[BUG] Chrome DevTools freezes and crashes when opening multiple Claude Code instances with MCP integration

When using Claude Code CLI with Chrome DevTools in one terminal, opening a second Claude Code instance (especially with MCP integration) causes the application to freeze and crash. While it appears that running Claude Code in two terminals should be possible, the presence of active Chrome DevTools in the first instance causes system instability.

Steps to Reproduce

1. Open a terminal and start Claude Code CLI with Chrome DevTools enabled
2. Open another terminal and start a new Claude Code instance for MCP integration/work
3. Attempt to interact with either instance
4. Observe that the system becomes unresponsive and eventually crashes both instances

Expected Behavior

• Multiple Claude Code instances should be able to run simultaneously without interference
• Chrome DevTools being active in one instance should not freeze other instances
• System should remain stable even with multiple instances accessing browser automation features

Actual Behavior

• The second Claude Code instance becomes unresponsive/frozen
• Chrome DevTools interaction causes system-wide freeze
• Both instances crash and close, requiring restart

Environment Information

• OS: macOS (version: Darwin 24.6.0)
• Features Used:
• Chrome DevTools (first instance)
• MCP integration (second instance)

Additional Context

This issue appears to be a resource contention problem between multiple Claude Code instances when both are attempting to access Chrome browser automation features. The issue specifically manifests when Chrome DevTools is actively in use in one terminal while launching a second Claude Code instance.

Possible Root Cause

• Port conflict between multiple Claude Code processes
• Chrome DevTools locks preventing access from second instance
• MCP server initialization conflict with active DevTools session
• Native messaging host being exclusively locked by first instance

Suggested Solution

Implement better handling of concurrent Claude Code instances:

1. Detect when another instance is using Chrome DevTools/browser automation
2. Queue requests or use a lock mechanism to prevent conflicts
3. Provide clear error messages to users when conflicts are detected
4. Alternatively, allow multiple instances to share the same Chrome DevTools session safely