[BUG] Windows flashes terminal window running "npm list" periodically

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?

When using claude from the terminal on Windows I'm periodically seeing a flash from a windows terminal window. I can see that it's cmd.exe and I can see it's running npm list. This is indicitive of spawning a process without specifying to hide the window. Common windows bug/issue. It's very annoying.

I then had claude write a small powershell script to watch for this and it identified...claude as the suspect. So I'm reporting it here. :-)

What Should Happen?

Claude should modify when it calls "npm list" or other similar commands in windows to hide the command window.

Error Messages/Logs

Steps to Reproduce

Here's the powershell script claude wrote that identifies itself. Then run queries against claude until this happens.

Watches for ALL new cmd.exe, powershell.exe, pwsh.exe, node.exe,

conhost.exe, and wt.exe processes. Catches short-lived flashing windows.

Press Ctrl+C to stop

Write-Host "Watching for all console/shell process creation... (Ctrl+C to stop)" -ForegroundColor Cyan

$query = @"
SELECT * FROM __InstanceCreationEvent WITHIN 0.5
WHERE TargetInstance ISA 'Win32_Process'
AND (
TargetInstance.Name = 'cmd.exe'
OR TargetInstance.Name = 'powershell.exe'
OR TargetInstance.Name = 'pwsh.exe'
OR TargetInstance.Name = 'node.exe'
OR TargetInstance.Name = 'npm.cmd'
OR TargetInstance.Name = 'conhost.exe'
)
"@

Register-WmiEvent -Query $query -SourceIdentifier "FlashWatcher" -Action {
$proc = $Event.SourceEventArgs.NewEvent.TargetInstance
$parentId = $proc.ParentProcessId
$parentProc = Get-CimInstance Win32_Process -Filter "ProcessId = $parentId" -ErrorAction SilentlyContinue

Write-Host "`n=== CAUGHT at $(Get-Date -Format 'HH:mm:ss') ===" -ForegroundColor Yellow
Write-Host "Process: $($proc.Name) (PID $($proc.ProcessId))" -ForegroundColor Green
Write-Host "CommandLine: $($proc.CommandLine)" -ForegroundColor White
Write-Host "Parent: $($parentProc.Name) (PID $parentId)" -ForegroundColor Magenta
Write-Host "Parent Cmd: $($parentProc.CommandLine)" -ForegroundColor Magenta
} | Out-Null

try {
while ($true) { Start-Sleep -Seconds 1 }
} finally {
Unregister-Event -SourceIdentifier "FlashWatcher"
Write-Host "`nStopped watching." -ForegroundColor Cyan
}

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.89 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

This is about it. Flashing terminal windows calling "npm list" when using claude code on Windows. Hide the window is all you have to do.