[BUG] bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to manually run /compact"

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?

bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to
manually run /compact"

What Should Happen?

bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to
manually run /compact"

Error Messages/Logs

bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to
  manually run /compact"

Steps to Reproduce

bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to
manually run /compact"

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to manually run /compact"

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

bug——"auto compaction not triggering at 95-100% context usage on Opus 4.6, version 2.1.159, have to
manually run /compact"