[BUG] Autocompact in planning mode trashes the plan

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 planning mode is started after completing some task, and auto-compact fires, it pollutes the planning. Apparently both things interact in a bad way causing the plan to end up built to do again what was completed already instead of the plan request.

What Should Happen?

If auto-compact fires in the middle of planning, the summarization should not contain the previous part and confuse the planning. Or summarization should contain parts relevant to the planning. Apparently both things interact in a bad way. Auto-compact should be "smarter" in that case and process in a different way planning vs editing.

Error Messages/Logs

No errors, just the plan ends up not being the one requested.

Steps to Reproduce

Complete a task. Afterwards when context is close to be filled launch planning mode to increase chances for auto-compact to fire. Request a different plan. Could be related or not. At the end of planning if auto-compact fires the plan ends up being the previous completed task.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.67

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_