Is Jev probabilistic programming? Critics say it gives marginals, not joints

ivan_bezdomny · x · 2026-09-19

A technical debate over whether Typesafe AI's Jev counts as probabilistic programming. headinthebox argues Jev is a cool API but calling it probabilistic programming — or a Kleisli arrow — is an exaggeration: per Claude Code's framing, "Jev gives you the marginals; a decoder gives you the joint," and asking N questions about one fixed state isn't joint modeling.

ivanbezdomny adds the guess that Jev works by answering questions in parallel and assuming independence — hence fast, but unable to truly reason or do recursive work like writing code; good enough, though, for thousands or millions of quick decisions. As the quoted line goes: "marginals don't determine the joint unless the coordinates are independent."

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