Windows: Console window flashing when executing tools

[guanknow]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Description

When using Claude Code on Windows (Windows Terminal), a console window briefly flashes/appears every time a tool is executed (Bash, Grep, Glob, Read, etc.).

Environment

• OS: Windows
• Terminal: Windows Terminal
• Platform: win32

Steps to Reproduce

1. Run Claude Code on Windows
2. Execute any command or let Claude use any tool
3. Observe brief window flash

Expected Behavior

Tools should execute without visible window flashing.

Possible Solution

When creating child processes on Windows, use CREATE_NO_WINDOW flag or STARTUPINFO.dwFlags = STARTF_USESHOWWINDOW with wShowWindow = SW_HIDE.

Workaround

Currently using WSL as a workaround.

---

What Should Happen?

11

Error Messages/Logs

Steps to Reproduce

11

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

2.0.74

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[GigiTiti-Kai]

I'm also experiencing this issue, and it extends beyond just tool execution.

Additional Context

The console window flashing also occurs when plugin hooks execute. For example, the claude-mem plugin registers hooks for SessionStart, UserPromptSubmit, PostToolUse, and Stop events that run node and bun commands. Each execution creates a visible console window.

What I tried (unsuccessfully)

1. VBS wrapper with hidden window - Wrapped commands in a VBS script using WScript.Shell.Run with vbHide flag. Failed due to quote escaping issues with cmd /c.

2. PowerShell -WindowStyle Hidden - Wrapped commands with powershell -WindowStyle Hidden -Command "...". The PowerShell window was hidden, but the spawned node.exe/bun.exe processes still created their own console windows.

Root Cause

On Windows, console applications (like node.exe, bun.exe) create console windows by default when spawned. The only reliable way to prevent this is to use the CREATE_NO_WINDOW flag when calling CreateProcess().

Environment

• OS: Windows 11
• Terminal: Windows Terminal
• Claude Code with claude-mem plugin

Request

Please consider implementing CREATE_NO_WINDOW for all child process spawning on Windows, including:

• Tool execution (Bash, Grep, etc.)
• Plugin hook execution
• MCP server processes

This would significantly improve the Windows user experience.

[TheDan64]

I've recently started to experience this on windows and it's a really bad user experience. You can't do anything else while claude is running or it'll get in the way

[EngDawood]

yes , it's very annoying

[PakAbhishek]

Hook execution also affected - critical UX impact for plugin users

User Experience Impact:

I'm experiencing this same issue with plugin hooks, not just tool execution. Every time a claude-mem plugin hook executes (SessionStart, UserPromptSubmit, PostToolUse, Stop), a Node.js console window flashes on screen, often stealing keyboard focus mid-sentence. This happens dozens of times per session and significantly disrupts workflow.

Root Cause:

The issue is in Claude Code's hook execution function (appears to be GE1() in the bundled CLI). The spawn call is missing the windowsHide option:

Current Code:

let V = spawn(command, [], {env: K, cwd: a1(), shell: true})

Required Fix:

let V = spawn(command, [], {
  env: K,
  cwd: a1(),
  shell: true,
  windowsHide: process.platform === 'win32'
})

Precedent:

This exact fix was already implemented in:

• claude-agent-sdk-typescript (Issue chore(internal): remove deno build anthropic-sdk-typescript#103)
• Standard Node.js practice for Windows subprocess spawning

Why Workarounds Don't Work:

All attempted workarounds fail because:

• PowerShell -WindowStyle Hidden → cmd.exe spawns first before PowerShell
• VBScript wrappers → Can't handle stdin properly (hooks need JSON input via stdin)
• Batch files with start /b → Still creates initial cmd.exe window
• PATH shims → Would also flash windows

The ONLY solution is fixing the spawn call at the source.

Impact Scope:

This affects:

• ✅ All Windows users of Claude Code
• ✅ Every tool execution (Bash, Read, Write, etc.)
• ✅ Every plugin hook execution (SessionStart, UserPromptSubmit, PostToolUse, Stop)
• ✅ MCP server startups via hooks

Business Impact:

For professional Windows users, this makes Claude Code nearly unusable. The constant window flashing:

• Disrupts typing mid-sentence
• Breaks focus during code reviews
• Makes screen recording unprofessional
• Prevents use in client-facing environments

Request:

Could this be prioritized for the next patch release? The fix is a one-line change that would immediately improve UX for all Windows users. I'm happy to test a beta build if that would help.

Environment:

• OS: Windows 11 64-bit
• Claude Code version: v2.1.2
• Plugin: claude-mem v9.0.0
• Terminal: PowerShell 7.x

Thank you for considering this!

[roy-enginner]

Hi team — adding an update since my duplicate report (#16880) was closed.

I can still reproduce the same “console window flash” on Windows when tools run, now on the VS Code extension as well:

• Claude Code for VS Code extension: 2.1.11
• OS: Windows 11
• Where it happens: VS Code (integrated terminal / Claude panel) — every Bash/tool invocation triggers a brief node.exe/console window flash

The worst part is that the flashing window steals foreground focus while it appears. During that moment I can’t interact with VS Code (keyboard input gets interrupted / clicks can be lost), so it effectively blocks other work. This is not just distracting — it actively breaks workflow.

Could you share the current status and when you expect a fix (e.g., a target version or timeframe)?
Thanks.

[jphoenix-dev]

This is extraordinarily disruptive when using CC on Win11. One workaround is to use an admin terminal but doing so creates its own downstream issues and shouldn't be necessary. This is seriously impacting workflow - desperate for a fix.

Update: Another workaround for those finding this really annoying; commands run by agents don't appear to trigger the flashing cmd window issue (at least for me on win11, Terminal, CC CLI, non-admin account), so if you can delegate a task via agents I recommend doing so.