diff --git a/plugins/commands/serve/client/capability_platform.rb b/plugins/commands/serve/client/capability_platform.rb
index 788efeb7e..fe4f9dbe5 100644
--- a/plugins/commands/serve/client/capability_platform.rb
+++ b/plugins/commands/serve/client/capability_platform.rb
@@ -35,15 +35,15 @@ module VagrantPlugins
               name: cap_name,
             )
           )
-          cb = proc do |name, args|
+          cb = lambda do |name, args|
             result = client.capability(
               SDK::Platform::Capability::NamedRequest.new(
                 name: name,
                 func_args: args,
               )
             )
-            return nil if result.nil?
-            mapper.map(result.result)
+            return nil if result.nil? || result.result.nil?
+            mapper.map(SDK::Args::Direct.new(arguments: [result.result])).arguments.first
           end
           [spec, cb]
         end
diff --git a/plugins/commands/serve/util/direct_conversions.rb b/plugins/commands/serve/util/direct_conversions.rb
index 27c7e1ea7..ff4861b24 100644
--- a/plugins/commands/serve/util/direct_conversions.rb
+++ b/plugins/commands/serve/util/direct_conversions.rb
@@ -373,7 +373,10 @@ end
 class Hashicorp::Vagrant::Sdk::Args::Direct
   def to_ruby
     VagrantPlugins::CommandServe::Type::Direct.new(
-      arguments: arguments.map(&:to_ruby)
+      arguments: arguments.map { |arg|
+        val = arg.to_ruby
+        val.is_a?(VagrantPlugins::CommandServe::Type) ? val.value : val
+      }
     )
   end
 end