MCP Chrome Extension Bridges Google Messages to Claude Code

Direct Integration Without Docker or Cloud Servers

A developer has created a Chrome extension that injects into Google Messages Web sessions and bridges them to Claude Code via Model Context Protocol (MCP). The architecture uses stdio transport between Claude Code and a Node.js MCP server, which communicates with the Chrome extension via WebSocket on localhost:7008.

What Works vs. Existing Solutions

The developer tried two existing approaches first:

OpenMessage: Docker container using libgm protocol with SSE sessions that expire after a few minutes of inactivity, causing "Invalid session ID" errors. It requires restarting the Docker container for new messages to sync and uses 7 MCP tools (~1,500 tokens per conversation).
TextBee: Android SMS gateway app that routes all private SMS messages through cloud servers (SMS only, no RCS). Requires webhook server plus Tailscale/ngrok tunnel, totaling five moving parts for basic texting.

The new Chrome extension approach has three working MCP tools with ~300 tokens overhead:

list_chats – Returns all conversations with names, snippets, and timestamps
read_messages – Provides full message history with sent/received direction
send_message – Fills in text but doesn't actually send (currently works as a draft tool)

The Angular Isolation Problem

Google Messages Web is an Angular app where Chrome extension content scripts run in an "isolated world" – a separate JavaScript context from the page. Angular's zone.js only patches event listeners in the main world, so when the extension sets the textarea value and clicks Send:

The text appears in the input ✓
The send button gets clicked ✓
Angular's form control doesn't detect the value change, so the click handler thinks the field is empty ✗

Attempted Solutions

The developer has tried multiple approaches:

Native value setter + input events
document.execCommand('insertText')
Full mouse event sequence (pointerdown/mousedown/mouseup/click)
Enter key simulation
Manifest V3 world: "MAIN" content script (gets closest but still doesn't send)

Debug output from the main world script shows: {"valueSet": true, "btnLabel": "Send end-to-end encrypted RCS message", "clicked": true, "inputAfter": "text still here...", "sentVia": "none"}

Potential Solutions to Explore

The developer is considering:

chrome.debugger API for trusted input events
Accessing Angular's NgZone via __ngContext__ on DOM elements
CDP (Chrome DevTools Protocol) for Input.dispatchKeyEvent

The project is open source with repository at https://github.com/GURSEWAKSINGHSANDHU/google-messages-mcp and issue tracking at https://github.com/GURSEWAKSINGHSANDHU/google-messages-mcp/issues/1.

📖 Read the full source: r/ClaudeAI