-codex variant models in earlier version were just fine tuned for coding work, and had a little better performance for related tool calling and maybe instruction calling.
in 5.4 it looks like the just collapsed that capability into the single frontier family model
They’ll likely come out with a 5.4-Codex at some point, that’s what they did with 5 and 5.2
Yes so I’m even more confused. Why would I use codex?
Presumably you don’t anymore if you have 5.4.
You choose gpt-5.4 in the /model picker inside the codex app/cli if you want.