False "Extra usage required for 1M context" / "Usage limit reached" error with no actual limits hit

<img width="870" height="851" alt="Image" src="https://github.com/user-attachments/assets/e47d25cb-fc94-4a01-a88c-20e758dcd3b5" />

Bug

Received this error on Sonnet 4.6 with no limits actually reached:

API Error: Extra usage is required for 1M context · enable extra usage at claude.ai/settings/usage, or use --model to switch to standard context

The UI also shows "Usage limit reached" — but inspecting the usage panel, nothing is close to any limit:

• 5-hour limit: 10% (resets 2h)
• Weekly · all models: 18% (resets 4d)
• Weekly · Claude Design: 0%
• Sonnet only: 5% (resets 4d)
• Context window: 59.8k / 400k (15%)
• Model: Sonnet 4.6 (max context 400k, not 1M)

So the error is wrong on multiple counts:

1. Not on a 1M-context model (Sonnet 4.6 caps at 400k)
2. Context usage is at 15%, far below any limit
3. No plan quota is anywhere near exhausted
4. The error message references "1M context" which isn't even applicable to this model

Screenshot attached below.

Expected

No error should appear, or the error should accurately describe the actual cause.

Environment

• Claude Code (terminal)
• Model: claude-sonnet-4-6
• macOS