diff --git a/.changeset/update-workflows-sdk.md b/.changeset/update-workflows-sdk.md
new file mode 100644
index 00000000..8475660d
--- /dev/null
+++ b/.changeset/update-workflows-sdk.md
@@ -0,0 +1,5 @@
+---
+"@llamaindex/workflows-client": minor
+---
+
+
diff --git a/packages/workflows-client/openapi.json b/packages/workflows-client/openapi.json
index 1214c778..ea09e785 100644
--- a/packages/workflows-client/openapi.json
+++ b/packages/workflows-client/openapi.json
@@ -2,7 +2,7 @@
   "openapi": "3.0.0",
   "info": {
     "title": "Workflows API",
-    "version": "2.8.3"
+    "version": "2.9.0"
   },
   "components": {
     "schemas": {
@@ -337,7 +337,7 @@
     "/events/{handler_id}": {
       "get": {
         "summary": "Stream workflow events",
-        "description": "Streams events produced by a workflow execution. Events are emitted as\nnewline-delimited JSON by default, or as Server-Sent Events when `sse=true`.\nEvent data is returned as an envelope that preserves backward-compatible fields\nand adds metadata for type-safety on the client:\n{\n  \"__is_pydantic\": true,\n  \"value\": <pydantic serialized value>,\n  \"qualified_name\": <python path to pydantic class>,  # deprecated, prefer `mro`\n  \"mro\": [<qualified class names from most to least specific>],\n  \"origin\": \"builtin\" | \"user\"\n}\n\nEvent queue is mutable. Elements are added to the queue by the workflow handler, and removed by any consumer of the queue.\nThe queue is protected by a lock that is acquired by the consumer, so only one consumer of the queue at a time is allowed.\n",
+        "description": "Streams events produced by a workflow execution. Events are emitted as\nnewline-delimited JSON by default, or as Server-Sent Events when `sse=true`.\nEvent data is returned as an envelope that preserves backward-compatible fields\nand adds metadata for type-safety on the client:\n{\n  \"value\": <pydantic serialized value>,\n  \"types\": [<class names from MRO excluding the event class and base Event>],\n  \"type\": <class name>,\n  \"qualified_name\": <python module path + class name>,\n}\n\nEvent queue is mutable. Elements are added to the queue by the workflow handler, and removed by any consumer of the queue.\nThe queue is protected by a lock that is acquired by the consumer, so only one consumer of the queue at a time is allowed.\n",
         "parameters": [
           {
             "in": "path",
@@ -377,6 +377,16 @@
               "default": 1
             },
             "description": "Timeout for acquiring the lock to iterate over the events."
+          },
+          {
+            "in": "query",
+            "name": "include_qualified_name",
+            "required": false,
+            "schema": {
+              "type": "boolean",
+              "default": true
+            },
+            "description": "If true, include the qualified name of the event in the response body."
           }
         ],
         "responses": {
@@ -392,6 +402,17 @@
                       "type": "object",
                       "description": "The event value."
                     },
+                    "type": {
+                      "type": "string",
+                      "description": "The class name of the event."
+                    },
+                    "types": {
+                      "type": "array",
+                      "description": "Superclass names from MRO (excluding the event class and base Event).",
+                      "items": {
+                        "type": "string"
+                      }
+                    },
                     "qualified_name": {
                       "type": "string",
                       "description": "The qualified name of the event."
@@ -399,7 +420,7 @@
                   },
                   "required": [
                     "value",
-                    "qualified_name"
+                    "type"
                   ]
                 }
               }
@@ -432,14 +453,30 @@
                 "type": "object",
                 "properties": {
                   "event": {
-                    "type": "string",
-                    "description": "Serialized event in JSON format.",
-                    "examples": {
-                      "type": "event_name",
-                      "data": {
-                        "key": "value"
+                    "description": "Serialized event. Accepts object or JSON-encoded string for backward compatibility.",
+                    "oneOf": [
+                      {
+                        "type": "string",
+                        "description": "JSON string of the event envelope or value.",
+                        "examples": [
+                          "{\"type\": \"ExternalEvent\", \"value\": {\"response\": \"hi\"}}"
+                        ]
+                      },
+                      {
+                        "type": "object",
+                        "properties": {
+                          "type": {
+                            "type": "string",
+                            "description": "The class name of the event."
+                          },
+                          "value": {
+                            "type": "object",
+                            "description": "The event value object (preferred over data)."
+                          }
+                        },
+                        "additionalProperties": true
                       }
-                    }
+                    ]
                   },
                   "step": {
                     "type": "string",
diff --git a/packages/workflows-client/src/generated/client/utils.gen.ts b/packages/workflows-client/src/generated/client/utils.gen.ts
index b4bcc4d1..4c48a9ee 100644
--- a/packages/workflows-client/src/generated/client/utils.gen.ts
+++ b/packages/workflows-client/src/generated/client/utils.gen.ts
@@ -12,9 +12,8 @@ import { getUrl } from '../core/utils.gen';
 import type { Client, ClientOptions, Config, RequestOptions } from './types.gen';
 
 export const createQuerySerializer = <T = unknown>({
-  allowReserved,
-  array,
-  object,
+  parameters = {},
+  ...args
 }: QuerySerializerOptions = {}) => {
   const querySerializer = (queryParams: T) => {
     const search: string[] = [];
@@ -26,29 +25,31 @@ export const createQuerySerializer = <T = unknown>({
           continue;
         }
 
+        const options = parameters[name] || args;
+
         if (Array.isArray(value)) {
           const serializedArray = serializeArrayParam({
-            allowReserved,
+            allowReserved: options.allowReserved,
             explode: true,
             name,
             style: 'form',
             value,
-            ...array,
+            ...options.array,
           });
           if (serializedArray) search.push(serializedArray);
         } else if (typeof value === 'object') {
           const serializedObject = serializeObjectParam({
-            allowReserved,
+            allowReserved: options.allowReserved,
             explode: true,
             name,
             style: 'deepObject',
             value: value as Record<string, unknown>,
-            ...object,
+            ...options.object,
           });
           if (serializedObject) search.push(serializedObject);
         } else {
           const serializedPrimitive = serializePrimitiveParam({
-            allowReserved,
+            allowReserved: options.allowReserved,
             name,
             value: value as string,
           });
diff --git a/packages/workflows-client/src/generated/core/bodySerializer.gen.ts b/packages/workflows-client/src/generated/core/bodySerializer.gen.ts
index 49cd8925..552b50f7 100644
--- a/packages/workflows-client/src/generated/core/bodySerializer.gen.ts
+++ b/packages/workflows-client/src/generated/core/bodySerializer.gen.ts
@@ -10,11 +10,19 @@ export type QuerySerializer = (query: Record<string, unknown>) => string;
 
 export type BodySerializer = (body: any) => any;
 
-export interface QuerySerializerOptions {
+type QuerySerializerOptionsObject = {
   allowReserved?: boolean;
-  array?: SerializerOptions<ArrayStyle>;
-  object?: SerializerOptions<ObjectStyle>;
-}
+  array?: Partial<SerializerOptions<ArrayStyle>>;
+  object?: Partial<SerializerOptions<ObjectStyle>>;
+};
+
+export type QuerySerializerOptions = QuerySerializerOptionsObject & {
+  /**
+   * Per-parameter serialization overrides. When provided, these settings
+   * override the global array/object settings for specific parameter names.
+   */
+  parameters?: Record<string, QuerySerializerOptionsObject>;
+};
 
 const serializeFormDataPair = (
   data: FormData,
diff --git a/packages/workflows-client/src/generated/sdk.gen.ts b/packages/workflows-client/src/generated/sdk.gen.ts
index 01b1d506..8103f9cb 100644
--- a/packages/workflows-client/src/generated/sdk.gen.ts
+++ b/packages/workflows-client/src/generated/sdk.gen.ts
@@ -100,11 +100,10 @@ export const getResultsByHandlerId = <ThrowOnError extends boolean = false>(opti
  * Event data is returned as an envelope that preserves backward-compatible fields
  * and adds metadata for type-safety on the client:
  * {
- * "__is_pydantic": true,
  * "value": <pydantic serialized value>,
- * "qualified_name": <python path to pydantic class>,  # deprecated, prefer `mro`
- * "mro": [<qualified class names from most to least specific>],
- * "origin": "builtin" | "user"
+ * "types": [<class names from MRO excluding the event class and base Event>],
+ * "type": <class name>,
+ * "qualified_name": <python module path + class name>,
  * }
  *
  * Event queue is mutable. Elements are added to the queue by the workflow handler, and removed by any consumer of the queue.
diff --git a/packages/workflows-client/src/generated/types.gen.ts b/packages/workflows-client/src/generated/types.gen.ts
index b4aa090a..935ce111 100644
--- a/packages/workflows-client/src/generated/types.gen.ts
+++ b/packages/workflows-client/src/generated/types.gen.ts
@@ -255,6 +255,10 @@ export type GetEventsByHandlerIdData = {
          * Timeout for acquiring the lock to iterate over the events.
          */
         acquire_timeout?: number;
+        /**
+         * If true, include the qualified name of the event in the response body.
+         */
+        include_qualified_name?: boolean;
     };
     url: '/events/{handler_id}';
 };
@@ -277,10 +281,18 @@ export type GetEventsByHandlerIdResponses = {
         value: {
             [key: string]: unknown;
         };
+        /**
+         * The class name of the event.
+         */
+        type: string;
+        /**
+         * Superclass names from MRO (excluding the event class and base Event).
+         */
+        types?: Array<string>;
         /**
          * The qualified name of the event.
          */
-        qualified_name: string;
+        qualified_name?: string;
     };
 };
 
@@ -289,9 +301,23 @@ export type GetEventsByHandlerIdResponse = GetEventsByHandlerIdResponses[keyof G
 export type PostEventsByHandlerIdData = {
     body: {
         /**
-         * Serialized event in JSON format.
+         * Serialized event. Accepts object or JSON-encoded string for backward compatibility.
          */
-        event: string;
+        event: string | {
+            /**
+             * The class name of the event.
+             */
+            type?: string;
+            /**
+             * The event value object (preferred over data).
+             */
+            value?: {
+                [key: string]: unknown;
+            };
+            [key: string]: unknown | string | {
+                [key: string]: unknown;
+            } | undefined;
+        };
         /**
          * Optional target step name. If not provided, event is sent to all steps.
          */