[BUG] Supplemental prompts executed in a wrong order

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 writing a prompt for already running prompt, if you enter it somewhere a few seconds before the main prompt completes, this supplemental prompt is not acted upon. It is not even reflected in prompt history. You can see it in the log but after it - nothing. So, at this point claude is done. The bug is that if you add a new main prompt, the un-executed supplemental prompt from the prior task gets thrown in midway of the execution of that new main prompt. Totally unexpected.

What Should Happen?

The supplemental prompt should be resolved before the main prompt stops.

Error Messages/Logs

Steps to Reproduce

1. Start with a prompt. While it is executing, near the end of it type in and send a new prompt. If you time it correctly when the main prompt is finishing, you'll see that the system will take the prompt, write it to the screen, but then stop.

1. After full stop of the prompt number 1, write a new prompt. Execute it. After a few second see that the prior unexecuted prompt somehow gets ingested..

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.27

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_