diff --git a/shared/McpSamples.Shared/OpenApi/McpDocumentTransformer.cs b/shared/McpSamples.Shared/OpenApi/McpDocumentTransformer.cs
index 8beb9b07..4a12a7a0 100644
--- a/shared/McpSamples.Shared/OpenApi/McpDocumentTransformer.cs
+++ b/shared/McpSamples.Shared/OpenApi/McpDocumentTransformer.cs
@@ -1,3 +1,4 @@
+using System.Net.Mime;
 using System.Text.Json.Nodes;
 
 using McpSamples.Shared.Configurations;
@@ -6,6 +7,8 @@
 using Microsoft.AspNetCore.OpenApi;
 using Microsoft.OpenApi;
 
+using ModelContextProtocol.Protocol;
+
 namespace McpSamples.Shared.OpenApi;
 
 /// <summary>
@@ -13,10 +16,10 @@ namespace McpSamples.Shared.OpenApi;
 /// </summary>
 /// <param name="appsettings"><see cref="AppSettings"/> instance.</param>
 /// <param name="accessor"><see cref="IHttpContextAccessor"/> instance.</param>
-public class McpDocumentTransformer<T>(T appsettings, IHttpContextAccessor accessor) : IOpenApiDocumentTransformer where T : AppSettings, new()
+public sealed class McpDocumentTransformer<T>(T appsettings, IHttpContextAccessor accessor) : IOpenApiDocumentTransformer where T : AppSettings, new()
 {
     /// <inheritdoc />
-    public Task TransformAsync(OpenApiDocument document, OpenApiDocumentTransformerContext context, CancellationToken cancellationToken)
+    public async Task TransformAsync(OpenApiDocument document, OpenApiDocumentTransformerContext context, CancellationToken cancellationToken)
     {
         document.Info = new OpenApiInfo
         {
@@ -33,10 +36,38 @@ public Task TransformAsync(OpenApiDocument document, OpenApiDocumentTransformerC
                     : "http://localhost:8080/"
             }
         ];
+
+        // Register JSON-RPC schemas as components
+        var jsonRpcRequest = await context.GetOrCreateSchemaAsync(typeof(JsonRpcRequest), cancellationToken: cancellationToken);
+        var jsonRpcNotification = await context.GetOrCreateSchemaAsync(typeof(JsonRpcNotification), cancellationToken: cancellationToken);
+        var jsonRpcResponse = await context.GetOrCreateSchemaAsync(typeof(JsonRpcResponse), cancellationToken: cancellationToken);
+        var jsonRpcError = await context.GetOrCreateSchemaAsync(typeof(JsonRpcError), cancellationToken: cancellationToken);
+
+        document.AddComponent(nameof(JsonRpcRequest), jsonRpcRequest);
+        document.AddComponent(nameof(JsonRpcNotification), jsonRpcNotification);
+        document.AddComponent(nameof(JsonRpcResponse), jsonRpcResponse);
+        document.AddComponent(nameof(JsonRpcError), jsonRpcError);
+
+        // Build oneOf schema for request body per MCP Streamable HTTP spec:
+        // "The body of the POST request MUST be a single JSON-RPC request, notification, or response."
+        var jsonRpcMessage = new OpenApiSchema
+        {
+            OneOf =
+            [
+                new OpenApiSchemaReference(nameof(JsonRpcRequest), document),
+                new OpenApiSchemaReference(nameof(JsonRpcNotification), document),
+                new OpenApiSchemaReference(nameof(JsonRpcResponse), document),
+            ]
+        };
+        document.AddComponent("JsonRpcMessage", jsonRpcMessage);
+
         var pathItem = new OpenApiPathItem();
+
+        // POST /mcp - Send a JSON-RPC request, notification, or response
         pathItem.AddOperation(HttpMethod.Post, new OpenApiOperation
         {
             Summary = "Invoke operation",
+            Description = "Send a JSON-RPC request, notification, or response to the MCP server.",
             Extensions = new Dictionary<string, IOpenApiExtension>
             {
                 ["x-ms-agentic-protocol"] = new JsonNodeExtension(JsonValue.Create("mcp-streamable-1.0"))
@@ -46,14 +77,190 @@ public Task TransformAsync(OpenApiDocument document, OpenApiDocumentTransformerC
             {
                 ["200"] = new OpenApiResponse
                 {
-                    Description = "Success",
-                }
-            }
+                    Description = "Success - returned when the input is a JSON-RPC request",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcResponse), document),
+                        },
+                        [MediaTypeNames.Text.EventStream] = new()
+                        {
+                            Schema = new OpenApiSchema
+                            {
+                                Type = JsonSchemaType.String,
+                                Description = "Server-Sent Events stream containing JSON-RPC responses",
+                            },
+                        },
+                    },
+                },
+                ["202"] = new OpenApiResponse
+                {
+                    Description = "Accepted - returned when the input is a JSON-RPC response or notification",
+                },
+                ["400"] = new OpenApiResponse
+                {
+                    Description = "Bad Request - invalid JSON-RPC message, unsupported protocol version, or missing/invalid session ID",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["403"] = new OpenApiResponse
+                {
+                    Description = "Forbidden - invalid Origin header, or the authenticated user does not match the user who initiated the session",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["404"] = new OpenApiResponse
+                {
+                    Description = "Not Found - the specified session ID was not found",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["406"] = new OpenApiResponse
+                {
+                    Description = "Not Acceptable - client must accept both application/json and text/event-stream",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+            },
+            RequestBody = new OpenApiRequestBody
+            {
+                Required = true,
+                Content = new Dictionary<string, OpenApiMediaType>
+                {
+                    [MediaTypeNames.Application.Json] = new()
+                    {
+                        Schema = new OpenApiSchemaReference("JsonRpcMessage", document),
+                    },
+                },
+            },
+        });
+
+        // GET /mcp - Open SSE stream for server-initiated messages (stateful mode only)
+        pathItem.AddOperation(HttpMethod.Get, new OpenApiOperation
+        {
+            Summary = "Open SSE stream",
+            Description = "Open a Server-Sent Events stream to receive server-initiated JSON-RPC messages. Only available in stateful mode.",
+            OperationId = "OpenMCPStream",
+            Responses = new OpenApiResponses
+            {
+                ["200"] = new OpenApiResponse
+                {
+                    Description = "SSE stream opened successfully",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Text.EventStream] = new()
+                        {
+                            Schema = new OpenApiSchema
+                            {
+                                Type = JsonSchemaType.String,
+                                Description = "Server-Sent Events stream containing JSON-RPC messages",
+                            },
+                        },
+                    },
+                },
+                ["400"] = new OpenApiResponse
+                {
+                    Description = "Bad Request - missing session ID, unsupported protocol version, or invalid Last-Event-ID",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["404"] = new OpenApiResponse
+                {
+                    Description = "Not Found - the specified session ID was not found",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["405"] = new OpenApiResponse
+                {
+                    Description = "Method Not Allowed - server does not offer an SSE stream at this endpoint",
+                },
+                ["406"] = new OpenApiResponse
+                {
+                    Description = "Not Acceptable - client must accept text/event-stream",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+            },
+        });
+
+        // DELETE /mcp - Terminate a session (stateful mode only)
+        pathItem.AddOperation(HttpMethod.Delete, new OpenApiOperation
+        {
+            Summary = "Terminate session",
+            Description = "Terminate an active MCP session and clean up server-side resources. Only available in stateful mode.",
+            OperationId = "TerminateMCPSession",
+            Responses = new OpenApiResponses
+            {
+                ["200"] = new OpenApiResponse
+                {
+                    Description = "Session terminated successfully",
+                },
+                ["400"] = new OpenApiResponse
+                {
+                    Description = "Bad Request - missing session ID or unsupported protocol version",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["404"] = new OpenApiResponse
+                {
+                    Description = "Not Found - the specified session ID was not found",
+                    Content = new Dictionary<string, OpenApiMediaType>
+                    {
+                        [MediaTypeNames.Application.Json] = new()
+                        {
+                            Schema = new OpenApiSchemaReference(nameof(JsonRpcError), document),
+                        },
+                    },
+                },
+                ["405"] = new OpenApiResponse
+                {
+                    Description = "Method Not Allowed - server does not allow clients to terminate sessions",
+                },
+            },
         });
 
         document.Paths ??= [];
         document.Paths.Add("/mcp", pathItem);
-
-        return Task.CompletedTask;
     }
-}
\ No newline at end of file
+}