[BUG] Terminal Renaming a tag causes the animated icon to disappear

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?

Before renaming the label, Claude Code or Codex worked perfectly and displayed the corresponding dynamic icons—such as “in progress” or “confirmation required”—but after the renaming, the icons became static. This affects the user experience, as the dynamic icons are no longer visible, which is very disappointing.

Tip: Confirmed by members of the Windows Terminal community. ”Unfortunately, Claude Code is writing graphical characters into the tab title rather than using the "operation in progress" VT sequence, OSC 9.“

What Should Happen?

After renaming a tab in Windows Terminal, the animated temperature icon displays normally

Error Messages/Logs

Steps to Reproduce

Using Claude Code CLI, observe the dynamic custom icons on the tab throughout the process—from startup to “In Progress” or “Authorization Required” to task completion. Then rename the tab and compare the results.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.128

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

<img width="629" height="49" alt="Image" src="https://github.com/user-attachments/assets/a3b0b84e-4410-49eb-901c-002178afbac7" />