Add open api docs

openapi/openapiv2.json

@@ -9778,9 +9778,23 @@
           "type": "string",
           "format": "int64",
           "description": "If non zero, indicates the server has discarded the workflow task that was being responded to.\nWill be the event ID of the last workflow task started event in the history before the new workflow task.\nServer is only expected to discard a workflow task if it could not have modified the workflow state."
+        },
+        "capabilities": {
+          "$ref": "#/definitions/v1RespondWorkflowTaskCompletedResponseCapabilities",
+          "description": "All capabilities the SDK supports."
         }
       }
     },
+    "v1RespondWorkflowTaskCompletedResponseCapabilities": {
+      "type": "object",
+      "properties": {
+        "discardSpeculativeWorkflowTaskWithCommandEvents": {
+          "type": "boolean",
+          "title": "True if the SDK can handle speculative workflow task with command events.\nIf true, the server may chosse, at its discretion, to discard a speculative workflow task\neven if that speculative task included command events the SDK had not previouly processed"
+        }
+      },
+      "description": "SDK capability details."
+    },
     "v1RespondWorkflowTaskFailedResponse": {
       "type": "object"
     },