Tabhand

Let AI agents use your real, logged-in Chrome. No debugger banner, no tab to keep open.

A free, open-source tool by Ciro Cesar Maciel.

Your agent needs a dashboard, an inbox or an account that only opens logged in as you. Tabhand gives it your own Chrome: it reads pages, clicks, types and takes pictures in a tab group of its own, in the window you are using. It works from anywhere: Claude Code on your laptop, or an agent running in the cloud.

Português

Why another browser tool

Most tools drive Chrome through its debugger (the Chrome DevTools Protocol). That is powerful, but Chrome shows "… started debugging this browser" on top of every window while it is on, and many tools need a tab or a window held open, or a new id to paste every time.

Tabhand uses only plain extension APIs (tabs, scripting, captureVisibleTab, userScripts), so:

• no banner, ever;

• no tab to keep open: the extension's service worker holds the connection, and turns itself back on with Chrome;

• one connection code, made once: paste it into your agent's settings and forget it;

• your window, your tabs: the agents' tabs open in the background, in their own tab group, never in another window.

Related MCP server: chrome-agent-mcp

Install the extension

1. Download tabhand-extension.zip from the latest release and unzip it into a folder you will keep.

2. Open chrome://extensions, turn on Developer mode, click Load unpacked and pick that folder.

3. Tabhand opens its page with your connection code. Copy it.

4. Optional: in the extension's Details, turn on Allow user scripts so agents can run code in pages (browser_script).

The Chrome Web Store listing is on the way.

Connect your agent

Claude Code

claude mcp add tabhand --scope user --env TABHAND_CODE="<your connection code>" -- npx -y github:ciro-maciel/tabhand

Cursor, Claude Desktop and other MCP clients

{
    "mcpServers": {
        "tabhand": {
            "command": "npx",
            "args": ["-y", "github:ciro-maciel/tabhand"],
            "env": { "TABHAND_CODE": "<your connection code>" }
        }
    }
}

Instead of the environment variable, you can save { "code": "<your connection code>" } in ~/.config/tabhand/config.json. The server needs Node 22+ (or Bun) and has no dependencies.

Your own app

import { call } from 'tabhand/client'
import { functionTools, toolOf } from 'tabhand/tools'

const tools = functionTools() // OpenAI-style tool definitions for your model
const result = await call(code, toolOf('browser_read').method, { tabId: 123 })

npm install github:ciro-maciel/tabhand. Each tool has a risk: read only looks or moves around, act changes something; if your app asks a person before acting, weigh the act ones.

The tools

How it works

your agent ──(MCP or tabhand/client)──▶ tunnel server ◀──(WebSocket, held by the service worker)── Tabhand in your Chrome
            wss://…/tunnel/<id>/extension                 wss://…/tunnel/<id>/upstream

The extension makes a random 128-bit id once and keeps one WebSocket open to the tunnel server. Your connection code is that id's address on the server; each request your agent sends travels through the tunnel to the extension, which answers it with extension APIs. The public server, wss://tabhand.ciromaciel.click, is free; it relays messages and stores nothing.

Run your own tunnel server

It is one Cloudflare Worker with a Durable Object, on the free plan:

git clone https://github.com/ciro-maciel/tabhand && cd tabhand
bunx wrangler deploy --config tunnel/wrangler.toml

Then, in the extension's popup, open Advanced and set the server to wss://<your worker's host>. Your connection code changes with it.

Security

The connection code is a key to your browser, logged in as you: whoever holds it can read and act in your tabs. Keep it like a password. If it leaks, open the popup and click Make a new code: the old one stops working at once. Turn off in the popup, or the icon's badge OFF, cuts every agent off.

Agents are told never to type passwords or card numbers, but that is an instruction, not a wall: give the code only to agents and apps you trust. See SECURITY.md to report a vulnerability.

Limits

• Chrome only photographs the tab on view: a screenshot shows the agent's tab for an instant.

• Clicks and typing are synthetic events; a few heavily protected pages ignore them.

• No console or network inspection: that needs the debugger, which is what Tabhand avoids.

More from Ciro Cesar Maciel

Free, open-source Mac apps and tools at ciromaciel.click.

License

MIT. The tunnel server is ported from Playwriter (MIT); see NOTICE.