How do AppEnum, AppEntity and EntityQuery work together, and how do parameter errors behave?

Predict first

What do the query, defaults and an early error give?

import AppIntents
import Foundation

enum Priority: String, AppEnum {
    case low, high
    static let typeDisplayRepresentation: TypeDisplayRepresentation = "Priority"
    static let caseDisplayRepresentations: [Priority: DisplayRepresentation] = [.low: "Low", .high: "High"]
}
struct ListEntity: AppEntity {
    static let typeDisplayRepresentation: TypeDisplayRepresentation = "List"
    static let defaultQuery = ListQuery()
    var id: String
    var name: String
    var displayRepresentation: DisplayRepresentation { DisplayRepresentation(title: "\(name)") }
}
struct ListQuery: EntityQuery {
    static let all = [ListEntity(id: "a", name: "Groceries"), ListEntity(id: "b", name: "Work")]
    func entities(for identifiers: [String]) async throws -> [ListEntity] { Self.all.filter { identifiers.contains($0.id) } }
    func suggestedEntities() async throws -> [ListEntity] { Self.all }
}
struct Open: AppIntent {
    static let title: LocalizedStringResource = "Open"
    @Parameter(title: "List") var list: ListEntity
    @Parameter(title: "Priority", default: .low) var priority: Priority
    @Parameter(title: "Count", default: 3) var count: Int
    func perform() async throws -> some IntentResult { .result() }
}
struct Greet: AppIntent {
    static let title: LocalizedStringResource = "Greet"
    @Parameter(title: "Name") var name: String
    func perform() async throws -> some IntentResult & ProvidesDialog {
        guard name.count > 2 else { throw $name.needsValueError("Name is too short") }
        return .result(dialog: "Hello")
    }
}
let q = ListQuery()
print(try await q.entities(for: ["b", "zzz"]).map(\.name))
print(try await q.suggestedEntities().map(\.id))
print(Priority.allCases.map(\.rawValue), Priority.caseDisplayRepresentations[.high]!.title.key)
let o = Open(); print("defaults:", o.priority, o.count)
var g = Greet(); g.name = "Al"
do { _ = try await g.perform() } catch { print("error type:", type(of: error)) }
print(Greet.openAppWhenRun, Greet.isDiscoverable, Greet.authenticationPolicy)

• ["Work"] / ["a", "b"] / both cases and the key "High" / defaults: low 3 / error type: AppIntentError / false true alwaysAllowed
• Both ids resolve
• The error is a plain Swift Error type