diff --git a/specification/ai/Azure.AI.Projects/datasets/routes.tsp b/specification/ai/Azure.AI.Projects/datasets/routes.tsp
index 3570aeaf96ed..00a615fbcb16 100644
--- a/specification/ai/Azure.AI.Projects/datasets/routes.tsp
+++ b/specification/ai/Azure.AI.Projects/datasets/routes.tsp
@@ -1,3 +1,4 @@
+import "@typespec/http";
 import "@typespec/rest";
 import "@azure-tools/typespec-autorest";
 import "@typespec/versioning";
@@ -50,12 +51,20 @@ interface Datasets
       ListLatestDataSetVersionParameters,
       ListDatasetVersionsParameters
     > {
-  /**
-   * Create or start a pending upload of a dataset
-   */
+  @doc("Create or start a pending upload of a dataset for a specific version.")
   startPendingUpload is ServicePatterns.VersionedResourceAction<
     DatasetVersion,
     PendingUploadRequest,
     PendingUploadResponse
   >;
+
+  @doc("Create or start a pending upload of a dataset. The dataset version will be generated by service.")
+  @Rest.actionSeparator("/")
+  @Rest.action("startPendingUpload")
+  @Http.post
+  startPendingUploadAutoIncrement is ServicePatterns.BuildingBlocks.RepeatableCoreOps.ResourceAction<
+    DatasetVersion,
+    PendingUploadRequest,
+    PendingUploadResponse
+  >;
 }
diff --git a/specification/ai/data-plane/Azure.AI.Projects/preview/2025-05-01-preview/azure-ai-projects-1dp.json b/specification/ai/data-plane/Azure.AI.Projects/preview/2025-05-01-preview/azure-ai-projects-1dp.json
index ffbd0747b3b6..b6826fa2b09f 100644
--- a/specification/ai/data-plane/Azure.AI.Projects/preview/2025-05-01-preview/azure-ai-projects-1dp.json
+++ b/specification/ai/data-plane/Azure.AI.Projects/preview/2025-05-01-preview/azure-ai-projects-1dp.json
@@ -553,6 +553,92 @@
         }
       }
     },
+    "/datasets/{name}/startPendingUpload": {
+      "post": {
+        "operationId": "Datasets_StartPendingUploadAutoIncrement",
+        "description": "Create or start a pending upload of a dataset. The dataset version will be generated by service.",
+        "parameters": [
+          {
+            "$ref": "#/parameters/Azure.Core.Foundations.ApiVersionParameter"
+          },
+          {
+            "name": "name",
+            "in": "path",
+            "description": "The name of the resource",
+            "required": true,
+            "type": "string"
+          },
+          {
+            "$ref": "#/parameters/Azure.Core.RepeatabilityRequestHeaders.repeatabilityRequestId"
+          },
+          {
+            "$ref": "#/parameters/Azure.Core.RepeatabilityRequestHeaders.repeatabilityFirstSent"
+          },
+          {
+            "$ref": "#/parameters/Azure.Core.ClientRequestIdHeader"
+          },
+          {
+            "name": "body",
+            "in": "body",
+            "required": true,
+            "schema": {
+              "$ref": "#/definitions/PendingUploadRequest"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "The request has succeeded.",
+            "schema": {
+              "$ref": "#/definitions/PendingUploadResponse"
+            },
+            "headers": {
+              "Repeatability-Result": {
+                "type": "string",
+                "description": "Indicates whether the repeatable request was accepted or rejected.",
+                "enum": [
+                  "accepted",
+                  "rejected"
+                ],
+                "x-ms-enum": {
+                  "name": "RepeatabilityResult",
+                  "modelAsString": false,
+                  "values": [
+                    {
+                      "name": "accepted",
+                      "value": "accepted",
+                      "description": "If the request was accepted and the server guarantees that the server state reflects a single execution of the operation."
+                    },
+                    {
+                      "name": "rejected",
+                      "value": "rejected",
+                      "description": "If the request was rejected because the combination of Repeatability-First-Sent and Repeatability-Request-ID were invalid\nor because the Repeatability-First-Sent value was outside the range of values held by the server."
+                    }
+                  ]
+                }
+              },
+              "x-ms-client-request-id": {
+                "type": "string",
+                "format": "uuid",
+                "description": "An opaque, globally-unique, client-generated string identifier for the request."
+              }
+            }
+          },
+          "default": {
+            "description": "An unexpected error response.",
+            "schema": {
+              "$ref": "#/definitions/Azure.Core.Foundations.ErrorResponse"
+            },
+            "headers": {
+              "x-ms-error-code": {
+                "type": "string",
+                "description": "String error code indicating what went wrong."
+              }
+            }
+          }
+        }
+      }
+    },
     "/datasets/{name}/versions": {
       "get": {
         "operationId": "Datasets_ListVersions",
@@ -887,7 +973,7 @@
     "/datasets/{name}/versions/{version}/startPendingUpload": {
       "post": {
         "operationId": "Datasets_StartPendingUpload",
-        "description": "Create or start a pending upload of a dataset",
+        "description": "Create or start a pending upload of a dataset for a specific version.",
         "parameters": [
           {
             "$ref": "#/parameters/Azure.Core.Foundations.ApiVersionParameter"