diff --git a/plugins/commands/serve/client/synced_folder.rb b/plugins/commands/serve/client/synced_folder.rb
index 0801e5d07..40e67753c 100644
--- a/plugins/commands/serve/client/synced_folder.rb
+++ b/plugins/commands/serve/client/synced_folder.rb
@@ -36,12 +36,10 @@ module VagrantPlugins
         # Prepare synced folders on guest
         #
         # @param machine [Vagrant::Machine] Guest machine
-        # @param folders [Array] Synced folders
+        # @param folders [Hash] Synced folders
         # @param opts [Hash] Options for folders
         def prepare(machine, folders, opts)
-          spec, cb = prepare_func
-          cb.call(generate_funcspec_args(spec,
-              machine, folders, Type::Direct.new(value: opts)))
+          run_func(machine, folders, Type::Direct.new(value: opts))
         end
 
         # Generate callback and spec for required arguments
@@ -58,7 +56,7 @@ module VagrantPlugins
         # Enable synced folders on guest
         #
         # @param machine [Vagrant::Machine] Guest machine
-        # @param folders [Array] Synced folders
+        # @param folders [Hash] Synced folders
         # @param opts [Hash] Options for folders
         def enable(machine, folders, opts)
           run_func(machine, folders, opts)
@@ -78,7 +76,7 @@ module VagrantPlugins
         # Disable synced folders on guest
         #
         # @param machine [Vagrant::Machine] Guest machine
-        # @param folders [Array] Synced folders
+        # @param folders [Hash] Synced folders
         # @param opts [Hash] Options for folders
         def disable(machine, folders, opts)
           run_func(machine, folders, opts)
diff --git a/plugins/commands/serve/service/synced_folder_service.rb b/plugins/commands/serve/service/synced_folder_service.rb
index 98c430d2f..98a3bc62d 100644
--- a/plugins/commands/serve/service/synced_folder_service.rb
+++ b/plugins/commands/serve/service/synced_folder_service.rb
@@ -98,7 +98,7 @@ module VagrantPlugins
                 name: "",
               ),
               SDK::FuncSpec::Value.new(
-                type: "hashicorp.vagrant.sdk.Args.Folder",
+                type: "hashicorp.vagrant.sdk.Args.Hash",
                 name: "",
               ),
               SDK::FuncSpec::Value.new(