[BUG] [Windows] Multiple claude.exe processes spawn each time Claude Code panel is opened, no process guard

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?

OS: Windows 10 Pro (10.0.19045), VSCode running as Administrator
Claude Code version: v2.1.69
VSCode version: v1.109.5

Bug:
Every time the Claude Code panel icon is clicked to open the GUI, a new claude.exe (32-bit)
background process is spawned. The previous process is never killed. Processes accumulate
indefinitely.

Symptoms:

• 4+ claude.exe (32-bit) processes visible in Task Manager after a few clicks
• Each consuming ~1.7 GB RAM and 23-24% CPU ("Very high" power usage)
• Total CPU hits 100%
• Claude Code GUI gets stuck on loading spinner
• Multiple floating cmd.exe windows appear (Claude Code (6), (5), (4)...)

Steps to reproduce:

1. Start Windows, open VSCode
2. Click the Claude Code panel icon to open the GUI
3. Open Task Manager → Background processes
4. Click the Claude Code icon again (close and reopen the panel)
5. Observe: a new claude.exe spawns each time — old ones are not terminated

Expected: One claude.exe process, reused across panel open/close
Actual: New process spawned every panel activation, no cleanup

Workaround:
Run taskkill /f /im claude.exe in PowerShell, then open the panel once for a clean start.
Or: install a specific older version + Reload Window resets state temporarily.

What Should Happen?

One claude.exe process should be spawned when the Claude Code panel is first opened.
If a claude.exe process is already running, the extension should reuse it instead of spawning a new one.
When the panel is closed or VSCode is shut down, the process should be cleanly terminated.

Error Messages/Logs

Checked VSCode Output panel (Claude Code channel) — no errors shown there.
Process accumulation visible only in Windows Task Manager under Background Processes.
Attaching Task Manager screenshot showing 4x claude.exe (32-bit) with ~1.7GB RAM each 
and "Very high" CPU power usage.

Steps to Reproduce

1. Start Windows and open VSCode (running as Administrator)
2. Open the Claude Code panel by clicking the Claude Code icon in the VSCode sidebar
3. Open Windows Task Manager → Background Processes tab
4. Note: 1 claude.exe (32-bit) process appears
5. Close the Claude Code panel
6. Click the Claude Code icon again to reopen the panel
7. Observe Task Manager: a second claude.exe (32-bit) process has spawned — the first one is still running
8. Repeat steps 5-6 several more times
9. Observe: each open spawns a new claude.exe, none are terminated
10. After 3-4 opens: Claude Code GUI gets stuck on loading spinner, CPU hits 100%

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — rolling back to a previous version via Extensions panel resolves it temporarily

Claude Code Version

2.1.69

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

<img width="1920" height="1080" alt="Image" src="https://github.com/user-attachments/assets/90e92def-8d9a-441b-a4ce-d199afd0e09c" />

!Image