--chrome-native-host crashes on Windows with Bun internal panic (v2.1.70)

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?

The Chrome native messaging host (--chrome-native-host) crashes immediately on startup due to a Bun v1.3.11 internal
assertion failure, making the Claude in Chrome extension completely non-functional.

Environment:

• Claude Code: v2.1.70
• OS: Windows 11 Home (10.0.26200)
• Chrome extension: v1.0.57 (ID: fcoeoabgfenejglbffodgkkbkcdhcgfn)
• Bun (bundled): v1.3.11

Steps to reproduce:

1. Install Claude Code v2.1.70 on Windows
2. Install the Claude Chrome extension
3. The extension attempts to connect via native messaging host
4. Chrome reports: Unchecked runtime.lastError: Native host has exited.

Running the native host directly reproduces the crash:
"C:\Users\<user>\.local\bin\claude.exe" --chrome-native-host

Crash output:
[Claude Chrome Native Host] Initializing...
[Claude Chrome Native Host] Creating socket listener: \\.\pipe\claude-mcp-browser-bridge-<user>
============================================================
Bun v1.3.11 (dea015ec) Windows x64 (baseline)

panic(main thread): Internal assertion failure
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

https://bun.report/1.3.11/e_1dea015eEkgggC+pvlG+zwB6kqnhB0njhhB__64hn3CA0eNrzzCtJLcpLzFFILC5OLSrJzM9TSEvMzCktSgUAiSkKP
g

Additional context:

• The native host manifest and registry entries are correctly configured
• Chrome successfully locates and launches the native host, but it crashes before establishing communication
• The Claude Desktop app's standalone chrome-native-host.exe does not have this issue, suggesting the crash is

specific to the Bun-bundled version

What Should Happen?

Claude chrome should be able to connect with claude code without errors

Error Messages/Logs

Steps to Reproduce

1. Install Claude Code v2.1.70 on Windows
2. Install the Claude Chrome extension
3. The extension attempts to connect via native messaging host
4. Chrome reports: Unchecked runtime.lastError: Native host has exited.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.70 (Claude code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_