diff --git a/plugins/commands/serve/mappers/capability.rb b/plugins/commands/serve/mappers/capability.rb
index da755e59f..f7172c76e 100644
--- a/plugins/commands/serve/mappers/capability.rb
+++ b/plugins/commands/serve/mappers/capability.rb
@@ -14,7 +14,7 @@ module VagrantPlugins
         end
 
         def converter(proto)
-          SDK::Args::NamedCapability.decode(proto.value.value).Capability
+          SDK::Args::NamedCapability.decode(proto.value.value).capability
         end
       end
     end