[BUG] Numeric keypad Enter key outputs escape sequence [57414u instead of newline

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?

Numeric keypad Enter key outputs escape sequence [57414u instead of newline

Environment

• OS: macOS (please add your version, e.g., Sonoma 14.x)
• Terminal: iTerm2 (please add version from iTerm2 → About)
• Keyboard: Extended keyboard with numeric keypad
• Claude Code version: (run claude --version)

Description

When using Claude Code in iTerm2, pressing the Enter key on the numeric keypad outputs the literal characters [57414u instead of executing a return/newline. The Return key on the main keyboard (above right Shift) works correctly.

The issue appears to be related to the CSI u (Kitty keyboard protocol) that Claude Code enables. The sequence 57414 is the Unicode codepoint for the numpad Enter key, suggesting the key press is being encoded in enhanced keyboard mode rather than interpreted as a newline.

Steps to Reproduce

1. Open iTerm2
2. Launch Claude Code (claude)
3. Press the Enter key on the numeric keypad
4. Observe [57414u appended to the input line instead of a newline

Expected Behavior

Numeric keypad Enter should function identically to the main keyboard Return key, sending a newline.

Actual Behavior

Keypad Enter outputs the raw escape sequence [57414u.

Additional Notes

• The main keyboard Return key works fine
• After exiting Claude Code, the keypad Enter continues to malfunction until running reset or printf '\e[?u' to disable CSI u mode
• This suggests Claude Code may not be fully restoring terminal state on exit

Workarounds

1. Use the main keyboard Return key instead of keypad Enter
2. Run reset after exiting Claude Code to restore terminal state
3. Add a custom key mapping in iTerm2 (Settings → Profiles → Keys → Key Mappings) to map keypad Enter to send \n

What Should Happen?

Numeric keypad Enter should function identically to the main keyboard Return key, sending a newline.

Error Messages/Logs

Observe [57414u appended to the input line instead of a newline

Steps to Reproduce

hit enter key on Mac extended keyboard

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

v2.1.3

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_