[BUG] Excessive screen flickering/jumping during “thinking” phase

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 Claude is processing a request (the “thinking” phase before output begins), the terminal screen flickers and jumps rapidly. This creates an unpleasant visual experience, especially in longer thinking periods.
Environment:
∙ Terminal: WezTerm (using native multiplexing)
∙ OS: Ubuntu running on Oracle VirtualBox VM

What Should Happen?

Expected behavior:
A stable visual indicator (spinner, static “thinking…” message, or progress dots) while processing, followed by the streamed response.
Current behavior:
Rapid screen refreshes/redraws that cause visible flickering and jumping, making it uncomfortable to watch.
Suggestion:
Consider buffering the thinking phase output or replacing it with a simple, stable loading indicator until the actual response begins streaming

Error Messages/Logs

Steps to Reproduce

1. Run claude in terminal
2. Submit any prompt that requires extended thinking
3. Observe the screen during the “thinking” phase before the response begins streaming

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_