Welcome to nbb v1.2.175!
user=> (require '[missionary.core :as m])
"#error {:message \"Unable to resolve classname: missionary.impl.Reduce\", :data {:type :sci/error, :line 4, :column 3, :message \"Unable to resolve classname: missionary.impl.Reduce\", :sci.impl/callstack #object[cljs.core.Volatile {:val ({:line 4, :column 3, :file \"/Users/martinklepsch/code/github.com/gatheround/gatheround/scripts/db-poke-perf-testing/.nbb/.cache/00141330b1bdad31190c7a9ff93264fbcf4540d4/nbb-deps/missionary/core.cljc\", :ns #object[Ur missionary.core]})}], :file \"/Users/martinklepsch/code/github.com/gatheround/gatheround/scripts/db-poke-perf-testing/.nbb/.cache/00141330b1bdad31190c7a9ff93264fbcf4540d4/nbb-deps/missionary/core.cljc\"}, :cause #object[Error Error: Unable to resolve classname: missionary.impl.Reduce]}"

(it appears that the library was added to the classpath as expected, since this error occurred loading missionary/core.cljs )

I guess missionary isn't compatible with SCI (or vice versa)

I don't understand how core.cljs does not load, but just imports the other impl .cljs file in missionary

You can work around this probably by requiring that impl namespace yourself before loading core

but I'm pretty sure you'll run into something else regarding deftype

ok cool, I'll poke around a bit but almost assumed it's not going to work but wanted to check/share 🙂