SPEC COMPLIANCE: Remove loose/passthrough types not allowed/defined by MCP spec + Task types

src/client/index.ts

@@ -28,11 +28,8 @@ import {
     ListToolsResultSchema,
     type LoggingLevel,
     McpError,
-    type Notification,
     type ReadResourceRequest,
     ReadResourceResultSchema,
-    type Request,
-    type Result,
     type ServerCapabilities,
     SUPPORTED_PROTOCOL_VERSIONS,
     type SubscribeRequest,
@@ -48,7 +45,10 @@ import {
     ResourceListChangedNotificationSchema,
     ListChangedOptions,
     ListChangedOptionsBaseSchema,
-    type ListChangedHandlers
+    type ListChangedHandlers,
+    type Request,
+    type Notification,
+    type Result
 } from '../types.js';
 import { AjvJsonSchemaValidator } from '../validation/ajv-provider.js';
 import type { JsonSchemaType, JsonSchemaValidator, jsonSchemaValidator } from '../validation/types.js';
@@ -368,14 +368,14 @@ export class Client<
                 }
 
                 const { params } = validatedRequest.data;
-                const mode = params.mode ?? 'form';
+                params.mode = params.mode ?? 'form';
                 const { supportsFormMode, supportsUrlMode } = getSupportedElicitationModes(this._capabilities.elicitation);
 
-                if (mode === 'form' && !supportsFormMode) {
+                if (params.mode === 'form' && !supportsFormMode) {
                     throw new McpError(ErrorCode.InvalidParams, 'Client does not support form-mode elicitation requests');
                 }
 
-                if (mode === 'url' && !supportsUrlMode) {
+                if (params.mode === 'url' && !supportsUrlMode) {
                     throw new McpError(ErrorCode.InvalidParams, 'Client does not support URL-mode elicitation requests');
                 }
 
@@ -404,9 +404,9 @@ export class Client<
                 }
 
                 const validatedResult = validationResult.data;
-                const requestedSchema = mode === 'form' ? (params.requestedSchema as JsonSchemaType) : undefined;
+                const requestedSchema = params.mode === 'form' ? (params.requestedSchema as JsonSchemaType) : undefined;
 
-                if (mode === 'form' && validatedResult.action === 'accept' && validatedResult.content && requestedSchema) {
+                if (params.mode === 'form' && validatedResult.action === 'accept' && validatedResult.content && requestedSchema) {
                     if (this._capabilities.elicitation?.form?.applyDefaults) {
                         try {
                             applyElicitationDefaults(requestedSchema, validatedResult.content);

src/client/streamableHttp.ts

@@ -1,5 +1,5 @@
 import { Transport, FetchLike, createFetchWithInit, normalizeHeaders } from '../shared/transport.js';
-import { isInitializedNotification, isJSONRPCRequest, isJSONRPCResponse, JSONRPCMessage, JSONRPCMessageSchema } from '../types.js';
+import { isInitializedNotification, isJSONRPCRequest, isJSONRPCResultResponse, JSONRPCMessage, JSONRPCMessageSchema } from '../types.js';
 import { auth, AuthResult, extractWWWAuthenticateParams, OAuthClientProvider, UnauthorizedError } from './auth.js';
 import { EventSourceParserStream } from 'eventsource-parser/stream';
 
@@ -350,7 +350,7 @@ export class StreamableHTTPClientTransport implements Transport {
                     if (!event.event || event.event === 'message') {
                         try {
                             const message = JSONRPCMessageSchema.parse(JSON.parse(event.data));
-                            if (isJSONRPCResponse(message)) {
+                            if (isJSONRPCResultResponse(message)) {
                                 // Mark that we received a response - no need to reconnect for this request
                                 receivedResponse = true;
                                 if (replayMessageId !== undefined) {

src/examples/server/simpleTaskInteractive.ts

@@ -34,7 +34,8 @@ import {
     ListToolsRequestSchema,
     CallToolRequestSchema,
     GetTaskRequestSchema,
-    GetTaskPayloadRequestSchema
+    GetTaskPayloadRequestSchema,
+    GetTaskPayloadResult
 } from '../../types.js';
 import { TaskMessageQueue, QueuedMessage, QueuedRequest, isTerminal, CreateTaskOptions } from '../../experimental/tasks/interfaces.js';
 import { InMemoryTaskStore } from '../../experimental/tasks/stores/in-memory.js';
@@ -618,7 +619,7 @@ const createServer = (): Server => {
     });
 
     // Handle tasks/result
-    server.setRequestHandler(GetTaskPayloadRequestSchema, async (request, extra): Promise<Result> => {
+    server.setRequestHandler(GetTaskPayloadRequestSchema, async (request, extra): Promise<GetTaskPayloadResult> => {
         const { taskId } = request.params;
         console.log(`[Server] tasks/result called for task ${taskId}`);
         return taskResultHandler.handle(taskId, server, extra.sessionId ?? '');

src/experimental/tasks/interfaces.ts

@@ -5,18 +5,18 @@
 
 import {
     Task,
-    Request,
     RequestId,
     Result,
     JSONRPCRequest,
     JSONRPCNotification,
-    JSONRPCResponse,
-    JSONRPCError,
+    JSONRPCResultResponse,
+    JSONRPCErrorResponse,
     ServerRequest,
     ServerNotification,
     CallToolResult,
     GetTaskResult,
-    ToolExecution
+    ToolExecution,
+    Request
 } from '../../types.js';
 import { CreateTaskResult } from './types.js';
 import type { RequestHandlerExtra, RequestTaskStore } from '../../shared/protocol.js';
@@ -124,13 +124,13 @@ export interface QueuedNotification extends BaseQueuedMessage {
 export interface QueuedResponse extends BaseQueuedMessage {
     type: 'response';
     /** The actual JSONRPC response */
-    message: JSONRPCResponse;
+    message: JSONRPCResultResponse;
 }
 
 export interface QueuedError extends BaseQueuedMessage {
     type: 'error';
     /** The actual JSONRPC error */
-    message: JSONRPCError;
+    message: JSONRPCErrorResponse;
 }
 
 /**

src/experimental/tasks/stores/in-memory.ts

@@ -5,7 +5,7 @@
  * @experimental
  */
 
-import { Task, Request, RequestId, Result } from '../../../types.js';
+import { Task, RequestId, Result, Request } from '../../../types.js';
 import { TaskStore, isTerminal, TaskMessageQueue, QueuedMessage, CreateTaskOptions } from '../interfaces.js';
 import { randomBytes } from 'node:crypto';
 

src/server/index.ts

@@ -26,10 +26,7 @@ import {
     LoggingLevelSchema,
     type LoggingMessageNotification,
     McpError,
-    type Notification,
-    type Request,
     type ResourceUpdatedNotification,
-    type Result,
     type ServerCapabilities,
     type ServerNotification,
     type ServerRequest,
@@ -40,7 +37,10 @@ import {
     type ToolUseContent,
     CallToolRequestSchema,
     CallToolResultSchema,
-    CreateTaskResultSchema
+    CreateTaskResultSchema,
+    type Request,
+    type Notification,
+    type Result
 } from '../types.js';
 import { AjvJsonSchemaValidator } from '../validation/ajv-provider.js';
 import type { JsonSchemaType, jsonSchemaValidator } from '../validation/types.js';

src/server/streamableHttp.ts

@@ -4,14 +4,14 @@ import {
     MessageExtraInfo,
     RequestInfo,
     isInitializeRequest,
-    isJSONRPCError,
     isJSONRPCRequest,
-    isJSONRPCResponse,
+    isJSONRPCResultResponse,
     JSONRPCMessage,
     JSONRPCMessageSchema,
     RequestId,
     SUPPORTED_PROTOCOL_VERSIONS,
-    DEFAULT_NEGOTIATED_PROTOCOL_VERSION
+    DEFAULT_NEGOTIATED_PROTOCOL_VERSION,
+    isJSONRPCErrorResponse
 } from '../types.js';
 import getRawBody from 'raw-body';
 import contentType from 'content-type';
@@ -871,7 +871,7 @@ export class StreamableHTTPServerTransport implements Transport {
 
     async send(message: JSONRPCMessage, options?: { relatedRequestId?: RequestId }): Promise<void> {
         let requestId = options?.relatedRequestId;
-        if (isJSONRPCResponse(message) || isJSONRPCError(message)) {
+        if (isJSONRPCResultResponse(message) || isJSONRPCErrorResponse(message)) {
             // If the message is a response, use the request ID from the message
             requestId = message.id;
         }
@@ -881,7 +881,7 @@ export class StreamableHTTPServerTransport implements Transport {
         // Those will be sent via dedicated response SSE streams
         if (requestId === undefined) {
             // For standalone SSE streams, we can only send requests and notifications
-            if (isJSONRPCResponse(message) || isJSONRPCError(message)) {
+            if (isJSONRPCResultResponse(message) || isJSONRPCErrorResponse(message)) {
                 throw new Error('Cannot send a response on a standalone SSE stream unless resuming a previous client request');
             }
 
@@ -924,7 +924,7 @@ export class StreamableHTTPServerTransport implements Transport {
             }
         }
 
-        if (isJSONRPCResponse(message) || isJSONRPCError(message)) {
+        if (isJSONRPCResultResponse(message) || isJSONRPCErrorResponse(message)) {
             this._requestResponseMap.set(requestId, message);
             const relatedIds = Array.from(this._requestToStreamMapping.entries())
                 .filter(([_, streamId]) => this._streamMapping.get(streamId) === response)

src/shared/protocol.ts

@@ -13,22 +13,20 @@ import {
     ListTasksResultSchema,
     CancelTaskRequestSchema,
     CancelTaskResultSchema,
-    isJSONRPCError,
+    isJSONRPCErrorResponse,
     isJSONRPCRequest,
-    isJSONRPCResponse,
+    isJSONRPCResultResponse,
     isJSONRPCNotification,
-    JSONRPCError,
+    JSONRPCErrorResponse,
     JSONRPCNotification,
     JSONRPCRequest,
     JSONRPCResponse,
     McpError,
-    Notification,
     PingRequestSchema,
     Progress,
     ProgressNotification,
     ProgressNotificationSchema,
     RELATED_TASK_META_KEY,
-    Request,
     RequestId,
     Result,
     ServerCapabilities,
@@ -41,7 +39,11 @@ import {
     CancelledNotification,
     Task,
     TaskStatusNotification,
-    TaskStatusNotificationSchema
+    TaskStatusNotificationSchema,
+    Request,
+    Notification,
+    JSONRPCResultResponse,
+    isTaskAugmentedRequestParams
 } from '../types.js';
 import { Transport, TransportSendOptions } from './transport.js';
 import { AuthInfo } from '../server/auth/types.js';
@@ -324,7 +326,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
     > = new Map();
     private _requestHandlerAbortControllers: Map<RequestId, AbortController> = new Map();
     private _notificationHandlers: Map<string, (notification: JSONRPCNotification) => Promise<void>> = new Map();
-    private _responseHandlers: Map<number, (response: JSONRPCResponse | Error) => void> = new Map();
+    private _responseHandlers: Map<number, (response: JSONRPCResultResponse | Error) => void> = new Map();
     private _progressHandlers: Map<number, ProgressCallback> = new Map();
     private _timeoutInfo: Map<number, TimeoutInfo> = new Map();
     private _pendingDebouncedNotifications = new Set<string>();
@@ -335,7 +337,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
     private _taskStore?: TaskStore;
     private _taskMessageQueue?: TaskMessageQueue;
 
-    private _requestResolvers: Map<RequestId, (response: JSONRPCResponse | Error) => void> = new Map();
+    private _requestResolvers: Map<RequestId, (response: JSONRPCResultResponse | Error) => void> = new Map();
 
     /**
      * Callback for when the connection is closed for any reason.
@@ -408,18 +410,18 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
                                 const requestId = message.id;
 
                                 // Lookup resolver in _requestResolvers map
-                                const resolver = this._requestResolvers.get(requestId);
+                                const resolver = this._requestResolvers.get(requestId as RequestId);
 
                                 if (resolver) {
                                     // Remove resolver from map after invocation
-                                    this._requestResolvers.delete(requestId);
+                                    this._requestResolvers.delete(requestId as RequestId);
 
                                     // Invoke resolver with response or error
                                     if (queuedMessage.type === 'response') {
-                                        resolver(message as JSONRPCResponse);
+                                        resolver(message as JSONRPCResultResponse);
                                     } else {
                                         // Convert JSONRPCError to McpError
-                                        const errorMessage = message as JSONRPCError;
+                                        const errorMessage = message as JSONRPCErrorResponse;
                                         const error = new McpError(
                                             errorMessage.error.code,
                                             errorMessage.error.message,
@@ -546,6 +548,9 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
     }
 
     private async _oncancel(notification: CancelledNotification): Promise<void> {
+        if (!notification.params.requestId) {
+            return;
+        }
         // Handle request cancellation
         const controller = this._requestHandlerAbortControllers.get(notification.params.requestId);
         controller?.abort(notification.params.reason);
@@ -616,7 +621,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
         const _onmessage = this._transport?.onmessage;
         this._transport.onmessage = (message, extra) => {
             _onmessage?.(message, extra);
-            if (isJSONRPCResponse(message) || isJSONRPCError(message)) {
+            if (isJSONRPCResultResponse(message) || isJSONRPCErrorResponse(message)) {
                 this._onresponse(message);
             } else if (isJSONRPCRequest(message)) {
                 this._onrequest(message, extra);
@@ -675,7 +680,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
         const relatedTaskId = request.params?._meta?.[RELATED_TASK_META_KEY]?.taskId;
 
         if (handler === undefined) {
-            const errorResponse: JSONRPCError = {
+            const errorResponse: JSONRPCErrorResponse = {
                 jsonrpc: '2.0',
                 id: request.id,
                 error: {
@@ -706,7 +711,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
         const abortController = new AbortController();
         this._requestHandlerAbortControllers.set(request.id, abortController);
 
-        const taskCreationParams = request.params?.task;
+        const taskCreationParams = isTaskAugmentedRequestParams(request.params) ? request.params.task : undefined;
         const taskStore = this._taskStore ? this.requestTaskStore(request, capturedTransport?.sessionId) : undefined;
 
         const fullExtra: RequestHandlerExtra<SendRequestT, SendNotificationT> = {
@@ -791,7 +796,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
                         return;
                     }
 
-                    const errorResponse: JSONRPCError = {
+                    const errorResponse: JSONRPCErrorResponse = {
                         jsonrpc: '2.0',
                         id: request.id,
                         error: {
@@ -852,14 +857,14 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
         handler(params);
     }
 
-    private _onresponse(response: JSONRPCResponse | JSONRPCError): void {
+    private _onresponse(response: JSONRPCResponse | JSONRPCErrorResponse): void {
         const messageId = Number(response.id);
 
         // Check if this is a response to a queued request
         const resolver = this._requestResolvers.get(messageId);
         if (resolver) {
             this._requestResolvers.delete(messageId);
-            if (isJSONRPCResponse(response)) {
+            if (isJSONRPCResultResponse(response)) {
                 resolver(response);
             } else {
                 const error = new McpError(response.error.code, response.error.message, response.error.data);
@@ -879,7 +884,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
 
         // Keep progress handler alive for CreateTaskResult responses
         let isTaskResponse = false;
-        if (isJSONRPCResponse(response) && response.result && typeof response.result === 'object') {
+        if (isJSONRPCResultResponse(response) && response.result && typeof response.result === 'object') {
             const result = response.result as Record<string, unknown>;
             if (result.task && typeof result.task === 'object') {
                 const task = result.task as Record<string, unknown>;
@@ -894,7 +899,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
             this._progressHandlers.delete(messageId);
         }
 
-        if (isJSONRPCResponse(response)) {
+        if (isJSONRPCResultResponse(response)) {
             handler(response);
         } else {
             const error = McpError.fromError(response.error.code, response.error.message, response.error.data);
@@ -1191,7 +1196,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
             const relatedTaskId = relatedTask?.taskId;
             if (relatedTaskId) {
                 // Store the response resolver for this request so responses can be routed back
-                const responseResolver = (response: JSONRPCResponse | Error) => {
+                const responseResolver = (response: JSONRPCResultResponse | Error) => {
                     const handler = this._responseHandlers.get(messageId);
                     if (handler) {
                         handler(response);