Audit protocol types

src/ModelContextProtocol.AspNetCore/StreamableHttpHandler.cs

@@ -250,6 +250,7 @@ private static Task WriteJsonRpcErrorAsync(HttpContext context, string errorMess
     {
         var jsonRpcError = new JsonRpcError
         {
+            Id = default,
             Error = new()
             {
                 Code = errorCode,

src/ModelContextProtocol.Core/AIContentExtensions.cs

@@ -226,6 +226,7 @@ internal static ContentBlock ToContent(this AIContent content) =>
                 {
                     Blob = dataContent.Base64Data.ToString(),
                     MimeType = dataContent.MediaType,
+                    Uri = string.Empty,
                 }
             },
 

src/ModelContextProtocol.Core/McpSessionHandler.cs

@@ -411,7 +411,7 @@ public async Task<JsonRpcResponse> SendRequestAsync(JsonRpcRequest request, Canc
         // Set request ID
         if (request.Id.Id is null)
         {
-            request = request.WithId(new RequestId(Interlocked.Increment(ref _lastRequestId)));
+            request.Id = new RequestId(Interlocked.Increment(ref _lastRequestId));
         }
 
         _propagator.InjectActivityContext(activity, request);

src/ModelContextProtocol.Core/Protocol/Annotations.cs

@@ -15,7 +15,7 @@ public sealed class Annotations
     /// Gets or sets the intended audience for this content as an array of <see cref="Role"/> values.
     /// </summary>
     [JsonPropertyName("audience")]
-    public IList<Role>? Audience { get; init; }
+    public IList<Role>? Audience { get; set; }
 
     /// <summary>
     /// Gets or sets a value indicating how important this data is for operating the server.
@@ -25,7 +25,7 @@ public sealed class Annotations
     /// 1 represents highest priority.
     /// </remarks>
     [JsonPropertyName("priority")]
-    public float? Priority { get; init; }
+    public float? Priority { get; set; }
 
     /// <summary>
     /// Gets or sets the moment the resource was last modified.

src/ModelContextProtocol.Core/Protocol/Argument.cs

@@ -15,7 +15,7 @@ public sealed class Argument
     /// Gets or sets the name of the argument being completed.
     /// </summary>
     [JsonPropertyName("name")]
-    public string Name { get; set; } = string.Empty;
+    public required string Name { get; set; }
 
     /// <summary>
     /// Gets or sets the current partial text value for which completion suggestions are requested.
@@ -25,5 +25,5 @@ public sealed class Argument
     /// options should be generated.
     /// </remarks>
     [JsonPropertyName("value")]
-    public string Value { get; set; } = string.Empty;
-}
+    public required string Value { get; set; }
+}

src/ModelContextProtocol.Core/Protocol/BlobResourceContents.cs

@@ -26,5 +26,5 @@ public sealed class BlobResourceContents : ResourceContents
     /// Gets or sets the base64-encoded string representing the binary data of the item.
     /// </summary>
     [JsonPropertyName("blob")]
-    public string Blob { get; set; } = string.Empty;
-}
+    public required string Blob { get; set; }
+}

src/ModelContextProtocol.Core/Protocol/CallToolRequestParams.cs

@@ -14,7 +14,7 @@ public sealed class CallToolRequestParams : RequestParams
 {
     /// <summary>Gets or sets the name of the tool to invoke.</summary>
     [JsonPropertyName("name")]
-    public required string Name { get; init; }
+    public required string Name { get; set; }
 
     /// <summary>
     /// Gets or sets optional arguments to pass to the tool when invoking it on the server.
@@ -24,5 +24,5 @@ public sealed class CallToolRequestParams : RequestParams
     /// a parameter name and its corresponding argument value.
     /// </remarks>
     [JsonPropertyName("arguments")]
-    public IReadOnlyDictionary<string, JsonElement>? Arguments { get; init; }
+    public IDictionary<string, JsonElement>? Arguments { get; set; }
 }

src/ModelContextProtocol.Core/Protocol/CancelledNotificationParams.cs

@@ -20,7 +20,7 @@ public sealed class CancelledNotificationParams : NotificationParams
     /// This must match the ID of an in-flight request that the sender wishes to cancel.
     /// </remarks>
     [JsonPropertyName("requestId")]
-    public RequestId RequestId { get; set; }
+    public required RequestId RequestId { get; set; }
 
     /// <summary>
     /// Gets or sets an optional string describing the reason for the cancellation request.

src/ModelContextProtocol.Core/Protocol/CompleteContext.cs

@@ -15,5 +15,5 @@ public sealed class CompleteContext
     /// Gets or sets previously-resolved variables in a URI template or prompt.
     /// </summary>
     [JsonPropertyName("arguments")]
-    public IDictionary<string, string>? Arguments { get; init; }
+    public IDictionary<string, string>? Arguments { get; set; }
 }

src/ModelContextProtocol.Core/Protocol/CompleteRequestParams.cs

@@ -23,18 +23,18 @@ public sealed class CompleteRequestParams : RequestParams
     /// Gets or sets the reference's information.
     /// </summary>
     [JsonPropertyName("ref")]
-    public required Reference Ref { get; init; }
+    public required Reference Ref { get; set; }
 
     /// <summary>
     /// Gets or sets the argument information for the completion request, specifying what is being completed
     /// and the current partial input.
     /// </summary>
     [JsonPropertyName("argument")]
-    public required Argument Argument { get; init; }
+    public required Argument Argument { get; set; }
 
     /// <summary>
     /// Gets or sets additional, optional context for completions.
     /// </summary>
     [JsonPropertyName("context")]
-    public CompleteContext? Context { get; init; }
+    public CompleteContext? Context { get; set; }
 }

src/ModelContextProtocol.Core/Protocol/ContentBlock.cs

@@ -1,6 +1,7 @@
 using Microsoft.Extensions.AI;
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using System.Text.Json.Serialization;
@@ -39,7 +40,7 @@ private protected ContentBlock()
     /// This determines the structure of the content object. Valid values include "image", "audio", "text", "resource", and "resource_link".
     /// </remarks>
     [JsonPropertyName("type")]
-    public string Type { get; set; } = string.Empty;
+    public abstract string Type { get; }
 
     /// <summary>
     /// Gets or sets optional annotations for the content.
@@ -49,7 +50,7 @@ private protected ContentBlock()
     /// and the priority level of the content. Clients can use this information to filter or prioritize content for different roles.
     /// </remarks>
     [JsonPropertyName("annotations")]
-    public Annotations? Annotations { get; init; }
+    public Annotations? Annotations { get; set; }
 
     /// <summary>
     /// Provides a <see cref="JsonConverter"/> for <see cref="ContentBlock"/>.
@@ -276,8 +277,8 @@ public override void Write(Utf8JsonWriter writer, ContentBlock value, JsonSerial
 /// <summary>Represents text provided to or from an LLM.</summary>
 public sealed class TextContentBlock : ContentBlock
 {
-    /// <summary>Initializes the instance of the <see cref="TextContentBlock"/> class.</summary>
-    public TextContentBlock() => Type = "text";
+    /// <inheritdoc/>
+    public override string Type => "text";
 
     /// <summary>
     /// Gets or sets the text content of the message.
@@ -298,8 +299,8 @@ public sealed class TextContentBlock : ContentBlock
 /// <summary>Represents an image provided to or from an LLM.</summary>
 public sealed class ImageContentBlock : ContentBlock
 {
-    /// <summary>Initializes the instance of the <see cref="ImageContentBlock"/> class.</summary>
-    public ImageContentBlock() => Type = "image";
+    /// <inheritdoc/>
+    public override string Type => "image";
 
     /// <summary>
     /// Gets or sets the base64-encoded image data.
@@ -331,8 +332,8 @@ public sealed class ImageContentBlock : ContentBlock
 /// <summary>Represents audio provided to or from an LLM.</summary>
 public sealed class AudioContentBlock : ContentBlock
 {
-    /// <summary>Initializes the instance of the <see cref="AudioContentBlock"/> class.</summary>
-    public AudioContentBlock() => Type = "audio";
+    /// <inheritdoc/>
+    public override string Type => "audio";
 
     /// <summary>
     /// Gets or sets the base64-encoded audio data.
@@ -367,8 +368,8 @@ public sealed class AudioContentBlock : ContentBlock
 /// </remarks>
 public sealed class EmbeddedResourceBlock : ContentBlock
 {
-    /// <summary>Initializes the instance of the <see cref="ResourceLinkBlock"/> class.</summary>
-    public EmbeddedResourceBlock() => Type = "resource";
+    /// <inheritdoc/>
+    public override string Type => "resource";
 
     /// <summary>
     /// Gets or sets the resource content of the message when <see cref="Type"/> is "resource".
@@ -399,20 +400,21 @@ public sealed class EmbeddedResourceBlock : ContentBlock
 /// </remarks>
 public sealed class ResourceLinkBlock : ContentBlock
 {
-    /// <summary>Initializes the instance of the <see cref="ResourceLinkBlock"/> class.</summary>
-    public ResourceLinkBlock() => Type = "resource_link";
+    /// <inheritdoc/>
+    public override string Type => "resource_link";
 
     /// <summary>
     /// Gets or sets the URI of this resource.
     /// </summary>
     [JsonPropertyName("uri")]
-    public required string Uri { get; init; }
+    [StringSyntax(StringSyntaxAttribute.Uri)]
+    public required string Uri { get; set; }
 
     /// <summary>
     /// Gets or sets a human-readable name for this resource.
     /// </summary>
     [JsonPropertyName("name")]
-    public required string Name { get; init; }
+    public required string Name { get; set; }
 
     /// <summary>
     /// Gets or sets a description of what this resource represents.
@@ -431,7 +433,7 @@ public sealed class ResourceLinkBlock : ContentBlock
     /// </para>
     /// </remarks>
     [JsonPropertyName("description")]
-    public string? Description { get; init; }
+    public string? Description { get; set; }
 
     /// <summary>
     /// Gets or sets the MIME type of this resource.
@@ -447,7 +449,7 @@ public sealed class ResourceLinkBlock : ContentBlock
     /// </para>
     /// </remarks>
     [JsonPropertyName("mimeType")]
-    public string? MimeType { get; init; }
+    public string? MimeType { get; set; }
 
     /// <summary>
     /// Gets or sets the size of the raw resource content (before base64 encoding), in bytes, if known.
@@ -456,5 +458,5 @@ public sealed class ResourceLinkBlock : ContentBlock
     /// This can be used by applications to display file sizes and estimate context window usage.
     /// </remarks>
     [JsonPropertyName("size")]
-    public long? Size { get; init; }
-}
+    public long? Size { get; set; }
+}

src/ModelContextProtocol.Core/Protocol/CreateMessageRequestParams.cs

@@ -19,7 +19,7 @@ public sealed class CreateMessageRequestParams : RequestParams
     /// The client may ignore this request.
     /// </remarks>
     [JsonPropertyName("includeContext")]
-    public ContextInclusion? IncludeContext { get; init; }
+    public ContextInclusion? IncludeContext { get; set; }
 
     /// <summary>
     /// Gets or sets the maximum number of tokens to generate in the LLM response, as requested by the server.
@@ -29,13 +29,13 @@ public sealed class CreateMessageRequestParams : RequestParams
     /// response length and computation time. The client may choose to sample fewer tokens than requested.
     /// </remarks>
     [JsonPropertyName("maxTokens")]
-    public int? MaxTokens { get; init; }
+    public required int MaxTokens { get; set; }
 
     /// <summary>
     /// Gets or sets the messages requested by the server to be included in the prompt.
     /// </summary>
     [JsonPropertyName("messages")]
-    public required IReadOnlyList<SamplingMessage> Messages { get; init; }
+    public IList<SamplingMessage> Messages { get; set; } = [];
 
     /// <summary>
     /// Gets or sets optional metadata to pass through to the LLM provider.
@@ -46,7 +46,7 @@ public sealed class CreateMessageRequestParams : RequestParams
     /// that are specific to certain AI models or providers.
     /// </remarks>
     [JsonPropertyName("metadata")]
-    public JsonElement? Metadata { get; init; }
+    public JsonElement? Metadata { get; set; }
 
     /// <summary>
     /// Gets or sets the server's preferences for which model to select.
@@ -66,7 +66,7 @@ public sealed class CreateMessageRequestParams : RequestParams
     /// </para>
     /// </remarks>
     [JsonPropertyName("modelPreferences")]
-    public ModelPreferences? ModelPreferences { get; init; }
+    public ModelPreferences? ModelPreferences { get; set; }
 
     /// <summary>
     /// Gets or sets optional sequences of characters that signal the LLM to stop generating text when encountered.
@@ -84,7 +84,7 @@ public sealed class CreateMessageRequestParams : RequestParams
     /// </para>
     /// </remarks>
     [JsonPropertyName("stopSequences")]
-    public IReadOnlyList<string>? StopSequences { get; init; }
+    public IList<string>? StopSequences { get; set; }
 
     /// <summary>
     /// Gets or sets an optional system prompt the server wants to use for sampling.
@@ -93,11 +93,11 @@ public sealed class CreateMessageRequestParams : RequestParams
     /// The client may modify or omit this prompt.
     /// </remarks>
     [JsonPropertyName("systemPrompt")]
-    public string? SystemPrompt { get; init; }
+    public string? SystemPrompt { get; set; }
 
     /// <summary>
     /// Gets or sets the temperature to use for sampling, as requested by the server.
     /// </summary>
     [JsonPropertyName("temperature")]
-    public float? Temperature { get; init; }
+    public float? Temperature { get; set; }
 }

src/ModelContextProtocol.Core/Protocol/CreateMessageResult.cs

@@ -14,7 +14,7 @@ public sealed class CreateMessageResult : Result
     /// Gets or sets the content of the message.
     /// </summary>
     [JsonPropertyName("content")]
-    public required ContentBlock Content { get; init; }
+    public required ContentBlock Content { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the model that generated the message.
@@ -29,7 +29,7 @@ public sealed class CreateMessageResult : Result
     /// </para>
     /// </remarks>
     [JsonPropertyName("model")]
-    public required string Model { get; init; }
+    public required string Model { get; set; }
 
     /// <summary>
     /// Gets or sets the reason why message generation (sampling) stopped, if known.
@@ -43,11 +43,11 @@ public sealed class CreateMessageResult : Result
     /// </list>
     /// </remarks>
     [JsonPropertyName("stopReason")]
-    public string? StopReason { get; init; }
+    public string? StopReason { get; set; }
 
     /// <summary>
     /// Gets or sets the role of the user who generated the message.
     /// </summary>
     [JsonPropertyName("role")]
-    public required Role Role { get; init; }
+    public required Role Role { get; set; }
 }

src/ModelContextProtocol.Core/Protocol/ElicitRequestParams.cs

@@ -15,7 +15,7 @@ public sealed class ElicitRequestParams
     /// Gets or sets the message to present to the user.
     /// </summary>
     [JsonPropertyName("message")]
-    public string Message { get; set; } = string.Empty;
+    public required string Message { get; set; }
 
     /// <summary>
     /// Gets or sets the requested schema.

src/ModelContextProtocol.Core/Protocol/ElicitResult.cs

@@ -67,6 +67,25 @@ public sealed class ElicitResult<T> : Result
     /// <summary>
     /// Gets or sets the user action in response to the elicitation.
     /// </summary>
+    /// <value>
+    /// Defaults to "cancel" if not explicitly set.
+    /// </value>
+    /// <remarks>
+    /// <list type="bullet">
+    ///   <item>
+    ///     <term>"accept"</term>
+    ///     <description>User submitted the form/confirmed the action</description>
+    ///   </item>
+    ///   <item>
+    ///     <term>"decline"</term>
+    ///     <description>User explicitly declined the action</description>
+    ///   </item>
+    ///   <item>
+    ///     <term>"cancel"</term>
+    ///     <description>User dismissed without making an explicit choice (default)</description>
+    ///   </item>
+    /// </list>
+    /// </remarks>
     public string Action { get; set; } = "cancel";
 
     /// <summary>

src/ModelContextProtocol.Core/Protocol/GetPromptRequestParams.cs

@@ -16,7 +16,7 @@ public sealed class GetPromptRequestParams : RequestParams
     /// Gets or sets the name of the prompt.
     /// </summary>
     [JsonPropertyName("name")]
-    public required string Name { get; init; }
+    public required string Name { get; set; }
 
     /// <summary>
     /// Gets or sets arguments to use for templating the prompt when retrieving it from the server.
@@ -27,5 +27,5 @@ public sealed class GetPromptRequestParams : RequestParams
     /// choose to use these arguments in any way it deems appropriate to generate the prompt.
     /// </remarks>
     [JsonPropertyName("arguments")]
-    public IReadOnlyDictionary<string, JsonElement>? Arguments { get; init; }
+    public IDictionary<string, JsonElement>? Arguments { get; set; }
 }