AskUserQuestion tool frequently returns blank/empty answers

Description

The AskUserQuestion tool intermittently returns empty answers — the response comes back as User has answered your questions: "..."="" with no actual selection captured. This happens across multiple sessions and projects.

Environment

• OS: WSL2 (Ubuntu) on Windows 11
• Claude Code model: Opus 4.6
• Reproducibility: Happens multiple times per session, not 100% of the time

Steps to reproduce

1. Claude calls AskUserQuestion with options
2. User selects an option in the UI
3. Tool result returns with blank answer value

Expected

The selected option text is returned in the answer field.

Actual

Answer field is empty/blank. Example response:

User has answered your questions: "Proceed with update?"=""

Impact

Claude proceeds as if the user confirmed, which can lead to unintended actions (running installs, making changes without actual consent). Workaround is adding instructions to CLAUDE.md to treat blank answers as "stop and ask again."