[Bug] Model switching to "opusplan" fails after selecting sonnet[1m], opus[1m], or haiku

Bug Description

If I select “sonnet[1m]”, “opus[1m]”, or “haiku” via /model and then run /model, I cannot switch to “opusplan”.

<img width="745" height="242" alt="Image" src="https://github.com/user-attachments/assets/4a413666-2528-430d-87bb-0333a563e540" />

However, if I select ‘default’ via /model and then run /model, I can switch to “opusplan”.

<img width="745" height="287" alt="Image" src="https://github.com/user-attachments/assets/62caca8a-4c1f-4251-8577-63dab451d26c" />

Even if we have selected “sonnet[1m]”, “opus[1m]”, or “haiku”, the expected behavior is that we can switch to “opusplan”

Preconditions

In settings.json, “availableModels”: [“default”, ‘opusplan’, “sonnet[1m]”, “opus[1m]”, “haiku”] was configured.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.85
• Feedback ID: 8c2dac2d-8479-4bbe-b112-047655b5e467

Errors

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