[BUG] VSCode integrated terminal opens unexpectedly when sending messages from external terminal

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?

I run Claude Code in a standalone terminal (iTerm/Terminal.app) rather than VSCode's integrated terminal. When I type a prompt and press Enter in my external terminal, VSCode's integrated terminal panel immediately opens/appears - even though:

• The terminal panel was previously closed in VSCode
• Claude hasn't run any bash commands yet
• Claude hasn't started responding

This happens on every single prompt, not just when Claude needs to execute commands.

What Should Happen?

The VSCode terminal panel should not open unless Claude Code explicitly needs to run a command there.

Error Messages/Logs

Steps to Reproduce

When running Claude Code in a standalone terminal (not VSCode's integrated terminal) with the VSCode IDE integration connected:

1. The VSCode integrated terminal panel is closed
2. I type a question/prompt in Claude Code (in my external terminal)
3. Immediately after pressing Enter, the VSCode integrated terminal panel opens
4. This happens before Claude responds or runs any commands

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.31

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_