Multi Round-Trip Requests (MRTR) (#1458)

tests/ModelContextProtocol.ConformanceServer/Prompts/IncompleteResultPrompts.cs

@@ -0,0 +1,68 @@
+#pragma warning disable MCPEXP001 // MRTR (SEP-2322) is experimental.
+
+using ModelContextProtocol;
+using ModelContextProtocol.Protocol;
+using ModelContextProtocol.Server;
+using System.ComponentModel;
+using System.Text.Json;
+
+namespace ConformanceServer.Prompts;
+
+/// <summary>
+/// Prompt implementing the SEP-2322 D1 conformance scenario (<c>incomplete-result-non-tool-request</c>),
+/// proving that <c>prompts/get</c> can return an <see cref="InputRequiredResult"/> just like
+/// <c>tools/call</c>.
+/// </summary>
+[McpServerPromptType]
+public sealed class IncompleteResultPrompts
+{
+    [McpServerPrompt(Name = "test_incomplete_result_prompt")]
+    [Description("SEP-2322 D1: prompts/get returns IncompleteResult until user_context is supplied.")]
+    public static GetPromptResult IncompleteResultPrompt(RequestContext<GetPromptRequestParams> context)
+    {
+        if (context.Params!.InputResponses is { } responses &&
+            responses.TryGetValue("user_context", out var response))
+        {
+            var elicit = response.Deserialize(InputResponse.ElicitResultJsonTypeInfo);
+            var contextValue = TryReadString(elicit?.Content, "context") ?? "(unknown)";
+            return new GetPromptResult
+            {
+                Description = "Prompt customized with elicited user context.",
+                Messages =
+                [
+                    new PromptMessage
+                    {
+                        Role = Role.User,
+                        Content = new TextContentBlock { Text = $"Please continue using context: {contextValue}" },
+                    },
+                ],
+            };
+        }
+
+        throw new InputRequiredException(
+            new Dictionary<string, InputRequest>
+            {
+                ["user_context"] = InputRequest.ForElicitation(new ElicitRequestParams
+                {
+                    Message = "What context should the prompt use?",
+                    RequestedSchema = new ElicitRequestParams.RequestSchema
+                    {
+                        Properties = new Dictionary<string, ElicitRequestParams.PrimitiveSchemaDefinition>
+                        {
+                            ["context"] = new ElicitRequestParams.StringSchema(),
+                        },
+                        Required = ["context"],
+                    },
+                }),
+            });
+    }
+
+    private static string? TryReadString(IDictionary<string, JsonElement>? content, string key)
+    {
+        if (content is null || !content.TryGetValue(key, out var element))
+        {
+            return null;
+        }
+        return element.ValueKind == JsonValueKind.String ? element.GetString() : element.ToString();
+    }
+}