Default draft protocol support: sessionless + handshake-less (SEP-2575 + SEP-2567) (#1610)

src/ModelContextProtocol.Core/Protocol/SubscriptionsAcknowledgedNotificationParams.cs

@@ -0,0 +1,27 @@
+using System.Text.Json.Serialization;
+
+namespace ModelContextProtocol.Protocol;
+
+/// <summary>
+/// Represents the parameters sent with a <see cref="NotificationMethods.SubscriptionsAcknowledgedNotification"/>.
+/// </summary>
+/// <remarks>
+/// <para>
+/// Introduced by the draft protocol revision (SEP-2575). This notification is the first message on a
+/// <see cref="RequestMethods.SubscriptionsListen"/> response stream and informs the client which
+/// subset of requested notification types the server has agreed to deliver.
+/// </para>
+/// </remarks>
+public sealed class SubscriptionsAcknowledgedNotificationParams
+{
+    /// <summary>
+    /// Gets or sets the notification subscriptions the server has agreed to honor.
+    /// </summary>
+    /// <remarks>
+    /// Only includes notification types the server actually supports. If the client requested an
+    /// unsupported notification type (e.g., <c>promptsListChanged</c> when the server has no prompts),
+    /// it is omitted from this set.
+    /// </remarks>
+    [JsonPropertyName("notifications")]
+    public required SubscriptionsListenNotifications Notifications { get; set; }
+}