Atlas Browser Connect

All the power of Chrome's extension APIs, accessible from any AI agent via the Model Context Protocol. One tool. Any model. Zero vendor lock-in.

Why Atlas?

Products like Claude for Chrome give browser superpowers to one AI model. Atlas gives them to all of them.

Atlas Browser Connect exposes a single MCP tool — chrome_call — that can invoke any chrome.* extension API. Since Chrome's API surface covers everything — tabs, scripting, debugger, downloads, cookies, history, bookmarks, storage, and 200+ more — one tool is all an agent needs to see, understand, and control the browser.

You decide how much power to grant by choosing which permissions to include when building the extension. The agent gets exactly the capabilities you allow, nothing more.

| | Claude for Chrome | Atlas Browser Connect | | --- | --- | --- | | AI model | Claude only | Any MCP-compatible agent | | Protocol | Proprietary | Open (MCP) | | Browser support | Chrome only | Chrome, Edge, Brave, Chromium | | Source | Closed | Open-source (MIT) | | Control level | UI-level | API-level (chrome.*) | | Capabilities | Fixed by Anthropic | You choose the permissions |

What Can an Agent Do?

Everything that Chrome extensions can do — it depends on the permissions you grant:

| Permission | What the agent can do | Example call | | --- | --- | --- | | tabs | Inspect, create, close, move tabs | tabs.query, tabs.create | | activeTab | Read the active tab's URL and title | tabs.get | | scripting | Inject scripts, read DOM, extract page content | scripting.executeScript | | debugger | Full Chrome DevTools Protocol access | debugger.attach, debugger.sendCommand | | tabCapture | Capture tab audio/video streams | tabCapture.capture | | windows | Manage browser windows | windows.getAll, windows.create | | bookmarks | Search and organize bookmarks | bookmarks.search, bookmarks.create | | history | Browse and search history | history.search, history.getVisits | | downloads | Download files, monitor progress | downloads.download, downloads.search | | cookies | Read and set cookies | cookies.getAll, cookies.set | | storage | Persistent key-value storage | storage.local.get, storage.local.set | | notifications | Show desktop notifications | notifications.create | | tabGroups | Organize tabs into groups | tabGroups.query, tabGroups.update | | alarms | Schedule timed events | alarms.create, alarms.getAll |

The full list: any API in the Chrome Extensions API reference that works from a MV3 service worker.

Power examples

Read a page's DOM (needs scripting):

{
  "namespace": "scripting",
  "method": "executeScript",
  "args": [{ "target": { "tabId": 123 }, "func": "() => document.body.innerText" }]
}

Take a screenshot (needs activeTab):

{
  "namespace": "tabs",
  "method": "captureVisibleTab",
  "args": [null, { "format": "png" }]
}

Access DevTools Protocol (needs debugger):

{
  "namespace": "debugger",
  "method": "sendCommand",
  "args": [{ "tabId": 123 }, "DOM.getDocument"]
}

Download a file (needs downloads):

{
  "namespace": "downloads",
  "method": "download",
  "args": [{ "url": "https://example.com/report.pdf" }]
}

Quick Start

1. Build the extension

npx -y atlas-browser-connect extension build

The default extension includes: tabs, tabGroups, activeTab, bookmarks, windows, nativeMessaging.

To customize permissions:

npx -y atlas-browser-connect extension build \
  --permissions tabs,scripting,debugger,downloads,cookies

2. Load it in your browser

| Browser | Extensions page | | -------- | ------------------------ | | Chrome | chrome://extensions | | Edge | edge://extensions | | Brave | brave://extensions | | Chromium | chromium://extensions |

Enable developer mode → Load unpacked → select the generated folder → copy the extension ID.

3. Register the Native Messaging host

npx -y atlas-browser-connect native register --extension-id <ID> --browser chrome

Supported browsers: chrome, edge, brave, chromium, chrome-for-testing.

4. Reload the extension

5. Connect your AI agent

{
  "mcpServers": {
    "atlas-browser-connect": {
      "command": "npx",
      "args": ["-y", "atlas-browser-connect@latest", "mcp"]
    }
  }
}

Works with Claude Desktop, VS Code, Cursor, Codex, Gemini CLI, or any MCP-compatible client.

.vscode/mcp.json:

{
  "servers": {
    "atlas-browser-connect": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "atlas-browser-connect@latest", "mcp"]
    }
  }
}

CLI Reference

| Command | Description | | --- | --- | | extension build [--out <path>] | Generate the unpacked extension | | native register --extension-id <id> --browser <b> | Register Native Messaging host | | native unregister --browser <b\|all> | Remove host registration | | mcp | Start the MCP stdio server | | doctor | Check local installation paths |

All commands: npx -y atlas-browser-connect <command>.

Architecture

src/
  shared/       Protocol types and bridge path config
  extension/    Chrome MV3 extension (background service worker)
  host/         Native Messaging host (stdin/stdout ↔ local pipe)
  server/       MCP stdio server (chrome_call tool)
  cli/          CLI surface (build, register, doctor)
    native/     Platform-specific registration
test/           Tests mirroring src/
scripts/        Build automation

Development

Requires Bun.

bun install
bun test
bun run typecheck
bun run check
bun run build

Troubleshooting

| Problem | Solution | | --- | --- | | Native host not found | Re-run native register, reload extension | | Access forbidden | Extension ID mismatch — re-run native register | | Host not connected | Reload extension after registering | | API call fails | Check permissions in manifest, MV3 availability |

License

MIT. See LICENSE.