diff --git a/specification/datamigration/resource-manager/Microsoft.DataMigration/preview/2018-07-15-preview/definitions/Tasks.json b/specification/datamigration/resource-manager/Microsoft.DataMigration/preview/2018-07-15-preview/definitions/Tasks.json
index 7a27c3a1a67a..7ad603981325 100644
--- a/specification/datamigration/resource-manager/Microsoft.DataMigration/preview/2018-07-15-preview/definitions/Tasks.json
+++ b/specification/datamigration/resource-manager/Microsoft.DataMigration/preview/2018-07-15-preview/definitions/Tasks.json
@@ -60,6 +60,13 @@
             "$ref": "./Commands.json#/definitions/CommandProperties"
           },
           "readOnly": true
+        },
+        "clientData": {
+          "type": "object",
+          "description": "Key value pairs of client data to attach meta data information to task",
+          "additionalProperties": {
+            "type": "string"
+          }
         }
       },
       "required": [ "taskType" ],