AskUserQuestion silently returns empty when called in the same turn as a Skill invocation

Description

AskUserQuestion fails to render its UI when called in the same assistant response turn that processes a Skill tool invocation. The tool call fires, returns successfully with empty answers, and Claude proceeds as if the user responded — but the user never sees the question UI.

Reproduction Steps

1. Create a Skill that instructs Claude to call AskUserQuestion (e.g., a settings configuration skill)
2. Invoke the skill: /my-skill
3. Claude loads the skill, runs any setup (Bash calls, Read calls), then calls AskUserQuestion
4. Expected: Question UI appears, user selects answers
5. Actual: No UI appears. Tool returns "User has answered your questions: ." with empty answers. Claude continues with its own defaults.

Key Evidence

In the same conversation:

• Direct AskUserQuestion call → works perfectly, UI renders
• Skill loads → Claude calls AskUserQuestion → fails silently, empty response
• Next turn after failure → direct AskUserQuestion → works again

This was tested multiple times in the same session. The failure is 100% reproducible when AskUserQuestion is the first interactive tool call after a Skill invocation.

Impact

Any plugin/workflow that uses the Skill tool to load prompts containing AskUserQuestion instructions will have questions silently skipped. Claude proceeds with its own assumptions instead of user input.

Environment

• Claude Code: 2.1.63
• macOS: 26.3
• Node: v22.17.0
• Shell: zsh
• Permission mode: skipDangerousModePermissionPrompt: true

Workaround

Force a turn boundary before calling AskUserQuestion: output text, stop, wait for user input, then call AskUserQuestion in the next turn. This is clunky but works.