[BUG] /mcp displays list in a fixed scroll container, cannot view/take action on items outside of the default view

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?

Actual behavior

When I run /mcp with a lot of servers but a short screen height, I see the last entries from my claude.ai group as part of the default viewport.

Despite using up/down arrows, I see the view FIXED on the original list. I cannot see or take action on the remaining items

Example (with server names redacted):

   claude.ai B · △ needs authentication
   claude.ai C · △ needs authentication
   claude.ai D · ✔ connected · x tools
   claude.ai E · △ needs authentication
   claude.ai F · ✔ connected · x tools
   claude.ai G · ✔ connected · x tools
   claude.ai H · △ connected · x tools
   claude.ai I · △ needs authentication
   claude.ai J · ✔ connected · x tools
   claude.ai K · ✔ connected · x tools
   claude.ai L · △ needs authentication
   claude.ai M · ✔ connected · x tools
   claude.ai N · ✔ connected · x tools
   claude.ai O · ✔ connected · x tools
   claude.ai P · △ needs authentication
   claude.ai Q · ✔ connected · x tool
   claude.ai R · ✔ connected · x tools
   claude.ai S · △ needs authentication
   claude.ai T · △ needs authentication
   claude.ai U · △ needs authentication
   claude.ai V · △ connected · x tools
   claude.ai W · ✔ connected · x tools
   claude.ai X · △ needs authentication
   claude.ai Y · △ needs authentication
   claude.ai Z · ✘ failed

 ※ Run claude --debug to see error logs
 https://code.claude.com/docs/en/mcp for help
↑↓ to navigate · Enter to confirm · Esc to cancel

What Should Happen?

Expected behavior

The MCP list scrolls along with my current cursor position, so that I can see the following entries
claude.ai A (above the current set)

Example (with server names redacted):

   Project MCPs
   xxxxx · ✔ connected · x tools
   xxxxx · ✔ connected · x tools

   User MCPs
   xxxxx · ✔ connected · x tools

   claude.ai
❯  claude.ai A · △ needs authentication
(----- the fold -----)
   claude.ai B · △ needs authentication
   claude.ai C · △ needs authentication
   claude.ai D · ✔ connected · x tools
   claude.ai E · △ needs authentication
   claude.ai F · ✔ connected · x tools
   claude.ai G · ✔ connected · x tools
   claude.ai H · △ connected · x tools
   claude.ai I · △ needs authentication
   claude.ai J · ✔ connected · x tools
   claude.ai K · ✔ connected · x tools
   claude.ai L · △ needs authentication
   claude.ai M · ✔ connected · x tools
   claude.ai N · ✔ connected · x tools
   claude.ai O · ✔ connected · x tools
   claude.ai P · △ needs authentication
   claude.ai Q · ✔ connected · x tool
   claude.ai R · ✔ connected · x tools
   claude.ai S · △ needs authentication
   claude.ai T · △ needs authentication
   claude.ai U · △ needs authentication
   claude.ai V · △ connected · x tools
   claude.ai W · ✔ connected · x tools
   claude.ai X · △ needs authentication
   claude.ai Y · △ needs authentication
   claude.ai Z · ✘ failed

 ※ Run claude --debug to see error logs
 https://code.claude.com/docs/en/mcp for help
↑↓ to navigate · Enter to confirm · Esc to cancel

Error Messages/Logs

Steps to Reproduce

1. Precondition 1: I have 25 MCPs from claude.ai and 15 MCPs in my current project
2. Precondition 2: I use tmux to multiplex my terminal, so some panels have ~30 lines of display height
3. Run /mcp
4. Attempt to use up/down arrow keys to select specific items

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.128

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_