[BUG] Files added via deeplink have no preview

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?

Files that support preview show no preview if added to Claude Desktop app's context via deeplink

What Should Happen?

I expect claude://cowork/new?file=<file_path> to behave similar to drag&drop.

Error Messages/Logs

Steps to Reproduce

1. Call claude://cowork/new?file=<url-encoded path to a PNG file>

• It is added with no preview

1. Add the same file via drag&drop

• It's preview is displayed

1. Click the deeplink-added file

• The window says "Could not load file preview"

Screen recording:
https://cloud.box.com/s/c307sm4jvbg0gpwg273h7y94c6w2skk4
(the link expires on September 13)

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.202

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_