diff --git a/packages/core-internal/src/types/spec.types.2026-07-28.ts b/packages/core-internal/src/types/spec.types.2026-07-28.ts
index a8ec4f8077..f4430b850f 100644
--- a/packages/core-internal/src/types/spec.types.2026-07-28.ts
+++ b/packages/core-internal/src/types/spec.types.2026-07-28.ts
@@ -3,7 +3,7 @@
  *
  * Source: https://github.com/modelcontextprotocol/modelcontextprotocol
  * Pulled from: https://raw.githubusercontent.com/modelcontextprotocol/modelcontextprotocol/main/schema/draft/schema.ts
- * Last updated from commit: f68d864a813754e188c6df52dcc5772a12f96c63
+ * Last updated from commit: 71e306956a4959c9655e5036be215d41986596e6
  *
  * DO NOT EDIT THIS FILE MANUALLY. Changes will be overwritten by automated updates.
  * To update this file, run: pnpm run fetch:spec-types 2026-07-28
@@ -82,12 +82,19 @@ export interface RequestMetaObject extends MetaObject {
      */
     'io.modelcontextprotocol/protocolVersion': string;
     /**
-     * Identifies the client software making the request. Required.
+     * Identifies the client software making the request. Clients SHOULD
+     * include this field on every request unless specifically configured not
+     * to do so.
      *
      * The {@link Implementation} schema requires `name` and `version`; other
      * fields are optional.
+     *
+     * The value is self-reported by the client and is not verified by the
+     * protocol. It is intended for display, logging, and debugging. Servers
+     * SHOULD NOT use it to change their behavior, and SHOULD NOT rely on it for
+     * security decisions.
      */
-    'io.modelcontextprotocol/clientInfo': Implementation;
+    'io.modelcontextprotocol/clientInfo'?: Implementation;
     /**
      * The client's capabilities for this specific request. Required.
      *
@@ -133,6 +140,30 @@ export interface NotificationMetaObject extends MetaObject {
     'io.modelcontextprotocol/subscriptionId'?: RequestId;
 }
 
+/**
+ * Extends {@link MetaObject} with additional result-specific fields. All key naming rules from `MetaObject` apply.
+ *
+ * @see {@link MetaObject} for key naming rules and reserved prefixes.
+ * @see [General fields: `_meta`](/specification/draft/basic/index#meta) for more details.
+ * @category Common Types
+ */
+export interface ResultMetaObject extends MetaObject {
+    /**
+     * Identifies the server software producing the response. Servers SHOULD
+     * include this field on every response unless specifically configured not
+     * to do so.
+     *
+     * The {@link Implementation} schema requires `name` and `version`; other
+     * fields are optional.
+     *
+     * The value is self-reported by the server and is not verified by the
+     * protocol. It is intended for display, logging, and debugging. Clients
+     * SHOULD NOT use it to change their behavior, and SHOULD NOT rely on it for
+     * security decisions.
+     */
+    'io.modelcontextprotocol/serverInfo'?: Implementation;
+}
+
 /**
  * A progress token, used to associate progress notifications with the original request.
  *
@@ -197,7 +228,7 @@ export type ResultType = 'complete' | 'input_required' | string;
  * @category Common Types
  */
 export interface Result {
-    _meta?: MetaObject;
+    _meta?: ResultMetaObject;
     /**
      * Indicates the type of the result, which allows the client to determine
      * how to parse the result object.
@@ -650,10 +681,6 @@ export interface DiscoverResult extends CacheableResult {
      * The capabilities of the server.
      */
     capabilities: ServerCapabilities;
-    /**
-     * Information about the server software implementation.
-     */
-    serverInfo: Implementation;
     /**
      * Natural-language guidance describing the server and its features.
      *
@@ -1284,13 +1311,13 @@ export interface SubscriptionsListenRequest extends JSONRPCRequest {
 }
 
 /**
- * Extends {@link MetaObject} with the subscription-stream identifier carried by a
+ * Extends {@link ResultMetaObject} with the subscription-stream identifier carried by a
  * {@link SubscriptionsListenResult}. All key naming rules from `MetaObject` apply.
  *
  * @see {@link MetaObject} for key naming rules and reserved prefixes.
  * @category `subscriptions/listen`
  */
-export interface SubscriptionsListenResultMeta extends MetaObject {
+export interface SubscriptionsListenResultMeta extends ResultMetaObject {
     /**
      * Identifies the subscription stream this response closes, so the client can
      * correlate it with the originating subscription — mirroring the same key on
@@ -1333,10 +1360,16 @@ export interface SubscriptionsAcknowledgedNotificationParams extends Notificatio
 }
 
 /**
- * Sent by the server as the first message on a
- * {@link SubscriptionsListenRequest | subscriptions/listen} stream to acknowledge
- * that the subscription has been established and to report which notification
- * types it agreed to honor.
+ * Sent by the server to acknowledge that a
+ * {@link SubscriptionsListenRequest | subscriptions/listen} subscription has been
+ * established and to report which notification types it agreed to honor.
+ *
+ * This notification MUST be the first message the server sends carrying the
+ * subscription's ID in `io.modelcontextprotocol/subscriptionId`. The server MUST
+ * NOT send any notification on the subscription before acknowledging it. On
+ * stdio, where every subscription shares one channel, this ordering is defined
+ * per subscription ID and not per channel: messages belonging to other
+ * subscriptions MAY be interleaved before it.
  *
  * @example Listen acknowledged
  * {@includeCode ./examples/SubscriptionsAcknowledgedNotification/listen-acknowledged.json}