[BUG] Claude Opus 4.6 in VS Code Suddenly reverted to 200K context window (from 1M) across all chats around 5pm PST

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?

Around 5pm PST I was working in Claude Code Opus 4.6 as usual in VS Code. Suddenly all my context windows said they were near or at compaction. when i checked /Context they were at 200K . Screenshot still says 1M context but you can see I only have 200K. I've tried in both Claude Extension for VS Code and Terminal and both only have 200K active. I"m a Claude Max 20X user.

Claude Code version: v2.1.81
OS: macOS (M4 MacBook Pro)
No config changes were made — ~/.claude/settings.json has no CLAUDE_CODE_DISABLE_1M_CONTEXT flag, ~/.zshrc is clean
Previously had 1M working for weeks — this reverted without any user action

<img width="870" height="597" alt="Image" src="https://github.com/user-attachments/assets/a6afaa6a-3c31-4e15-af5c-42d463ebf635" />

Date/time: April 1, 2026 ~5:00 PM PST

<img width="1216" height="421" alt="Image" src="https://github.com/user-attachments/assets/5ed8c1d0-bc3b-4d62-ad2a-22401121e387" />

What Should Happen?

1M context by default + per my settings

Error Messages/Logs

no errors just 200K instead of 1M.  see screenshots

Steps to Reproduce

I don't know. it did it on its own. My context windows were working fine and then suddenly they all changed to 200K in the middle of a sessoin . No changes on my end.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

same version i'm using now 2.1.81

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

Its happening in both terminal and through Anthropic Claude extension for vs code