Up arrow key destroys composed message in input

Summary

Pressing the up arrow key while composing a multi-line message in the input field replaces the entire composed text with the previous message from history. No confirmation, no undo. The work is gone.

Steps to Reproduce

1. Start composing a long, multi-line message in the Claude Code CLI input
2. Accidentally press the up arrow key
3. The entire composed message is replaced by the previous history entry
4. No way to recover the lost text

Expected Behavior

Either:

• Up arrow should not replace text while mid-composition (only activate history navigation when input is empty)
• Or provide an undo mechanism (e.g., down arrow restores the draft)

Impact

Loss of significant user work mid-thought. Particularly painful for detailed, multi-paragraph prompts that take time to compose.

Environment

• Platform: Linux
• Shell: bash