[BUG] 1M context window regressed to 200K on Max plan (~March 26-27)

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?

Claude Code v2.1.87, macOS, VS Code extension
Plan: Claude Max
Model: claude-opus-4-6 (set in ~/.claude/settings.json)
1M context was working until approximately March 26-27, 2026
Now /context shows 200K consistently, including in fresh sessions
No CLAUDE_CODE_DISABLE_1M_CONTEXT set
Setting ANTHROPIC_DEFAULT_OPUS_MODEL=claude-opus-4-6[1m] has no effect — model displays as claude-opus-4-6 and context remains 200K

What Should Happen?

/context should show 1000000 .

Compaction should not occur at 200000 tokens.

Error Messages/Logs

Steps to Reproduce

• Start VS Code.
• Create a new Claude Code session.
• Type /context <NL>
• Scroll to the top of the output and look for "Tokens:"

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Current as of March 26.

Claude Code Version

v2.1.87

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_