feat: enable server side MCP and disable all other AFC when server side MCP is configured.

wanlin31 · copybara-github · commit c7888c4aec34 · 2026-02-20T12:32:50.000-08:00
PiperOrigin-RevId: 873027776
diff --git a/api-report/genai-node.api.md b/api-report/genai-node.api.md
@@ -2542,6 +2542,12 @@ export enum MaskReferenceMode {
     MASK_MODE_USER_PROVIDED = "MASK_MODE_USER_PROVIDED"
 }
 
+// @public
+export interface McpServer {
+    name?: string;
+    streamableHttpTransport?: StreamableHttpTransport;
+}
+
 // @public
 export function mcpToTool(...args: [...Client[], CallableToolConfig | Client]): CallableTool;
 
@@ -3240,6 +3246,15 @@ export enum StartSensitivity {
     START_SENSITIVITY_UNSPECIFIED = "START_SENSITIVITY_UNSPECIFIED"
 }
 
+// @public
+export interface StreamableHttpTransport {
+    headers?: Record<string, string>;
+    sseReadTimeout?: string;
+    terminateOnClose?: boolean;
+    timeout?: string;
+    url?: string;
+}
+
 // @public
 export interface StringList {
     values?: string[];
@@ -3404,6 +3419,7 @@ export interface Tool {
     googleMaps?: GoogleMaps;
     googleSearch?: GoogleSearch;
     googleSearchRetrieval?: GoogleSearchRetrieval;
+    mcpServers?: McpServer[];
     retrieval?: Retrieval;
     urlContext?: UrlContext;
 }
diff --git a/api-report/genai-web.api.md b/api-report/genai-web.api.md
@@ -2542,6 +2542,12 @@ export enum MaskReferenceMode {
     MASK_MODE_USER_PROVIDED = "MASK_MODE_USER_PROVIDED"
 }
 
+// @public
+export interface McpServer {
+    name?: string;
+    streamableHttpTransport?: StreamableHttpTransport;
+}
+
 // @public
 export function mcpToTool(...args: [...Client[], CallableToolConfig | Client]): CallableTool;
 
@@ -3240,6 +3246,15 @@ export enum StartSensitivity {
     START_SENSITIVITY_UNSPECIFIED = "START_SENSITIVITY_UNSPECIFIED"
 }
 
+// @public
+export interface StreamableHttpTransport {
+    headers?: Record<string, string>;
+    sseReadTimeout?: string;
+    terminateOnClose?: boolean;
+    timeout?: string;
+    url?: string;
+}
+
 // @public
 export interface StringList {
     values?: string[];
@@ -3404,6 +3419,7 @@ export interface Tool {
     googleMaps?: GoogleMaps;
     googleSearch?: GoogleSearch;
     googleSearchRetrieval?: GoogleSearchRetrieval;
+    mcpServers?: McpServer[];
     retrieval?: Retrieval;
     urlContext?: UrlContext;
 }
diff --git a/api-report/genai.api.md b/api-report/genai.api.md
@@ -2542,6 +2542,12 @@ export enum MaskReferenceMode {
     MASK_MODE_USER_PROVIDED = "MASK_MODE_USER_PROVIDED"
 }
 
+// @public
+export interface McpServer {
+    name?: string;
+    streamableHttpTransport?: StreamableHttpTransport;
+}
+
 // @public
 export function mcpToTool(...args: [...Client[], CallableToolConfig | Client]): CallableTool;
 
@@ -3240,6 +3246,15 @@ export enum StartSensitivity {
     START_SENSITIVITY_UNSPECIFIED = "START_SENSITIVITY_UNSPECIFIED"
 }
 
+// @public
+export interface StreamableHttpTransport {
+    headers?: Record<string, string>;
+    sseReadTimeout?: string;
+    terminateOnClose?: boolean;
+    timeout?: string;
+    url?: string;
+}
+
 // @public
 export interface StringList {
     values?: string[];
@@ -3404,6 +3419,7 @@ export interface Tool {
     googleMaps?: GoogleMaps;
     googleSearch?: GoogleSearch;
     googleSearchRetrieval?: GoogleSearchRetrieval;
+    mcpServers?: McpServer[];
     retrieval?: Retrieval;
     urlContext?: UrlContext;
 }
diff --git a/src/converters/_batches_converters.ts b/src/converters/_batches_converters.ts
@@ -1838,5 +1838,16 @@ export function toolToMldev(fromObject: types.Tool): Record<string, unknown> {
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);
+  if (fromMcpServers != null) {
+    let transformedList = fromMcpServers;
+    if (Array.isArray(transformedList)) {
+      transformedList = transformedList.map((item) => {
+        return item;
+      });
+    }
+    common.setValueByPath(toObject, ['mcpServers'], transformedList);
+  }
+
   return toObject;
 }
diff --git a/src/converters/_caches_converters.ts b/src/converters/_caches_converters.ts
@@ -854,6 +854,17 @@ export function toolToMldev(fromObject: types.Tool): Record<string, unknown> {
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);
+  if (fromMcpServers != null) {
+    let transformedList = fromMcpServers;
+    if (Array.isArray(transformedList)) {
+      transformedList = transformedList.map((item) => {
+        return item;
+      });
+    }
+    common.setValueByPath(toObject, ['mcpServers'], transformedList);
+  }
+
   return toObject;
 }
 
@@ -931,6 +942,10 @@ export function toolToVertex(fromObject: types.Tool): Record<string, unknown> {
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  if (common.getValueByPath(fromObject, ['mcpServers']) !== undefined) {
+    throw new Error('mcpServers parameter is not supported in Vertex AI.');
+  }
+
   return toObject;
 }
 
diff --git a/src/converters/_live_converters.ts b/src/converters/_live_converters.ts
@@ -1893,6 +1893,17 @@ export function toolToMldev(fromObject: types.Tool): Record<string, unknown> {
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);
+  if (fromMcpServers != null) {
+    let transformedList = fromMcpServers;
+    if (Array.isArray(transformedList)) {
+      transformedList = transformedList.map((item) => {
+        return item;
+      });
+    }
+    common.setValueByPath(toObject, ['mcpServers'], transformedList);
+  }
+
   return toObject;
 }
 
@@ -1970,6 +1981,10 @@ export function toolToVertex(fromObject: types.Tool): Record<string, unknown> {
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  if (common.getValueByPath(fromObject, ['mcpServers']) !== undefined) {
+    throw new Error('mcpServers parameter is not supported in Vertex AI.');
+  }
+
   return toObject;
 }
 
diff --git a/src/converters/_models_converters.ts b/src/converters/_models_converters.ts
@@ -4805,6 +4805,17 @@ export function toolToMldev(
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);
+  if (fromMcpServers != null) {
+    let transformedList = fromMcpServers;
+    if (Array.isArray(transformedList)) {
+      transformedList = transformedList.map((item) => {
+        return item;
+      });
+    }
+    common.setValueByPath(toObject, ['mcpServers'], transformedList);
+  }
+
   return toObject;
 }
 
@@ -4885,6 +4896,10 @@ export function toolToVertex(
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  if (common.getValueByPath(fromObject, ['mcpServers']) !== undefined) {
+    throw new Error('mcpServers parameter is not supported in Vertex AI.');
+  }
+
   return toObject;
 }
 
diff --git a/src/converters/_tokens_converters.ts b/src/converters/_tokens_converters.ts
@@ -657,5 +657,16 @@ export function toolToMldev(fromObject: types.Tool): Record<string, unknown> {
     common.setValueByPath(toObject, ['urlContext'], fromUrlContext);
   }
 
+  const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);
+  if (fromMcpServers != null) {
+    let transformedList = fromMcpServers;
+    if (Array.isArray(transformedList)) {
+      transformedList = transformedList.map((item) => {
+        return item;
+      });
+    }
+    common.setValueByPath(toObject, ['mcpServers'], transformedList);
+  }
+
   return toObject;
 }
diff --git a/src/types.ts b/src/types.ts
@@ -2012,6 +2012,28 @@ export declare interface GoogleSearchRetrieval {
 /** Tool to support URL context. */
 export declare interface UrlContext {}
 
+/** A transport that can stream HTTP requests and responses. Next ID: 6. This data type is not supported in Vertex AI. */
+export declare interface StreamableHttpTransport {
+  /** Optional: Fields for authentication headers, timeouts, etc., if needed. */
+  headers?: Record<string, string>;
+  /** Timeout for SSE read operations. */
+  sseReadTimeout?: string;
+  /** Whether to close the client session when the transport closes. */
+  terminateOnClose?: boolean;
+  /** HTTP timeout for regular operations. */
+  timeout?: string;
+  /** The full URL for the MCPServer endpoint. Example: "https://api.example.com/mcp". */
+  url?: string;
+}
+
+/** A MCPServer is a server that can be called by the model to perform actions. It is a server that implements the MCP protocol. Next ID: 5. This data type is not supported in Vertex AI. */
+export declare interface McpServer {
+  /** The name of the MCPServer. */
+  name?: string;
+  /** A transport that can stream HTTP requests and responses. */
+  streamableHttpTransport?: StreamableHttpTransport;
+}
+
 /** Tool details of a tool that the model may use to generate a response. */
 export declare interface Tool {
   /** Optional. Retrieval tool type. System will always execute the provided retrieval tool(s) to get external knowledge to answer the prompt. Retrieval results are presented to the model for generation. This field is not supported in Gemini API. */
@@ -2036,6 +2058,8 @@ export declare interface Tool {
   googleSearchRetrieval?: GoogleSearchRetrieval;
   /** Optional. Tool to support URL context retrieval. */
   urlContext?: UrlContext;
+  /** Optional. MCP Servers to connect to. This field is not supported in Vertex AI. */
+  mcpServers?: McpServer[];
 }
 
 /** An object that represents a latitude/longitude pair.
diff --git a/test/system/node/chats_test.ts b/test/system/node/chats_test.ts
@@ -201,6 +201,34 @@ describe('Chats Tests', () => {
           'What is the title of the story?',
         ],
       },
+      {
+        name: 'multiple messages with server side MCP tools',
+        clientParams: {vertexai: false, apiKey: GEMINI_API_KEY},
+        model: 'gemini-2.5-flash',
+        config: {
+          tools: [
+            {
+              mcpServers: [
+                {
+                  streamableHttpTransport: {
+                    url: 'https://gemini-api-demos.uc.r.appspot.com/mcp',
+                    headers: {
+                      'AUTHORIZATION': 'Bearer github_pat_XXXX',
+                    },
+                    timeout: '10s',
+                  },
+                  name: 'weather_server',
+                },
+              ],
+            },
+          ],
+        },
+        history: [],
+        messages: [
+          'What is the weather in San Francisco on 02/02/2026?',
+          'What is the weather in Boston on 02/02/2026?',
+        ],
+      },
     ];
 
     testCases.forEach(async (testCase) => {
diff --git a/test/system/node/client_test.ts b/test/system/node/client_test.ts
@@ -1241,6 +1241,92 @@ describe('Client Tests', () => {
     });
   });
 
+  describe('server side MCP server', () => {
+    it('ML Dev should call server side MCP server', async () => {
+      const client = new GoogleGenAI({
+        vertexai: false,
+        apiKey: GOOGLE_API_KEY,
+        httpOptions,
+      });
+
+      const response = await client.models.generateContent({
+        model: MODEL,
+        contents: 'What is the weather like in New York ON 02/02/2026?',
+        config: {
+          tools: [
+            {
+              mcpServers: [
+                {
+                  streamableHttpTransport: {
+                    url: 'https://gemini-api-demos.uc.r.appspot.com/mcp',
+                    headers: {
+                      'AUTHORIZATION': 'Bearer github_pat_XXXX',
+                    },
+                    timeout: '10s',
+                  },
+                  name: 'weather_server',
+                },
+              ],
+            },
+          ],
+        },
+      });
+      expect(response.functionCalls?.[0]?.name).toBe(
+        'weather_server_get_weather',
+      );
+      expect(
+        response.candidates?.[0]?.content?.parts?.[1]?.functionResponse?.name,
+      ).toBe('weather_server_get_weather');
+    });
+    it('ML Dev should call server side MCP server, stream', async () => {
+      const client = new GoogleGenAI({
+        vertexai: false,
+        apiKey: GOOGLE_API_KEY,
+        httpOptions,
+      });
+
+      const response = await client.models.generateContentStream({
+        model: MODEL,
+        contents: 'What is the weather like in New York ON 02/02/2026?',
+        config: {
+          tools: [
+            {
+              mcpServers: [
+                {
+                  streamableHttpTransport: {
+                    url: 'https://gemini-api-demos.uc.r.appspot.com/mcp',
+                    headers: {
+                      'AUTHORIZATION': 'Bearer github_pat_XXXX',
+                    },
+                    timeout: '10s',
+                  },
+                  name: 'weather_server',
+                },
+              ],
+            },
+          ],
+        },
+      });
+      let seen_function_call = false;
+      let seen_function_response = false;
+      for await (const chunk of response) {
+        const parts = chunk.candidates?.[0]?.content?.parts;
+        if (Array.isArray(parts)) {
+          for (const part of parts) {
+            if (part.functionCall?.name === 'weather_server_get_weather') {
+              seen_function_call = true;
+            }
+            if (part.functionResponse?.name === 'weather_server_get_weather') {
+              seen_function_response = true;
+            }
+          }
+        }
+      }
+      expect(seen_function_call).toBeTrue();
+      expect(seen_function_response).toBeTrue();
+    });
+  });
+
   describe('cachedContent', () => {
     let originalTimeout: number;
 
diff --git a/test/system/recordings/Chats_Tests_sendMessage_multiple_messages_with_server_side_MCP_tools.json b/test/system/recordings/Chats_Tests_sendMessage_multiple_messages_with_server_side_MCP_tools.json
diff --git a/test/system/recordings/Chats_Tests_sendMessage_multiple_messages_with_server_side_MCP_tools_stream.json b/test/system/recordings/Chats_Tests_sendMessage_multiple_messages_with_server_side_MCP_tools_stream.json
diff --git a/test/system/recordings/Client_Tests_server_side_MCP_server_ML_Dev_should_call_server_side_MCP_server,_stream.json b/test/system/recordings/Client_Tests_server_side_MCP_server_ML_Dev_should_call_server_side_MCP_server,_stream.json
diff --git a/test/system/recordings/Client_Tests_server_side_MCP_server_ML_Dev_should_call_server_side_MCP_server.json b/test/system/recordings/Client_Tests_server_side_MCP_server_ML_Dev_should_call_server_side_MCP_server.json

Original file line number	Diff line number	Diff line change
`@@ -854,6 +854,17 @@ export function toolToMldev(fromObject: types.Tool): Record<string, unknown> {`
`854`	`854`	`common.setValueByPath(toObject, ['urlContext'], fromUrlContext);`
`855`	`855`	`}`
`856`	`856`
	`857`	`+ const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);`
	`858`	`+ if (fromMcpServers != null) {`
	`859`	`+ let transformedList = fromMcpServers;`
	`860`	`+ if (Array.isArray(transformedList)) {`
	`861`	`+ transformedList = transformedList.map((item) => {`
	`862`	`+ return item;`
	`863`	`+ });`
	`864`	`+ }`
	`865`	`+ common.setValueByPath(toObject, ['mcpServers'], transformedList);`
	`866`	`+ }`
	`867`	`+`
`857`	`868`	`return toObject;`
`858`	`869`	`}`
`859`	`870`
`@@ -931,6 +942,10 @@ export function toolToVertex(fromObject: types.Tool): Record<string, unknown> {`
`931`	`942`	`common.setValueByPath(toObject, ['urlContext'], fromUrlContext);`
`932`	`943`	`}`
`933`	`944`
	`945`	`+ if (common.getValueByPath(fromObject, ['mcpServers']) !== undefined) {`
	`946`	`+ throw new Error('mcpServers parameter is not supported in Vertex AI.');`
	`947`	`+ }`
	`948`	`+`
`934`	`949`	`return toObject;`
`935`	`950`	`}`
`936`	`951`
Original file line number	Diff line number	Diff line change
`@@ -1893,6 +1893,17 @@ export function toolToMldev(fromObject: types.Tool): Record<string, unknown> {`
`1893`	`1893`	`common.setValueByPath(toObject, ['urlContext'], fromUrlContext);`
`1894`	`1894`	`}`
`1895`	`1895`
	`1896`	`+ const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);`
	`1897`	`+ if (fromMcpServers != null) {`
	`1898`	`+ let transformedList = fromMcpServers;`
	`1899`	`+ if (Array.isArray(transformedList)) {`
	`1900`	`+ transformedList = transformedList.map((item) => {`
	`1901`	`+ return item;`
	`1902`	`+ });`
	`1903`	`+ }`
	`1904`	`+ common.setValueByPath(toObject, ['mcpServers'], transformedList);`
	`1905`	`+ }`
	`1906`	`+`
`1896`	`1907`	`return toObject;`
`1897`	`1908`	`}`
`1898`	`1909`
`@@ -1970,6 +1981,10 @@ export function toolToVertex(fromObject: types.Tool): Record<string, unknown> {`
`1970`	`1981`	`common.setValueByPath(toObject, ['urlContext'], fromUrlContext);`
`1971`	`1982`	`}`
`1972`	`1983`
	`1984`	`+ if (common.getValueByPath(fromObject, ['mcpServers']) !== undefined) {`
	`1985`	`+ throw new Error('mcpServers parameter is not supported in Vertex AI.');`
	`1986`	`+ }`
	`1987`	`+`
`1973`	`1988`	`return toObject;`
`1974`	`1989`	`}`
`1975`	`1990`
Original file line number	Diff line number	Diff line change
`@@ -4805,6 +4805,17 @@ export function toolToMldev(`
`4805`	`4805`	`common.setValueByPath(toObject, ['urlContext'], fromUrlContext);`
`4806`	`4806`	`}`
`4807`	`4807`
	`4808`	`+ const fromMcpServers = common.getValueByPath(fromObject, ['mcpServers']);`
	`4809`	`+ if (fromMcpServers != null) {`
	`4810`	`+ let transformedList = fromMcpServers;`
	`4811`	`+ if (Array.isArray(transformedList)) {`
	`4812`	`+ transformedList = transformedList.map((item) => {`
	`4813`	`+ return item;`
	`4814`	`+ });`
	`4815`	`+ }`
	`4816`	`+ common.setValueByPath(toObject, ['mcpServers'], transformedList);`
	`4817`	`+ }`
	`4818`	`+`
`4808`	`4819`	`return toObject;`
`4809`	`4820`	`}`
`4810`	`4821`
`@@ -4885,6 +4896,10 @@ export function toolToVertex(`
`4885`	`4896`	`common.setValueByPath(toObject, ['urlContext'], fromUrlContext);`
`4886`	`4897`	`}`
`4887`	`4898`
	`4899`	`+ if (common.getValueByPath(fromObject, ['mcpServers']) !== undefined) {`
	`4900`	`+ throw new Error('mcpServers parameter is not supported in Vertex AI.');`
	`4901`	`+ }`
	`4902`	`+`
`4888`	`4903`	`return toObject;`
`4889`	`4904`	`}`
`4890`	`4905`