[BUG] Auto compact off, but asking me to compact before 100% context usage

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?

Since updating from 2.1.2 to 2.1.7, Auto-compact is disabled. Context usage is at 66%, with a 3k buffer for compaction. However, it blocks and prompts to compact manually (at 66%) rather than reaching 100% and prompting to compact.

What Should Happen?

Let me reach 9X% context usage

Error Messages/Logs

Steps to Reproduce

Use Claude Code with auto-compact off until it reaches 6X% context.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.2

Claude Code Version

2.1.7

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_