diff --git a/src/PVE/JSONSchema.pm b/src/PVE/JSONSchema.pm
index 32d461c..cb2d56e 100644
--- a/src/PVE/JSONSchema.pm
+++ b/src/PVE/JSONSchema.pm
@@ -967,6 +967,11 @@ my $method_schema = {
 	    description => "JSON Schema for parameters.",
 	    optional => 1,
 	},
+        formatter => {
+	    type => 'object',
+	    description => "Used to store page formatter information (set by PVE::RESTHandler->register_page_formatter).",
+	    optional => 1,
+        },
 	returns => {
 	    type => 'object',
 	    description => "JSON Schema for return value.",