[BUG] Copy-paste from Claude Code introduces extra spaces/characters in code blocks (still broken)

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?

The bug in https://github.com/anthropics/claude-code/issues/4686 has not been resolved. It was marked as a duplicate of https://github.com/anthropics/claude-code/issues/5097, which was closed as a duplicate of 4686, even though they are not actually duplicates of each other, and 4686 has not been resolved!

What Should Happen?

See https://github.com/anthropics/claude-code/issues/4686

Error Messages/Logs

Steps to Reproduce

see https://github.com/anthropics/claude-code/issues/4686

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.42

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information