[BUG] click registered in UI but empty payload reached the assistant

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?

When the assistant invokes the AskUserQuestion tool to present a multiple-choice card, clicking an option in the UI sometimes results in the assistant receiving an empty answer payload, as if the user had cancelled. The user must then re-state the selection in plain chat.

What Should Happen?

The assistant should receive the selected option label and continue the workflow with that selection.

Error Messages/Logs

It looks like the user canceled their question, so there's nothing for me to respond to.

Steps to Reproduce

1. Start a new Claude Code / Copilot session.
2. Issue a request that causes the assistant to ask a clarifying question via the AskUserQuestion tool — for example: "Summarise my most recent meeting." When no meeting ended in the last 2 hours, the assistant presents an AskUserQuestion card listing 2–4 candidate meetings.
3. Click one of the option buttons on the card (do not type a custom answer).
4. Observe the assistant's next response.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Code (Copilot Cowork session)

Platform

Other

Operating System

WSL Linux sandbox

Terminal/Shell

Other

Additional Information

Environment:

Product: Claude Code (Copilot Cowork session)
Model: Claude Opus 4.6
Platform: Web/desktop (please confirm your client)