diff --git a/specification/cognitiveservices/data-plane/FormRecognizer/preview/v1.0/FormRecognizer.json b/specification/cognitiveservices/data-plane/FormRecognizer/preview/v1.0/FormRecognizer.json
index febeee2f6215..e0226e528af1 100644
--- a/specification/cognitiveservices/data-plane/FormRecognizer/preview/v1.0/FormRecognizer.json
+++ b/specification/cognitiveservices/data-plane/FormRecognizer/preview/v1.0/FormRecognizer.json
@@ -296,6 +296,26 @@
           "maxLength": 2048,
           "minLength": 0,
           "type": "string"
+        },
+        "sourceFilter":{
+          "$ref":"#/definitions/TrainSourceFilter",
+          "description":"Get or set filter to further search the\r\nsource path for content."
+        }
+      }
+    },
+    "TrainSourceFilter":{
+      "description":"Filters to be applied when traversing a data source.",
+      "type":"object",
+      "properties":{
+        "prefix":{
+          "description":"A case-sensitive prefix string to filter content\r\nunder the source location. For e.g., when using a Azure Blob\r\nUri use the prefix to restrict subfolders for content.",
+          "maxLength":128,
+          "minLength":0,
+          "type":"string"
+        },
+        "includeSubFolders":{
+          "description":"A flag to indicate of sub folders within the set of\r\nprefix folders will also need to included when searching\r\nfor content to be preprocessed.",
+          "type":"boolean"
         }
       }
     },