[BUG] When rewinding to edit existing messages and editing/adding the word `think` control characters appear

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 using the rewind (esc) feature to edit an existing message, and editing/adding the word think, control characters appear where the word was edited - for example thi[7mnk

!Image

What Should Happen?

Claude Code should correctly edit the message without displaying [7m or other control characters.

Error Messages/Logs

Steps to Reproduce

1. In an existing session, press esc to enter rewind mode
2. Select a message to edit
3. Type in think somewhere in that message

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.0.128 (Claude Code)

Platform

Google Vertex AI

Operating System

macOS

Terminal/Shell

Warp

Additional Information

Screenshot above is from warp, but reproduced this in Terminal.app as well.