V2 prompt input hides model reasoning selector

[aidan0x13]

Description

The desktop beta/dev app uses the v2 prompt input, which shows the selected model but does not render the model variant selector. For models with reasoning variants, such as GPT-5.5, users can select the model but cannot change reasoning level from the prompt controls even though the provider response includes variants.

This is related to #28686, but this issue is scoped specifically to the missing model variant/reasoning selector in the v2 prompt input.

Plugins

N/A

OpenCode version

0.0.0-beta-202605240006 / dev desktop build

Steps to reproduce

1. Open the desktop beta/dev app with the v2 prompt input enabled.
2. Select a model that has variants, such as openai/gpt-5.5.
3. Inspect the prompt controls next to the model picker.
4. The model picker shows GPT-5.5, but the reasoning/model variant selector is not visible.

Screenshot and/or share link

N/A

Operating System

macOS

Terminal

Desktop app

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• No issue template was used. Bug reports must include the required fields: Description, Steps to Reproduce, OpenCode version, and Operating System. Please resubmit using the Bug Report template.

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be a duplicate of existing issues. Please check:

• Desktop V2 UI hides prompt controls and status popover #28686: Desktop V2 UI hides prompt controls and status popover — same root cause (V2 prompt input hiding model variant/thinking selector and other controls)

If you believe this was flagged incorrectly, please let a maintainer know.

[aidan0x13]

Updated the issue to use the bug report fields. This is related to #28686, but kept separate because PR #29050 is scoped only to the missing model variant/reasoning selector in the v2 prompt input.

[github-actions]

Thanks for updating the issue! It now follows the bug report template with all the required fields filled in. The needs:compliance label has been removed.

[Salloxy]

Current-release context: this same missing reasoning/model variant selector appears to affect v1.15.12 in the newly user-toggleable Desktop UI. The model can be selected, but the UI no longer exposes a way to change the reasoning level for models with variants.

[aidan0x13]

fixed in #30646