[BUG] Chrome native host crashes with Bun panic on Windows 11 (v2.1.25)

Bug Description

The Chrome native host (claude.exe --chrome-native-host) crashes immediately with a Bun runtime panic on Windows 11, making the Claude in Chrome extension completely non-functional.

Environment

• Claude Code version: 2.1.25
• OS: Windows 11
• Chrome Extension: v1.0.40 (Claude in Chrome)
• Installation method: Native (C:\Users\<user>\.local\bin\claude.exe)

Steps to Reproduce

1. Install Claude Code v2.1.25 natively on Windows
2. Install the Claude in Chrome extension (v1.0.40)
3. Run claude and try to use any mcp__claude-in-chrome__* tool (e.g., tabs_context_mcp)
4. Or manually test: echo '{"type":"ping"}' | claude.exe --chrome-native-host

Expected Behavior

The native host should start, create the named pipe, and bridge communication between the Chrome extension and Claude Code.

Actual Behavior

The native host crashes immediately with a Bun internal assertion failure:

[Claude Chrome Native Host] Initializing...
[Claude Chrome Native Host] Creating socket listener: \.\pipe\claude-mcp-browser-bridge-<user>
============================================================
Bun v1.3.5 (1e86cebd) Windows x64 (baseline)
Windows v.win11_dt
CPU: sse42 avx avx2 avx512
Args: "C:\Users\<user>\.local\bin\claude.exe" "--chrome-native-host"
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) jsc standalone_executable
...
Elapsed: 636ms | User: 828ms | Sys: 234ms
RSS: 0.51GB | Peak: 0.51GB | Commit: 0.49GB | Faults: 126053

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

To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:

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

Configuration Verified

All configuration is correct:

• Registry: HKCU\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_code_browser_extension points to the JSON manifest
• JSON manifest (com.anthropic.claude_code_browser_extension.json) correctly references chrome-native-host.bat
• BAT file correctly calls claude.exe --chrome-native-host
• The crash happens at the Bun runtime level before any browser connection can be established

Related Issues

This appears to be the root cause behind several recent Windows reports:

• #21300
• #21363
• #21371
• #20862

Labels

bug, platform:windows, claude-in-chrome