[BUG] Claude Code removes comments from preexisting code

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?

As Claude Code is modifying files in my repo it strips comments from code.

What Should Happen?

It should not remove the comments.

Error Messages/Logs

asking Claude why it did this, it froze for 5 minutes, but after cancelling that prompt and trying again, it said

> It's from my system prompt — "Default to writing no comments." I applied that rule to existing code during a refactor, which is wrong. The
> rule governs writing new code; it shouldn't retro-strip comments the prior author deliberately left in (like "casting here reduces TSServer
> diagnostic time significantly" or "@WARNING any nested entities may still be available" on _hardDelete).

Steps to Reproduce

ask claude to move some code from one file to another.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.112 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_