Visible cmd.exe console window flashes every ~5 minutes from Claude in Chrome native messaging host (Windows/Edge)

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?

Environment:

• OS: Windows 10/11
• Browser: Microsoft Edge (msedge.exe, Default profile)
• Extension: Claude in Chrome, extension ID fcoeoabgfenejglbffodgkkbkcdhcgfn
• Native host path: C:\Users\<user>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\ChromeNativeHost\chrome-native-host.exe

Description:

A visible cmd.exe console window briefly opens and stays visible on screen, recurring roughly every 5 minutes. Confirmed via process monitoring that the window is spawned by Edge (msedge.exe) launching the Claude Chrome native messaging host through a cmd.exe /d /s /c wrapper, with stdin/stdout piped through Windows named pipes for native messaging:

\\\
C:\WINDOWS\system32\cmd.exe /d /s /c ""C:\Users\<user>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\ChromeNativeHost\chrome-native-host.exe" chrome-extension://fcoeoabgfenejglbffodgkkbkcdhcgfn/ --parent-window=0" < \\.\pipe\chrome.nativeMessaging.in.<id> > \\.\pipe\chrome.nativeMessaging.out.<id>
\\\

Parent process confirmed as msedge.exe --profile-directory=Default.

What Should Happen?

The native host should launch without a visible console window, as is standard for background native messaging hosts.

Error Messages/Logs

Steps to Reproduce

1. Install the Claude desktop app on Windows and connect the Claude in Chrome extension in Microsoft Edge.
2. Leave Edge open and idle with the extension active.
3. Observe a cmd.exe console window flashing/opening approximately every 5 minutes.
4. Confirm via Process Explorer / PowerShell (Get-CimInstance Win32_Process) that the parent process is msedge.exe and the command line matches the native host wrapper above.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Code CLI: 2.1.197.

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Likely root cause:

When a Windows native messaging host is invoked via a cmd.exe wrapper rather than directly as an .exe, Chromium historically doesn't apply start_hidden/CREATE_NO_WINDOW the way it does for direct .exe invocations. Chromium landed a fix ("Directly Launch Native Hosts") to invoke .exe-based native hosts directly instead of routing through cmd.exe. It's possible Claude's native host registration is still using the older cmd.exe-wrapped invocation path.

Suggested fix:

• Register the native host manifest to point directly at chrome-native-host.exe rather than through a cmd.exe/batch wrapper.
• Alternatively, have chrome-native-host.exe explicitly set CREATE_NO_WINDOW / build with SUBSYSTEM:WINDOWS if it's currently a console-subsystem binary.

Impact: Cosmetic/annoyance only — no functional breakage, but the window steals focus periodically during normal use.