[ambrosebs]

Rich hasn't been directly involved, aside from providing encouragement.

Almost all the design/implementation work was done via Typed Racket anyway. I stole a lot of it and spent most of the time on Clojure-specific problems.

[Kototama]

How was it decided that it will be part of core contrib?

[puredanger]

Ambrose proposed it and the Clojure core team accepted it.