[Desktop/Cowork] claude://cowork/new with both q and folder: clicking Continue on the folder dialog clears the prefilled prompt

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?

Opening a Cowork deep link that carries both a prompt (q) and a folder (folder) loses the prompt.

Claude Desktop opens a new Cowork task with the prompt correctly prefilled in the composer, and at the same time shows the folder confirmation dialog:

Another app attached "project" /Users/<you>/project You've allowed this folder before. Continue to add it to this session. [Cancel] [Continue]

The prompt is visible in the composer behind the dialog. Clicking Continue attaches the folder but clears the composer, so the prefilled prompt is gone and the handoff does nothing.

• Without &folder=… the prompt survives (no dialog).
• The equivalent claude://code/new?q=…&folder=… (Claude Code in Desktop) keeps the prompt.

This breaks any app that hands a task to Cowork together with the project folder, which the Open Claude Desktop with a link article documents as supported (q, folder, file on cowork/new).

What Should Happen?

After clicking Continue on the folder dialog, the folder is attached and the prefilled prompt stays in the composer, ready to send. That's how claude://code/new behaves with the same parameters.

Error Messages/Logs

No error is shown. The composer is just cleared.

Steps to Reproduce

1. Pick any folder you've already allowed in Cowork, e.g. /Users/<you>/project.
2. In Terminal, run:

``
open 'claude://cowork/new?q=hello%20from%20a%20deep%20link&folder=%2FUsers%2F<you>%2Fproject'
``

1. Claude Desktop opens a new Cowork task. The composer shows "hello from a deep link", and the "Another app attached …" dialog appears on top of it.
2. Click Continue.
3. Result: the folder is attached, but the composer is empty.

Control, the same link without folder:

open 'claude://cowork/new?q=hello%20from%20a%20deep%20link'

No dialog appears, and the prompt stays in the composer.

Reproduced on macOS.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Desktop 2.7032.0 (Cowork); not the CLI

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

In the desktop app's main process, the cowork/new handler forwards q and folder to /task/new?q=…&folder=…&src=external. So the prompt reaches the task view, which is why it's visible behind the dialog. It looks like accepting the external-folder dialog resets the composer state.

The desktop app's own "Send to Claude" Finder service also uses cowork/new?…&folder=…, but it never passes q, so it wouldn't hit this.

Possible workaround: copy the prompt to the clipboard before opening the link, so the user can paste it back.