>The world knowledge of these models is not necessarily up to date :)
It's amazing how this still needs to be said. Codex was released in April 2025. The initial GPT-5 and 5.1 still had a knowledge cutoff in late 2024. Like, what did you expect? Always beware the knowledge cutoff for LLMs (although recent releases have gotten much better with researching the web for updates before answering modern software topics).
OpenAI being more aware of the implications would help too--last year I also struggled with using Codex to write scripts to run Codex headless, because it kept insisting that Codex was a retired model from the GPT-3 days and not a program that could be called by a script.