Make options types fully mutable

src/ModelContextProtocol/Client/McpClientOptions.cs

@@ -7,25 +7,25 @@ namespace ModelContextProtocol.Client;
 /// protocol version.
 /// <see href="https://spec.modelcontextprotocol.io/specification/2024-11-05/basic/lifecycle/">See the protocol specification for details on capability negotiation</see>
 /// </summary>
-public record McpClientOptions
+public class McpClientOptions
 {
     /// <summary>
     /// Information about this client implementation.
     /// </summary>
-    public required Implementation ClientInfo { get; init; }
+    public required Implementation ClientInfo { get; set; }
 
     /// <summary>
     /// Client capabilities to advertise to the server.
     /// </summary>
-    public ClientCapabilities? Capabilities { get; init; }
+    public ClientCapabilities? Capabilities { get; set; }
 
     /// <summary>
     /// Protocol version to request from the server.
     /// </summary>
-    public string ProtocolVersion { get; init; } = "2024-11-05";
+    public string ProtocolVersion { get; set; } = "2024-11-05";
 
     /// <summary>
     /// Timeout for initialization sequence.
     /// </summary>
-    public TimeSpan InitializationTimeout { get; init; } = TimeSpan.FromSeconds(60);
+    public TimeSpan InitializationTimeout { get; set; } = TimeSpan.FromSeconds(60);
 }

src/ModelContextProtocol/Configuration/McpServerOptionsSetup.cs

@@ -25,22 +25,14 @@ public void Configure(McpServerOptions options)
 
         // Configure the option's server information based on the current process,
         // if it otherwise lacks server information.
-        var assemblyName = (Assembly.GetEntryAssembly() ?? Assembly.GetCallingAssembly()).GetName();
-        if (options.ServerInfo is not { } serverInfo ||
-            serverInfo.Name is null ||
-            serverInfo.Version is null)
+        if (options.ServerInfo is not { } serverInfo)
         {
-            options.ServerInfo = options.ServerInfo is null ?
-                new()
-                {
-                    Name = assemblyName.Name ?? "McpServer",
-                    Version = assemblyName.Version?.ToString() ?? "1.0.0",
-                } :
-                options.ServerInfo with
-                {
-                    Name = options.ServerInfo.Name ?? assemblyName.Name ?? "McpServer",
-                    Version = options.ServerInfo.Version ?? assemblyName.Version?.ToString() ?? "1.0.0",
-                };
+            var assemblyName = (Assembly.GetEntryAssembly() ?? Assembly.GetCallingAssembly()).GetName();
+            options.ServerInfo = new()
+            {
+                Name = assemblyName.Name ?? "McpServer",
+                Version = assemblyName.Version?.ToString() ?? "1.0.0",
+            };
         }
 
         // Collect all of the provided tools into a tools collection. If the options already has
@@ -55,14 +47,9 @@ options.ServerInfo with
 
         if (!toolsCollection.IsEmpty)
         {
-            options.Capabilities = options.Capabilities is null ?
-                new() { Tools = new() { ToolCollection = toolsCollection } } :
-                options.Capabilities with
-                {
-                    Tools = options.Capabilities.Tools is null ?
-                        new() { ToolCollection = toolsCollection } :
-                        options.Capabilities.Tools with { ToolCollection = toolsCollection },
-                };
+            options.Capabilities ??= new();
+            options.Capabilities.Tools ??= new();
+            options.Capabilities.Tools.ToolCollection = toolsCollection;
         }
 
         // Apply custom server handlers.

src/ModelContextProtocol/Protocol/Types/Capabilities.cs

@@ -7,62 +7,62 @@ namespace ModelContextProtocol.Protocol.Types;
 /// Represents the capabilities that a client may support.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record ClientCapabilities
+public class ClientCapabilities
 {
     /// <summary>
     /// Experimental, non-standard capabilities that the client supports.
     /// </summary>
     [JsonPropertyName("experimental")]
-    public Dictionary<string, object>? Experimental { get; init; }
+    public Dictionary<string, object>? Experimental { get; set; }
 
     /// <summary>
     /// Present if the client supports listing roots.
     /// </summary>
     [JsonPropertyName("roots")]
-    public RootsCapability? Roots { get; init; }
+    public RootsCapability? Roots { get; set; }
 
     /// <summary>
     /// Present if the client supports sampling from an LLM.
     /// </summary>
     [JsonPropertyName("sampling")]
-    public SamplingCapability? Sampling { get; init; }
+    public SamplingCapability? Sampling { get; set; }
 }
 
 /// <summary>
 /// Represents the roots capability configuration.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record RootsCapability
+public class RootsCapability
 {
     /// <summary>
     /// Whether the client supports notifications for changes to the roots list.
     /// </summary>
     [JsonPropertyName("listChanged")]
-    public bool? ListChanged { get; init; }
+    public bool? ListChanged { get; set; }
 
     /// <summary>Gets or sets the handler for sampling requests.</summary>
     [JsonIgnore]
-    public Func<ListRootsRequestParams?, CancellationToken, Task<ListRootsResult>>? RootsHandler { get; init; }
+    public Func<ListRootsRequestParams?, CancellationToken, Task<ListRootsResult>>? RootsHandler { get; set; }
 }
 
 /// <summary>
 /// Represents the sampling capability configuration.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record SamplingCapability
+public class SamplingCapability
 {
     // Currently empty in the spec, but may be extended in the future
 
     /// <summary>Gets or sets the handler for sampling requests.</summary>
     [JsonIgnore]
-    public Func<CreateMessageRequestParams?, CancellationToken, Task<CreateMessageResult>>? SamplingHandler { get; init; }
+    public Func<CreateMessageRequestParams?, CancellationToken, Task<CreateMessageResult>>? SamplingHandler { get; set; }
 }
 
 /// <summary>
 /// Represents the logging capability configuration.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record LoggingCapability
+public class LoggingCapability
 {
     // Currently empty in the spec, but may be extended in the future
 
@@ -71,106 +71,106 @@ public record LoggingCapability
     /// Gets or sets the handler for set logging level requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<SetLevelRequestParams>, CancellationToken, Task<EmptyResult>>? SetLoggingLevelHandler { get; init; }
+    public Func<RequestContext<SetLevelRequestParams>, CancellationToken, Task<EmptyResult>>? SetLoggingLevelHandler { get; set; }
 }
 
 /// <summary>
 /// Represents the prompts capability configuration.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record PromptsCapability
+public class PromptsCapability
 {
     /// <summary>
     /// Whether this server supports notifications for changes to the prompt list.
     /// </summary>
     [JsonPropertyName("listChanged")]
-    public bool? ListChanged { get; init; }
+    public bool? ListChanged { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for list prompts requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<ListPromptsRequestParams>, CancellationToken, Task<ListPromptsResult>>? ListPromptsHandler { get; init; }
+    public Func<RequestContext<ListPromptsRequestParams>, CancellationToken, Task<ListPromptsResult>>? ListPromptsHandler { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for get prompt requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<GetPromptRequestParams>, CancellationToken, Task<GetPromptResult>>? GetPromptHandler { get; init; }
+    public Func<RequestContext<GetPromptRequestParams>, CancellationToken, Task<GetPromptResult>>? GetPromptHandler { get; set; }
 }
 
 /// <summary>
 /// Represents the resources capability configuration.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record ResourcesCapability
+public class ResourcesCapability
 {
     /// <summary>
     /// Whether this server supports subscribing to resource updates.
     /// </summary>
     [JsonPropertyName("subscribe")]
-    public bool? Subscribe { get; init; }
+    public bool? Subscribe { get; set; }
 
     /// <summary>
     /// Whether this server supports notifications for changes to the resource list.
     /// </summary>
     [JsonPropertyName("listChanged")]
-    public bool? ListChanged { get; init; }
+    public bool? ListChanged { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for list resource templates requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<ListResourceTemplatesRequestParams>, CancellationToken, Task<ListResourceTemplatesResult>>? ListResourceTemplatesHandler { get; init; }
+    public Func<RequestContext<ListResourceTemplatesRequestParams>, CancellationToken, Task<ListResourceTemplatesResult>>? ListResourceTemplatesHandler { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for list resources requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<ListResourcesRequestParams>, CancellationToken, Task<ListResourcesResult>>? ListResourcesHandler { get; init; }
+    public Func<RequestContext<ListResourcesRequestParams>, CancellationToken, Task<ListResourcesResult>>? ListResourcesHandler { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for read resources requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<ReadResourceRequestParams>, CancellationToken, Task<ReadResourceResult>>? ReadResourceHandler { get; init; }
+    public Func<RequestContext<ReadResourceRequestParams>, CancellationToken, Task<ReadResourceResult>>? ReadResourceHandler { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for subscribe to resources messages.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<SubscribeRequestParams>, CancellationToken, Task<EmptyResult>>? SubscribeToResourcesHandler { get; init; }
+    public Func<RequestContext<SubscribeRequestParams>, CancellationToken, Task<EmptyResult>>? SubscribeToResourcesHandler { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for unsubscribe from resources messages.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<UnsubscribeRequestParams>, CancellationToken, Task<EmptyResult>>? UnsubscribeFromResourcesHandler { get; init; }
+    public Func<RequestContext<UnsubscribeRequestParams>, CancellationToken, Task<EmptyResult>>? UnsubscribeFromResourcesHandler { get; set; }
 }
 
 /// <summary>
 /// Represents the tools capability configuration.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record ToolsCapability
+public class ToolsCapability
 {
     /// <summary>
     /// Gets or sets whether this server supports notifications for changes to the tool list.
     /// </summary>
     [JsonPropertyName("listChanged")]
-    public bool? ListChanged { get; init; }
+    public bool? ListChanged { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for list tools requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<ListToolsRequestParams>, CancellationToken, Task<ListToolsResult>>? ListToolsHandler { get; init; }
+    public Func<RequestContext<ListToolsRequestParams>, CancellationToken, Task<ListToolsResult>>? ListToolsHandler { get; set; }
 
     /// <summary>
     /// Gets or sets the handler for call tool requests.
     /// </summary>
     [JsonIgnore]
-    public Func<RequestContext<CallToolRequestParams>, CancellationToken, Task<CallToolResponse>>? CallToolHandler { get; init; }
+    public Func<RequestContext<CallToolRequestParams>, CancellationToken, Task<CallToolResponse>>? CallToolHandler { get; set; }
 
     /// <summary>Gets or sets a collection of tools served by the server.</summary>
     /// <remarks>
@@ -182,5 +182,5 @@ public record ToolsCapability
     /// will be invoked as a fallback.
     /// </remarks>
     [JsonIgnore]
-    public McpServerToolCollection? ToolCollection { get; init; }
+    public McpServerToolCollection? ToolCollection { get; set; }
 }

src/ModelContextProtocol/Protocol/Types/Implementation.cs

@@ -6,17 +6,17 @@ namespace ModelContextProtocol.Protocol.Types;
 /// Describes the name and version of an MCP implementation.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record Implementation
+public class Implementation
 {
     /// <summary>
     /// Name of the implementation.
     /// </summary>
     [JsonPropertyName("name")]
-    public required string Name { get; init; }
+    public required string Name { get; set; }
 
     /// <summary>
     /// Version of the implementation.
     /// </summary>
     [JsonPropertyName("version")]
-    public required string Version { get; init; }
+    public required string Version { get; set; }
 }

src/ModelContextProtocol/Protocol/Types/ServerCapabilities.cs

@@ -6,35 +6,35 @@ namespace ModelContextProtocol.Protocol.Types;
 /// Represents the capabilities that a server may support.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
-public record ServerCapabilities
+public class ServerCapabilities
 {
     /// <summary>
     /// Experimental, non-standard capabilities that the server supports.
     /// </summary>
     [JsonPropertyName("experimental")]
-    public Dictionary<string, object>? Experimental { get; init; }
+    public Dictionary<string, object>? Experimental { get; set; }
 
     /// <summary>
     /// Present if the server supports sending log messages to the client.
     /// </summary>
     [JsonPropertyName("logging")]
-    public LoggingCapability? Logging { get; init; }
+    public LoggingCapability? Logging { get; set; }
 
     /// <summary>
     /// Present if the server offers any prompt templates.
     /// </summary>
     [JsonPropertyName("prompts")]
-    public PromptsCapability? Prompts { get; init; }
+    public PromptsCapability? Prompts { get; set; }
 
     /// <summary>
     /// Present if the server offers any resources to read.
     /// </summary>
     [JsonPropertyName("resources")]
-    public ResourcesCapability? Resources { get; init; }
+    public ResourcesCapability? Resources { get; set; }
 
     /// <summary>
     /// Present if the server offers any tools to call.
     /// </summary>
     [JsonPropertyName("tools")]
-    public ToolsCapability? Tools { get; init; }
+    public ToolsCapability? Tools { get; set; }
 }

src/ModelContextProtocol/Server/McpServer.cs

@@ -263,25 +263,14 @@ private void SetToolsHandler(ref McpServerOptions options)
                 return tool.InvokeAsync(request, cancellationToken);
             };
 
-            toolsCapability = toolsCapability is null ?
-                new()
-                {
-                    CallToolHandler = callToolHandler,
-                    ListToolsHandler = listToolsHandler,
-                    ToolCollection = tools,
-                    ListChanged = true,
-                } :
-                toolsCapability with
-                {
-                    CallToolHandler = callToolHandler,
-                    ListToolsHandler = listToolsHandler,
-                    ToolCollection = tools,
-                    ListChanged = true,
-                };
-
-            options.Capabilities = options.Capabilities is null ?
-                new() { Tools = toolsCapability } :
-                options.Capabilities with { Tools = toolsCapability };
+            toolsCapability ??= new();
+            toolsCapability.CallToolHandler = callToolHandler;
+            toolsCapability.ListToolsHandler = listToolsHandler;
+            toolsCapability.ToolCollection = tools;
+            toolsCapability.ListChanged = true;
+
+            options.Capabilities ??= new();
+            options.Capabilities.Tools = toolsCapability;
 
             tools.Changed += delegate
             {