GPT 5.5 Pro is only in chat/API, not Codex.

In Codex, GPT‑5.5 is available for Plus, Pro, Business, Enterprise, Edu, and Go plans with a 400K context window.

	▲	artdigital 3 days ago \| parent [-]
		He’s talking about “gpt-5.5-pro”. This model is not part of the subscription plans in codex. It’s a different model than gpt-5.5-xhigh You can use Pro on the web if you’re on the Pro plan but not in Codex