Merge branch 'main' of https://github.com/modelcontextprotocol/inspector

.github/workflows/main.yml

@@ -26,6 +26,10 @@ jobs:
       # - run: npm ci
       - run: npm install --no-package-lock
 
+      - name: Check linting
+        working-directory: ./client
+        run: npm run lint
+
       - name: Run client tests
         working-directory: ./client
         run: npm test
@@ -54,8 +58,6 @@ jobs:
       # - run: npm ci
       - run: npm install --no-package-lock
 
-      - run: npm run build
-
       # TODO: Add --provenance once the repo is public
       - run: npm run publish-all
         env:

cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector-cli",
-  "version": "0.10.2",
+  "version": "0.11.0",
   "description": "CLI for the Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",
@@ -21,7 +21,7 @@
   },
   "devDependencies": {},
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.10.0",
+    "@modelcontextprotocol/sdk": "^1.11.0",
     "commander": "^13.1.0",
     "spawn-rx": "^5.1.2"
   }

client/bin/client.js

@@ -9,10 +9,34 @@ const __dirname = dirname(fileURLToPath(import.meta.url));
 const distPath = join(__dirname, "../dist");
 
 const server = http.createServer((request, response) => {
-  return handler(request, response, {
+  const handlerOptions = {
     public: distPath,
     rewrites: [{ source: "/**", destination: "/index.html" }],
-  });
+    headers: [
+      {
+        // Ensure index.html is never cached
+        source: "index.html",
+        headers: [
+          {
+            key: "Cache-Control",
+            value: "no-cache, no-store, max-age=0",
+          },
+        ],
+      },
+      {
+        // Allow long-term caching for hashed assets
+        source: "assets/**",
+        headers: [
+          {
+            key: "Cache-Control",
+            value: "public, max-age=31536000, immutable",
+          },
+        ],
+      },
+    ],
+  };
+
+  return handler(request, response, handlerOptions);
 });
 
 const port = process.env.PORT || 6274;

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/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector-client",
-  "version": "0.10.2",
+  "version": "0.11.0",
   "description": "Client-side application for the Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",
@@ -23,7 +23,7 @@
     "test:watch": "jest --config jest.config.cjs --watch"
   },
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.10.0",
+    "@modelcontextprotocol/sdk": "^1.11.0",
     "@radix-ui/react-checkbox": "^1.1.4",
     "@radix-ui/react-dialog": "^1.1.3",
     "@radix-ui/react-icons": "^1.3.0",

client/src/App.tsx

@@ -81,9 +81,14 @@ const App = () => {
   const [sseUrl, setSseUrl] = useState<string>(() => {
     return localStorage.getItem("lastSseUrl") || "http://localhost:3001/sse";
   });
-  const [transportType, setTransportType] = useState<"stdio" | "sse">(() => {
+  const [transportType, setTransportType] = useState<
+    "stdio" | "sse" | "streamable-http"
+  >(() => {
     return (
-      (localStorage.getItem("lastTransportType") as "stdio" | "sse") || "stdio"
+      (localStorage.getItem("lastTransportType") as
+        | "stdio"
+        | "sse"
+        | "streamable-http") || "stdio"
     );
   });
   const [logLevel, setLogLevel] = useState<LoggingLevel>("debug");
@@ -642,6 +647,7 @@ const App = () => {
                       setSelectedPrompt={(prompt) => {
                         clearError("prompts");
                         setSelectedPrompt(prompt);
+                        setPromptContent("");
                       }}
                       handleCompletion={handleCompletion}
                       completionsSupported={completionsSupported}

client/src/components/DynamicJsonForm.tsx

@@ -250,7 +250,12 @@ const DynamicJsonForm = ({
     <div className="space-y-4">
       <div className="flex justify-end space-x-2">
         {isJsonMode && (
-          <Button variant="outline" size="sm" onClick={formatJson}>
+          <Button
+            type="button"
+            variant="outline"
+            size="sm"
+            onClick={formatJson}
+          >
             Format JSON
           </Button>
         )}

client/src/components/JsonView.tsx

@@ -3,7 +3,7 @@ import type { JsonValue } from "@/utils/jsonUtils";
 import clsx from "clsx";
 import { Copy, CheckCheck } from "lucide-react";
 import { Button } from "@/components/ui/button";
-import { useToast } from "@/hooks/use-toast";
+import { useToast } from "@/lib/hooks/useToast";
 import { getDataType, tryParseJson } from "@/utils/jsonUtils";
 
 interface JsonViewProps {

client/src/components/OAuthCallback.tsx

@@ -2,7 +2,7 @@ import { useEffect, useRef } from "react";
 import { InspectorOAuthClientProvider } from "../lib/auth";
 import { SESSION_KEYS } from "../lib/constants";
 import { auth } from "@modelcontextprotocol/sdk/client/auth.js";
-import { useToast } from "@/hooks/use-toast.ts";
+import { useToast } from "@/lib/hooks/useToast";
 import {
   generateOAuthErrorDescription,
   parseOAuthCallbackParams,

client/src/components/SamplingRequest.tsx

@@ -0,0 +1,167 @@
+import { Button } from "@/components/ui/button";
+import JsonView from "./JsonView";
+import { useMemo, useState } from "react";
+import {
+  CreateMessageResult,
+  CreateMessageResultSchema,
+} from "@modelcontextprotocol/sdk/types.js";
+import { PendingRequest } from "./SamplingTab";
+import DynamicJsonForm from "./DynamicJsonForm";
+import { useToast } from "@/lib/hooks/useToast";
+import { JsonSchemaType, JsonValue } from "@/utils/jsonUtils";
+
+export type SamplingRequestProps = {
+  request: PendingRequest;
+  onApprove: (id: number, result: CreateMessageResult) => void;
+  onReject: (id: number) => void;
+};
+
+const SamplingRequest = ({
+  onApprove,
+  request,
+  onReject,
+}: SamplingRequestProps) => {
+  const { toast } = useToast();
+
+  const [messageResult, setMessageResult] = useState<JsonValue>({
+    model: "stub-model",
+    stopReason: "endTurn",
+    role: "assistant",
+    content: {
+      type: "text",
+      text: "",
+    },
+  });
+
+  const contentType = (
+    (messageResult as { [key: string]: JsonValue })?.content as {
+      [key: string]: JsonValue;
+    }
+  )?.type;
+
+  const schema = useMemo(() => {
+    const s: JsonSchemaType = {
+      type: "object",
+      description: "Message result",
+      properties: {
+        model: {
+          type: "string",
+          default: "stub-model",
+          description: "model name",
+        },
+        stopReason: {
+          type: "string",
+          default: "endTurn",
+          description: "Stop reason",
+        },
+        role: {
+          type: "string",
+          default: "endTurn",
+          description: "Role of the model",
+        },
+        content: {
+          type: "object",
+          properties: {
+            type: {
+              type: "string",
+              default: "text",
+              description: "Type of content",
+            },
+          },
+        },
+      },
+    };
+
+    if (contentType === "text" && s.properties) {
+      s.properties.content.properties = {
+        ...s.properties.content.properties,
+        text: {
+          type: "string",
+          default: "",
+          description: "text content",
+        },
+      };
+      setMessageResult((prev) => ({
+        ...(prev as { [key: string]: JsonValue }),
+        content: {
+          type: contentType,
+          text: "",
+        },
+      }));
+    } else if (contentType === "image" && s.properties) {
+      s.properties.content.properties = {
+        ...s.properties.content.properties,
+        data: {
+          type: "string",
+          default: "",
+          description: "Base64 encoded image data",
+        },
+        mimeType: {
+          type: "string",
+          default: "",
+          description: "Mime type of the image",
+        },
+      };
+      setMessageResult((prev) => ({
+        ...(prev as { [key: string]: JsonValue }),
+        content: {
+          type: contentType,
+          data: "",
+          mimeType: "",
+        },
+      }));
+    }
+
+    return s;
+  }, [contentType]);
+
+  const handleApprove = (id: number) => {
+    const validationResult = CreateMessageResultSchema.safeParse(messageResult);
+    if (!validationResult.success) {
+      toast({
+        title: "Error",
+        description: `There was an error validating the message result: ${validationResult.error.message}`,
+        variant: "destructive",
+      });
+      return;
+    }
+
+    onApprove(id, validationResult.data);
+  };
+
+  return (
+    <div
+      data-testid="sampling-request"
+      className="flex gap-4 p-4 border rounded-lg space-y-4"
+    >
+      <div className="flex-1 bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-2 rounded">
+        <JsonView data={JSON.stringify(request.request)} />
+      </div>
+      <form className="flex-1 space-y-4">
+        <div className="space-y-2">
+          <DynamicJsonForm
+            schema={schema}
+            value={messageResult}
+            onChange={(newValue: JsonValue) => {
+              setMessageResult(newValue);
+            }}
+          />
+        </div>
+        <div className="flex space-x-2 mt-1">
+          <Button type="button" onClick={() => handleApprove(request.id)}>
+            Approve
+          </Button>
+          <Button
+            type="button"
+            variant="outline"
+            onClick={() => onReject(request.id)}
+          >
+            Reject
+          </Button>
+        </div>
+      </form>
+    </div>
+  );
+};
+
+export default SamplingRequest;

client/src/components/SamplingTab.tsx

@@ -1,11 +1,10 @@
 import { Alert, AlertDescription } from "@/components/ui/alert";
-import { Button } from "@/components/ui/button";
 import { TabsContent } from "@/components/ui/tabs";
 import {
   CreateMessageRequest,
   CreateMessageResult,
 } from "@modelcontextprotocol/sdk/types.js";
-import JsonView from "./JsonView";
+import SamplingRequest from "./SamplingRequest";
 
 export type PendingRequest = {
   id: number;
@@ -19,19 +18,6 @@ export type Props = {
 };
 
 const SamplingTab = ({ pendingRequests, onApprove, onReject }: Props) => {
-  const handleApprove = (id: number) => {
-    // For now, just return a stub response
-    onApprove(id, {
-      model: "stub-model",
-      stopReason: "endTurn",
-      role: "assistant",
-      content: {
-        type: "text",
-        text: "This is a stub response.",
-      },
-    });
-  };
-
   return (
     <TabsContent value="sampling">
       <div className="h-96">
@@ -44,21 +30,12 @@ const SamplingTab = ({ pendingRequests, onApprove, onReject }: Props) => {
         <div className="mt-4 space-y-4">
           <h3 className="text-lg font-semibold">Recent Requests</h3>
           {pendingRequests.map((request) => (
-            <div key={request.id} className="p-4 border rounded-lg space-y-4">
+            <SamplingRequest
-              <JsonView
+              key={request.id}
-                className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 rounded"
+              request={request}
-                data={JSON.stringify(request.request)}
+              onApprove={onApprove}
+              onReject={onReject}
             />
-
-              <div className="flex space-x-2">
-                <Button onClick={() => handleApprove(request.id)}>
-                  Approve
-                </Button>
-                <Button variant="outline" onClick={() => onReject(request.id)}>
-                  Reject
-                </Button>
-              </div>
-            </div>
           ))}
           {pendingRequests.length === 0 && (
             <p className="text-gray-500">No pending requests</p>

client/src/components/Sidebar.tsx

@@ -31,7 +31,7 @@ import {
 } from "@modelcontextprotocol/sdk/types.js";
 import { InspectorConfig } from "@/lib/configurationTypes";
 import { ConnectionStatus } from "@/lib/constants";
-import useTheme from "../lib/useTheme";
+import useTheme from "../lib/hooks/useTheme";
 import { version } from "../../../package.json";
 import {
   Tooltip,
@@ -42,8 +42,8 @@ import { useToast } from "@/hooks/use-toast";
 
 interface SidebarProps {
   connectionStatus: ConnectionStatus;
-  transportType: "stdio" | "sse";
+  transportType: "stdio" | "sse" | "streamable-http";
-  setTransportType: (type: "stdio" | "sse") => void;
+  setTransportType: (type: "stdio" | "sse" | "streamable-http") => void;
   command: string;
   setCommand: (command: string) => void;
   args: string;
@@ -229,7 +229,7 @@ const Sidebar = ({
             </label>
             <Select
               value={transportType}
-              onValueChange={(value: "stdio" | "sse") =>
+              onValueChange={(value: "stdio" | "sse" | "streamable-http") =>
                 setTransportType(value)
               }
             >
@@ -239,6 +239,7 @@ const Sidebar = ({
               <SelectContent>
                 <SelectItem value="stdio">STDIO</SelectItem>
                 <SelectItem value="sse">SSE</SelectItem>
+                <SelectItem value="streamable-http">Streamable HTTP</SelectItem>
               </SelectContent>
             </Select>
           </div>

client/src/components/__tests__/Sidebar.test.tsx

@@ -7,7 +7,7 @@ import { InspectorConfig } from "@/lib/configurationTypes";
 import { TooltipProvider } from "@/components/ui/tooltip";
 
 // Mock theme hook
-jest.mock("../../lib/useTheme", () => ({
+jest.mock("../../lib/hooks/useTheme", () => ({
   __esModule: true,
   default: () => ["light", jest.fn()],
 }));

client/src/components/__tests__/samplingRequest.test.tsx

@@ -0,0 +1,73 @@
+import { render, screen, fireEvent } from "@testing-library/react";
+import SamplingRequest from "../SamplingRequest";
+import { PendingRequest } from "../SamplingTab";
+
+const mockRequest: PendingRequest = {
+  id: 1,
+  request: {
+    method: "sampling/createMessage",
+    params: {
+      messages: [
+        {
+          role: "user",
+          content: {
+            type: "text",
+            text: "What files are in the current directory?",
+          },
+        },
+      ],
+      systemPrompt: "You are a helpful file system assistant.",
+      includeContext: "thisServer",
+      maxTokens: 100,
+    },
+  },
+};
+
+describe("Form to handle sampling response", () => {
+  const mockOnApprove = jest.fn();
+  const mockOnReject = jest.fn();
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it("should call onApprove with correct text content when Approve button is clicked", () => {
+    render(
+      <SamplingRequest
+        request={mockRequest}
+        onApprove={mockOnApprove}
+        onReject={mockOnReject}
+      />,
+    );
+
+    // Click the Approve button
+    fireEvent.click(screen.getByRole("button", { name: /approve/i }));
+
+    // Assert that onApprove is called with the correct arguments
+    expect(mockOnApprove).toHaveBeenCalledWith(mockRequest.id, {
+      model: "stub-model",
+      stopReason: "endTurn",
+      role: "assistant",
+      content: {
+        type: "text",
+        text: "",
+      },
+    });
+  });
+
+  it("should call onReject with correct request id when Reject button is clicked", () => {
+    render(
+      <SamplingRequest
+        request={mockRequest}
+        onApprove={mockOnApprove}
+        onReject={mockOnReject}
+      />,
+    );
+
+    // Click the Approve button
+    fireEvent.click(screen.getByRole("button", { name: /Reject/i }));
+
+    // Assert that onApprove is called with the correct arguments
+    expect(mockOnReject).toHaveBeenCalledWith(mockRequest.id);
+  });
+});

client/src/components/__tests__/samplingTab.test.tsx

@@ -0,0 +1,55 @@
+import { render, screen } from "@testing-library/react";
+import { Tabs } from "@/components/ui/tabs";
+import SamplingTab, { PendingRequest } from "../SamplingTab";
+
+describe("Sampling tab", () => {
+  const mockOnApprove = jest.fn();
+  const mockOnReject = jest.fn();
+
+  const renderSamplingTab = (pendingRequests: PendingRequest[]) =>
+    render(
+      <Tabs defaultValue="sampling">
+        <SamplingTab
+          pendingRequests={pendingRequests}
+          onApprove={mockOnApprove}
+          onReject={mockOnReject}
+        />
+      </Tabs>,
+    );
+
+  it("should render 'No pending requests' when there are no pending requests", () => {
+    renderSamplingTab([]);
+    expect(
+      screen.getByText(
+        "When the server requests LLM sampling, requests will appear here for approval.",
+      ),
+    ).toBeTruthy();
+    expect(screen.findByText("No pending requests")).toBeTruthy();
+  });
+
+  it("should render the correct number of requests", () => {
+    renderSamplingTab(
+      Array.from({ length: 5 }, (_, i) => ({
+        id: i,
+        request: {
+          method: "sampling/createMessage",
+          params: {
+            messages: [
+              {
+                role: "user",
+                content: {
+                  type: "text",
+                  text: "What files are in the current directory?",
+                },
+              },
+            ],
+            systemPrompt: "You are a helpful file system assistant.",
+            includeContext: "thisServer",
+            maxTokens: 100,
+          },
+        },
+      })),
+    );
+    expect(screen.getAllByTestId("sampling-request").length).toBe(5);
+  });
+});

client/src/components/ui/toaster.tsx

@@ -1,4 +1,4 @@
-import { useToast } from "@/hooks/use-toast";
+import { useToast } from "@/lib/hooks/useToast";
 import {
   Toast,
   ToastClose,

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

@@ -37,7 +37,7 @@ jest.mock("@modelcontextprotocol/sdk/client/auth.js", () => ({
 }));
 
 // Mock the toast hook
-jest.mock("@/hooks/use-toast", () => ({
+jest.mock("@/lib/hooks/useToast", () => ({
   useToast: () => ({
     toast: jest.fn(),
   }),

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,
@@ -26,7 +27,7 @@ import {
 } from "@modelcontextprotocol/sdk/types.js";
 import { RequestOptions } from "@modelcontextprotocol/sdk/shared/protocol.js";
 import { useState } from "react";
-import { useToast } from "@/hooks/use-toast";
+import { useToast } from "@/lib/hooks/useToast";
 import { z } from "zod";
 import { ConnectionStatus } from "../constants";
 import { Notification, StdErrNotificationSchema } from "../notificationTypes";
@@ -42,7 +43,7 @@ import { getMCPServerRequestTimeout } from "@/utils/configUtils";
 import { InspectorConfig } from "../configurationTypes";
 
 interface UseConnectionOptions {
-  transportType: "stdio" | "sse";
+  transportType: "stdio" | "sse" | "streamable-http";
   command: string;
   args: string;
   sseUrl: string;
@@ -278,15 +279,29 @@ export function useConnection({
       setConnectionStatus("error-connecting-to-proxy");
       return;
     }
-    const mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/sse`);
+    let mcpProxyServerUrl;
-    mcpProxyServerUrl.searchParams.append("transportType", transportType);
+    switch (transportType) {
-    if (transportType === "stdio") {
+      case "stdio":
+        mcpProxyServerUrl = new URL(`${getMCPProxyAddress(config)}/stdio`);
         mcpProxyServerUrl.searchParams.append("command", command);
         mcpProxyServerUrl.searchParams.append("args", args);
         mcpProxyServerUrl.searchParams.append("env", JSON.stringify(env));
-    } else {
+        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) {
         [

client/src/utils/__tests__/schemaUtils.test.ts

@@ -51,13 +51,13 @@ describe("generateDefaultValue", () => {
 
   test("generates null for non-required primitive types", () => {
     expect(generateDefaultValue({ type: "string", required: false })).toBe(
-      null,
+      undefined,
     );
     expect(generateDefaultValue({ type: "number", required: false })).toBe(
-      null,
+      undefined,
     );
     expect(generateDefaultValue({ type: "boolean", required: false })).toBe(
-      null,
+      undefined,
     );
   });
 

client/src/utils/schemaUtils.ts

@@ -13,7 +13,7 @@ export function generateDefaultValue(schema: JsonSchemaType): JsonValue {
   if (!schema.required) {
     if (schema.type === "array") return [];
     if (schema.type === "object") return {};
-    return null;
+    return undefined;
   }
 
   switch (schema.type) {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector",
-  "version": "0.10.2",
+  "version": "0.11.0",
   "description": "Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",
@@ -26,6 +26,7 @@
     "build-server": "cd server && npm run build",
     "build-client": "cd client && npm run build",
     "build-cli": "cd cli && npm run build",
+    "clean": "rimraf ./node_modules ./client/node_modules ./cli/node_modules ./build ./client/dist ./server/build ./cli/build ./package-lock.json && npm install",
     "dev": "concurrently \"cd client && npm run dev\" \"cd server && npm run dev\"",
     "dev:windows": "concurrently \"cd client && npm run dev\" \"cd server && npm run dev:windows\"",
     "start": "node client/bin/start.js",
@@ -35,13 +36,14 @@
     "test-cli": "cd cli && npm run test",
     "prettier-fix": "prettier --write .",
     "prettier-check": "prettier --check .",
+    "prepare": "npm run build",
     "publish-all": "npm publish --workspaces --access public && npm publish --access public"
   },
   "dependencies": {
-    "@modelcontextprotocol/inspector-cli": "^0.10.2",
+    "@modelcontextprotocol/inspector-cli": "^0.11.0",
-    "@modelcontextprotocol/inspector-client": "^0.10.2",
+    "@modelcontextprotocol/inspector-client": "^0.11.0",
-    "@modelcontextprotocol/inspector-server": "^0.10.2",
+    "@modelcontextprotocol/inspector-server": "^0.11.0",
-    "@modelcontextprotocol/sdk": "^1.10.0",
+    "@modelcontextprotocol/sdk": "^1.11.0",
     "concurrently": "^9.0.1",
     "shell-quote": "^1.8.2",
     "spawn-rx": "^5.1.2",
@@ -52,7 +54,9 @@
     "@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",
+    "rimraf": "^6.0.1",
     "typescript": "^5.4.2"
   }
 }

server/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector-server",
-  "version": "0.10.2",
+  "version": "0.11.0",
   "description": "Server-side application for the Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",
@@ -27,7 +27,7 @@
     "typescript": "^5.6.2"
   },
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.10.0",
+    "@modelcontextprotocol/sdk": "^1.11.0",
     "cors": "^2.8.5",
     "express": "^5.1.0",
     "ws": "^8.18.0",

server/src/index.ts

@@ -12,13 +12,21 @@ import {
   StdioClientTransport,
   getDefaultEnvironment,
 } from "@modelcontextprotocol/sdk/client/stdio.js";
-import { Transport } from "@modelcontextprotocol/sdk/shared/transport.js";
+import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";
+import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
 import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
+import { Transport } from "@modelcontextprotocol/sdk/shared/transport.js";
 import express from "express";
 import { findActualExecutable } from "spawn-rx";
 import mcpProxy from "./mcpProxy.js";
+import { randomUUID } from "node:crypto";
 
 const SSE_HEADERS_PASSTHROUGH = ["authorization"];
+const STREAMABLE_HTTP_HEADERS_PASSTHROUGH = [
+  "authorization",
+  "mcp-session-id",
+  "last-event-id",
+];
 
 const defaultEnvironment = {
   ...getDefaultEnvironment(),
@@ -35,8 +43,12 @@ const { values } = parseArgs({
 
 const app = express();
 app.use(cors());
+app.use((req, res, next) => {
+  res.header("Access-Control-Expose-Headers", "mcp-session-id");
+  next();
+});
 
-let webAppTransports: SSEServerTransport[] = [];
+const webAppTransports: Map<string, Transport> = new Map<string, Transport>(); // Transports by sessionId
 
 const createTransport = async (req: express.Request): Promise<Transport> => {
   const query = req.query;
@@ -94,6 +106,31 @@ const createTransport = async (req: express.Request): Promise<Transport> => {
 
     console.log("Connected to SSE transport");
     return transport;
+  } else if (transportType === "streamable-http") {
+    const headers: HeadersInit = {
+      Accept: "text/event-stream, application/json",
+    };
+
+    for (const key of STREAMABLE_HTTP_HEADERS_PASSTHROUGH) {
+      if (req.headers[key] === undefined) {
+        continue;
+      }
+
+      const value = req.headers[key];
+      headers[key] = Array.isArray(value) ? value[value.length - 1] : value;
+    }
+
+    const transport = new StreamableHTTPClientTransport(
+      new URL(query.url as string),
+      {
+        requestInit: {
+          headers,
+        },
+      },
+    );
+    await transport.start();
+    console.log("Connected to Streamable HTTP transport");
+    return transport;
   } else {
     console.error(`Invalid transport type: ${transportType}`);
     throw new Error("Invalid transport type specified");
@@ -102,9 +139,96 @@ const createTransport = async (req: express.Request): Promise<Transport> => {
 
 let backingServerTransport: Transport | undefined;
 
-app.get("/sse", async (req, res) => {
+app.get("/mcp", async (req, res) => {
+  const sessionId = req.headers["mcp-session-id"] as string;
+  console.log(`Received GET message for sessionId ${sessionId}`);
   try {
-    console.log("New SSE connection");
+    const transport = webAppTransports.get(
+      sessionId,
+    ) as StreamableHTTPServerTransport;
+    if (!transport) {
+      res.status(404).end("Session not found");
+      return;
+    } else {
+      await transport.handleRequest(req, res);
+    }
+  } catch (error) {
+    console.error("Error in /mcp route:", error);
+    res.status(500).json(error);
+  }
+});
+
+app.post("/mcp", async (req, res) => {
+  const sessionId = req.headers["mcp-session-id"] as string | undefined;
+  console.log(`Received POST message for sessionId ${sessionId}`);
+  if (!sessionId) {
+    try {
+      console.log("New streamable-http connection");
+      try {
+        await backingServerTransport?.close();
+        backingServerTransport = await createTransport(req);
+      } catch (error) {
+        if (error instanceof SseError && error.code === 401) {
+          console.error(
+            "Received 401 Unauthorized from MCP server:",
+            error.message,
+          );
+          res.status(401).json(error);
+          return;
+        }
+
+        throw error;
+      }
+
+      console.log("Connected MCP client to backing server transport");
+
+      const webAppTransport = new StreamableHTTPServerTransport({
+        sessionIdGenerator: randomUUID,
+        onsessioninitialized: (sessionId) => {
+          webAppTransports.set(sessionId, webAppTransport);
+          console.log("Created streamable web app transport " + sessionId);
+        },
+      });
+
+      await webAppTransport.start();
+
+      mcpProxy({
+        transportToClient: webAppTransport,
+        transportToServer: backingServerTransport,
+      });
+
+      await (webAppTransport as StreamableHTTPServerTransport).handleRequest(
+        req,
+        res,
+        req.body,
+      );
+    } catch (error) {
+      console.error("Error in /mcp POST route:", error);
+      res.status(500).json(error);
+    }
+  } else {
+    try {
+      const transport = webAppTransports.get(
+        sessionId,
+      ) as StreamableHTTPServerTransport;
+      if (!transport) {
+        res.status(404).end("Transport not found for sessionId " + sessionId);
+      } else {
+        await (transport as StreamableHTTPServerTransport).handleRequest(
+          req,
+          res,
+        );
+      }
+    } catch (error) {
+      console.error("Error in /mcp route:", error);
+      res.status(500).json(error);
+    }
+  }
+});
+
+app.get("/stdio", async (req, res) => {
+  try {
+    console.log("New connection");
 
     try {
       await backingServerTransport?.close();
@@ -125,15 +249,14 @@ app.get("/sse", async (req, res) => {
     console.log("Connected MCP client to backing server transport");
 
     const webAppTransport = new SSEServerTransport("/message", res);
-    console.log("Created web app transport");
+    webAppTransports.set(webAppTransport.sessionId, webAppTransport);
 
-    webAppTransports.push(webAppTransport);
     console.log("Created web app transport");
 
     await webAppTransport.start();
-
+    (backingServerTransport as StdioClientTransport).stderr!.on(
-    if (backingServerTransport instanceof StdioClientTransport) {
+      "data",
-      backingServerTransport.stderr!.on("data", (chunk) => {
+      (chunk) => {
         webAppTransport.send({
           jsonrpc: "2.0",
           method: "notifications/stderr",
@@ -141,8 +264,50 @@ app.get("/sse", async (req, res) => {
             content: chunk.toString(),
           },
         });
+      },
+    );
+
+    mcpProxy({
+      transportToClient: webAppTransport,
+      transportToServer: backingServerTransport,
     });
+
+    console.log("Set up MCP proxy");
+  } catch (error) {
+    console.error("Error in /stdio route:", error);
+    res.status(500).json(error);
   }
+});
+
+app.get("/sse", async (req, res) => {
+  try {
+    console.log(
+      "New SSE connection. NOTE: The sse transport is deprecated and has been replaced by streamable-http",
+    );
+
+    try {
+      await backingServerTransport?.close();
+      backingServerTransport = await createTransport(req);
+    } catch (error) {
+      if (error instanceof SseError && error.code === 401) {
+        console.error(
+          "Received 401 Unauthorized from MCP server:",
+          error.message,
+        );
+        res.status(401).json(error);
+        return;
+      }
+
+      throw error;
+    }
+
+    console.log("Connected MCP client to backing server transport");
+
+    const webAppTransport = new SSEServerTransport("/message", res);
+    webAppTransports.set(webAppTransport.sessionId, webAppTransport);
+    console.log("Created web app transport");
+
+    await webAppTransport.start();
 
     mcpProxy({
       transportToClient: webAppTransport,
@@ -161,7 +326,9 @@ app.post("/message", async (req, res) => {
     const sessionId = req.query.sessionId;
     console.log(`Received message for sessionId ${sessionId}`);
 
-    const transport = webAppTransports.find((t) => t.sessionId === sessionId);
+    const transport = webAppTransports.get(
+      sessionId as string,
+    ) as SSEServerTransport;
     if (!transport) {
       res.status(404).end("Session not found");
       return;