[BUG] CLI becoming slow and unresponsive after a few prompts in claude code 2.1.3+

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?

The CLI slows down for text input from the user after only a few prompts.

It's not Claudes responses that are slow. But the user input of text is very laggy. On /resume of a larger session or even just after larger ~2-3 prompts on a clean session I almost can't navigate my prompts (long delay on key press before anything happens in the CLI).

Even just writing /exit takes ~5-10 seconds for the CLI to shutdown.

I downgraded to 2.1.2 and the issue is gone and the CLI is fully performant again even in longer sessions.
I tried 2.1.3, 2.1.4 and 2.1.5 and all of them has the same issue.

I am on Manjaro KDE with kernel 6.12.63-1-MANJARO
konsole 25.12.0

Also using wayland on an old RX 580 series GPU, 9950x3d and 128gb of ram if that helps prove the point that the CLI shouldn't slow down to a halt for user input.

The video shows me spamming the keyboard to show just how slow it is at getting the text input on /resume of the a 3 prompt session.

https://github.com/user-attachments/assets/21d2ceb6-48fd-4f69-85d3-7f85bc301df5

What Should Happen?

Claude Code CLI should continue to run at full speed and not slow down.

It should run like the attached mp4 file shows.
The video shows me spamming the keyboard on claude 2.1.2 where it's smooth on /resume of the same 3 prompts session.

https://github.com/user-attachments/assets/87d24f2a-2ed7-40e7-b9b0-f3abfbb8b83f

Error Messages/Logs

Steps to Reproduce

1. Create a session on claude 2.1.5 and have it edit a codebase until the CLI has about ~700 lines
2. Feel the slow input
3. Exit claude and do a resume
4. Confirm input is still slow
5. Downgrade to 2.1.2 and confirm the issue is gone

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.2

Claude Code Version

2.1.5

Platform

Anthropic API

Operating System

Other Linux

Terminal/Shell

Other

Additional Information

_No response_