diff --git a/scheduler-server/src/main/java/gov/nasa/jpl/aerie/scheduler/server/services/GraphQLMerlinDatabaseService.java b/scheduler-server/src/main/java/gov/nasa/jpl/aerie/scheduler/server/services/GraphQLMerlinDatabaseService.java
index 77288576f9..fef071f5e8 100644
--- a/scheduler-server/src/main/java/gov/nasa/jpl/aerie/scheduler/server/services/GraphQLMerlinDatabaseService.java
+++ b/scheduler-server/src/main/java/gov/nasa/jpl/aerie/scheduler/server/services/GraphQLMerlinDatabaseService.java
@@ -649,14 +649,20 @@ private void modifyActivityDirectives(
   {
     ensurePlanExists(planId);
     final var request = new StringBuilder();
-    request.append("mutation updatePlanActivityDirectives($activities: [activity_directive_set_input!]!) {");
-    var index = 0;
-    final var activitiesObject = Json.createArrayBuilder();
+    request.append("mutation updatePlanActivityDirectives(");
+    request.append(String.join(
+        ",",
+        activities.stream().map($ -> "$activity_%d: activity_directive_set_input!".formatted($.id().id())).toList()
+    ));
+    request.append(") {");
+    final var arguments = Json.createObjectBuilder();
     for (final var act : activities) {
+      final var id = act.id().id();
       request.append("""
-                         update_%d: update_activity_directive_by_pk(pk_columns: {id: %d, plan_id: %d}, _set: $activities[%d]) {}
-                         """.formatted(act.id().id(), act.id().id(), planId.id(), index));
-      index++;
+                         update_%d: update_activity_directive_by_pk(pk_columns: {id: %d, plan_id: %d}, _set: $activity_%d) {
+                           affected_rows
+                         }
+                         """.formatted(id, id, planId.id(), id));
 
       final var activityObject = Json
           .createObjectBuilder()
@@ -669,13 +675,9 @@ private void modifyActivityDirectives(
         insertionObjectArguments.add(arg.getKey(), serializedValueP.unparse(arg.getValue()));
       }
       activityObject.add("arguments", insertionObjectArguments.build());
-      activitiesObject.add(activityObject);
+      arguments.add("activity_%d".formatted(id), activityObject);
     }
-    final var arguments = Json
-        .createObjectBuilder()
-        .add("activities", activitiesObject.build())
-        .build();
-    postRequest(request.toString(), arguments).orElseThrow(() -> new NoSuchPlanException(planId));
+    postRequest(request.toString(), arguments.build()).orElseThrow(() -> new NoSuchPlanException(planId));
   }
 
   private void deleteActivityDirectives(
@@ -689,9 +691,10 @@ private void deleteActivityDirectives(
     request.append("mutation deletePlanActivityDirectives {");
     for (final var id : ids) {
       request.append("""
-                         delete_%d: delete_activity_directive_by_pk(id: %d, plan_id: %d) {}
+                         delete_%d: delete_activity_directive_by_pk(id: %d, plan_id: %d) {affected_rows}
                          """.formatted(id.id(), id.id(), planId.id()));
     }
+    request.append("}");
     postRequest(request.toString()).orElseThrow(() -> new NoSuchPlanException(planId));
   }