diff --git a/specification/apicenter/ApiCenter.Management/ApiDefinition.tsp b/specification/apicenter/ApiCenter.Management/ApiDefinition.tsp
index 9bd2fcbc2869..c621c0a52e81 100644
--- a/specification/apicenter/ApiCenter.Management/ApiDefinition.tsp
+++ b/specification/apicenter/ApiCenter.Management/ApiDefinition.tsp
@@ -41,10 +41,9 @@ interface ApiDefinitions {
   @doc("Returns a collection of API definitions.")
   list is ArmResourceListByParent<ApiDefinition>;
   @doc("Imports the API specification.")
-  importSpecification is ArmResourceActionAsync<
+  importSpecification is ArmResourceActionNoResponseContentAsync<
     ApiDefinition,
-    ApiSpecImportRequest,
-    OkResponse
+    ApiSpecImportRequest
   >;
   @doc("Exports the API specification.")
   exportSpecification is ArmResourceActionAsync<
diff --git a/specification/apicenter/ApiCenter.Management/examples/2024-03-01/ApiDefinitions_ImportSpecification.json b/specification/apicenter/ApiCenter.Management/examples/2024-03-01/ApiDefinitions_ImportSpecification.json
index b3b497508524..18a7861cec0d 100644
--- a/specification/apicenter/ApiCenter.Management/examples/2024-03-01/ApiDefinitions_ImportSpecification.json
+++ b/specification/apicenter/ApiCenter.Management/examples/2024-03-01/ApiDefinitions_ImportSpecification.json
@@ -20,7 +20,6 @@
     }
   },
   "responses": {
-    "200": {},
     "202": {
       "headers": {
         "location": "https://..."
diff --git a/specification/apicenter/ApiCenter.Management/examples/2024-03-15-preview/ApiDefinitions_ImportSpecification.json b/specification/apicenter/ApiCenter.Management/examples/2024-03-15-preview/ApiDefinitions_ImportSpecification.json
index c7ec03bab582..c5e51564d8cb 100644
--- a/specification/apicenter/ApiCenter.Management/examples/2024-03-15-preview/ApiDefinitions_ImportSpecification.json
+++ b/specification/apicenter/ApiCenter.Management/examples/2024-03-15-preview/ApiDefinitions_ImportSpecification.json
@@ -20,7 +20,6 @@
     }
   },
   "responses": {
-    "200": {},
     "202": {
       "headers": {
         "location": "https://..."
diff --git a/specification/apicenter/ApiCenter.Management/examples/2024-06-01-preview/ApiDefinitions_ImportSpecification.json b/specification/apicenter/ApiCenter.Management/examples/2024-06-01-preview/ApiDefinitions_ImportSpecification.json
index e5b9fc19fee7..9ce5b698f26d 100644
--- a/specification/apicenter/ApiCenter.Management/examples/2024-06-01-preview/ApiDefinitions_ImportSpecification.json
+++ b/specification/apicenter/ApiCenter.Management/examples/2024-06-01-preview/ApiDefinitions_ImportSpecification.json
@@ -20,7 +20,6 @@
     }
   },
   "responses": {
-    "200": {},
     "202": {
       "headers": {
         "location": "https://..."
diff --git a/specification/apicenter/ApiCenter.Management/tspconfig.yaml b/specification/apicenter/ApiCenter.Management/tspconfig.yaml
index e253d1ff4d9e..3190e70a8ef9 100644
--- a/specification/apicenter/ApiCenter.Management/tspconfig.yaml
+++ b/specification/apicenter/ApiCenter.Management/tspconfig.yaml
@@ -15,6 +15,7 @@ options:
     namespace: "com.azure.resourcemanager.apicenter"
     service-name: "Api Center"
     flavor: azure
+    use-object-for-unknown: true
   "@azure-typespec/http-client-csharp-mgmt":
     namespace: "Azure.ResourceManager.ApiCenter"
     emitter-output-dir: "{output-dir}/{service-dir}/{namespace}"
diff --git a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/apicenter.json b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/apicenter.json
index 6f16093a9779..5c4607d71f9c 100644
--- a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/apicenter.json
+++ b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/apicenter.json
@@ -3148,9 +3148,6 @@
           }
         ],
         "responses": {
-          "200": {
-            "description": "The request has succeeded."
-          },
           "202": {
             "description": "Resource operation accepted.",
             "headers": {
@@ -4850,10 +4847,6 @@
         "url"
       ]
     },
-    "TypeSpec.Http.OkResponse": {
-      "type": "object",
-      "description": "The request has succeeded."
-    },
     "Workspace": {
       "type": "object",
       "description": "Workspace entity.",
diff --git a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/examples/ApiDefinitions_ImportSpecification.json b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/examples/ApiDefinitions_ImportSpecification.json
index c7ec03bab582..c5e51564d8cb 100644
--- a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/examples/ApiDefinitions_ImportSpecification.json
+++ b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-03-15-preview/examples/ApiDefinitions_ImportSpecification.json
@@ -20,7 +20,6 @@
     }
   },
   "responses": {
-    "200": {},
     "202": {
       "headers": {
         "location": "https://..."
diff --git a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/apicenter.json b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/apicenter.json
index 9ef7353320e0..95fab491c674 100644
--- a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/apicenter.json
+++ b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/apicenter.json
@@ -3516,9 +3516,6 @@
           }
         ],
         "responses": {
-          "200": {
-            "description": "The request has succeeded."
-          },
           "202": {
             "description": "Resource operation accepted.",
             "headers": {
@@ -5419,10 +5416,6 @@
         "url"
       ]
     },
-    "TypeSpec.Http.OkResponse": {
-      "type": "object",
-      "description": "The request has succeeded."
-    },
     "Workspace": {
       "type": "object",
       "description": "Workspace entity.",
diff --git a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/examples/ApiDefinitions_ImportSpecification.json b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/examples/ApiDefinitions_ImportSpecification.json
index e5b9fc19fee7..9ce5b698f26d 100644
--- a/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/examples/ApiDefinitions_ImportSpecification.json
+++ b/specification/apicenter/resource-manager/Microsoft.ApiCenter/preview/2024-06-01-preview/examples/ApiDefinitions_ImportSpecification.json
@@ -20,7 +20,6 @@
     }
   },
   "responses": {
-    "200": {},
     "202": {
       "headers": {
         "location": "https://..."
diff --git a/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/apicenter.json b/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/apicenter.json
index 2dda5e2b5ddf..9f69bdea31b9 100644
--- a/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/apicenter.json
+++ b/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/apicenter.json
@@ -2959,9 +2959,6 @@
           }
         ],
         "responses": {
-          "200": {
-            "description": "The request has succeeded."
-          },
           "202": {
             "description": "Resource operation accepted.",
             "headers": {
@@ -4585,10 +4582,6 @@
         "url"
       ]
     },
-    "TypeSpec.Http.OkResponse": {
-      "type": "object",
-      "description": "The request has succeeded."
-    },
     "Workspace": {
       "type": "object",
       "description": "Workspace entity.",
diff --git a/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/examples/ApiDefinitions_ImportSpecification.json b/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/examples/ApiDefinitions_ImportSpecification.json
index b3b497508524..18a7861cec0d 100644
--- a/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/examples/ApiDefinitions_ImportSpecification.json
+++ b/specification/apicenter/resource-manager/Microsoft.ApiCenter/stable/2024-03-01/examples/ApiDefinitions_ImportSpecification.json
@@ -20,7 +20,6 @@
     }
   },
   "responses": {
-    "200": {},
     "202": {
       "headers": {
         "location": "https://..."