diff --git a/plugins/commands/serve/service/command_service.rb b/plugins/commands/serve/service/command_service.rb
index 54864c45e..c2538556a 100644
--- a/plugins/commands/serve/service/command_service.rb
+++ b/plugins/commands/serve/service/command_service.rb
@@ -28,6 +28,10 @@ module VagrantPlugins
                 type: "hashicorp.vagrant.sdk.Args.TerminalUI",
                 name: "",
               ),
+              SDK::FuncSpec::Value.new(
+                type: "hashicorp.vagrant.sdk.Args.Project",
+                name: "",
+              ),
               SDK::FuncSpec::Value.new(
                 type: "hashicorp.vagrant.sdk.Command.Arguments",
                 name: "",