diff --git a/docs/concepts/logging/samples/Directory.Build.props b/docs/concepts/logging/samples/Directory.Build.props
new file mode 100644
index 000000000..22f945ad0
--- /dev/null
+++ b/docs/concepts/logging/samples/Directory.Build.props
@@ -0,0 +1,9 @@
+<Project>
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)..'))" />
+
+  <PropertyGroup>
+    <!-- Suppress the Logging obsoletion warning (SEP-2577) in the logging sample projects,
+         which demonstrate the deprecated logging feature that continues to work. -->
+    <NoWarn>$(NoWarn);MCP9005</NoWarn>
+  </PropertyGroup>
+</Project>
diff --git a/docs/list-of-diagnostics.md b/docs/list-of-diagnostics.md
index 26a44bd78..babf54b21 100644
--- a/docs/list-of-diagnostics.md
+++ b/docs/list-of-diagnostics.md
@@ -38,3 +38,4 @@ When APIs are marked as obsolete, a diagnostic is emitted to warn users that the
 | `MCP9002` | Removed | The `AddXxxFilter` extension methods on `IMcpServerBuilder` (e.g., `AddListToolsFilter`, `AddCallToolFilter`, `AddIncomingMessageFilter`) were superseded by `WithRequestFilters()` and `WithMessageFilters()`. |
 | `MCP9003` | In place | The `RequestContext<TParams>(McpServer, JsonRpcRequest)` constructor is obsolete. Use the overload that accepts a `parameters` argument: `RequestContext<TParams>(McpServer, JsonRpcRequest, TParams)`. |
 | `MCP9004` | In place | <xref:ModelContextProtocol.AspNetCore.HttpServerTransportOptions.EnableLegacySse> opts into the legacy SSE transport which has no built-in HTTP-level backpressure. Use Streamable HTTP instead. See [Stateless — Legacy SSE transport](xref:stateless#legacy-sse-transport) for details. |
+| `MCP9005` | In place | The Roots, Sampling, and Logging features are deprecated as of specification version 2026-07-28 and may be removed in a future version. See SEP-2577 for more information. |
diff --git a/samples/Directory.Build.props b/samples/Directory.Build.props
new file mode 100644
index 000000000..1aa7321e0
--- /dev/null
+++ b/samples/Directory.Build.props
@@ -0,0 +1,9 @@
+<Project>
+  <Import Project="$([MSBuild]::GetPathOfFileAbove('Directory.Build.props', '$(MSBuildThisFileDirectory)..'))" />
+
+  <PropertyGroup>
+    <!-- Suppress the Roots, Sampling, and Logging obsoletion warning (SEP-2577) in sample projects
+         that demonstrate the deprecated features, which continue to work. -->
+    <NoWarn>$(NoWarn);MCP9005</NoWarn>
+  </PropertyGroup>
+</Project>
diff --git a/src/Common/Obsoletions.cs b/src/Common/Obsoletions.cs
index 46ea782d8..511f828ac 100644
--- a/src/Common/Obsoletions.cs
+++ b/src/Common/Obsoletions.cs
@@ -33,4 +33,13 @@ internal static class Obsoletions
     public const string EnableLegacySse_DiagnosticId = "MCP9004";
     public const string EnableLegacySse_Message = "Legacy SSE transport has no built-in request backpressure and should only be used with completely trusted clients in isolated processes. Use Streamable HTTP instead.";
     public const string EnableLegacySse_Url = "https://github.com/modelcontextprotocol/csharp-sdk/blob/main/docs/list-of-diagnostics.md#obsolete-apis";
+
+    // SEP-2577 deprecates the Roots, Sampling, and Logging features as a single coordinated
+    // deprecation. They share one diagnostic ID (MCP9005) so consumers can opt out with a single
+    // suppression, while the feature-specific messages keep the diagnostics distinguishable.
+    public const string Deprecated_DiagnosticId = "MCP9005";
+    public const string Deprecated_Url = "https://github.com/modelcontextprotocol/csharp-sdk/blob/main/docs/list-of-diagnostics.md#mcp9005";
+    public const string DeprecatedRoots_Message = "The Roots feature is deprecated as of specification version 2026-07-28 and may be removed in a future version. See SEP-2577 for more information.";
+    public const string DeprecatedSampling_Message = "The Sampling feature is deprecated as of specification version 2026-07-28 and may be removed in a future version. See SEP-2577 for more information.";
+    public const string DeprecatedLogging_Message = "The Logging feature is deprecated as of specification version 2026-07-28 and may be removed in a future version. See SEP-2577 for more information.";
 }
diff --git a/src/ModelContextProtocol.Core/AIContentExtensions.cs b/src/ModelContextProtocol.Core/AIContentExtensions.cs
index bf5fd05de..affb8b20a 100644
--- a/src/ModelContextProtocol.Core/AIContentExtensions.cs
+++ b/src/ModelContextProtocol.Core/AIContentExtensions.cs
@@ -34,6 +34,7 @@ public static class AIContentExtensions
     /// </para>
     /// </remarks>
     /// <exception cref="ArgumentNullException"><paramref name="chatClient"/> is <see langword="null"/>.</exception>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static Func<CreateMessageRequestParams?, IProgress<ProgressNotificationValue>, CancellationToken, ValueTask<CreateMessageResult>> CreateSamplingHandler(
         this IChatClient chatClient,
         JsonSerializerOptions? serializerOptions = null)
diff --git a/src/ModelContextProtocol.Core/Client/McpClient.Methods.cs b/src/ModelContextProtocol.Core/Client/McpClient.Methods.cs
index f3355e76d..22245a924 100644
--- a/src/ModelContextProtocol.Core/Client/McpClient.Methods.cs
+++ b/src/ModelContextProtocol.Core/Client/McpClient.Methods.cs
@@ -1208,6 +1208,7 @@ public async ValueTask<ResultOrCreatedTask<CallToolResult>> CallToolRawAsync(
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task representing the asynchronous operation.</returns>
     /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public Task SetLoggingLevelAsync(LogLevel level, RequestOptions? options = null, CancellationToken cancellationToken = default) =>
         SetLoggingLevelAsync(McpServerImpl.ToLoggingLevel(level), options, cancellationToken);
 
@@ -1219,6 +1220,7 @@ public Task SetLoggingLevelAsync(LogLevel level, RequestOptions? options = null,
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task representing the asynchronous operation.</returns>
     /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public Task SetLoggingLevelAsync(LoggingLevel level, RequestOptions? options = null, CancellationToken cancellationToken = default)
     {
         return SetLoggingLevelAsync(
@@ -1238,6 +1240,7 @@ public Task SetLoggingLevelAsync(LoggingLevel level, RequestOptions? options = n
     /// <returns>The result of the request.</returns>
     /// <exception cref="ArgumentNullException"><paramref name="requestParams"/> is <see langword="null"/>.</exception>
     /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public Task SetLoggingLevelAsync(
         SetLevelRequestParams requestParams,
         CancellationToken cancellationToken = default)
diff --git a/src/ModelContextProtocol.Core/Client/McpClientHandlers.cs b/src/ModelContextProtocol.Core/Client/McpClientHandlers.cs
index 0866e4aef..396b5876b 100644
--- a/src/ModelContextProtocol.Core/Client/McpClientHandlers.cs
+++ b/src/ModelContextProtocol.Core/Client/McpClientHandlers.cs
@@ -1,4 +1,4 @@
-using Microsoft.Extensions.AI;
+using Microsoft.Extensions.AI;
 using ModelContextProtocol.Protocol;
 using System.Diagnostics.CodeAnalysis;
 
@@ -50,6 +50,7 @@ public sealed class McpClientHandlers
     /// This handler is invoked when the server sends a <see cref="RequestMethods.RootsList"/> request to retrieve available roots.
     /// The handler receives request parameters and should return a <see cref="ListRootsResult"/> containing the collection of available roots.
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public Func<ListRootsRequestParams?, CancellationToken, ValueTask<ListRootsResult>>? RootsHandler { get; set; }
 
     /// <summary>
@@ -85,5 +86,6 @@ public sealed class McpClientHandlers
     /// method with any implementation of <see cref="IChatClient"/>.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public Func<CreateMessageRequestParams?, IProgress<ProgressNotificationValue>, CancellationToken, ValueTask<CreateMessageResult>>? SamplingHandler { get; set; }
 }
diff --git a/src/ModelContextProtocol.Core/ModelContextProtocol.Core.csproj b/src/ModelContextProtocol.Core/ModelContextProtocol.Core.csproj
index 23045b317..455c36798 100644
--- a/src/ModelContextProtocol.Core/ModelContextProtocol.Core.csproj
+++ b/src/ModelContextProtocol.Core/ModelContextProtocol.Core.csproj
@@ -9,6 +9,11 @@
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <!-- Suppress the experimental extensions warning -->
     <NoWarn>$(NoWarn);MCPEXP001</NoWarn>
+    <!-- Core implements the Roots, Sampling, and Logging features deprecated by SEP-2577 (MCP9005).
+         The deprecated types remain in the source-generated JsonSerializerContext and are used throughout
+         the implementation, so the obsolete-usage diagnostic is suppressed project-wide here while staying
+         active for external consumers of the package. -->
+    <NoWarn>$(NoWarn);MCP9005</NoWarn>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(TargetFramework)' != 'netstandard2.0'">
diff --git a/src/ModelContextProtocol.Core/Protocol/ClientCapabilities.cs b/src/ModelContextProtocol.Core/Protocol/ClientCapabilities.cs
index f41f50fd8..fd93dcee7 100644
--- a/src/ModelContextProtocol.Core/Protocol/ClientCapabilities.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/ContentBlock.cs b/src/ModelContextProtocol.Core/Protocol/ContentBlock.cs
index 83cc9d16b..d0b1b80ec 100644
--- a/src/ModelContextProtocol.Core/Protocol/ContentBlock.cs
+++ b/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/>
diff --git a/src/ModelContextProtocol.Core/Protocol/ContextInclusion.cs b/src/ModelContextProtocol.Core/Protocol/ContextInclusion.cs
index fbe6be56f..5979fa868 100644
--- a/src/ModelContextProtocol.Core/Protocol/ContextInclusion.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/CreateMessageRequestParams.cs b/src/ModelContextProtocol.Core/Protocol/CreateMessageRequestParams.cs
index bb27d70fd..7a4f32984 100644
--- a/src/ModelContextProtocol.Core/Protocol/CreateMessageRequestParams.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/CreateMessageResult.cs b/src/ModelContextProtocol.Core/Protocol/CreateMessageResult.cs
index 94472421b..7568b4552 100644
--- a/src/ModelContextProtocol.Core/Protocol/CreateMessageResult.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/InputRequest.cs b/src/ModelContextProtocol.Core/Protocol/InputRequest.cs
index bd9161423..68d767d99 100644
--- a/src/ModelContextProtocol.Core/Protocol/InputRequest.cs
+++ b/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 static InputRequest ForElicitation(ElicitRequestParams requestParams)
     /// </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);
diff --git a/src/ModelContextProtocol.Core/Protocol/InputResponse.cs b/src/ModelContextProtocol.Core/Protocol/InputResponse.cs
index 465ea3235..d2e51eeb1 100644
--- a/src/ModelContextProtocol.Core/Protocol/InputResponse.cs
+++ b/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 static InputResponse FromElicitResult(ElicitResult result)
     /// </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);
diff --git a/src/ModelContextProtocol.Core/Protocol/ListRootsRequestParams.cs b/src/ModelContextProtocol.Core/Protocol/ListRootsRequestParams.cs
index 5f3bf5d0f..602ee502b 100644
--- a/src/ModelContextProtocol.Core/Protocol/ListRootsRequestParams.cs
+++ b/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;
diff --git a/src/ModelContextProtocol.Core/Protocol/ListRootsResult.cs b/src/ModelContextProtocol.Core/Protocol/ListRootsResult.cs
index 115283e98..66debfef8 100644
--- a/src/ModelContextProtocol.Core/Protocol/ListRootsResult.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/LoggingCapability.cs b/src/ModelContextProtocol.Core/Protocol/LoggingCapability.cs
index 18d8f0c28..f33072929 100644
--- a/src/ModelContextProtocol.Core/Protocol/LoggingCapability.cs
+++ b/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
 {
 }
\ No newline at end of file
diff --git a/src/ModelContextProtocol.Core/Protocol/LoggingLevel.cs b/src/ModelContextProtocol.Core/Protocol/LoggingLevel.cs
index 5fadf7fbc..c8d39064c 100644
--- a/src/ModelContextProtocol.Core/Protocol/LoggingLevel.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/LoggingMessageNotificationParams.cs b/src/ModelContextProtocol.Core/Protocol/LoggingMessageNotificationParams.cs
index 600f620a5..0840c9c7c 100644
--- a/src/ModelContextProtocol.Core/Protocol/LoggingMessageNotificationParams.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/ModelHint.cs b/src/ModelContextProtocol.Core/Protocol/ModelHint.cs
index 37e1001a3..9be4c755f 100644
--- a/src/ModelContextProtocol.Core/Protocol/ModelHint.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/ModelPreferences.cs b/src/ModelContextProtocol.Core/Protocol/ModelPreferences.cs
index 5c7a50acc..f20b33956 100644
--- a/src/ModelContextProtocol.Core/Protocol/ModelPreferences.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/NotificationMethods.cs b/src/ModelContextProtocol.Core/Protocol/NotificationMethods.cs
index cab98a5bc..825abd92b 100644
--- a/src/ModelContextProtocol.Core/Protocol/NotificationMethods.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/RequestMethods.cs b/src/ModelContextProtocol.Core/Protocol/RequestMethods.cs
index 6967dd07d..a6f22148e 100644
--- a/src/ModelContextProtocol.Core/Protocol/RequestMethods.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/Root.cs b/src/ModelContextProtocol.Core/Protocol/Root.cs
index 622dbddb9..debeefd57 100644
--- a/src/ModelContextProtocol.Core/Protocol/Root.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/RootsCapability.cs b/src/ModelContextProtocol.Core/Protocol/RootsCapability.cs
index 0b2f9e762..eebcb741d 100644
--- a/src/ModelContextProtocol.Core/Protocol/RootsCapability.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/RootsListChangedNotificationParams.cs b/src/ModelContextProtocol.Core/Protocol/RootsListChangedNotificationParams.cs
index 62312ab32..b4fe33b5f 100644
--- a/src/ModelContextProtocol.Core/Protocol/RootsListChangedNotificationParams.cs
+++ b/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;
diff --git a/src/ModelContextProtocol.Core/Protocol/SamplingCapability.cs b/src/ModelContextProtocol.Core/Protocol/SamplingCapability.cs
index cb530e795..7a4d015de 100644
--- a/src/ModelContextProtocol.Core/Protocol/SamplingCapability.cs
+++ b/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>
diff --git a/src/ModelContextProtocol.Core/Protocol/SamplingContextCapability.cs b/src/ModelContextProtocol.Core/Protocol/SamplingContextCapability.cs
index bae960f3a..a26bc5ccc 100644
--- a/src/ModelContextProtocol.Core/Protocol/SamplingContextCapability.cs
+++ b/src/ModelContextProtocol.Core/Protocol/SamplingContextCapability.cs
@@ -3,4 +3,5 @@ namespace ModelContextProtocol.Protocol;
 /// <summary>
 /// Represents the sampling context capability.
 /// </summary>
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class SamplingContextCapability;
\ No newline at end of file
diff --git a/src/ModelContextProtocol.Core/Protocol/SamplingMessage.cs b/src/ModelContextProtocol.Core/Protocol/SamplingMessage.cs
index d929a6877..1e2fa4c10 100644
--- a/src/ModelContextProtocol.Core/Protocol/SamplingMessage.cs
+++ b/src/ModelContextProtocol.Core/Protocol/SamplingMessage.cs
@@ -28,6 +28,7 @@ namespace ModelContextProtocol.Protocol;
 /// </para>
 /// </remarks>
 [DebuggerDisplay("{DebuggerDisplay,nq}")]
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class SamplingMessage
 {
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Protocol/SamplingToolsCapability.cs b/src/ModelContextProtocol.Core/Protocol/SamplingToolsCapability.cs
index f93b79725..276c36089 100644
--- a/src/ModelContextProtocol.Core/Protocol/SamplingToolsCapability.cs
+++ b/src/ModelContextProtocol.Core/Protocol/SamplingToolsCapability.cs
@@ -3,4 +3,5 @@ namespace ModelContextProtocol.Protocol;
 /// <summary>
 /// Represents the sampling tools capability.
 /// </summary>
+[Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class SamplingToolsCapability;
\ No newline at end of file
diff --git a/src/ModelContextProtocol.Core/Protocol/ServerCapabilities.cs b/src/ModelContextProtocol.Core/Protocol/ServerCapabilities.cs
index 92ffff424..0f1c4f540 100644
--- a/src/ModelContextProtocol.Core/Protocol/ServerCapabilities.cs
+++ b/src/ModelContextProtocol.Core/Protocol/ServerCapabilities.cs
@@ -41,6 +41,7 @@ public sealed class ServerCapabilities
     /// Gets or sets a server's logging capability for sending log messages to the client.
     /// </summary>
     [JsonPropertyName("logging")]
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public LoggingCapability? Logging { get; set; }
 
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Protocol/SetLevelRequestParams.cs b/src/ModelContextProtocol.Core/Protocol/SetLevelRequestParams.cs
index 9441d39ac..2352eb966 100644
--- a/src/ModelContextProtocol.Core/Protocol/SetLevelRequestParams.cs
+++ b/src/ModelContextProtocol.Core/Protocol/SetLevelRequestParams.cs
@@ -10,6 +10,7 @@ namespace ModelContextProtocol.Protocol;
 /// This request allows clients to configure the level of logging information they want to receive from the server.
 /// The server will send notifications for log events at the specified level and all higher (more severe) levels.
 /// </remarks>
+[Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
 public sealed class SetLevelRequestParams : RequestParams
 {
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Protocol/ToolChoice.cs b/src/ModelContextProtocol.Core/Protocol/ToolChoice.cs
index ebb80552f..903e978c6 100644
--- a/src/ModelContextProtocol.Core/Protocol/ToolChoice.cs
+++ b/src/ModelContextProtocol.Core/Protocol/ToolChoice.cs
@@ -5,6 +5,9 @@ namespace ModelContextProtocol.Protocol;
 /// <summary>
 /// Controls tool selection behavior for sampling requests.
 /// </summary>
+// Sampling support type: only used to configure tool selection 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 ToolChoice
 {
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Server/DestinationBoundMcpServer.cs b/src/ModelContextProtocol.Core/Server/DestinationBoundMcpServer.cs
index bf87980e5..b8f96237a 100644
--- a/src/ModelContextProtocol.Core/Server/DestinationBoundMcpServer.cs
+++ b/src/ModelContextProtocol.Core/Server/DestinationBoundMcpServer.cs
@@ -14,6 +14,7 @@ internal sealed class DestinationBoundMcpServer(McpServerImpl server, ITransport
     public override Implementation? ClientInfo => server.ClientInfo;
     public override McpServerOptions ServerOptions => server.ServerOptions;
     public override IServiceProvider? Services => server.Services;
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public override LoggingLevel? LoggingLevel => server.LoggingLevel;
 
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Server/McpRequestFilters.cs b/src/ModelContextProtocol.Core/Server/McpRequestFilters.cs
index e778d9d1b..9d9774e8b 100644
--- a/src/ModelContextProtocol.Core/Server/McpRequestFilters.cs
+++ b/src/ModelContextProtocol.Core/Server/McpRequestFilters.cs
@@ -264,6 +264,7 @@ public IList<McpRequestFilter<UnsubscribeRequestParams, EmptyResult>> Unsubscrib
     /// at or above the specified level to the client as notifications/message notifications.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public IList<McpRequestFilter<SetLevelRequestParams, EmptyResult>> SetLoggingLevelFilters
     {
         get => field ??= [];
diff --git a/src/ModelContextProtocol.Core/Server/McpServer.Methods.cs b/src/ModelContextProtocol.Core/Server/McpServer.Methods.cs
index a0d788a27..99cd7e80d 100644
--- a/src/ModelContextProtocol.Core/Server/McpServer.Methods.cs
+++ b/src/ModelContextProtocol.Core/Server/McpServer.Methods.cs
@@ -67,6 +67,7 @@ public static McpServer Create(
     /// then returns to <see cref="McpTaskStatus.Working"/> when the response is received.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public ValueTask<CreateMessageResult> SampleAsync(
         CreateMessageRequestParams requestParams,
         CancellationToken cancellationToken = default)
@@ -107,6 +108,7 @@ public ValueTask<CreateMessageResult> SampleAsync(
     /// <exception cref="ArgumentNullException"><paramref name="messages"/> is <see langword="null"/>.</exception>
     /// <exception cref="InvalidOperationException">The client does not support sampling.</exception>
     /// <exception cref="McpException">The request failed or the client returned an error response.</exception>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public async Task<ChatResponse> SampleAsync(
         IEnumerable<ChatMessage> messages, ChatOptions? chatOptions = default, JsonSerializerOptions? serializerOptions = null, CancellationToken cancellationToken = default)
     {
@@ -243,6 +245,7 @@ public async Task<ChatResponse> SampleAsync(
     /// <see cref="JsonRpcMessageContext.RelatedTransport"/>, which is always open for the duration of
     /// the request, rather than relying on the optional standalone GET SSE stream.
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public IChatClient AsSamplingChatClient(JsonSerializerOptions? serializerOptions = null)
     {
         ThrowIfSamplingUnsupported();
@@ -252,6 +255,7 @@ public IChatClient AsSamplingChatClient(JsonSerializerOptions? serializerOptions
 
     /// <summary>Gets an <see cref="ILogger"/> on which logged messages will be sent as notifications to the client.</summary>
     /// <returns>An <see cref="ILogger"/> that can be used to log to the client.</returns>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public ILoggerProvider AsClientLoggerProvider() => 
         new ClientLoggerProvider(this);
 
@@ -271,6 +275,7 @@ public ILoggerProvider AsClientLoggerProvider() =>
     /// <see cref="JsonRpcMessageContext.RelatedTransport"/>, which is always open for the duration of
     /// the request, rather than relying on the optional standalone GET SSE stream.
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedRoots_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public ValueTask<ListRootsResult> RequestRootsAsync(
         ListRootsRequestParams requestParams,
         CancellationToken cancellationToken = default)
diff --git a/src/ModelContextProtocol.Core/Server/McpServer.cs b/src/ModelContextProtocol.Core/Server/McpServer.cs
index 444365361..fb6d7074a 100644
--- a/src/ModelContextProtocol.Core/Server/McpServer.cs
+++ b/src/ModelContextProtocol.Core/Server/McpServer.cs
@@ -62,6 +62,7 @@ protected McpServer()
     public abstract IServiceProvider? Services { get; }
 
     /// <summary>Gets the last logging level set by the client, or <see langword="null"/> if it's never been set.</summary>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public abstract LoggingLevel? LoggingLevel { get; }
 
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Server/McpServerHandlers.cs b/src/ModelContextProtocol.Core/Server/McpServerHandlers.cs
index f650a0011..4f9509b9d 100644
--- a/src/ModelContextProtocol.Core/Server/McpServerHandlers.cs
+++ b/src/ModelContextProtocol.Core/Server/McpServerHandlers.cs
@@ -199,6 +199,7 @@ public McpRequestHandler<CallToolRequestParams, ResultOrCreatedTask<CallToolResu
     /// at or above the specified level to the client as notifications/message notifications.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public McpRequestHandler<SetLevelRequestParams, EmptyResult>? SetLoggingLevelHandler { get; set; }
 
     /// <summary>
diff --git a/src/ModelContextProtocol.Core/Server/McpServerImpl.cs b/src/ModelContextProtocol.Core/Server/McpServerImpl.cs
index d6759ac79..9ef1782ca 100644
--- a/src/ModelContextProtocol.Core/Server/McpServerImpl.cs
+++ b/src/ModelContextProtocol.Core/Server/McpServerImpl.cs
@@ -169,6 +169,7 @@ void Register<TPrimitive>(McpServerPrimitiveCollection<TPrimitive>? collection,
     public override IServiceProvider? Services { get; }
 
     /// <inheritdoc />
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public override LoggingLevel? LoggingLevel => _loggingLevel?.Value;
 
     /// <inheritdoc />
diff --git a/src/ModelContextProtocol.Core/Server/McpServerOptions.cs b/src/ModelContextProtocol.Core/Server/McpServerOptions.cs
index 32c13da27..eb99913d5 100644
--- a/src/ModelContextProtocol.Core/Server/McpServerOptions.cs
+++ b/src/ModelContextProtocol.Core/Server/McpServerOptions.cs
@@ -187,6 +187,7 @@ public McpServerFilters Filters
     /// This value is used in <see cref="McpServer.SampleAsync(IEnumerable{Microsoft.Extensions.AI.ChatMessage}, Microsoft.Extensions.AI.ChatOptions?, System.Text.Json.JsonSerializerOptions?, CancellationToken)"/>
     /// when <see cref="Microsoft.Extensions.AI.ChatOptions.MaxOutputTokens"/> is not set in the request options.
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedSampling_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public int MaxSamplingOutputTokens { get; set; } = 1000;
 
     /// <summary>
diff --git a/src/ModelContextProtocol/McpRequestFilterBuilderExtensions.cs b/src/ModelContextProtocol/McpRequestFilterBuilderExtensions.cs
index 8ee7fb064..2ed06355f 100644
--- a/src/ModelContextProtocol/McpRequestFilterBuilderExtensions.cs
+++ b/src/ModelContextProtocol/McpRequestFilterBuilderExtensions.cs
@@ -165,6 +165,7 @@ public static IMcpRequestFilterBuilder AddUnsubscribeFromResourcesFilter(this IM
     /// <param name="builder">The request filter builder instance.</param>
     /// <param name="filter">The filter function that wraps the handler.</param>
     /// <returns>The builder provided in <paramref name="builder"/>.</returns>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static IMcpRequestFilterBuilder AddSetLoggingLevelFilter(this IMcpRequestFilterBuilder builder, McpRequestFilter<SetLevelRequestParams, EmptyResult> filter)
     {
         Throw.IfNull(builder);
diff --git a/src/ModelContextProtocol/McpServerBuilderExtensions.cs b/src/ModelContextProtocol/McpServerBuilderExtensions.cs
index da63dc31d..7f07be67e 100644
--- a/src/ModelContextProtocol/McpServerBuilderExtensions.cs
+++ b/src/ModelContextProtocol/McpServerBuilderExtensions.cs
@@ -878,6 +878,7 @@ public static IMcpServerBuilder WithUnsubscribeFromResourcesHandler(this IMcpSer
     /// most recently set level.
     /// </para>
     /// </remarks>
+    [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public static IMcpServerBuilder WithSetLoggingLevelHandler(this IMcpServerBuilder builder, McpRequestHandler<SetLevelRequestParams, EmptyResult> handler)
     {
         Throw.IfNull(builder);
diff --git a/src/ModelContextProtocol/ModelContextProtocol.csproj b/src/ModelContextProtocol/ModelContextProtocol.csproj
index 07167c438..0d717ef10 100644
--- a/src/ModelContextProtocol/ModelContextProtocol.csproj
+++ b/src/ModelContextProtocol/ModelContextProtocol.csproj
@@ -16,6 +16,11 @@
     <IsAotCompatible>true</IsAotCompatible>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
+    <!-- CS0436: Allow ObsoleteAttribute to be redefined internally -->
+    <NoWarn>$(NoWarn);CS0436</NoWarn>
+  </PropertyGroup>
+
   <ItemGroup>
     <Compile Include="..\Common\Throw.cs" Link="Throw.cs" />
     <Compile Include="..\Common\Obsoletions.cs" Link="Obsoletions.cs" />
diff --git a/tests/Directory.Build.props b/tests/Directory.Build.props
index bc169333f..b4a79a31e 100644
--- a/tests/Directory.Build.props
+++ b/tests/Directory.Build.props
@@ -7,5 +7,8 @@
     <NoWarn>$(NoWarn);MCPEXP001</NoWarn>
     <!-- Suppress the obsolete SSE warning in test projects that need to test legacy SSE -->
     <NoWarn>$(NoWarn);MCP9004</NoWarn>
+    <!-- Suppress the Roots, Sampling, and Logging obsoletion warning (SEP-2577) in test projects
+         that need to verify the deprecated features continue to work. -->
+    <NoWarn>$(NoWarn);MCP9005</NoWarn>
   </PropertyGroup>
 </Project>
diff --git a/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs b/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs
index 7ed3c35e3..87f363f03 100644
--- a/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs
+++ b/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs
@@ -1368,7 +1368,10 @@ public override Task<JsonRpcResponse> SendRequestAsync(JsonRpcRequest request, C
         public override string? NegotiatedProtocolVersion => throw new NotImplementedException();
         public override Implementation? ClientInfo => throw new NotImplementedException();
         public override IServiceProvider? Services => throw new NotImplementedException();
+        // McpServer.LoggingLevel is obsolete (SEP-2577) but abstract, so this test double must override it.
+#pragma warning disable CS0672 // Member overrides obsolete member
         public override LoggingLevel? LoggingLevel => throw new NotImplementedException();
+#pragma warning restore CS0672
         public override Task SendMessageAsync(JsonRpcMessage message, CancellationToken cancellationToken = default) =>
             throw new NotImplementedException();
         public override Task RunAsync(CancellationToken cancellationToken = default) =>