Found a :decode/string approach here https://clojurians-log.clojureverse.org/reitit/2021-12-05/1638960049.130700

IIRC, this will work out of the box for reitit and malli, coercing a string to UUID

:parameters {:path [:map [:my-id [:uuid]]]}

Do you have the correct middleware? eg.

reitit.http.interceptors.parameters/parameters-interceptor
reitit.http.coercion/coerce-request-interceptor

It works! Thank you.