The 'capability' and 'include' parameters of the $package operation are currently defined as strings. The documentation for each makes it clear that the parameter supports a well-defined set of values and so the type for each should be changed to code and the parameter bound to a value set that includes the set of values described in the parameter documentation.

Possible values for each parameter (per the documentation):

capability

• computable - to include computable elements in packaged content;
• executable to include executable elements in packaged content;
• publishable to include publishable elements in packaged content. }

include

• all (default) - all resource types
• artifact - the specified artifact
• canonical - canonical resources (i.e. resources with a defined url element or that can be canonical resources using the artifact-url extension)
• terminology - terminology resources (i.e. CodeSystem, ValueSet, NamingSystem, ConceptMap)
• conformance - conformance resources (i.e. StructureDefinition, StructureMap, SearchParameter, CompartmentDefinition)
• profiles - profile definitions (i.e. StructureDefinition resources that define profiles)
• extensions - extension definitions (i.e. StructureDefinition resources that define extensions)
• knowledge - knowledge artifacts (i.e. ActivityDefinition, Library, PlanDefinition, Measure, Questionnaire)
• tests - test cases and data (i.e. test cases as defined by the testing specification in this implementation guide)
• examples - example resources (i.e. resources identified as examples in the implementation guide)