Opus 4.6 with 1M context unavailable for Max 5x subscriber

I'm a Claude Max 5x subscriber. According to the March 13, 2026 announcement, Opus 4.6 now supports 1M context and should be enabled by default for Max users.

However, in Claude Code v2.1.76 (Opus 4.6 · Claude Max), running /model opus[1m] returns:

Opus 4.6 with 1M context is not available for your account.

Environment:

• macOS (Darwin 24.6.0)
• Claude Code v2.1.76
• Plan: Claude Max 5x

Is this still rolling out, or is there a configuration step I'm missing?

<img width="1232" height="167" alt="Image" src="https://github.com/user-attachments/assets/9ac7f1b6-ea5f-4ae8-9f62-baafa0ff50e8" />