page you are looking at, without leaving the editor.

What it does

• Many tabs, not one. Each browser tab is an editor tab, so it splits, drags between groups, and reopens where you left it.

• Sessions persist. Cookies and local storage survive a restart and are shared by every tab, so signing into Slack once is enough.

• Sites that refuse to be framed still work. GitHub, Slack and Google all send X-Frame-Options: DENY, which is why the built-in Simple Browser cannot show them.

• Claude drives it. The extension hosts an MCP endpoint with tools to list tabs, navigate, snapshot a page, click, type, and read the console.

• It is a real DOM. Not a video stream of a browser: input latency is native, text selection and the find widget work, and audio plays.

Getting started

yarn install
yarn build

Press F5 to launch an Extension Development Host, then run Claude Browser: Open Browser Tab from the command palette.

To let Claude drive it, open a terminal in the same window and run claude. The extension writes its endpoint into the workspace .mcp.json, so the tools are there already. Run Claude Browser: Show MCP Endpoint if you would rather register it by hand.

Commands

Settings

How it works, in one paragraph

A VS Code webview is a sandboxed iframe, and the sites worth keeping open refuse to be framed. So the extension runs a local rewriting proxy: each site is served from its own loopback origin such as github.com.s.localhost:41998, with the framing and transport headers rewritten on the way through. Cookies never reach the browser at all; the proxy holds them and re-attaches them upstream, which is the only way __Host- prefixed session cookies can survive being served from a different origin. A small shim is injected into every page to reroute its network calls, keep navigation on the proxy, and carry out commands from MCP tools.

The details, and the things this approach cannot do, are in docs/.

Documentation

• Architecture — the pieces and how they talk

• Proxy — origin mapping, header rewriting, the page shim

• Persistence — where sessions live and what survives what

• MCP — the tools and how to connect

• Security — the threat model and the request guard

• Limitations — what does not work, and why

• Development — building, testing, releasing