diff --git a/src/test/kotlin/org/opensearch/commons/alerting/AlertTests.kt b/src/test/kotlin/org/opensearch/commons/alerting/AlertTests.kt
index cf6a4947..8b4db7c4 100644
--- a/src/test/kotlin/org/opensearch/commons/alerting/AlertTests.kt
+++ b/src/test/kotlin/org/opensearch/commons/alerting/AlertTests.kt
@@ -23,6 +23,7 @@ class AlertTests {
         assertEquals(templateArgs[Alert.START_TIME_FIELD], alert.startTime.toEpochMilli(), "Template args start time does not")
         assertEquals(templateArgs[Alert.LAST_NOTIFICATION_TIME_FIELD], null, "Template args last notification time does not match")
         assertEquals(templateArgs[Alert.SEVERITY_FIELD], alert.severity, "Template args severity does not match")
+        assertEquals(templateArgs[Alert.CLUSTERS_FIELD], alert.clusters?.joinToString(","), "Template args clusters does not match")
     }
 
     @Test
@@ -40,6 +41,7 @@ class AlertTests {
         assertEquals(templateArgs[Alert.START_TIME_FIELD], alert.startTime.toEpochMilli(), "Template args start time does not")
         assertEquals(templateArgs[Alert.LAST_NOTIFICATION_TIME_FIELD], null, "Template args last notification time does not match")
         assertEquals(templateArgs[Alert.SEVERITY_FIELD], alert.severity, "Template args severity does not match")
+        assertEquals(templateArgs[Alert.CLUSTERS_FIELD], alert.clusters?.joinToString(","), "Template args clusters does not match")
         assertEquals(
             templateArgs[Alert.BUCKET_KEYS],
             alert.aggregationResultBucket?.bucketKeys?.joinToString(","),
diff --git a/src/test/kotlin/org/opensearch/commons/alerting/TestHelpers.kt b/src/test/kotlin/org/opensearch/commons/alerting/TestHelpers.kt
index 43196200..e95c88d8 100644
--- a/src/test/kotlin/org/opensearch/commons/alerting/TestHelpers.kt
+++ b/src/test/kotlin/org/opensearch/commons/alerting/TestHelpers.kt
@@ -527,9 +527,11 @@ fun assertUserNull(monitor: Monitor) {
 fun randomAlert(monitor: Monitor = randomQueryLevelMonitor()): Alert {
     val trigger = randomQueryLevelTrigger()
     val actionExecutionResults = mutableListOf(randomActionExecutionResult(), randomActionExecutionResult())
+    val clusterCount = (-1..5).random()
+    val clusters = if (clusterCount == -1) null else (0..clusterCount).map { "index-$it" }
     return Alert(
         monitor, trigger, Instant.now().truncatedTo(ChronoUnit.MILLIS), null,
-        actionExecutionResults = actionExecutionResults
+        actionExecutionResults = actionExecutionResults, clusters = clusters
     )
 }
 
diff --git a/src/test/kotlin/org/opensearch/commons/alerting/model/XContentTests.kt b/src/test/kotlin/org/opensearch/commons/alerting/model/XContentTests.kt
index 7c52ff42..e56d4aab 100644
--- a/src/test/kotlin/org/opensearch/commons/alerting/model/XContentTests.kt
+++ b/src/test/kotlin/org/opensearch/commons/alerting/model/XContentTests.kt
@@ -450,7 +450,8 @@ class XContentTests {
             errorMessage = "some error",
             lastNotificationTime = Instant.now(),
             workflowId = "",
-            executionId = ""
+            executionId = "",
+            clusters = listOf()
         )
         assertEquals("Round tripping alert doesn't work", alert.triggerName, "NoOp trigger")
     }
@@ -462,7 +463,8 @@ class XContentTests {
             "\"state\":\"ACTIVE\",\"error_message\":null,\"alert_history\":[],\"severity\":\"1\",\"action_execution_results\"" +
             ":[{\"action_id\":\"ghe1-XQBySl0wQKDBkOG\",\"last_execution_time\":1601917224583,\"throttled_count\":-1478015168}," +
             "{\"action_id\":\"gxe1-XQBySl0wQKDBkOH\",\"last_execution_time\":1601917224583,\"throttled_count\":-768533744}]," +
-            "\"start_time\":1601917224599,\"last_notification_time\":null,\"end_time\":null,\"acknowledged_time\":null}"
+            "\"start_time\":1601917224599,\"last_notification_time\":null,\"end_time\":null,\"acknowledged_time\":null," +
+            "\"clusters\":[\"cluster-1\",\"cluster-2\"]}"
         val parsedAlert = Alert.parse(parser(alertStr))
         OpenSearchTestCase.assertNull(parsedAlert.monitorUser)
     }
@@ -475,7 +477,8 @@ class XContentTests {
                 "\"state\":\"ACTIVE\",\"error_message\":null,\"alert_history\":[],\"severity\":\"1\",\"action_execution_results\"" +
                 ":[{\"action_id\":\"ghe1-XQBySl0wQKDBkOG\",\"last_execution_time\":1601917224583,\"throttled_count\":-1478015168}," +
                 "{\"action_id\":\"gxe1-XQBySl0wQKDBkOH\",\"last_execution_time\":1601917224583,\"throttled_count\":-768533744}]," +
-                "\"start_time\":1601917224599,\"last_notification_time\":null,\"end_time\":null,\"acknowledged_time\":null}"
+                "\"start_time\":1601917224599,\"last_notification_time\":null,\"end_time\":null,\"acknowledged_time\":null," +
+                "\"clusters\":[\"cluster-1\",\"cluster-2\"]}"
         val parsedAlert = Alert.parse(parser(alertStr))
         OpenSearchTestCase.assertNull(parsedAlert.monitorUser)
     }