[BUG] Claude Code's integration with Cursor does not work when CC is launched inside tmux

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?

Claude Code does not show diffs in Cursor IDE, and instead shows text-based diffs in the conversation view.
A similar issue was filed before (and closed).

What Should Happen?

Cursor's diff viewer should be used.

Steps to Reproduce

Run CC in tmux and ask for changes to a file.

Claude Model

Opus

Is this a regression?

I don't know

Claude Code Version

2.1.22

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Cursor

Additional Information

Exporting TERM_PROGRAM to cursor, vscode, or code-insiders does not resolve the issue.

The output of /ide is

 Select IDE
 Connect to an IDE for integrated development features.

 No available IDEs detected. Make sure your IDE has the Claude Code extension or plugin
 installed and is running.

 Enter to confirm · Esc to cancel

The output of /status includes the following line

IDE: Installed Cursor extension

Running Claude Code outside tmux works as intended.