save commit

Author: KKonstantinov

src/client/index.test.ts

@@ -822,6 +822,7 @@ describe('outputSchema validation', () => {
         server.setRequestHandler(CallToolRequestSchema, async request => {
             if (request.params.name === 'test-tool') {
                 return {
+                    content: [],
                     structuredContent: { result: 'success', count: 42 }
                 };
             }
@@ -897,6 +898,7 @@ describe('outputSchema validation', () => {
             if (request.params.name === 'test-tool') {
                 // Return invalid structured content (count is string instead of number)
                 return {
+                    content: [],
                     structuredContent: { result: 'success', count: 'not a number' }
                 };
             }
@@ -1124,6 +1126,7 @@ describe('outputSchema validation', () => {
         server.setRequestHandler(CallToolRequestSchema, async request => {
             if (request.params.name === 'complex-tool') {
                 return {
+                    content: [],
                     structuredContent: {
                         name: 'John Doe',
                         age: 30,
@@ -1209,6 +1212,7 @@ describe('outputSchema validation', () => {
             if (request.params.name === 'strict-tool') {
                 // Return structured content with extra property
                 return {
+                    content: [],
                     structuredContent: {
                         name: 'John',
                         extraField: 'not allowed'

src/client/index.ts

@@ -7,7 +7,6 @@ import {
     type ClientNotification,
     type ClientRequest,
     type ClientResult,
-    type CompatibilityCallToolResultSchema,
     type CompleteRequest,
     CompleteResultSchema,
     EmptyResultSchema,
@@ -27,18 +26,19 @@ import {
     ListToolsResultSchema,
     type LoggingLevel,
     McpError,
-    type Notification,
     type ReadResourceRequest,
     ReadResourceResultSchema,
-    type Request,
-    type Result,
     type ServerCapabilities,
     SUPPORTED_PROTOCOL_VERSIONS,
     type SubscribeRequest,
     type Tool,
     type UnsubscribeRequest,
     ElicitResultSchema,
-    ElicitRequestSchema
+    ElicitRequestSchema,
+    type RequestGeneric,
+    type NotificationGeneric,
+    type ResultGeneric,
+    Result
 } from '../types.js';
 import { AjvJsonSchemaValidator } from '../validation/ajv-provider.js';
 import type { JsonSchemaType, JsonSchemaValidator, jsonSchemaValidator } from '../validation/types.js';
@@ -149,9 +149,9 @@ export type ClientOptions = ProtocolOptions & {
  * ```
  */
 export class Client<
-    RequestT extends Request = Request,
-    NotificationT extends Notification = Notification,
-    ResultT extends Result = Result
+    RequestT extends RequestGeneric = RequestGeneric,
+    NotificationT extends NotificationGeneric = NotificationGeneric,
+    ResultT extends ResultGeneric = Result
 > extends Protocol<ClientRequest | RequestT, ClientNotification | NotificationT, ClientResult | ResultT> {
     private _serverCapabilities?: ServerCapabilities;
     private _serverVersion?: Implementation;
@@ -461,7 +461,7 @@ export class Client<
 
     async callTool(
         params: CallToolRequest['params'],
-        resultSchema: typeof CallToolResultSchema | typeof CompatibilityCallToolResultSchema = CallToolResultSchema,
+        resultSchema: typeof CallToolResultSchema = CallToolResultSchema,
         options?: RequestOptions
     ) {
         const result = await this.request({ method: 'tools/call', params }, resultSchema, options);

src/server/index.ts

@@ -20,16 +20,17 @@ import {
     LoggingLevelSchema,
     type LoggingMessageNotification,
     McpError,
-    type Notification,
-    type Request,
     type ResourceUpdatedNotification,
-    type Result,
     type ServerCapabilities,
     type ServerNotification,
     type ServerRequest,
     type ServerResult,
     SetLevelRequestSchema,
-    SUPPORTED_PROTOCOL_VERSIONS
+    SUPPORTED_PROTOCOL_VERSIONS,
+    type RequestGeneric,
+    type NotificationGeneric,
+    type ResultGeneric,
+    Result
 } from '../types.js';
 import { AjvJsonSchemaValidator } from '../validation/ajv-provider.js';
 import type { JsonSchemaType, jsonSchemaValidator } from '../validation/types.js';
@@ -104,9 +105,9 @@ 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,
-    ResultT extends Result = Result
+    RequestT extends RequestGeneric = RequestGeneric,
+    NotificationT extends NotificationGeneric = NotificationGeneric,
+    ResultT extends ResultGeneric = Result
 > extends Protocol<ServerRequest | RequestT, ServerNotification | NotificationT, ServerResult | ResultT> {
     private _clientCapabilities?: ClientCapabilities;
     private _clientVersion?: Implementation;

src/server/mcp.test.ts

@@ -4273,6 +4273,7 @@ describe('elicitInput()', () => {
 
         expect(checkAvailability).toHaveBeenCalledWith('ABC Restaurant', '2024-12-25', 2);
         expect(findAlternatives).not.toHaveBeenCalled();
+
         expect(result.content).toEqual([
             {
                 type: 'text',

src/shared/protocol.test.ts

@@ -1,5 +1,5 @@
 import { ZodType, z } from 'zod';
-import { ClientCapabilities, ErrorCode, McpError, Notification, Request, Result, ServerCapabilities } from '../types.js';
+import { ClientCapabilities, ErrorCode, McpError, NotificationGeneric, RequestGeneric, Result, ServerCapabilities } from '../types.js';
 import { Protocol, mergeCapabilities } from './protocol.js';
 import { Transport } from './transport.js';
 import { MockInstance } from 'vitest';
@@ -18,14 +18,14 @@ class MockTransport implements Transport {
 }
 
 describe('protocol tests', () => {
-    let protocol: Protocol<Request, Notification, Result>;
+    let protocol: Protocol<RequestGeneric, NotificationGeneric, Result>;
     let transport: MockTransport;
     let sendSpy: MockInstance;
 
     beforeEach(() => {
         transport = new MockTransport();
         sendSpy = vi.spyOn(transport, 'send');
-        protocol = new (class extends Protocol<Request, Notification, Result> {
+        protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
             protected assertCapabilityForMethod(): void {}
             protected assertNotificationCapability(): void {}
             protected assertRequestHandlerCapability(): void {}
@@ -479,7 +479,7 @@ describe('protocol tests', () => {
 
         it('should NOT debounce a notification that has parameters', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}
@@ -500,7 +500,7 @@ describe('protocol tests', () => {
 
         it('should NOT debounce a notification that has a relatedRequestId', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}
@@ -519,7 +519,7 @@ describe('protocol tests', () => {
 
         it('should clear pending debounced notifications on connection close', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}
@@ -543,7 +543,7 @@ describe('protocol tests', () => {
 
         it('should debounce multiple synchronous calls when params property is omitted', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}
@@ -570,7 +570,7 @@ describe('protocol tests', () => {
 
         it('should debounce calls when params is explicitly undefined', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}
@@ -595,7 +595,7 @@ describe('protocol tests', () => {
 
         it('should send non-debounced notifications immediately and multiple times', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}
@@ -628,7 +628,7 @@ describe('protocol tests', () => {
 
         it('should handle sequential batches of debounced notifications correctly', async () => {
             // ARRANGE
-            protocol = new (class extends Protocol<Request, Notification, Result> {
+            protocol = new (class extends Protocol<RequestGeneric, NotificationGeneric, Result> {
                 protected assertCapabilityForMethod(): void {}
                 protected assertNotificationCapability(): void {}
                 protected assertRequestHandlerCapability(): void {}

src/shared/protocol.ts

@@ -19,11 +19,13 @@ import {
     ProgressNotificationSchema,
     Request,
     RequestId,
-    Result,
     ServerCapabilities,
     RequestMeta,
     MessageExtraInfo,
-    RequestInfo
+    RequestInfo,
+    type RequestGeneric,
+    type NotificationGeneric,
+    type ResultGeneric
 } from '../types.js';
 import { Transport, TransportSendOptions } from './transport.js';
 import { AuthInfo } from '../server/auth/types.js';
@@ -171,7 +173,11 @@ 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 ResultGeneric
+> {
     private _transport?: Transport;
     private _requestMessageId = 0;
     private _requestHandlers: Map<

src/spec.types.test.ts

@@ -62,6 +62,12 @@ type MakeUnknownsNotOptional<T> =
                       }
           : T;
 
+/**
+ * Spec Patches
+ *
+ * Temporary spec type patches, to be used until the spec is updated to fix the issues.
+ */
+
 // Targeted fix: in spec, treat ClientCapabilities.elicitation?: object as Record<string, unknown>
 type FixSpecClientCapabilities<T> = T extends { elicitation?: object }
     ? Omit<T, 'elicitation'> & { elicitation?: Record<string, unknown> }
@@ -75,6 +81,14 @@ type FixSpecInitializeRequest<T> = T extends { params: infer P } ? Omit<T, 'para
 
 type FixSpecClientRequest<T> = T extends { params: infer P } ? Omit<T, 'params'> & { params: FixSpecInitializeRequestParams<P> } : T;
 
+// ElicitResult - spec does not allow undefined values in the content object
+type SpecElicitResultPatched = Omit<SpecTypes.ElicitResult, 'content'> & {
+    action: SpecTypes.ElicitResult['action'];
+    content?: {
+        [key: string]: string | number | boolean | string[] | undefined;
+    };
+};
+
 const sdkTypeChecks = {
     RequestParams: (sdk: SDKTypes.RequestParams, spec: SpecTypes.RequestParams) => {
         sdk = spec;
@@ -205,7 +219,7 @@ const sdkTypeChecks = {
         sdk = spec;
         spec = sdk;
     },
-    ElicitResult: (sdk: SDKTypes.ElicitResult, spec: SpecTypes.ElicitResult) => {
+    ElicitResult: (sdk: SDKTypes.ElicitResult, spec: SpecElicitResultPatched) => {
         sdk = spec;
         spec = sdk;
     },

src/types.ts

@@ -42,7 +42,7 @@ const BaseRequestParamsSchema = z.object({
     /**
      * See [General fields: `_meta`](/specification/draft/basic/index#meta) for notes on `_meta` usage.
      */
-    _meta: RequestMetaSchema.optional()
+    _meta: z.intersection(RequestMetaSchema.optional(), z.record(z.string(), z.unknown()).optional()).optional()
 });
 
 export const RequestSchema = z.object({
@@ -56,9 +56,11 @@ export const RequestSchema = z.object({
  * Used in {@link JSONRPCRequestSchema} for generic shape matching.
  */
 export const RequestSchemaGeneric = RequestSchema.extend({
-    params: z.intersection(RequestSchema.shape.params, z.record(z.string(), z.unknown()).optional())
+    params: z.intersection(RequestSchema.shape.params.optional(), z.record(z.string(), z.unknown()).optional())
 });
 
+export type RequestGeneric = ExpandRecursively<z.infer<typeof RequestSchemaGeneric>>;
+
 const NotificationsParamsSchema = z.object({
     /**
      * See [MCP specification](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/47339c03c143bb4ec01a26e721a1b8fe66634ebe/docs/specification/draft/basic/index.mdx#general-fields)
@@ -81,20 +83,26 @@ export const NotificationSchemaGeneric = NotificationSchema.extend({
     params: z.intersection(NotificationSchema.shape.params, z.record(z.string(), z.unknown()).optional())
 });
 
-export const ResultSchema = z.object({
-    /**
-     * See [MCP specification](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/47339c03c143bb4ec01a26e721a1b8fe66634ebe/docs/specification/draft/basic/index.mdx#general-fields)
-     * for notes on _meta usage.
-     */
-    _meta: z.record(z.string(), z.unknown()).optional()
-});
+export type NotificationGeneric = z.infer<typeof NotificationSchemaGeneric>;
+
+export const ResultSchema = z
+    .object({
+        /**
+         * See [MCP specification](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/47339c03c143bb4ec01a26e721a1b8fe66634ebe/docs/specification/draft/basic/index.mdx#general-fields)
+         * for notes on _meta usage.
+         */
+        _meta: z.record(z.string(), z.unknown()).optional()
+    })
+    .catchall(z.unknown());
 
 /**
  * Generic result schema that allows any additional fields to be added to the result.
  *
  * Used in {@link JSONRPCResponseSchema} for generic shape matching.
  */
 export const ResultSchemaGeneric = z.intersection(ResultSchema, z.record(z.string(), z.unknown()).optional());
+
+export type ResultGeneric = ExpandRecursively<z.infer<typeof ResultSchemaGeneric>>;
 /**
  * A uniquely identifying ID for a request in JSON-RPC.
  */
@@ -1035,14 +1043,18 @@ export const CallToolResultSchema = ResultSchema.extend({
     isError: z.boolean().optional()
 });
 
-/**
- * CallToolResultSchema extended with backwards compatibility to protocol version 2024-10-07.
- */
-export const CompatibilityCallToolResultSchema = CallToolResultSchema.or(
-    ResultSchema.extend({
-        toolResult: z.unknown()
-    })
-);
+// const LegacyCallToolResultSchema = ResultSchema.extend({
+//     toolResult: z.unknown()
+// });
+
+// export type LegacyCallToolResult = z.infer<typeof LegacyCallToolResultSchema>;
+
+// export const isLegacyCallToolResult = (value: unknown): value is LegacyCallToolResult => LegacyCallToolResultSchema.safeParse(value).success;
+
+// /**
+//  * CallToolResultSchema extended with backwards compatibility to protocol version 2024-10-07.
+//  */
+// export const CompatibilityCallToolResultSchema = CallToolResultSchema.or(LegacyCallToolResultSchema);
 
 /**
  * Parameters for a `tools/call` request.
@@ -1389,7 +1401,7 @@ export const ElicitResultSchema = ResultSchema.extend({
      * The submitted form data, only present when action is "accept".
      * Contains values matching the requested schema.
      */
-    content: z.record(z.union([z.string(), z.number(), z.boolean(), z.array(z.string())])).optional()
+    content: z.record(z.union([z.string(), z.number(), z.boolean(), z.array(z.string()), z.undefined()])).optional()
 });
 
 /* Autocomplete */
@@ -1733,7 +1745,7 @@ export type ListToolsRequest = Infer<typeof ListToolsRequestSchema>;
 export type ListToolsResult = Infer<typeof ListToolsResultSchema>;
 export type CallToolRequestParams = Infer<typeof CallToolRequestParamsSchema>;
 export type CallToolResult = Infer<typeof CallToolResultSchema>;
-export type CompatibilityCallToolResult = Infer<typeof CompatibilityCallToolResultSchema>;
+// export type CompatibilityCallToolResult = Infer<typeof CompatibilityCallToolResultSchema>;
 export type CallToolRequest = Infer<typeof CallToolRequestSchema>;
 export type ToolListChangedNotification = Infer<typeof ToolListChangedNotificationSchema>;