[BUG] @ search not triggering when using previous prompt

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?

If you arrow-key up and use a previous prompt and try to edit it to include a file, the @ search autocomplete does not appear.

What Should Happen?

It should show the search autocomplete results.

Steps to Reproduce

1. Open new session
2. Click arrow-up key and navigate to a previous prompt
3. Edit the prompt to include a file
4. Notice it doesn't show the search autocomplete

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.17

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_