diff --git a/rmf_task_msgs/srv/SubmitTask.srv b/rmf_task_msgs/srv/SubmitTask.srv
index d17232a2e..fc39faf92 100644
--- a/rmf_task_msgs/srv/SubmitTask.srv
+++ b/rmf_task_msgs/srv/SubmitTask.srv
@@ -17,6 +17,12 @@ Delivery delivery
 Clean clean
 # Patrol patrol
 
+# fleet selection evaluator
+uint8 evaluator
+uint8 LOWEST_DIFF_COST_EVAL=0
+uint8 LOWEST_COST_EVAL=1
+uint8 QUICKEST_FINISH_EVAL=2
+
 ---
 
 # Confirmation that this service call is processed