[BUG] Desktop (Windows): "Download and open in VS Code" silently fails for .py files — blocked by executable extension filter

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?

In the Claude Desktop app (Windows), clicking the "Download and open" button (VS Code option) on a .py file card shows a brief loading spinner and then nothing happens. No error message is shown to the user.

main.log reveals the root cause: the download step rejects .py as a "blocked executable extension", so the open-in-VS-Code flow dies silently.

"Download all" (zip) works fine, and the same file downloads normally via claude.ai in a browser. VS Code 1.128.1 is installed and code is available on PATH (verified). Reproducible 100% of the time with .py files.

What Should Happen?

Either .py files should be allowed in this flow (the file is being opened in a code editor, not executed), or a clear error message should be shown explaining why the action was blocked, instead of failing silently.

main.log

Error Messages/Logs

2026-07-15 15:27:37 [error] fetchToDownloads: rejected filename: Blocked executable extension: .py

Steps to Reproduce

1. Open the Claude Desktop app on Windows (MSIX install)
2. Ask Claude to generate a Python (.py) file in a chat
3. Click the "Download and open" button (VS Code option) on the .py file card
4. Observe: loading spinner flashes briefly, nothing opens, no error is shown
5. Check %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjc\LocalCache\Roaming\Claude\logs\main.log — the rejection error appears at the exact time of the click

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — worked as of ~July 8, 2026 (before machine reformat brought a newer app version)

Claude Code Version

1.21459.0 (Claude Desktop for Windows, build f7518f) — bug is in the Desktop app, not the CLI

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Windows 11 build 26200, Claude Desktop installed via official website installer (MSIX package Claude_pzs8sxrjxfjc)

The "Download and open" button works fine for other file types in the same message (.ico, .png) — only the .py file fails.

Screenshot: file cards in the same response — the .py "Baixar e abrir" (Download and open in VS Code) button does nothing when clicked.

<img width="803" height="334" alt="Image" src="https://github.com/user-attachments/assets/083b5349-6d08-4f4b-9754-4bc1ccb991e4" />