Feature: Add Ultra reasoning support for GPT-5.6 Luna

[Zennmn]

Area

Catalog / models

What are you trying to accomplish?

I would like gpt-5.6-luna to support the ultra reasoning level in OpenCodex.

What prevents this today?

Currently, gpt-5.6-luna does not expose ultra, while other GPT-5.6 models such as Sol and Terra support it.

As a result, Luna cannot use the Ultra reasoning mode through the normal reasoning-level selection.

What should OpenCodex do?

Please consider adding ultra reasoning support for gpt-5.6-luna.

If Luna does not advertise ultra upstream, perhaps OpenCodex could map Ultra to Luna's highest supported reasoning effort while preserving the Ultra behavior on the Codex side.

Example usage or interface

Current:

gpt-5.6-luna
Ultra: unavailable

Proposed:

gpt-5.6-luna
Ultra: available

Alternatives or workarounds

There is currently no direct way to select Ultra for gpt-5.6-luna through the normal reasoning-level surface.

Additional context

Is there any technical or upstream limitation that prevents gpt-5.6-luna from supporting Ultra in OpenCodex?

Checks

• I searched existing issues and documentation.
• This request describes a concrete OpenCodex workflow rather than merely naming a desired technology.
• I removed secrets and personal data.

[github-actions]

Issue reopened

The report now contains the information required by the automated check. Thanks for updating it.

[Ingwannu]

This is an upstream capability boundary rather than an OpenCodex omission.

Current dev preserves the native Codex model entry from src/codex/data/upstream-models.json. The upstream gpt-5.6-luna row advertises exactly low, medium, high, xhigh, and max; it does not advertise ultra. By contrast, native rows that support Ultra include it explicitly and describe it as maximum reasoning with automatic task delegation.

Mapping Luna's ultra selector to max would therefore publish a capability the native model does not claim and would conflate Ultra's delegation contract with the ordinary maximum reasoning rung. OpenCodex should keep the exact native ladder and pick up Ultra automatically if a future upstream Codex catalog adds it.

Closing as not planned for now. This can be reconsidered with primary upstream evidence that Luna supports Ultra as a distinct advertised effort.