[BUG][BUG] Claude in Chrome (Cowork) MCP connection fails on macOS Sequoia + Apple Silicon M4 Pro

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Bug Description

Claude in Chrome (Cowork) MCP connection consistently fails with "No Chrome extension connected" error on macOS Sequoia with Apple Silicon M4 Pro.

Environment

• OS: macOS Sequoia (Apple Silicon M4 Pro, 24GB RAM)
• Browser: Google Chrome (latest)
• Claude in Chrome extension version: 1.0.56
• Claude plan: Max

Steps to Reproduce

1. Open Chrome with Claude in Chrome extension enabled and active
2. Go to claude.ai and start a conversation
3. Attempt to use Cowork/browser automation (e.g., tabs_context_mcp)
4. Extension returns: "No Chrome extension connected"

Expected Behavior

Claude in Chrome should establish MCP connection and allow browser automation.

Actual Behavior

Every attempt to connect returns "No Chrome extension connected" regardless of:

• Refreshing the page
• Toggling the extension on/off
• Restarting Chrome

The extension appears installed and enabled in chrome://extensions but never establishes a connection with claude.ai.

Related Issues

• #27931 (Claude in Chrome crashes on macOS Sequoia + Apple Silicon)
• #27530 (Chrome crashes on Apple Silicon)
• #27492 (Cowork MCP issue)

Impact

Cowork/browser automation is completely unusable. This is a core feature of the Max plan ($200/month).

What Should Happen?

Bug Description

Claude in Chrome (Cowork) MCP connection consistently fails with "No Chrome extension connected" error on macOS Sequoia with Apple Silicon M4 Pro.

Environment

• OS: macOS Sequoia (Apple Silicon M4 Pro, 24GB RAM)
• Browser: Google Chrome (latest)
• Claude in Chrome extension version: 1.0.56
• Claude plan: Max

Steps to Reproduce

1. Open Chrome with Claude in Chrome extension enabled and active
2. Go to claude.ai and start a conversation
3. Attempt to use Cowork/browser automation (e.g., tabs_context_mcp)
4. Extension returns: "No Chrome extension connected"

Expected Behavior

Claude in Chrome should establish MCP connection and allow browser automation.

Actual Behavior

Every attempt to connect returns "No Chrome extension connected" regardless of:

• Refreshing the page
• Toggling the extension on/off
• Restarting Chrome

The extension appears installed and enabled in chrome://extensions but never establishes a connection with claude.ai.

Related Issues

• #27931 (Claude in Chrome crashes on macOS Sequoia + Apple Silicon)
• #27530 (Chrome crashes on Apple Silicon)
• #27492 (Cowork MCP issue)

Impact

Cowork/browser automation is completely unusable. This is a core feature of the Max plan ($200/month).

Error Messages/Logs

## Bug Description

Claude in Chrome (Cowork) MCP connection consistently fails with "No Chrome extension connected" error on macOS Sequoia with Apple Silicon M4 Pro.

## Environment

- **OS**: macOS Sequoia (Apple Silicon M4 Pro, 24GB RAM)
- **Browser**: Google Chrome (latest)
- **Claude in Chrome extension version**: 1.0.56
- **Claude plan**: Max

## Steps to Reproduce

1. Open Chrome with Claude in Chrome extension enabled and active
2. Go to claude.ai and start a conversation
3. Attempt to use Cowork/browser automation (e.g., `tabs_context_mcp`)
4. Extension returns: `"No Chrome extension connected"`

## Expected Behavior

Claude in Chrome should establish MCP connection and allow browser automation.

## Actual Behavior

Every attempt to connect returns `"No Chrome extension connected"` regardless of:
- Refreshing the page
- Toggling the extension on/off
- Restarting Chrome

The extension appears installed and enabled in `chrome://extensions` but never establishes a connection with claude.ai.

## Related Issues

- #27931 (Claude in Chrome crashes on macOS Sequoia + Apple Silicon)
- #27530 (Chrome crashes on Apple Silicon)
- #27492 (Cowork MCP issue)

## Impact

Cowork/browser automation is completely unusable. This is a core feature of the Max plan ($200/month).

Steps to Reproduce

Bug Description

Claude in Chrome (Cowork) MCP connection consistently fails with "No Chrome extension connected" error on macOS Sequoia with Apple Silicon M4 Pro.

Environment

• OS: macOS Sequoia (Apple Silicon M4 Pro, 24GB RAM)
• Browser: Google Chrome (latest)
• Claude in Chrome extension version: 1.0.56
• Claude plan: Max

Steps to Reproduce

1. Open Chrome with Claude in Chrome extension enabled and active
2. Go to claude.ai and start a conversation
3. Attempt to use Cowork/browser automation (e.g., tabs_context_mcp)
4. Extension returns: "No Chrome extension connected"

Expected Behavior

Claude in Chrome should establish MCP connection and allow browser automation.

Actual Behavior

Every attempt to connect returns "No Chrome extension connected" regardless of:

• Refreshing the page
• Toggling the extension on/off
• Restarting Chrome

The extension appears installed and enabled in chrome://extensions but never establishes a connection with claude.ai.

Related Issues

• #27931 (Claude in Chrome crashes on macOS Sequoia + Apple Silicon)
• #27530 (Chrome crashes on Apple Silicon)
• #27492 (Cowork MCP issue)

Impact

Cowork/browser automation is completely unusable. This is a core feature of the Max plan ($200/month).

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Bug Description Claude in Chrome (Cowork) MCP connection consistently fails with "No Chrome extension connected" error on macOS Sequoia with Apple Silicon M4 Pro. ## Environment - OS: macOS Sequoia (Apple Silicon M4 Pro, 24GB RAM) - Browser: Google Chrome (latest) - Claude in Chrome extension version: 1.0.56 - Claude plan: Max ## Steps to Reproduce 1. Open Chrome with Claude in Chrome extension enabled and active 2. Go to claude.ai and start a conversation 3. Attempt to use Cowork/browser automation (e.g., tabs_context_mcp) 4. Extension returns: "No Chrome extension connected" ## Expected Behavior Claude in Chrome should establish MCP connection and allow browser automation. ## Actual Behavior Every attempt to connect returns "No Chrome extension connected" regardless of: - Refreshing the page - Toggling the extension on/off - Restarting Chrome The extension appears installed and enabled in chrome://extensions but never establishes a connection with claude.ai. ## Related Issues - #27931 (Claude in Chrome crashes on macOS Sequoia + Apple Silicon) - #27530 (Chrome crashes on Apple Silicon) - #27492 (Cowork MCP issue) ## Impact Cowork/browser automation is completely unusable. This is a core feature of the Max plan ($200/month).

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_