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 RequestGeneric,
+    type NotificationGeneric,
+    type Result
 } from '../types.js';
 import { AjvJsonSchemaValidator } from '../validation/ajv-provider.js';
 import type { JsonSchemaType, JsonSchemaValidator, jsonSchemaValidator } from '../validation/types.js';
@@ -231,8 +231,8 @@ export type ClientOptions = ProtocolOptions & {
  * ```
  */
 export class Client<
-    RequestT extends Request = Request,
-    NotificationT extends Notification = Notification,
+    RequestT extends RequestGeneric = RequestGeneric,
+    NotificationT extends NotificationGeneric = NotificationGeneric,
     ResultT extends Result = Result
 > extends Protocol<ClientRequest | RequestT, ClientNotification | NotificationT, ClientResult | ResultT> {
     private _serverCapabilities?: ServerCapabilities;
@@ -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/experimental/tasks/interfaces.ts

@@ -5,7 +5,6 @@
 
 import {
     Task,
-    Request,
     RequestId,
     Result,
     JSONRPCRequest,
@@ -16,7 +15,8 @@ import {
     ServerNotification,
     CallToolResult,
     GetTaskResult,
-    ToolExecution
+    ToolExecution,
+    RequestGeneric
 } from '../../types.js';
 import { CreateTaskResult } from './types.js';
 import type { RequestHandlerExtra, RequestTaskStore } from '../../shared/protocol.js';
@@ -226,7 +226,7 @@ export interface TaskStore {
      * @param sessionId - Optional session ID for binding the task to a specific session
      * @returns The created task object
      */
-    createTask(taskParams: CreateTaskOptions, requestId: RequestId, request: Request, sessionId?: string): Promise<Task>;
+    createTask(taskParams: CreateTaskOptions, requestId: RequestId, request: RequestGeneric, sessionId?: string): Promise<Task>;
 
     /**
      * Gets the current status of a task.

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

@@ -5,13 +5,13 @@
  * @experimental
  */
 
-import { Task, Request, RequestId, Result } from '../../../types.js';
+import { Task, RequestId, Result, RequestGeneric } from '../../../types.js';
 import { TaskStore, isTerminal, TaskMessageQueue, QueuedMessage, CreateTaskOptions } from '../interfaces.js';
 import { randomBytes } from 'node:crypto';
 
 interface StoredTask {
     task: Task;
-    request: Request;
+    request: RequestGeneric;
     requestId: RequestId;
     result?: Result;
 }
@@ -39,7 +39,7 @@ export class InMemoryTaskStore implements TaskStore {
         return randomBytes(16).toString('hex');
     }
 
-    async createTask(taskParams: CreateTaskOptions, requestId: RequestId, request: Request, _sessionId?: string): Promise<Task> {
+    async createTask(taskParams: CreateTaskOptions, requestId: RequestId, request: RequestGeneric, _sessionId?: string): Promise<Task> {
         // Generate a unique task ID
         const taskId = this.generateTaskId();
 

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 RequestGeneric,
+    type NotificationGeneric,
+    type Result
 } from '../types.js';
 import { AjvJsonSchemaValidator } from '../validation/ajv-provider.js';
 import type { JsonSchemaType, jsonSchemaValidator } from '../validation/types.js';
@@ -127,8 +127,8 @@ export type ServerOptions = ProtocolOptions & {
  * @deprecated Use `McpServer` instead for the high-level API. Only use `Server` for advanced use cases.
  */
 export class Server<
-    RequestT extends Request = Request,
-    NotificationT extends Notification = Notification,
+    RequestT extends RequestGeneric = RequestGeneric,
+    NotificationT extends NotificationGeneric = NotificationGeneric,
     ResultT extends Result = Result
 > extends Protocol<ServerRequest | RequestT, ServerNotification | NotificationT, ServerResult | ResultT> {
     private _clientCapabilities?: ClientCapabilities;

src/shared/protocol.ts

@@ -22,13 +22,11 @@ import {
     JSONRPCRequest,
     JSONRPCResponse,
     McpError,
-    Notification,
     PingRequestSchema,
     Progress,
     ProgressNotification,
     ProgressNotificationSchema,
     RELATED_TASK_META_KEY,
-    Request,
     RequestId,
     Result,
     ServerCapabilities,
@@ -41,7 +39,9 @@ import {
     CancelledNotification,
     Task,
     TaskStatusNotification,
-    TaskStatusNotificationSchema
+    TaskStatusNotificationSchema,
+    RequestGeneric,
+    NotificationGeneric
 } from '../types.js';
 import { Transport, TransportSendOptions } from './transport.js';
 import { AuthInfo } from '../server/auth/types.js';
@@ -232,7 +232,7 @@ export interface RequestTaskStore {
 /**
  * Extra data given to request handlers.
  */
-export type RequestHandlerExtra<SendRequestT extends Request, SendNotificationT extends Notification> = {
+export type RequestHandlerExtra<SendRequestT extends RequestGeneric, SendNotificationT extends NotificationGeneric> = {
     /**
      * An abort signal used to communicate if the request was cancelled from the sender's side.
      */
@@ -315,7 +315,11 @@ type TimeoutInfo = {
  * Implements MCP protocol framing on top of a pluggable transport, including
  * features like request/response linking, notifications, and progress.
  */
-export abstract class Protocol<SendRequestT extends Request, SendNotificationT extends Notification, SendResultT extends Result> {
+export abstract class Protocol<
+    SendRequestT extends RequestGeneric,
+    SendNotificationT extends NotificationGeneric,
+    SendResultT extends Result
+> {
     private _transport?: Transport;
     private _requestMessageId = 0;
     private _requestHandlers: Map<
@@ -359,7 +363,7 @@ export abstract class Protocol<SendRequestT extends Request, SendNotificationT e
     /**
      * A handler to invoke for any notification types that do not have their own handler installed.
      */
-    fallbackNotificationHandler?: (notification: Notification) => Promise<void>;
+    fallbackNotificationHandler?: (notification: NotificationGeneric) => Promise<void>;
 
     constructor(private _options?: ProtocolOptions) {
         this.setNotificationHandler(CancelledNotificationSchema, notification => {