The value for an aws-api CreateStack is described like this

:Parameters
 [:seq-of
  {:ParameterKey string,
   :ParameterValue string,
   :UsePreviousValue boolean,
   :ResolvedValue string}]

[{:ParameterKey "AppName", :ParameterValue "api"}]

{ :path [ :Parameters :ParameterValue ], :pred clojure.core/string?, :val 2, :via [ :cognitect.aws.cloudformation/CreateStackInput :cognitect.aws.cloudformation/Parameters :cognitect.aws.cloudformation/Parameter :cognitect.aws.cloudformation/ParameterValue ], :in [ :Parameters 1 :ParameterValue ] }

"Parameters: [AppName ...] must have values

You're missing a literal key named :Parameters

Nested under the :request

(def cf (aws/client {:api :cloudformation}))
(aws/doc cf :CreateStack)

^^ to figure this kind of thing out using the built-ins

the abbreviated request is {:Parameters [{"ParameterKey" "AppName", "ParameterValue" "api"} ...]} Maybe it's supposed to just be {:Parameters {"AppName" "api"}}

err

{:Parameters [{"AppName" "api"}...]}

the error you had was { :path [ :Parameters :ParameterValue ], :pred clojure.core/string?, :val 2 - which looks like the :ParameterValue value was supposed to be a string, but was the number 2

then you "So i make the key a string" - I think you took the wrong turn here

hmm yes

Thanks Alex, i forgot the first rule (for me at least) is to just use expound rather then try to manually read the spec. It was the fact that one of the values wasn't a string