Jev is a new model that’s been very popular on X these past two days. Its idea is interesting.
Human thinking can be divided into two modes: System 1 (fast thinking) and System 2 (slow thinking).
The TypeSafe team’s argument is:
Today’s mainstream models are all System 2. They tend to write out their reasoning as a paragraph, then spit it out token by token, very slowly.
So they call things like Jev System One Models: they don’t chat, they don’t explain, they don’t write sentences, and they’re specifically built to “take in the state and immediately give a structured judgment.”
The official wording is roughly: treat it as a function call for frontier intelligence — unstructured state goes in, probabilistic typed decisions come out.
I’m going to try it. If it works, then I’ll do an episode video talking about it.