diff --git a/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/examples/Library_Append.json b/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/examples/Library_Append.json
index 4226a3127d75..d9a0eb6dc607 100644
--- a/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/examples/Library_Append.json
+++ b/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/examples/Library_Append.json
@@ -2,6 +2,7 @@
   "parameters": {
     "endpoint": "exampleWorkspace.dev.azuresynapse.net",
     "libraryName": "exampleLibraryName.jar",
+    "comp": "appendblock",
     "api-version": "2019-06-01-preview",
     "content": "file binary chunk",
     "x-ms-blob-condition-appendpos": 12324
diff --git a/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/library.json b/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/library.json
index d2943c7752a4..0a1acf5e94c2 100644
--- a/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/library.json
+++ b/specification/synapse/data-plane/Microsoft.Synapse/preview/2019-06-01-preview/library.json
@@ -295,6 +295,7 @@
           },
           {
             "name": "x-ms-blob-condition-appendpos",
+            "x-ms-client-name": "blobConditionAppendPosition",
             "in": "header",
             "description": "Set this header to a byte offset at which the block is expected to be appended. The request succeeds only if the current offset matches this value. Otherwise, the request fails with the AppendPositionConditionNotMet error (HTTP status code 412 – Precondition Failed)",
             "required": false,
@@ -313,7 +314,18 @@
             }
           }
         }
-      }
+      },
+      "parameters": [
+        {
+          "name": "comp",
+          "in": "query",
+          "required": true,
+          "type": "string",
+          "enum": [
+            "appendblock"
+          ]
+        }
+      ]
     }
   },
   "definitions": {