[BUG] slash command auto-complete is broken (highlighted command doesn't match what I'm typing)

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?

I open a vanilla terminal on a MacBook Pro OSX 15.6.1
I start typing /context but the auto-complete jumps to "/compact"
I fully type out /context and press Enter but it runs the /compact command!

Screenshots:

<img width="396" height="94" alt="Image" src="https://github.com/user-attachments/assets/60610097-121a-44a0-97ac-5e6233e448b8" /> <br />

<img width="418" height="104" alt="Image" src="https://github.com/user-attachments/assets/b2e0d1af-2ce0-4f46-bdf7-a1eb506d68c2" /> <br />

<img width="535" height="114" alt="Image" src="https://github.com/user-attachments/assets/abab1c51-60d8-40b6-a023-f26c7bf0c936" /> <br />

<img width="502" height="159" alt="Image" src="https://github.com/user-attachments/assets/65bbac65-7a46-48dc-a0ae-50eeadd8eb65" /> <br />

<img width="489" height="137" alt="Image" src="https://github.com/user-attachments/assets/adb47dd9-1336-4169-9948-a507ad1cb648" /> <br />

If I press Enter at the end here, it runs /compact instead of /context

If I press Esc instead, it finally switches the autocomplete to /context:

<img width="440" height="147" alt="Image" src="https://github.com/user-attachments/assets/877df571-2f69-415d-a148-8d6eead2dbce" />

What Should Happen?

After I type /con the autocomplete should jump to /context

Error Messages/Logs

Steps to Reproduce

Start typing /context

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.12

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_