[BUG] AskUserQuestion invoked with placeholder content while waiting on background agent

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?

During a session with a backgrounded subagent (test-runner re-running a test), the main agent showed an AskUserQuestion prompt with the header “placeholder,” the question “placeholder; waiting on background agent, no actual question,” and options “ok” and “ok2.” The prompt appeared right after the “Agent … finished · 2m 59s” notification.

<img width="3024" height="4032" alt="Image" src="https://github.com/user-attachments/assets/eaba3011-9daf-4363-b9a0-6821d9b6d7f4" />

What Should Happen?

The agent should wait for or process the background agent’s result without prompting the user. It should never create a question with no real decision behind it.

Error Messages/Logs

Steps to Reproduce

1. Start a Claude Code session in terminal, with custom subagents defined in .claude/agents/.
2. Ask Claude to run a task through a subagent that gets backgrounded (in my case, test-runner re-running a Playwright test against a live app).
3. While the background agent is still running, send a follow-up message in the main session.
4. Wait for the background agent to finish.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.283 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

<img width="3024" height="4032" alt="Image" src="https://github.com/user-attachments/assets/621b3a8a-d685-4a26-8fff-7e56949eee54" />