Obsolete Roots, Sampling, and Logging surface area per SEP-2577 (#1651)

Co-authored-by: Tarek Mahmoud Sayed <tarekms@ntdev.microsoft.com>

src/ModelContextProtocol.Core/Protocol/ClientCapabilities.cs

@@ -52,6 +52,7 @@ public sealed class ClientCapabilities
     /// </para>
     /// </remarks>
     [JsonPropertyName("roots")]
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public RootsCapability? Roots { get; set; }
 
     /// <summary>
@@ -59,6 +60,7 @@ public sealed class ClientCapabilities
     /// supports issuing requests to an LLM on behalf of the server.
     /// </summary>
     [JsonPropertyName("sampling")]
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public SamplingCapability? Sampling { get; set; }
 
     /// <summary>

src/ModelContextProtocol.Core/Protocol/ContentBlock.cs

@@ -760,6 +760,9 @@ public sealed class ResourceLinkBlock : ContentBlock
 
 /// <summary>Represents a request from the assistant to call a tool.</summary>
 [DebuggerDisplay("Name = {Name}, Id = {Id}")]
+// Sampling support type: this content block only appears inside sampling messages (an assistant tool call),
+// so it is deprecated together with sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class ToolUseContentBlock : ContentBlock
 {
     /// <inheritdoc/>
@@ -789,6 +792,9 @@ public sealed class ToolUseContentBlock : ContentBlock
 
 /// <summary>Represents the result of a tool use, provided by the user back to the assistant.</summary>
 [DebuggerDisplay("{DebuggerDisplay,nq}")]
+// Sampling support type: this content block only appears inside sampling messages (a tool result returned to
+// the assistant), so it is deprecated together with sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class ToolResultContentBlock : ContentBlock
 {
     /// <inheritdoc/>

src/ModelContextProtocol.Core/Protocol/ContextInclusion.cs

@@ -16,6 +16,9 @@ namespace ModelContextProtocol.Protocol;
 /// </para>
 /// </remarks>
 [JsonConverter(typeof(JsonStringEnumConverter<ContextInclusion>))]
+// Sampling support type: only used to select what context to include on sampling (createMessage) requests,
+// so it is deprecated together with sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public enum ContextInclusion
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/CreateMessageRequestParams.cs

@@ -11,6 +11,9 @@ namespace ModelContextProtocol.Protocol;
 /// <remarks>
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </remarks>
+// Sampling support type: "createMessage" is the sampling request, so this is deprecated together with
+// sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class CreateMessageRequestParams : RequestParams
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/CreateMessageResult.cs

@@ -8,6 +8,9 @@ namespace ModelContextProtocol.Protocol;
 /// <remarks>
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </remarks>
+// Sampling support type: "createMessage" is the sampling request, so this result is deprecated together
+// with sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class CreateMessageResult : Result
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/InputRequest.cs

@@ -54,6 +54,7 @@ public sealed class InputRequest
     /// </summary>
     /// <returns>The deserialized sampling parameters, or <see langword="null"/> if the method does not match or params are absent.</returns>
     [JsonIgnore]
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public CreateMessageRequestParams? SamplingParams =>
         string.Equals(Method, RequestMethods.SamplingCreateMessage, StringComparison.Ordinal) && Params is { } p
             ? JsonSerializer.Deserialize(p, McpJsonUtilities.JsonContext.Default.CreateMessageRequestParams)
@@ -76,6 +77,7 @@ public sealed class InputRequest
     /// </summary>
     /// <returns>The deserialized roots list parameters, or <see langword="null"/> if the method does not match or params are absent.</returns>
     [JsonIgnore]
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public ListRootsRequestParams? RootsParams =>
         string.Equals(Method, RequestMethods.RootsList, StringComparison.Ordinal) && Params is { } p
             ? JsonSerializer.Deserialize(p, McpJsonUtilities.JsonContext.Default.ListRootsRequestParams)
@@ -86,6 +88,7 @@ public sealed class InputRequest
     /// </summary>
     /// <param name="requestParams">The sampling request parameters.</param>
     /// <returns>A new <see cref="InputRequest"/> instance.</returns>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static InputRequest ForSampling(CreateMessageRequestParams requestParams)
     {
         Throw.IfNull(requestParams);
@@ -116,6 +119,7 @@ public sealed class InputRequest
     /// </summary>
     /// <param name="requestParams">The roots list request parameters.</param>
     /// <returns>A new <see cref="InputRequest"/> instance.</returns>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static InputRequest ForRootsList(ListRootsRequestParams requestParams)
     {
         Throw.IfNull(requestParams);

src/ModelContextProtocol.Core/Protocol/InputResponse.cs

@@ -58,6 +58,7 @@ public sealed class InputResponse
     /// <see cref="Deserialize{T}"/> when the corresponding <see cref="InputRequest.Method"/> is
     /// <see cref="RequestMethods.SamplingCreateMessage"/>.
     /// </summary>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static JsonTypeInfo<CreateMessageResult> CreateMessageResultJsonTypeInfo => McpJsonUtilities.JsonContext.Default.CreateMessageResult;
 
     /// <summary>
@@ -65,6 +66,7 @@ public sealed class InputResponse
     /// <see cref="Deserialize{T}"/> when the corresponding <see cref="InputRequest.Method"/> is
     /// <see cref="RequestMethods.RootsList"/>.
     /// </summary>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static JsonTypeInfo<ListRootsResult> ListRootsResultJsonTypeInfo => McpJsonUtilities.JsonContext.Default.ListRootsResult;
 
     /// <summary>
@@ -72,6 +74,7 @@ public sealed class InputResponse
     /// </summary>
     /// <param name="result">The sampling result.</param>
     /// <returns>A new <see cref="InputResponse"/> instance.</returns>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static InputResponse FromSamplingResult(CreateMessageResult result)
     {
         Throw.IfNull(result);
@@ -100,6 +103,7 @@ public sealed class InputResponse
     /// </summary>
     /// <param name="result">The roots list result.</param>
     /// <returns>A new <see cref="InputResponse"/> instance.</returns>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static InputResponse FromRootsResult(ListRootsResult result)
     {
         Throw.IfNull(result);

src/ModelContextProtocol.Core/Protocol/ListRootsRequestParams.cs

@@ -8,4 +8,5 @@ namespace ModelContextProtocol.Protocol;
 /// The client responds with a <see cref="ListRootsResult"/> containing the client's roots.
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class ListRootsRequestParams : RequestParams;

src/ModelContextProtocol.Core/Protocol/ListRootsResult.cs

@@ -16,6 +16,7 @@ namespace ModelContextProtocol.Protocol;
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </para>
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class ListRootsResult : Result
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/LoggingCapability.cs

@@ -18,6 +18,7 @@ namespace ModelContextProtocol.Protocol;
 /// specification may extend this capability with additional configuration options.
 /// </para>
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class LoggingCapability
 {
 }

src/ModelContextProtocol.Core/Protocol/LoggingLevel.cs

@@ -1,4 +1,4 @@
-using System.Text.Json.Serialization;
+using System.Text.Json.Serialization;
 
 namespace ModelContextProtocol.Protocol;
 
@@ -9,6 +9,7 @@ namespace ModelContextProtocol.Protocol;
 /// These values map to syslog message severities, as specified in <see href="https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1">RFC-5424</see>.
 /// </remarks>
 [JsonConverter(typeof(JsonStringEnumConverter<LoggingLevel>))]
+[Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public enum LoggingLevel
 {
     /// <summary>Detailed debug information, typically only valuable to developers.</summary>

src/ModelContextProtocol.Core/Protocol/LoggingMessageNotificationParams.cs

@@ -20,6 +20,7 @@ namespace ModelContextProtocol.Protocol;
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </para>
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class LoggingMessageNotificationParams : NotificationParams
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/ModelHint.cs

@@ -14,6 +14,9 @@ namespace ModelContextProtocol.Protocol;
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </para>
 /// </remarks>
+// Sampling support type: only used inside ModelPreferences to hint a model for sampling (createMessage)
+// requests, so it is deprecated together with sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class ModelHint
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/ModelPreferences.cs

@@ -22,6 +22,9 @@ namespace ModelContextProtocol.Protocol;
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </para>
 /// </remarks>
+// Sampling support type: only used to express model selection preferences on sampling (createMessage)
+// requests, so it is deprecated together with sampling per SEP-2577.
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class ModelPreferences
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/NotificationMethods.cs

@@ -63,6 +63,7 @@ public static class NotificationMethods
     /// method to get the updated list of roots from the client.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public const string RootsListChangedNotification = "notifications/roots/list_changed";
 
     /// <summary>
@@ -80,6 +81,7 @@ public static class NotificationMethods
     /// the server can determine which messages to send based on its own configuration.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public const string LoggingMessageNotification = "notifications/message";
 
     /// <summary>

src/ModelContextProtocol.Core/Protocol/RequestMethods.cs

@@ -55,6 +55,7 @@ public static class RequestMethods
     /// <summary>
     /// The name of the request method sent from the server to request a list of the client's roots.
     /// </summary>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public const string RootsList = "roots/list";
 
     /// <summary>
@@ -71,6 +72,7 @@ public static class RequestMethods
     /// send log messages with severity at or above the specified level to the client as
     /// <see cref="NotificationMethods.LoggingMessageNotification"/> notifications.
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public const string LoggingSetLevel = "logging/setLevel";
 
     /// <summary>
@@ -91,6 +93,7 @@ public static class RequestMethods
     /// based on provided messages. It is part of the sampling capability in the Model Context Protocol and enables servers to access
     /// client-side AI models without needing direct API access to those models.
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public const string SamplingCreateMessage = "sampling/createMessage";
 
     /// <summary>

src/ModelContextProtocol.Core/Protocol/Root.cs

@@ -14,6 +14,7 @@ namespace ModelContextProtocol.Protocol;
 /// guidance rather than an access-control mechanism. Each root has a URI that uniquely identifies
 /// it and optional metadata like a human-readable name.
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class Root
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/RootsCapability.cs

@@ -21,6 +21,7 @@ namespace ModelContextProtocol.Protocol;
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </para>
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class RootsCapability
 {
     /// <summary>

src/ModelContextProtocol.Core/Protocol/RootsListChangedNotificationParams.cs

@@ -12,4 +12,5 @@ namespace ModelContextProtocol.Protocol;
 /// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
 /// </para>
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class RootsListChangedNotificationParams : NotificationParams;

src/ModelContextProtocol.Core/Protocol/SamplingCapability.cs

@@ -17,6 +17,7 @@ namespace ModelContextProtocol.Protocol;
 /// using an AI model. The client must set a <see cref="McpClientHandlers.SamplingHandler"/> to process these requests.
 /// </para>
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class SamplingCapability
 {
     /// <summary>