Sonnet 4.6 1M context not exposed in desktop app model picker (Max plan)

Bug

The Claude Code desktop app's model picker shows Opus 4.7 1M as a persistent option but does not list Sonnet 4.6 1M, even on the Max plan which includes 1M Sonnet access.

The model alias works correctly when set per-session via /model sonnet[1m], and the claude-sonnet-4-6 model with 1M context is documented as available on Max plans. So this appears to be a UI gap rather than an entitlement issue.

Steps to reproduce

1. Open the Claude Code desktop app on a Max plan
2. Open the model picker (⇧⌘I)
3. Observe available models:

• Opus 4.7
• Opus 4.7 1M
• Sonnet 4.6
• Haiku 4.5
• Opus 4.6 Legacy

1. Note that there is no "Sonnet 4.6 1M" option

Expected behavior

A "Sonnet 4.6 1M" option should appear in the picker alongside "Opus 4.7 1M" so it can be selected as a persistent default.

Workarounds attempted

• Setting "model": "sonnet[1m]" in ~/.claude/settings.json is not honored by the desktop app's picker (the checkmark stays on plain Sonnet 4.6 after restart)
• Per-session /model sonnet[1m] does work, but has to be re-entered every session

Environment

• Claude Code desktop app, version 2.1.121
• macOS
• Max plan