[BUG] Why has the auto-compaction mechanism been triggering recently whenever the conversation context reaches around 50–60%?

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?

Why has the auto-compaction mechanism been triggering recently whenever the conversation context reaches around 50–60%? It keeps causing long-running tasks to lose memory, and then the context starts drifting all over the place, with OPUS beginning to make its own assumptions and decisions.

What Should Happen?

The context compression should only be triggered when usage reaches around 80–90% at the very least. It used to work fine before, but over the past week, the auto-compression mechanism has been triggering as soon as a conversation reaches 50–60% context usage.

Error Messages/Logs

Steps to Reproduce

For any long-running task, once the context usage reaches around 50–60%, compression is guaranteed to be triggered.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.133

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_