[BUG] Shift+Enter does not insert newline when running Claude Code via SSH (v2.1)

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?

In version 2.1.0, the changelog states:

Changed Shift+Enter to work out of the box in iTerm2, WezTerm, Ghostty, and Kitty without modifying terminal configs

However, when running Claude Code over an SSH connection (even from these supported terminals), pressing Shift+Enter still does not insert a newline.

What Should Happen?

Pressing Shift+Enter should insert a newline character, allowing users to compose multi-line messages before submitting.

This behavior works correctly when running Claude Code locally in these terminals, but breaks over SSH.

Error Messages/Logs

Steps to Reproduce

1. Use a supported terminal (iTerm2, WezTerm, Ghostty, or Kitty) on your local machine
2. Connect to a remote server via SSH (e.g., ssh user@remote-host)
3. Start Claude Code in the remote terminal (claude)
4. Type some text in the input prompt
5. Press Shift+Enter to try to insert a newline
6. Observe that the input is submitted

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.1

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_