There are several params in the apidoc that are wrongly documented as enum types. Authors most likely intended to validate the parameter for multiple allowed values, but apipie interprets the array syntax as enum.
E.g.:

param :value, LookupKey::KEY_TYPES # -> [ string, boolean, integer, real, array, hash, yaml, json ]

As a result hammer validates such options and raises an exception if ti contains values other than enumerated, which makes the commands unusable.