Max subscription: 'Extra usage is required for 1M context' error on default model

Description

On a Max subscription, selecting the default model (Opus 4.6 with 1M context) produces the error:

API Error: Extra usage is required for 1M context · run /extra-usage to enable, or /model to switch to standard context

This shouldn't happen — Opus 4.6 with 1M context is the default model for Max subscribers and shouldn't require extra usage to be enabled.

Steps to Reproduce

1. Be on a Max subscription plan
2. Launch Claude Code (latest version)
3. Use default model (Opus 4.6 with 1M context)
4. Attempt any prompt

Expected Behavior

Prompt executes normally. Max subscription includes 1M context by default.

Actual Behavior

Error message blocks execution, suggesting /extra-usage or /model switch.

Environment

• Subscription: Max
• Model: Opus 4.6 (1M context) — default
• Persists after restart and update to latest version
• Platform: macOS