[BUG] in tmux, CC assumes the prefix key is ctrl-b

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 you're in tmux, it says (ctrl+b ctrl+b (twice) to run in background) - regardless of whether your prefix key is, in fact, ctrl-b.

What Should Happen?

Claude should either find out what the prefix key is and use that, or say "prefix key".

Or maybe this isn't a problem because anyone who changes their prefix key is presumably smart enough to know it.

Error Messages/Logs

Steps to Reproduce

Run anything in CC in the background.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.80 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_