2ManyTabs MCP

List, group, deduplicate, bulk-close, activate, and update browser tabs with natural language — from any MCP client.

A browser extension (Chrome and Firefox, one source tree built with WXT) proxies a fixed set of browser.tabs, browser.tabGroups, and browser.scripting operations. A Node.js MCP host handles all the logic (filtering, grouping, dedup) and talks to your AI client over stdio. Everything runs locally on loopback. Tools that only filter or reshape data from existing browser operations ship without any extension change; adding a genuinely new browser operation requires a new handler in the extension's dispatch() (and sometimes a new manifest permission) plus a rebuild/reload.

Browsers

Works with any Chromium browser, and Firefox:

The extension is built with WXT, which generates a Chrome MV3 build and a Firefox MV2 build from one source tree — tab groups (Chrome-only) are feature-detected and disabled cleanly on Firefox. Safari is planned.

Prerequisites

Node.js v18+
Local port 9876 available

Step 1 · Install the MCP Host

Pick your client below. They all run the same server — just different config locations.

Verified Clients

Claude Code

claude mcp add 2manytabs-mcp -- npx -y 2manytabs-mcp-host

Claude Desktop

Add to your config file:

OS	Path
macOS	`~/Library/Application Support/Claude/claude_desktop_config.json`
Windows	`%APPDATA%\Claude\claude_desktop_config.json`
Linux	`~/.config/claude/claude_desktop_config.json`

{
  "mcpServers": {
    "2manytabs-mcp": {
      "command": "npx",
      "args": ["-y", "2manytabs-mcp-host"]
    }
  }
}

Restart Claude Desktop after saving.

VS Code / GitHub Copilot Chat

Create .vscode/mcp.json in your workspace (or add to your user settings.json under "mcp"):

{
  "mcpServers": {
    "2manytabs-mcp": {
      "command": "npx",
      "args": ["-y", "2manytabs-mcp-host"]
    }
  }
}

See the VS Code MCP docs for details.

Cursor

Open Settings → MCP and add a new server, or create/edit .cursor/mcp.json:

{
  "mcpServers": {
    "2manytabs-mcp": {
      "command": "npx",
      "args": ["-y", "2manytabs-mcp-host"]
    }
  }
}

Windsurf

Open Settings → Cascade → MCP, or create/edit mcp_config.json:

{
  "mcpServers": {
    "2manytabs-mcp": {
      "command": "npx",
      "args": ["-y", "2manytabs-mcp-host"]
    }
  }
}

See the Windsurf MCP guide for details.

Continue

Add to .continue/config.json (or create .continue/mcpServers/2manytabs-mcp.json):

{
  "mcpServers": {
    "2manytabs-mcp": {
      "command": "npx",
      "args": ["-y", "2manytabs-mcp-host"]
    }
  }
}

See the Continue MCP docs for details.

Cline

Open the MCP Servers panel in Cline and add a new server:

Command: npx
Args: -y 2manytabs-mcp-host

Or edit the Cline MCP config JSON directly with the same block used above. See the Cline MCP docs for details.

Hermes Agent

hermes mcp add 2manytabs-mcp --command "npx -y 2manytabs-mcp-host"

Restart your session (/reset or start a new hermes invocation), then verify:

hermes mcp list
hermes mcp test 2manytabs-mcp

Config lives at ~/.hermes/config.yaml under the mcp section.

Should Also Work

These clients support MCP but we haven't tested them directly. The same JSON config block should work — just drop it into the client's MCP config file:

Client	Notes
LibreChat	MCP agent/tool server support documented
ChatGPT	MCP connectors exist; local stdio flow unverified
Sourcegraph Cody	MCP via OpenCTX; setup syntax unverified
Genkit	`genkitx-mcp` plugin can consume MCP servers
Zed	Tool support is experimental — prompts/resources only in some builds

If your client speaks MCP over stdio, it will work. Point it at npx -y 2manytabs-mcp-host and you're set.

Step 2 · Load the Browser Extension

First build it — the extension is a WXT project, so it needs a build step (the native host does not):

cd extension
npm install
npm run build           # → .output/chrome-mv3/  (Chrome, Brave, Edge, Opera, Comet)
npm run build:firefox   # → .output/firefox-mv2/  (Firefox)

Chrome / Chromium

Go to chrome://extensions/ (or edge://extensions/, brave://extensions/, etc.)
Enable Developer mode (toggle in the top-right)
Click Load unpacked
Select extension/.output/chrome-mv3/
Click the extension icon in the toolbar — the popup should show Connected once the host is running

Firefox

Go to about:debugging#/runtime/this-firefox
Click Load Temporary Add-on…
Select extension/.output/firefox-mv2/manifest.json
Click the extension icon in the toolbar — the popup should show Connected once the host is running

Temporary add-ons are unloaded when Firefox restarts; reload as needed during development. Tab-group tools are unsupported on Firefox (no tabGroups API) and fail with a clear error instead of breaking other tools.

Extension development

Run from extension/:

npm run dev / npm run dev:firefox — launches Chrome/Firefox with the extension loaded and hot-reloads on save
npm run build / npm run build:firefox — production build to .output/<target>/
npm run zip / npm run zip:firefox — packages a distributable .zip for each target

What You Can Say

Just talk to your AI client:

"Show me all my open tabs."
"Find and close duplicate tabs."
"Close everything matching 'youtube'."
"Do a dry run of closing all tabs from reddit.com."
"Group my tabs by domain and show the breakdown."

Tools

The host exposes ten tools:

`list_tabs`

Read-only. Returns a domain histogram with proportional bars and a per-domain listing with titles, pinned (📌), and audible (🔊) flags.

Param	Type	Default	Description
`query`	string	—	Substring filter on title or URL
`group_by`	`"domain"` · `"window"` · `"none"`	`"domain"`	How to group results
`duplicates_only`	boolean	`false`	Show only duplicate URLs

`close_tabs`

Closes tabs. Exactly one selection mode required:

Param	Type	Description
`tab_ids`	number[]	Close specific tab IDs
`match`	string	Close tabs matching this substring
`duplicates`	boolean	Close all duplicates (keeps first occurrence)
`dry_run`	boolean	Preview what would close without closing

`open_tabs`

Opens new tabs in the browser.

Param	Type	Description
`urls`	string[]	Array of URLs to open. Required. If no protocol is provided, `https://` is prepended automatically.

`list_tab_groups`

Read-only. Lists all existing native Chrome Tab Groups in the current browser session, including their IDs, titles, colors, collapsed states, and parent window IDs.

Param	Type	Description
`title_query`	string	Case-insensitive substring filter for group titles.

`group_tabs`

Groups open Chrome tabs into native Chrome Tab Groups. Can create a new group or add tabs to an existing group.

Param	Type	Description
`tab_ids`	number[]	Array of tab IDs to add to the group. Required.
`group_id`	number	Add to an existing group ID. If omitted, a new group is created.
`title`	string	Title to set on the group (new or existing).
`color`	`"grey"` · `"blue"` · `"red"` · `"yellow"` · `"green"` · `"pink"` · `"purple"` · `"cyan"` · `"orange"`	Color to set on the group (new or existing).

`ungroup_tabs`

Removes one or more open Chrome tabs from their current native Tab Groups.

Param	Type	Description
`tab_ids`	number[]	Array of tab IDs to remove from any groups. Required.

`update_tab_group`

Updates properties of an existing native Chrome Tab Group.

Param	Type	Description
`group_id`	number	The numeric ID of the tab group to update. Required. Obtain from `list_tab_groups` or `list_tabs`.
`title`	string	New title for the group.
`color`	`"grey"` · `"blue"` · `"red"` · `"yellow"` · `"green"` · `"pink"` · `"purple"` · `"cyan"` · `"orange"`	New color for the group.
`collapsed`	boolean	Set `true` to collapse the group, `false` to expand it.

`activate_tab`

Brings a specific browser tab to the foreground, activating it and focusing its containing window.

Param	Type	Description
`tab_id`	number	The numeric ID of the tab to activate. Required.

`update_tab`

Modifies properties of an open browser tab: navigate it to a new URL, pin/unpin it, or mute/unmute its audio.

Param	Type	Description
`tab_id`	number	The numeric ID of the tab to update. Required.
`url`	string	A new URL to navigate the tab to. If no protocol is provided, `https://` is prepended.
`pinned`	boolean	Set `true` to pin the tab, `false` to unpin it.
`muted`	boolean	Set `true` to mute the tab, `false` to unmute it.

`get_tab_text`

Read-only. Extracts the plain body text of a loaded browser tab via chrome.scripting. Useful for summarization or classification. Fails on restricted internal browser pages (e.g., chrome://, edge://, or extension pages) or if the tab is not loaded.

Param	Type	Description
`tab_id`	number	The numeric ID of the tab whose body text to extract. Required.

Architecture

  AI Client ◄──stdio──► MCP Host ──WebSocket :9876──► Browser Extension (Chrome / Firefox)
                           │
                           ▼
                      Follower Hosts

One extension source tree (extension/, built with WXT) produces a Chrome MV3 build and a Firefox MV2 build. The extension proxies a fixed set of browser.tabs, browser.tabGroups, and browser.scripting operations (extension/lib/tab-ops.js); browser.tabGroups has no Firefox equivalent and is feature-detected, failing only the affected tools with a clear error. All selection, filtering, and reshaping logic lives in the host. Tools that only filter or reshape data from an existing browser operation ship with no extension change; adding a genuinely new browser operation requires a new case in dispatch() (and sometimes a new manifest permission in wxt.config.ts) plus a rebuild/reload.
Multiple AI clients can share one browser. Hosts self-organize: one binds port 9876 (owner), the rest proxy through it (followers). On owner death, followers re-elect automatically.
The extension reconnects via browser.alarms every 30s (MV3 idle behavior).
native-host/ is browser-agnostic and shared unchanged by both builds — the WXT build step only affects extension/; installing or configuring the MCP host is unaffected.

Security

Loopback only — the server binds to 127.0.0.1, not 0.0.0.0.
Origin validation — only chrome-extension:// or moz-extension:// origins can connect. Web pages attempting loopback attacks get rejected with a 4003 close code.
No cloud, no daemon — everything stays on your machine.

Contributing

PRs welcome. Safari support is the biggest gap right now:

For a local dev setup: run bash install.sh for the MCP host, and see Extension development for the browser side.

License

MIT — see LICENSE.

Name		Name	Last commit message	Last commit date
.github/workflows		.github/workflows
extension		extension
native-host		native-host
.gitattributes		.gitattributes
.gitignore		.gitignore
CHANGELOG.md		CHANGELOG.md
LICENSE		LICENSE
README.md		README.md
install.sh		install.sh
llms.txt		llms.txt

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2ManyTabs MCP

Browsers

Prerequisites

Step 1 · Install the MCP Host

Verified Clients

Should Also Work

Step 2 · Load the Browser Extension

Extension development

What You Can Say

Tools

`list_tabs`

`close_tabs`

`open_tabs`

`list_tab_groups`

`group_tabs`

`ungroup_tabs`

`update_tab_group`

`activate_tab`

`update_tab`

`get_tab_text`

Architecture

Security

Contributing

License

About

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Repository files navigation

2ManyTabs MCP

Browsers

Prerequisites

Step 1 · Install the MCP Host

Verified Clients

Should Also Work

Step 2 · Load the Browser Extension

Extension development

What You Can Say

Tools

list_tabs

close_tabs

open_tabs

list_tab_groups

group_tabs

ungroup_tabs

update_tab_group

activate_tab

update_tab

get_tab_text

Architecture

Security

Contributing

License

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`list_tabs`

`close_tabs`

`open_tabs`

`list_tab_groups`

`group_tabs`

`ungroup_tabs`

`update_tab_group`

`activate_tab`

`update_tab`

`get_tab_text`