[BUG] Stalling when using @ to reference files

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?

Just this week Claude Code started to stall a long time when I enter @ to reference files. I do not have a lot of files. I just found this happens in a new project. It stalls for a long time, possibly 30 seconds or more. It is critical to reference specific files and this is making Claude Code unusable.

What Should Happen?

When I used @ in previous weeks it would list files immediately and filter based on what I typed next. Now it stalls a long time before it even allows me to type. It should at least allow me to type. This is a serious performance regression.

Error Messages/Logs

Claude Code does not know how to find any logs.

Steps to Reproduce

1. Use Claude Code
2. Enter @ and observe the long delay and how you cannot even type more characters

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.81 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

I am using cmux which is based on the Ghostty library. I don't see how it would be an issue as it was not a problem with it last week.