WebMCP - Model Context Tool Inspector

A Chrome Extension that allows developers to inspect, monitor, and execute tools exposed via the experimental navigator.modelContextTesting Web API.

Prerequisites

Important: This extension relies on the experimental navigator.modelContextTesting Web API. You must enable the "WebMCP for testing" flag in chrome://flags to turn it on in Chrome 146.0.7672.0 or higher.

Installation

You can install this extension either directly from the Chrome Web Store or manually from the source code.

Option 1: Chrome Web Store (recommended)

Install the extension directly via the Chrome Web Store.

Option 2: Install from source

1. Download the Source: Clone this repository or download the source files into a directory.

2. Install dependencies: In the directory, run npm install.

3. Open Chrome Extensions: Navigate to chrome://extensions/ in your browser address bar.

4. Enable Developer Mode: Toggle the Developer mode switch in the top right corner of the Extensions page.

5. Load Unpacked: Click the Load unpacked button that appears in the top left. Select the directory containing manifest.json (the folder where you saved the files).

Usage

1. Navigate to a Page: Open a web page that exposes Model Context tools.

2. Open the Inspector: Click the extension's action icon (the puzzle piece or pinned icon) in the Chrome toolbar. This will open the Side Panel.

3. Inspect Tools:

   • The extension will inject a content script to query the page.
   • A table will appear listing all available tools found on the page.

4. Execute a Tool:

   • Tool: Select the desired tool from the dropdown menu.
   • Input Arguments: Enter the arguments for the tool in the text area.
     • Note: The input must be valid JSON (e.g., {"text": "hello world"}).
   • Click Execute Tool.

Disclaimer

This is not an officially supported Google product. This project is not eligible for the Google Open Source Software Vulnerability Rewards Program.