Claude Code breaks drag-and-drop of macOS screenshot thumbnails when custom pseudoterminal is open

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?

Drag-and-drop of temporary macOS screenshot thumbnails into Claude Code chat fails
silently when a custom pseudoterminal extension is open. This started after Claude Code
auto-updated on Nov 6-7, 2025. The issue affects both Cursor AND VS Code, confirming
it's Claude Code causing the problem.

When dragging the temporary screenshot thumbnail (the floating preview that appears
after Cmd+Shift+4):

• No hover hint appears
• No visual feedback
• Drop fails silently

Note: Dragging SAVED files works fine. Only the temporary screenshot thumbnail fails.

What Should Happen?

Expected the screenshot to upload successfully, as it does when:

• Using built-in terminals with Claude Code active
• Using custom pseudoterminals WITHOUT Claude Code active
• This behavior worked before the recent Claude Code update (Nov 6-7, 2025)

Error Messages/Logs

Steps to Reproduce

1. Install any custom pseudoterminal extension (e.g., a custom terminal extension)
2. Create a terminal using that extension
3. Start Claude Code agent in the chat
4. Take a screenshot using Cmd+Shift+4 on macOS
5. Try to drag the temporary screenshot thumbnail into Claude Code chat
6. Observe: Drop fails silently with no feedback

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.0.35

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Cursor

Additional Information

Claude Code Version
Latest (auto-updated Nov 6-7, 2025)

Editor
Both Cursor 2.0.64 and VS Code (unupdated) - issue occurs in BOTH editors

Operating System
macOS 15.6 (24G84)

Additional context
Key evidence showing this is Claude Code specific:
✅ Built-in terminal + Claude Code + screenshot = Works
✅ Custom pseudoterminal + NO Claude Code + screenshot = Works
✅ Custom pseudoterminal + Claude Code + SAVED FILE = Works
❌ Custom pseudoterminal + Claude Code + screenshot thumbnail = FAILS