[BUG] Tailscale SSH causes full screen redraw/scroll on user interaction

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 running Claude Code over Tailscale SSH, the entire conversation scrolls to the top and back to the current position every time the user takes an action (responding to permission prompts, typing input, etc.). This makes the experience unusable.

Possible rootcause: Tailscale SSH has its own PTY implementation (separate from OpenSSH's sshd) that doesn't properly handle alternate screen buffer operations used by Claude Code's TUI.

What Should Happen?

Shouldn't redraw/scroll from top

Error Messages/Logs

Steps to Reproduce

1. Enable Tailscale SSH on a remote server (tailscale set --ssh=true)
2. Connect via Tailscale SSH (ssh user@hostname where SSH is handled by tailscaled)
3. Run claude
4. Have a conversation with a few messages
5. Interact with any prompt (permission request, input field, etc.)
6. Observe: the entire chat history visually scrolls from the top before returning to the current position

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.76 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

Environment

• Terminal: Ghostty
• TERM: xterm-256color
• Connection: Tailscale SSH
• tmux: Tried, same issue