Fix support for streamable-http connections

client/jest.config.cjs

@@ -1,6 +1,6 @@
 module.exports = {
   preset: "ts-jest",
-  testEnvironment: "jsdom",
+  testEnvironment: "jest-fixed-jsdom",
   moduleNameMapper: {
     "^@/(.*)$": "<rootDir>/src/$1",
     "\\.css$": "<rootDir>/src/__mocks__/styleMock.js",

client/src/lib/hooks/useConnection.ts

@@ -3,6 +3,7 @@ import {
   SSEClientTransport,
   SseError,
 } from "@modelcontextprotocol/sdk/client/sse.js";
+import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";
 import {
   ClientNotification,
   ClientRequest,
@@ -278,15 +279,29 @@ export function useConnection({
       setConnectionStatus("error-connecting-to-proxy");
       return;
     }
-    const mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/sse`);
-    mcpProxyServerUrl.searchParams.append("transportType", transportType);
-    if (transportType === "stdio") {
-      mcpProxyServerUrl.searchParams.append("command", command);
-      mcpProxyServerUrl.searchParams.append("args", args);
-      mcpProxyServerUrl.searchParams.append("env", JSON.stringify(env));
-    } else {
-      mcpProxyServerUrl.searchParams.append("url", sseUrl);
+    let mcpProxyServerUrl;
+    switch (transportType) {
+      case "stdio":
+        mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/stdio`);
+        mcpProxyServerUrl.searchParams.append("command", command);
+        mcpProxyServerUrl.searchParams.append("args", args);
+        mcpProxyServerUrl.searchParams.append("env", JSON.stringify(env));
+        break;
+
+      case "sse":
+        mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/sse`);
+        mcpProxyServerUrl.searchParams.append("url", sseUrl);
+        break;
+
+      case "streamable-http":
+        mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/mcp`);
+        mcpProxyServerUrl.searchParams.append("url", sseUrl);
+        break;
     }
+    (mcpProxyServerUrl as URL).searchParams.append(
+      "transportType",
+      transportType,
+    );
 
     try {
       // Inject auth manually instead of using SSEClientTransport, because we're
@@ -304,14 +319,24 @@ export function useConnection({
         headers[authHeaderName] = `Bearer ${token}`;
       }
 
-      const clientTransport = new SSEClientTransport(mcpProxyServerUrl, {
+      // Create appropriate transport
+      const transportOptions = {
         eventSourceInit: {
-          fetch: (url, init) => fetch(url, { ...init, headers }),
+          fetch: (
+            url: string | URL | globalThis.Request,
+            init: RequestInit | undefined,
+          ) => fetch(url, { ...init, headers }),
         },
         requestInit: {
           headers,
         },
-      });
+      };
+      const clientTransport =
+        transportType === "streamable-http"
+          ? new StreamableHTTPClientTransport(mcpProxyServerUrl as URL, {
+              sessionId: undefined,
+            })
+          : new SSEClientTransport(mcpProxyServerUrl as URL, transportOptions);
 
       if (onNotification) {
         [

package.json

@@ -41,7 +41,7 @@
     "@modelcontextprotocol/inspector-cli": "^0.10.2",
     "@modelcontextprotocol/inspector-client": "^0.10.2",
     "@modelcontextprotocol/inspector-server": "^0.10.2",
-    "@modelcontextprotocol/sdk": "^1.10.0",
+    "@modelcontextprotocol/sdk": "^1.10.2",
     "concurrently": "^9.0.1",
     "shell-quote": "^1.8.2",
     "spawn-rx": "^5.1.2",
@@ -52,6 +52,7 @@
     "@types/jest": "^29.5.14",
     "@types/node": "^22.7.5",
     "@types/shell-quote": "^1.7.5",
+    "jest-fixed-jsdom": "^0.0.9",
     "prettier": "3.3.3",
     "typescript": "^5.4.2"
   }