This may be relevant: OpenAI removed GPT-5.3 Codex from the ChatGPT plans in June. The model is now only available via the API – but it appears to be the ‘default’ model in the Codex settings for the XCode Agents.
With other models such as GPT-5.4, GPT-5.4-Mini and GPT-5.5 (depending on what’s available in your GPT account), agent mode should work in a new Codex session.
BTW: Is it just me, or is there no UI to set the reasoning level for the agents?
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Topic:
Developer Tools & Services
SubTopic:
Xcode
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