feat!: make mcp the default protocol

packages/toolbox-adk/src/toolbox_adk/client.ts

@@ -17,6 +17,7 @@ import {
   AuthTokenGetters,
   BoundParams,
   ClientHeadersConfig,
+  Protocol,
 } from '@toolbox-sdk/core';
 import {ToolboxTool, CoreTool} from './tool.js';
 import type {AxiosInstance} from 'axios';
@@ -44,8 +45,14 @@ export class ToolboxClient {
     url: string,
     session?: AxiosInstance | null,
     clientHeaders?: ClientHeadersConfig | null,
+    protocol: Protocol = Protocol.MCP,
   ) {
-    this.coreClient = new CoreToolboxClient(url, session, clientHeaders);
+    this.coreClient = new CoreToolboxClient(
+      url,
+      session,
+      clientHeaders,
+      protocol,
+    );
   }
 
   /**

packages/toolbox-adk/src/toolbox_adk/index.ts

@@ -17,3 +17,4 @@
 // Export the main factory function and the core tool type
 export {ToolboxClient} from './client.js';
 export {ToolboxTool} from './tool.js';
+export {Protocol} from '@toolbox-sdk/core';

packages/toolbox-adk/test/e2e/test.e2e.ts

@@ -12,8 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import {ToolboxClient} from '../../src/toolbox_adk/client.js';
-import {ToolboxTool} from '../../src/toolbox_adk/tool.js';
+import {
+  ToolboxClient,
+  ToolboxTool,
+  Protocol,
+} from '../../src/toolbox_adk/index.js';
 
 import {AxiosError} from 'axios';
 import {CustomGlobal} from './types.js';
@@ -30,7 +33,12 @@ describe('ToolboxClient E2E Tests', () => {
   const mockToolContext = {} as ToolContext;
 
   beforeAll(async () => {
-    commonToolboxClient = new ToolboxClient(testBaseUrl);
+    commonToolboxClient = new ToolboxClient(
+      testBaseUrl,
+      undefined,
+      undefined,
+      Protocol.TOOLBOX,
+    );
   });
 
   beforeEach(async () => {

packages/toolbox-adk/test/test.client.ts

@@ -34,6 +34,7 @@ type MockCoreClientConstructor = (
   url: string,
   session?: AxiosInstance | null,
   clientHeaders?: ClientHeadersConfig | null,
+  protocol?: string | null,
 ) => MockCoreClient;
 
 const mockLoadTool =
@@ -66,6 +67,10 @@ const MockToolboxTool = jest.fn();
 
 jest.unstable_mockModule('@toolbox-sdk/core', () => ({
   ToolboxClient: MockCoreToolboxClient,
+  Protocol: {
+    MCP: 'mcp-default',
+    TOOLBOX: 'toolbox',
+  },
 }));
 
 jest.unstable_mockModule('../src/toolbox_adk/tool.js', () => ({
@@ -94,6 +99,7 @@ describe('ToolboxClient', () => {
       'http://test.url',
       mockSession,
       mockHeaders,
+      'mcp-default',
     );
   });
 

packages/toolbox-core/src/toolbox_core/client.ts

@@ -56,7 +56,7 @@ class ToolboxClient {
     url: string,
     session?: AxiosInstance | null,
     clientHeaders?: ClientHeadersConfig | null,
-    protocol: Protocol = Protocol.TOOLBOX,
+    protocol: Protocol = Protocol.MCP,
   ) {
     this.#clientHeaders = clientHeaders || {};
     if (protocol === Protocol.TOOLBOX) {

packages/toolbox-core/test/e2e/test.e2e.ts

@@ -14,6 +14,7 @@
 
 import {ToolboxClient} from '../../src/toolbox_core/client';
 import {ToolboxTool} from '../../src/toolbox_core/tool';
+import {Protocol} from '../../src/toolbox_core/protocol';
 
 import {AxiosError} from 'axios';
 import {CustomGlobal} from './types';
@@ -27,7 +28,12 @@ describe('ToolboxClient E2E Tests', () => {
   const projectId = (globalThis as CustomGlobal).__GOOGLE_CLOUD_PROJECT__;
 
   beforeAll(async () => {
-    commonToolboxClient = new ToolboxClient(testBaseUrl);
+    commonToolboxClient = new ToolboxClient(
+      testBaseUrl,
+      undefined,
+      undefined,
+      Protocol.TOOLBOX,
+    );
   });
 
   beforeEach(async () => {

packages/toolbox-core/test/test.client.ts

@@ -96,20 +96,28 @@ describe('ToolboxClient', () => {
   });
 
   describe('Initialization', () => {
-    it('should initialize with the correct base URL (default Toolbox)', () => {
+    it('should initialize with the correct base URL (default MCP)', () => {
       client = new ToolboxClient(testBaseUrl);
-      expect(ToolboxTransport).toHaveBeenCalledWith(testBaseUrl, undefined);
+      expect(McpHttpTransportV20250618).toHaveBeenCalledWith(
+        testBaseUrl,
+        undefined,
+        Protocol.MCP_v20250618,
+      );
     });
 
-    it('should pass provided axios session to transport (Toolbox)', () => {
+    it('should pass provided axios session to transport (default MCP)', () => {
       const mockSession = {
         get: jest.fn(),
       } as unknown as import('axios').AxiosInstance;
       client = new ToolboxClient(testBaseUrl, mockSession);
-      expect(ToolboxTransport).toHaveBeenCalledWith(testBaseUrl, mockSession);
+      expect(McpHttpTransportV20250618).toHaveBeenCalledWith(
+        testBaseUrl,
+        mockSession,
+        Protocol.MCP_v20250618,
+      );
     });
 
-    it('should initialize with MCP transport (default) when specified', () => {
+    it('should initialize with MCP transport (explicit) when specified', () => {
       client = new ToolboxClient(
         testBaseUrl,
         undefined,