I think this announcement says a lot about OpenAI and their relationship to partners like Microsoft and NVIDIA, not to mention the attitude of their leadership team.

On Microsoft Foundry I can see the new Codex 4.6 model right now, but GPT-5.3 is nowhere to be seen.

I have a pre-paid account directly with OpenAI that has credits, but if I use that key with the Codex CLI, it can't access 5.3 either.

The press release very prominently includes this quote: "GPT‑5.3-Codex was co-designed for, trained with, and served on NVIDIA GB200 NVL72 systems. We are grateful to NVIDIA for their partnership."

Sounds like OpenAI's ties with their vendors are fraying while at the same time they're struggling to execute on the basics like "make our own models available to our own coding agents", let alone via third-party portals like Microsoft Foundry.