fix: STDIO and SSE transports need MCP_FULL_PROXY_ADDRESS

client/src/lib/hooks/__tests__/useConnection.test.tsx

@@ -740,6 +740,129 @@ describe("useConnection", () => {
     });
   });
 
+  describe("MCP_PROXY_FULL_ADDRESS Configuration", () => {
+    beforeEach(() => {
+      jest.clearAllMocks();
+      // Reset the mock transport objects
+      mockSSETransport.url = undefined;
+      mockSSETransport.options = undefined;
+      mockStreamableHTTPTransport.url = undefined;
+      mockStreamableHTTPTransport.options = undefined;
+    });
+
+    test("sends proxyFullAddress query parameter for stdio transport when configured", async () => {
+      const propsWithProxyFullAddress = {
+        ...defaultProps,
+        transportType: "stdio" as const,
+        command: "test-command",
+        args: "test-args",
+        env: {},
+        config: {
+          ...DEFAULT_INSPECTOR_CONFIG,
+          MCP_PROXY_FULL_ADDRESS: {
+            ...DEFAULT_INSPECTOR_CONFIG.MCP_PROXY_FULL_ADDRESS,
+            value: "https://example.com/inspector/mcp_proxy",
+          },
+        },
+      };
+
+      const { result } = renderHook(() =>
+        useConnection(propsWithProxyFullAddress),
+      );
+
+      await act(async () => {
+        await result.current.connect();
+      });
+
+      // Check that the URL contains the proxyFullAddress parameter
+      expect(mockSSETransport.url?.searchParams.get("proxyFullAddress")).toBe(
+        "https://example.com/inspector/mcp_proxy",
+      );
+    });
+
+    test("sends proxyFullAddress query parameter for sse transport when configured", async () => {
+      const propsWithProxyFullAddress = {
+        ...defaultProps,
+        transportType: "sse" as const,
+        sseUrl: "http://localhost:8080",
+        config: {
+          ...DEFAULT_INSPECTOR_CONFIG,
+          MCP_PROXY_FULL_ADDRESS: {
+            ...DEFAULT_INSPECTOR_CONFIG.MCP_PROXY_FULL_ADDRESS,
+            value: "https://example.com/inspector/mcp_proxy",
+          },
+        },
+      };
+
+      const { result } = renderHook(() =>
+        useConnection(propsWithProxyFullAddress),
+      );
+
+      await act(async () => {
+        await result.current.connect();
+      });
+
+      // Check that the URL contains the proxyFullAddress parameter
+      expect(mockSSETransport.url?.searchParams.get("proxyFullAddress")).toBe(
+        "https://example.com/inspector/mcp_proxy",
+      );
+    });
+
+    test("does not send proxyFullAddress parameter when MCP_PROXY_FULL_ADDRESS is empty", async () => {
+      const propsWithEmptyProxy = {
+        ...defaultProps,
+        transportType: "stdio" as const,
+        command: "test-command",
+        args: "test-args",
+        env: {},
+        config: {
+          ...DEFAULT_INSPECTOR_CONFIG,
+          MCP_PROXY_FULL_ADDRESS: {
+            ...DEFAULT_INSPECTOR_CONFIG.MCP_PROXY_FULL_ADDRESS,
+            value: "",
+          },
+        },
+      };
+
+      const { result } = renderHook(() => useConnection(propsWithEmptyProxy));
+
+      await act(async () => {
+        await result.current.connect();
+      });
+
+      // Check that the URL does not contain the proxyFullAddress parameter
+      expect(
+        mockSSETransport.url?.searchParams.get("proxyFullAddress"),
+      ).toBeNull();
+    });
+
+    test("does not send proxyFullAddress parameter for streamable-http transport", async () => {
+      const propsWithStreamableHttp = {
+        ...defaultProps,
+        transportType: "streamable-http" as const,
+        sseUrl: "http://localhost:8080",
+        config: {
+          ...DEFAULT_INSPECTOR_CONFIG,
+          MCP_PROXY_FULL_ADDRESS: {
+            ...DEFAULT_INSPECTOR_CONFIG.MCP_PROXY_FULL_ADDRESS,
+            value: "https://example.com/inspector/mcp_proxy",
+          },
+        },
+      };
+
+      const { result } = renderHook(() =>
+        useConnection(propsWithStreamableHttp),
+      );
+
+      await act(async () => {
+        await result.current.connect();
+      });
+
+      // Check that streamable-http transport doesn't get proxyFullAddress parameter
+      expect(
+        mockStreamableHTTPTransport.url?.searchParams.get("proxyFullAddress"),
+      ).toBeNull();
+
   describe("OAuth Error Handling with Scope Discovery", () => {
     beforeEach(() => {
       jest.clearAllMocks();
@@ -875,6 +998,7 @@ describe("useConnection", () => {
         serverUrl: defaultProps.sseUrl,
         scope: undefined,
       });
+
     });
   });
 });

client/src/lib/hooks/useConnection.ts

@@ -408,11 +408,20 @@ export function useConnection({
 
       let mcpProxyServerUrl;
       switch (transportType) {
-        case "stdio":
+        case "stdio": {
           mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/stdio`);
           mcpProxyServerUrl.searchParams.append("command", command);
           mcpProxyServerUrl.searchParams.append("args", args);
           mcpProxyServerUrl.searchParams.append("env", JSON.stringify(env));
+
+          const proxyFullAddress = config.MCP_PROXY_FULL_ADDRESS
+            .value as string;
+          if (proxyFullAddress) {
+            mcpProxyServerUrl.searchParams.append(
+              "proxyFullAddress",
+              proxyFullAddress,
+            );
+          }
           transportOptions = {
             authProvider: serverAuthProvider,
             eventSourceInit: {
@@ -430,10 +439,20 @@ export function useConnection({
             },
           };
           break;
+        }
 
-        case "sse":
+        case "sse": {
           mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/sse`);
           mcpProxyServerUrl.searchParams.append("url", sseUrl);
+
+          const proxyFullAddressSSE = config.MCP_PROXY_FULL_ADDRESS
+            .value as string;
+          if (proxyFullAddressSSE) {
+            mcpProxyServerUrl.searchParams.append(
+              "proxyFullAddress",
+              proxyFullAddressSSE,
+            );
+          }
           transportOptions = {
             eventSourceInit: {
               fetch: (
@@ -450,6 +469,7 @@ export function useConnection({
             },
           };
           break;
+        }
 
         case "streamable-http":
           mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/mcp`);

server/src/index.ts

@@ -378,7 +378,6 @@ app.get(
       let serverTransport: Transport | undefined;
       try {
         serverTransport = await createTransport(req);
-        console.log("Created server transport");
       } catch (error) {
         if (error instanceof SseError && error.code === 401) {
           console.error(
@@ -391,11 +390,16 @@ app.get(
         throw error;
       }
 
-      const webAppTransport = new SSEServerTransport("/message", res);
-      console.log("Created client transport");
+      const proxyFullAddress = (req.query.proxyFullAddress as string) || "";
+      const prefix = proxyFullAddress || "";
+      const endpoint = `${prefix}/message`;
 
+      const webAppTransport = new SSEServerTransport(endpoint, res);
       webAppTransports.set(webAppTransport.sessionId, webAppTransport);
+      console.log("Created client transport");
+
       serverTransports.set(webAppTransport.sessionId, serverTransport);
+      console.log("Created server transport");
 
       await webAppTransport.start();
 
@@ -442,7 +446,7 @@ app.get(
   async (req, res) => {
     try {
       console.log(
-        "New SSE connection request. NOTE: The sse transport is deprecated and has been replaced by StreamableHttp",
+        "New SSE connection request. NOTE: The SSE transport is deprecated and has been replaced by StreamableHttp",
       );
       let serverTransport: Transport | undefined;
       try {
@@ -469,9 +473,14 @@ app.get(
       }
 
       if (serverTransport) {
-        const webAppTransport = new SSEServerTransport("/message", res);
+        const proxyFullAddress = (req.query.proxyFullAddress as string) || "";
+        const prefix = proxyFullAddress || "";
+        const endpoint = `${prefix}/message`;
+
+        const webAppTransport = new SSEServerTransport(endpoint, res);
         webAppTransports.set(webAppTransport.sessionId, webAppTransport);
         console.log("Created client transport");
+
         serverTransports.set(webAppTransport.sessionId, serverTransport!);
         console.log("Created server transport");