[BUG] UX: Pressing ↑ arrow discards current typed prompt when navigating history

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?

If a prompt is being written, pressing ↑ (arrow up/down) should not discard it — either save the draft or ignore history navigation until the line is empty".

What Should Happen?

Either save the draft or ignore history navigation until the line is empty. Arrows should be used only to navigate the prompt.

Error Messages/Logs

Steps to Reproduce

UX element. co code

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_