Manual

Install

1. Install from the Chrome Web Store.
2. Pin the toolbar icon. Clicking it opens the side panel, which is the main surface.
3. Nothing else is required. The free tier works immediately with no account.

Permissions

Installing grants seven permissions — activeTab, alarms, debugger, scripting, sidePanel, storage, tabs — and access to 127.0.0.1 only, which reaches the optional local daemon and nothing on the web.

debugger is declared at install because Chrome does not allow it to be optional. Nothing attaches a debugger session until you start network capture, console capture or PDF export, and Chrome shows its own banner on the tab whenever one is active.

Everything else is requested the first time you use the feature that needs it, with an explanation shown before the browser's own prompt:

Declining is safe. The tool returns a PERMISSION_REQUIRED error naming what it needed and why, and every other feature keeps working.

Connect an MCP client

Add the native messaging host to your client's configuration. For a Claude Desktop-style config:

{
  "mcpServers": {
    "t3rnel-browser": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-host.js"]
    }
  }
}

The extension then exposes all 84 tools. Calls arriving this way are treated as untrusted: high-risk tools stop and ask before they run.

The approval gate

By default, high-risk tools — clicking, filling, typing, evaluating JavaScript, uploading, and every vault operation — require your approval when the caller is an MCP client. The agent receives a refusal naming the exact action, for example:

APPROVAL_REQUIRED: 'browser_click' is high risk and this profile
requires confirmation before it runs. Requested action:
browser_click (selector=#place-order).

Approve it in the side panel and the action runs once. The next one asks again. You can add specific tools to a never-ask list, mark extra tools always-ask, or pin whole origins as protected so anything aimed at them is gated regardless of risk.

Activate Pro

1. Open the side panel → Licence → Buy Pro, and enter your email.
2. Complete the PayNow checkout in the tab that opens.
3. Return to the extension and collect your licence key. Keep it. It is what activates your other machines.
4. On another machine, paste the key into Licence → Activate.

One licence covers three installations. Reinstalling on a machine that already has a slot does not consume another. Activation is the only time the extension contacts our server; every later start verifies your licence offline.

Troubleshooting