diff --git a/otmonitor.vfs/mqtt.tcl b/otmonitor.vfs/mqtt.tcl
index b357bb5..83456aa 100644
--- a/otmonitor.vfs/mqtt.tcl
+++ b/otmonitor.vfs/mqtt.tcl
@@ -211,7 +211,7 @@ proc mqttstatus {topic data retained {prop {}}} {
     }
 }
 
-proc mqttaction {topic data retain props args} {
+proc mqttaction {topic data retain {props {}} args} {
     global cfg mqttactions actionid
     if {[dict exists $props ResponseTopic]} {
 	# To be able to provide a response, the proc must run as a coroutine