[BUG] The Claude Code VSCode extension has inconsistent behavior when attaching multiple images

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?

The VSCode extension allows attaching multiple images using copy-paste (Ctrl+V), but drag-and-drop only accepts one image. When attempting to drag a second image, it doesn't load - only the first image remains attached.

What Should Happen?

Drag-and-drop should allow attaching multiple images consecutively, just like copy-paste does. Both methods should have the same behavior for consistency.

Error Messages/Logs

No error messages displayed. The UI silently ignores the second drag-and-drop attempt.

Steps to Reproduce

1. Open Claude Code chat in VSCode
2. Take a screenshot and drag-and-drop it into the chat input → Image appears
3. Take another screenshot and drag-and-drop it into the same chat input → Second image doesn't appear
4. Result: Only 1 image attached

Working workaround:

1. Open Claude Code chat in VSCode
2. Take a screenshot and copy it (Cmd+C or screenshot tool)
3. Paste with Ctrl+V into chat → First image appears
4. Take another screenshot and copy it
5. Paste with Ctrl+V into chat again → Second image appears
6. Result: Both images attached successfully

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.9 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• The official documentation mentions support for multiple images but doesn't specify this drag-and-drop limitation
• This creates inconsistent UX where copy-paste works but drag-and-drop doesn't
• Found evidence of a copilot_chat_attach_multiple_images feature flag in the codebase, which may be related