spawn_agent does not expose gpt-5.6-luna

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#34,964 8 comments 15 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
66/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Quiet
Tech stack
rust
Domain
cli, tooling

Research direction

Start at the spawn_agent implementation and trace how available session models become model overrides. Reproduce the selector behavior with gpt-5.6-luna available, then verify that Luna is exposed alongside gpt-5.6-sol and gpt-5.6-terra without exposing it when unavailable.

Written by the indexing model from the issue text.

Description

app bug subagent
What version of the Codex App are you using (From “About Codex” dialog)?

Version 26.715.72028

What subscription do you have?

Pro

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

The Codex model selector indicates that gpt-5.6-luna is available.

However, when configuring a subagent with spawn_agent, the available model
overrides expose only gpt-5.6-sol and gpt-5.6-terra. Luna cannot be selected
for the subagent, even though it is presented as available.

Expected behavior:
gpt-5.6-luna should be selectable for spawn_agent when it is available in the
current Codex session.

Actual behavior:
The spawn_agent model selection does not expose gpt-5.6-luna.

What steps can reproduce the bug?

Steps to reproduce:

  1. Open Codex and confirm that gpt-5.6-luna is listed as an available model.
  2. Start a task that requires delegating work to a subagent.
  3. Call spawn_agent and try to select gpt-5.6-luna as the subagent model.
  4. Inspect the available model overrides.

Result:
Only gpt-5.6-sol and gpt-5.6-terra are available. gpt-5.6-luna is not exposed as a selectable subagent model.

What is the expected behavior?

No response

Additional information

No response

Dominant language
Rust
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