update simple-server example

examples/simple-react/package.json

@@ -1,24 +0,0 @@
-{
-  "name": "simple-app-react",
-  "version": "1.0.0",
-  "private": true,
-  "type": "module",
-  "scripts": {
-    "dev": "vite",
-    "build": "vite build",
-    "preview": "vite preview"
-  },
-  "dependencies": {
-    "@modelcontextprotocol/ext-apps": "file:../..",
-    "@modelcontextprotocol/sdk": "^1.20.1",
-    "react": "^19.2.0",
-    "react-dom": "^19.2.0"
-  },
-  "devDependencies": {
-    "@types/react": "^19.2.2",
-    "@types/react-dom": "^19.2.2",
-    "@vitejs/plugin-react": "^4.3.4",
-    "typescript": "^5.7.2",
-    "vite": "^6.0.0"
-  }
-}

examples/simple-react/vite.config.ts

@@ -1,14 +0,0 @@
-import { defineConfig } from "vite";
-import react from "@vitejs/plugin-react";
-
-export default defineConfig({
-  plugins: [react()],
-  build: {
-    // Output single HTML file with inlined JS for easy distribution
-    rollupOptions: {
-      output: {
-        inlineDynamicImports: true,
-      },
-    },
-  },
-});

examples/simple-server/package.json

@@ -0,0 +1,33 @@
+{
+  "name": "simple-server",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "rm -rf dist && VITE_ENTRY=ui-vanilla vite build && VITE_ENTRY=ui-react vite build",
+    "preview": "vite preview",
+    "server": "tsx server.ts",
+    "start": "npm run build && npm run server"
+  },
+  "dependencies": {
+    "@modelcontextprotocol/ext-apps": "file:../..",
+    "@modelcontextprotocol/sdk": "^1.20.1",
+    "react": "^19.2.0",
+    "react-dom": "^19.2.0",
+    "zod": "^3.25.0"
+  },
+  "devDependencies": {
+    "@types/express": "^5.0.0",
+    "@types/node": "^22.0.0",
+    "@types/react": "^19.2.2",
+    "@types/react-dom": "^19.2.2",
+    "@vitejs/plugin-react": "^4.3.4",
+    "cors": "^2.8.5",
+    "express": "^5.1.0",
+    "tsx": "^4.20.6",
+    "typescript": "^5.7.2",
+    "vite": "^6.0.0",
+    "vite-plugin-singlefile": "^2.3.0"
+  }
+}

examples/simple-server/server.ts

@@ -0,0 +1,269 @@
+import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import express, { Request, Response } from "express";
+import { randomUUID } from "node:crypto";
+import { z } from "zod";
+import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
+import {
+  CallToolResult,
+  isInitializeRequest,
+  ReadResourceResult,
+  Resource,
+} from "@modelcontextprotocol/sdk/types.js";
+import { InMemoryEventStore } from "@modelcontextprotocol/sdk/examples/shared/inMemoryEventStore.js";
+import cors from "cors";
+import path from "node:path";
+import fs from "node:fs/promises";
+import { fileURLToPath } from "node:url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// Load both UI HTML files from dist/
+const distDir = path.join(__dirname, "dist");
+const loadHtml = async (name: string) => {
+  const htmlPath = path.join(distDir, `${name}.html`);
+  return fs.readFile(htmlPath, "utf-8");
+};
+
+// Create an MCP server with both UI tools
+const getServer = async () => {
+  const server = new McpServer(
+    {
+      name: "simple-mcp-server",
+      version: "1.0.0",
+    },
+    { capabilities: { logging: {} } },
+  );
+
+  // Load HTML for both UIs
+  const [vanillaHtml, reactHtml] = await Promise.all([
+    loadHtml("ui-vanilla"),
+    loadHtml("ui-react"),
+  ]);
+
+  // --- Vanilla UI Resource & Tool ---
+  const vanillaResource: Resource = {
+    name: "ui-vanilla-template",
+    uri: "ui://vanilla",
+    title: "Vanilla UI Template",
+    description: "A simple vanilla JS UI",
+    mimeType: "text/html",
+  };
+
+  server.registerResource(
+    vanillaResource.name,
+    vanillaResource.uri,
+    vanillaResource,
+    async (): Promise<ReadResourceResult> => ({
+      contents: [
+        {
+          uri: vanillaResource.uri,
+          mimeType: vanillaResource.mimeType,
+          text: vanillaHtml,
+        },
+      ],
+    }),
+  );
+
+  server.registerTool(
+    "create-ui-vanilla",
+    {
+      title: "Vanilla UI",
+      description: "A tool that returns a simple vanilla JS UI",
+      inputSchema: {
+        message: z.string().describe("Message to display"),
+      },
+      _meta: {
+        "ui/resourceUri": vanillaResource.uri,
+      },
+    },
+    async ({ message }): Promise<CallToolResult> => ({
+      content: [{ type: "text", text: JSON.stringify({ message }) }],
+      structuredContent: { message },
+    }),
+  );
+
+  // --- React UI Resource & Tool ---
+  const reactResource: Resource = {
+    name: "ui-react-template",
+    uri: "ui://react",
+    title: "React UI Template",
+    description: "A React-based UI",
+    mimeType: "text/html",
+  };
+
+  server.registerResource(
+    reactResource.name,
+    reactResource.uri,
+    reactResource,
+    async (): Promise<ReadResourceResult> => ({
+      contents: [
+        {
+          uri: reactResource.uri,
+          mimeType: reactResource.mimeType,
+          text: reactHtml,
+        },
+      ],
+    }),
+  );
+
+  server.registerTool(
+    "create-ui-react",
+    {
+      title: "React UI",
+      description: "A tool that returns a React-based UI",
+      inputSchema: {
+        message: z.string().describe("Message to display"),
+      },
+      _meta: {
+        "ui/resourceUri": reactResource.uri,
+      },
+    },
+    async ({ message }): Promise<CallToolResult> => ({
+      content: [{ type: "text", text: JSON.stringify({ message }) }],
+      structuredContent: { message },
+    }),
+  );
+
+  // --- Common tool: get-weather ---
+  server.registerTool(
+    "get-weather",
+    {
+      title: "Get Weather",
+      description: "Returns current weather for a location",
+      inputSchema: {
+        location: z.string().describe("Location to get weather for"),
+      },
+    },
+    async ({ location }): Promise<CallToolResult> => {
+      const temperature = 25;
+      const condition = "sunny";
+      return {
+        content: [
+          {
+            type: "text",
+            text: `The weather in ${location} is ${condition}, ${temperature}°C.`,
+          },
+        ],
+        structuredContent: { temperature, condition },
+      };
+    },
+  );
+
+  return server;
+};
+
+const MCP_PORT = process.env.MCP_PORT
+  ? parseInt(process.env.MCP_PORT, 10)
+  : 3001;
+
+const app = express();
+app.use(express.json());
+app.use(
+  cors({
+    origin: "*",
+    exposedHeaders: ["Mcp-Session-Id"],
+  }),
+);
+
+// Map to store transports by session ID
+const transports: { [sessionId: string]: StreamableHTTPServerTransport } = {};
+
+const mcpPostHandler = async (req: Request, res: Response) => {
+  const sessionId = req.headers["mcp-session-id"] as string | undefined;
+
+  try {
+    let transport: StreamableHTTPServerTransport;
+    if (sessionId && transports[sessionId]) {
+      transport = transports[sessionId];
+    } else if (!sessionId && isInitializeRequest(req.body)) {
+      const eventStore = new InMemoryEventStore();
+      transport = new StreamableHTTPServerTransport({
+        sessionIdGenerator: () => randomUUID(),
+        eventStore,
+        onsessioninitialized: (sessionId) => {
+          console.log(`Session initialized: ${sessionId}`);
+          transports[sessionId] = transport;
+        },
+      });
+
+      transport.onclose = () => {
+        const sid = transport.sessionId;
+        if (sid && transports[sid]) {
+          console.log(`Session closed: ${sid}`);
+          delete transports[sid];
+        }
+      };
+
+      const server = await getServer();
+      await server.connect(transport);
+      await transport.handleRequest(req, res, req.body);
+      return;
+    } else {
+      res.status(400).json({
+        jsonrpc: "2.0",
+        error: { code: -32000, message: "Bad Request: No valid session ID" },
+        id: null,
+      });
+      return;
+    }
+
+    await transport.handleRequest(req, res, req.body);
+  } catch (error) {
+    console.error("Error handling MCP request:", error);
+    if (!res.headersSent) {
+      res.status(500).json({
+        jsonrpc: "2.0",
+        error: { code: -32603, message: "Internal server error" },
+        id: null,
+      });
+    }
+  }
+};
+
+app.post("/mcp", mcpPostHandler);
+
+app.get("/mcp", async (req: Request, res: Response) => {
+  const sessionId = req.headers["mcp-session-id"] as string | undefined;
+  if (!sessionId || !transports[sessionId]) {
+    res.status(400).send("Invalid or missing session ID");
+    return;
+  }
+  const transport = transports[sessionId];
+  await transport.handleRequest(req, res);
+});
+
+app.delete("/mcp", async (req: Request, res: Response) => {
+  const sessionId = req.headers["mcp-session-id"] as string | undefined;
+  if (!sessionId || !transports[sessionId]) {
+    res.status(400).send("Invalid or missing session ID");
+    return;
+  }
+  try {
+    const transport = transports[sessionId];
+    await transport.handleRequest(req, res);
+  } catch (error) {
+    console.error("Error handling session termination:", error);
+    if (!res.headersSent) {
+      res.status(500).send("Error processing session termination");
+    }
+  }
+});
+
+app.listen(MCP_PORT, () => {
+  console.log(`MCP Server listening on http://localhost:${MCP_PORT}/mcp`);
+  console.log(`  Tools: create-ui-vanilla, create-ui-react, get-weather`);
+});
+
+process.on("SIGINT", async () => {
+  console.log("Shutting down...");
+  for (const sessionId in transports) {
+    try {
+      await transports[sessionId].close();
+      delete transports[sessionId];
+    } catch (error) {
+      console.error(`Error closing session ${sessionId}:`, error);
+    }
+  }
+  process.exit(0);
+});

examples/simple-server/src/ui-react.tsx

@@ -1,14 +1,14 @@
 import { useState, useCallback } from "react";
 import { createRoot } from "react-dom/client";
-import { useApp } from "@modelcontextprotocol/ext-apps/react/useApp";
+import {
+  useApp,
+  McpUiSizeChangeNotificationSchema,
+  McpUiToolResultNotificationSchema,
+} from "@modelcontextprotocol/ext-apps/react";
 import type {
   CallToolResult,
   Implementation,
 } from "@modelcontextprotocol/sdk/types.js";
-import {
-  McpUiSizeChangeNotificationSchema,
-  McpUiToolResultNotificationSchema,
-} from "@modelcontextprotocol/ext-apps/types";
 
 const APP_INFO: Implementation = {
   name: "MCP UI React Example Client",

examples/simple-server/src/ui-vanilla.ts

@@ -0,0 +1,143 @@
+import {
+  App,
+  PostMessageTransport,
+  McpUiToolInputNotificationSchema,
+  McpUiSizeChangeNotificationSchema,
+  McpUiToolResultNotificationSchema,
+} from "@modelcontextprotocol/ext-apps";
+
+window.addEventListener("load", async () => {
+  const root = document.getElementById("root")!;
+  const appendText = (textContent: string, opts = {}) => {
+    root.appendChild(
+      Object.assign(document.createElement("div"), {
+        textContent,
+        ...opts,
+      }),
+    );
+  };
+  const appendError = (error: unknown) =>
+    appendText(
+      `Error: ${error instanceof Error ? error.message : String(error)}`,
+      { style: "color: red;" },
+    );
+
+  const transport = new PostMessageTransport(window.parent);
+  const app = new App({
+    name: "MCP UI Client (Vanilla)",
+    version: "1.0.0",
+  });
+
+  app.setNotificationHandler(
+    McpUiToolResultNotificationSchema,
+    async ({ params: { content, structuredContent, isError } }) => {
+      appendText(
+        `Tool call result received: isError=${isError}, content=${content}, structuredContent=${JSON.stringify(structuredContent)}`,
+      );
+    },
+  );
+  app.setNotificationHandler(
+    McpUiSizeChangeNotificationSchema,
+    async ({ params: { width, height } }) => {
+      appendText(
+        `Size change notification received: width=${width}, height=${height}`,
+      );
+    },
+  );
+  app.setNotificationHandler(
+    McpUiToolInputNotificationSchema,
+    async ({ params }) => {
+      appendText(
+        `Tool call input received: ${JSON.stringify(params.arguments)}`,
+      );
+    },
+  );
+
+  document.body.addEventListener("resize", () => {
+    app.sendSizeChange({
+      width: document.body.scrollWidth,
+      height: document.body.scrollHeight,
+    });
+  });
+
+  root.appendChild(
+    Object.assign(document.createElement("button"), {
+      textContent: "Get Weather (Tool)",
+      onclick: async () => {
+        try {
+          const result = await app.callServerTool({
+            name: "get-weather",
+            arguments: { location: "Tokyo" },
+          });
+          appendText(`Weather tool result: ${JSON.stringify(result)}`);
+        } catch (e) {
+          appendError(e);
+        }
+      },
+    }),
+  );
+
+  root.appendChild(
+    Object.assign(document.createElement("button"), {
+      textContent: "Notify Cart Updated",
+      onclick: async () => {
+        try {
+          await app.sendLog({
+            level: "info",
+            data: "cart-updated",
+          });
+        } catch (e) {
+          appendError(e);
+        }
+      },
+    }),
+  );
+
+  root.appendChild(
+    Object.assign(document.createElement("button"), {
+      textContent: "Prompt Weather in Tokyo",
+      onclick: async () => {
+        const signal = AbortSignal.timeout(5000);
+        try {
+          const { isError } = await app.sendMessage(
+            {
+              role: "user",
+              content: [
+                {
+                  type: "text",
+                  text: "What is the weather in Tokyo?",
+                },
+              ],
+            },
+            { signal },
+          );
+          appendText(`Prompt result: ${isError ? "error" : "success"}`);
+        } catch (e) {
+          if (signal.aborted) {
+            appendError("Prompt request timed out");
+            return;
+          }
+          appendError(e);
+        }
+      },
+    }),
+  );
+
+  root.appendChild(
+    Object.assign(document.createElement("button"), {
+      textContent: "Open Link to Google",
+      onclick: async () => {
+        try {
+          const { isError } = await app.sendOpenLink({
+            url: "https://www.google.com",
+          });
+          appendText(`Open link result: ${isError ? "error" : "success"}`);
+        } catch (e) {
+          appendError(e);
+        }
+      },
+    }),
+  );
+
+  await app.connect(transport);
+});

examples/simple-server/tsconfig.json

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "useDefineForClassFields": true,
+    "lib": ["ES2020", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "skipLibCheck": true,
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react-jsx",
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true
+  },
+  "include": ["src"]
+}

examples/simple-server/ui-react.html

@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>MCP UI Client (React)</title>
+</head>
+<body>
+    <div id="root"></div>
+    <script type="module" src="/src/ui-react.tsx"></script>
+</body>
+</html>

examples/simple-server/ui-vanilla.html

@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>MCP UI Client (Vanilla)</title>
+</head>
+<body>
+    <div id="root"></div>
+    <script type="module" src="/src/ui-vanilla.ts"></script>
+</body>
+</html>

examples/simple-server/vite.config.ts

@@ -0,0 +1,18 @@
+import { defineConfig } from "vite";
+import react from "@vitejs/plugin-react";
+import { viteSingleFile } from "vite-plugin-singlefile";
+import { resolve } from "path";
+
+// Get the entry from environment variable, default to ui-react
+const entry = process.env.VITE_ENTRY || "ui-react";
+
+export default defineConfig({
+  plugins: [react(), viteSingleFile()],
+  build: {
+    rollupOptions: {
+      input: resolve(__dirname, `${entry}.html`),
+    },
+    outDir: `dist`,
+    emptyOutDir: false,
+  },
+});