Add McpServerPrompt / McpClientPrompt and friends (#126)

src/ModelContextProtocol/Client/McpClientPrompt.cs

@@ -0,0 +1,41 @@
+using ModelContextProtocol.Protocol.Types;
+
+namespace ModelContextProtocol.Client;
+
+/// <summary>Provides an invocable prompt.</summary>
+public sealed class McpClientPrompt
+{
+    private readonly IMcpClient _client;
+
+    internal McpClientPrompt(IMcpClient client, Prompt prompt)
+    {
+        _client = client;
+        ProtocolPrompt = prompt;
+    }
+
+    /// <summary>Gets the protocol <see cref="Prompt"/> type for this instance.</summary>
+    public Prompt ProtocolPrompt { get; }
+
+    /// <summary>
+    /// Retrieves a specific prompt with optional arguments.
+    /// </summary>
+    /// <param name="arguments">Optional arguments for the prompt</param>
+    /// <param name="cancellationToken">A token to cancel the operation.</param>
+    /// <returns>A task containing the prompt's content and messages.</returns>
+    public async ValueTask<GetPromptResult> GetAsync(
+        IEnumerable<KeyValuePair<string, object?>>? arguments = null,
+        CancellationToken cancellationToken = default)
+    {
+        IReadOnlyDictionary<string, object?>? argDict =
+            arguments as IReadOnlyDictionary<string, object?> ??
+            arguments?.ToDictionary();
+
+        return await _client.GetPromptAsync(ProtocolPrompt.Name, argDict, cancellationToken).ConfigureAwait(false);
+    }
+
+    /// <summary>Gets the name of the prompt.</summary>
+    public string Name => ProtocolPrompt.Name;
+
+    /// <summary>Gets a description of the prompt.</summary>
+    public string? Description => ProtocolPrompt.Description;
+}