Claude in Chrome native host crashes on Windows with Bun assertion failure

Description

The Claude in Chrome MCP integration fails on Windows because the native host process crashes immediately on startup with a Bun internal assertion failure.

Environment

• Claude Code version: 2.1.21 (also reproduced on 2.1.20)
• OS: Windows 11
• Bun version: 1.3.5 (bundled)

Steps to Reproduce

1. Have Claude in Chrome extension installed in Chrome
2. Try to use any mcp__claude-in-chrome__* tool from Claude Code
3. Get error: "Browser extension is not connected"

Running the native host directly shows the crash:

C:\Users\Owner\.claude\chrome\chrome-native-host.bat

Actual Behavior

The native host crashes before it can accept connections:

[Claude Chrome Native Host] Initializing...
[Claude Chrome Native Host] Creating socket listener: \\.\pipe\claude-mcp-browser-bridge-Owner
============================================================
Bun v1.3.5 (1e86cebd) Windows x64 (baseline)
Windows v.win11_dt
CPU: sse42 avx avx2
Args: "C:\Users\Owner\.local\bin\claude.exe" "--chrome-native-host"
...
panic(main thread): Internal assertion failure
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Expected Behavior

The native host should start successfully and allow the Chrome extension to connect.

Bun Crash Report

https://bun.report/1.3.5/e_11e86cebEugggC++08F+mvBoxhkf0389e__0shkwCA0eNrzzCtJLcpLzFFILC5OLSrJzM9TSEvMzCktSgUAiSkKPg

Native Host Configuration

The native host manifest at C:\Users\Owner\AppData\Roaming\Claude Code\ChromeNativeHost\com.anthropic.claude_code_browser_extension.json is correctly configured and registered in the Windows registry.

Additional Context

• The Chrome extension works fine when used directly via the sidebar (connecting to claude.ai)
• The crash occurs specifically when trying to create the named pipe for MCP communication
• Chrome DevTools MCP (separate integration) works fine