Add missing exception documentation to McpSession, McpClient, and McpServer public APIs

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>

Author: Copilot

src/ModelContextProtocol.Core/Client/McpClient.Methods.cs

@@ -77,6 +77,7 @@ public McpClientPrompt(McpClient client, Prompt prompt)
     /// <param name="serializerOptions">The serialization options governing argument serialization.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="ValueTask"/> containing the prompt's result with content and messages.</returns>
+    /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
     /// <remarks>
     /// <para>
     /// This method sends a request to the MCP server to execute this prompt with the provided arguments.

src/ModelContextProtocol.Core/Client/McpClientPrompt.cs

@@ -76,6 +76,7 @@ public McpClientResource(McpClient client, Resource resource)
     /// </summary>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="ValueTask{ReadResourceResult}"/> containing the resource's result with content and messages.</returns>
+    /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
     /// <remarks>
     /// <para>
     /// This is a convenience method that internally calls <see cref="McpClient.ReadResourceAsync(string, RequestOptions, CancellationToken)"/>.

src/ModelContextProtocol.Core/Client/McpClientResource.cs

@@ -80,6 +80,7 @@ public McpClientResourceTemplate(McpClient client, ResourceTemplate resourceTemp
     /// </param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="ValueTask{ReadResourceResult}"/> containing the resource template's result with content and messages.</returns>
+    /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
     public ValueTask<ReadResourceResult> ReadAsync(
         IReadOnlyDictionary<string, object?> arguments,
         CancellationToken cancellationToken = default) =>

src/ModelContextProtocol.Core/Client/McpClientResourceTemplate.cs

@@ -18,6 +18,9 @@ public abstract partial class McpSession : IAsyncDisposable
     /// <param name="serializerOptions">The options governing request serialization.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task that represents the asynchronous operation. The task result contains the deserialized result.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="method"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="method"/> is empty or composed entirely of whitespace.</exception>
+    /// <exception cref="McpException">The request failed or the server returned an error response.</exception>
     public ValueTask<TResult> SendRequestAsync<TParameters, TResult>(
         string method,
         TParameters parameters,

src/ModelContextProtocol.Core/McpSession.Methods.cs

@@ -86,6 +86,8 @@ public abstract partial class McpSession : IAsyncDisposable
     /// <param name="method">The notification method.</param>
     /// <param name="handler">The handler to be invoked.</param>
     /// <returns>An <see cref="IDisposable"/> that will remove the registered handler when disposed.</returns>
+    /// <exception cref="ArgumentNullException"><paramref name="method"/> or <paramref name="handler"/> is <see langword="null"/>.</exception>
+    /// <exception cref="ArgumentException"><paramref name="method"/> is empty or composed entirely of whitespace.</exception>
     public abstract IAsyncDisposable RegisterNotificationHandler(string method, Func<JsonRpcNotification, CancellationToken, ValueTask> handler);
 
     /// <inheritdoc/>

src/ModelContextProtocol.Core/McpSession.cs

@@ -52,6 +52,7 @@ public static McpServer Create(
     /// <returns>A task containing the sampling result from the client.</returns>
     /// <exception cref="ArgumentNullException"><paramref name="requestParams"/> 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>
     public ValueTask<CreateMessageResult> SampleAsync(
         CreateMessageRequestParams requestParams,
         CancellationToken cancellationToken = default)
@@ -76,6 +77,7 @@ public ValueTask<CreateMessageResult> SampleAsync(
     /// <returns>A task containing the chat response from the model.</returns>
     /// <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>
     public async Task<ChatResponse> SampleAsync(
         IEnumerable<ChatMessage> messages, ChatOptions? chatOptions = default, CancellationToken cancellationToken = default)
     {
@@ -222,6 +224,7 @@ public ILoggerProvider AsClientLoggerProvider() =>
     /// <returns>A task containing the list of roots exposed by the client.</returns>
     /// <exception cref="ArgumentNullException"><paramref name="requestParams"/> is <see langword="null"/>.</exception>
     /// <exception cref="InvalidOperationException">The client does not support roots.</exception>
+    /// <exception cref="McpException">The request failed or the client returned an error response.</exception>
     public ValueTask<ListRootsResult> RequestRootsAsync(
         ListRootsRequestParams requestParams,
         CancellationToken cancellationToken = default)
@@ -245,6 +248,7 @@ public ValueTask<ListRootsResult> RequestRootsAsync(
     /// <returns>A task containing the elicitation result.</returns>
     /// <exception cref="ArgumentNullException"><paramref name="requestParams"/> is <see langword="null"/>.</exception>
     /// <exception cref="InvalidOperationException">The client does not support elicitation.</exception>
+    /// <exception cref="McpException">The request failed or the client returned an error response.</exception>
     public ValueTask<ElicitResult> ElicitAsync(
         ElicitRequestParams requestParams, 
         CancellationToken cancellationToken = default)
@@ -272,6 +276,7 @@ public ValueTask<ElicitResult> ElicitAsync(
     /// <exception cref="ArgumentNullException"><paramref name="message"/> is <see langword="null"/>.</exception>
     /// <exception cref="ArgumentException"><paramref name="message"/> is empty or composed entirely of whitespace.</exception>
     /// <exception cref="InvalidOperationException">The client does not support elicitation.</exception>
+    /// <exception cref="McpException">The request failed or the client returned an error response.</exception>
     /// <remarks>
     /// Elicitation uses a constrained subset of JSON Schema and only supports strings, numbers/integers, booleans and string enums.
     /// Unsupported member types are ignored when constructing the schema.