[BUG] Alt+Backspace deletes entire Greek text instead of one word at a time in Claude Code promp

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 typing Greek text in the Claude Code interactive prompt and pressing Alt+Backspace to delete the last word, it deletes the entire Greek sentence or paragraph instead of just one word.

This makes it very time-consuming to edit Greek text, as you have to retype everything.

What Should Happen?

Alt+Backspace should delete one Greek word at a time, just like it does with English text. Word boundaries should be properly detected for Greek (and other Unicode) characters.

Error Messages/Logs

Steps to Reproduce

1. Open Claude Code in terminal
2. Start typing Greek text in the prompt (e.g., "Γεια σου πως είσαι σήμερα καλά")
3. Press Alt+Backspace to delete the last word
4. Observe that all Greek text gets deleted instead of just "καλά"

Note: The same Alt+Backspace shortcut works correctly with English text (deletes one word) and works correctly with Greek text in the regular terminal (outside Claude Code).

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

v2.0.31

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

zsh shell in iTerm2 is used