Add dynamic example orchestration script

Replace hardcoded port assignments and npm scripts with run-all.ts that:
- Auto-discovers example directories and assigns ports
- Passes server URLs to basic-host via SERVERS env var
- Supports start, dev, and build commands

Update basic-host to fetch server list from /api/servers endpoint
and display server names from MCP server metadata.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: jonathanhefner

examples/basic-host/serve.ts

@@ -18,6 +18,7 @@ const __dirname = dirname(__filename);
 const HOST_PORT = parseInt(process.env.HOST_PORT || "8080", 10);
 const SANDBOX_PORT = parseInt(process.env.SANDBOX_PORT || "8081", 10);
 const DIRECTORY = join(__dirname, "dist");
+const SERVERS: string[] = process.env.SERVERS ? JSON.parse(process.env.SERVERS) : [];
 
 // ============ Host Server (port 8080) ============
 const hostApp = express();
@@ -34,6 +35,11 @@ hostApp.use((req, res, next) => {
 
 hostApp.use(express.static(DIRECTORY));
 
+// API endpoint to get configured server URLs
+hostApp.get("/api/servers", (_req, res) => {
+  res.json(SERVERS);
+});
+
 hostApp.get("/", (_req, res) => {
   res.redirect("/index.html");
 });
@@ -70,15 +76,15 @@ sandboxApp.use((_req, res) => {
 });
 
 // ============ Start both servers ============
-hostApp.listen(HOST_PORT, err => {
+hostApp.listen(HOST_PORT, (err) => {
   if (err) {
     console.error("Error starting server:", err);
     process.exit(1);
   }
   console.log(`Host server:    http://localhost:${HOST_PORT}`);
 });
 
-sandboxApp.listen(SANDBOX_PORT, err => {
+sandboxApp.listen(SANDBOX_PORT, (err) => {
   if (err) {
     console.error("Error starting server:", err);
     process.exit(1);

examples/basic-host/src/implementation.ts

@@ -17,6 +17,7 @@ export const log = {
 
 
 export interface ServerInfo {
+  name: string;
   client: Client;
   tools: Map<string, Tool>;
   appHtmlCache: Map<string, string>;
@@ -30,11 +31,13 @@ export async function connectToServer(serverUrl: URL): Promise<ServerInfo> {
   await client.connect(new StreamableHTTPClientTransport(serverUrl));
   log.info("Connection successful");
 
+  const name = client.getServerVersion()?.name ?? serverUrl.href;
+
   const toolsList = await client.listTools();
   const tools = new Map(toolsList.tools.map((tool) => [tool.name, tool]));
   log.info("Server tools:", Array.from(tools.keys()));
 
-  return { client, tools, appHtmlCache: new Map() };
+  return { name, client, tools, appHtmlCache: new Map() };
 }
 
 

examples/basic-host/src/index.tsx

@@ -4,113 +4,80 @@ import { callTool, connectToServer, hasAppHtml, initializeApp, loadSandboxProxy,
 import styles from "./index.module.css";
 
 
-// Available MCP servers - using ports 3101+ to avoid conflicts with common dev ports
-const SERVERS = [
-  { name: "Basic React", port: 3101 },
-  { name: "Vanilla JS", port: 3102 },
-  { name: "Budget Allocator", port: 3103 },
-  { name: "Cohort Heatmap", port: 3104 },
-  { name: "Customer Segmentation", port: 3105 },
-  { name: "Scenario Modeler", port: 3106 },
-  { name: "System Monitor", port: 3107 },
-] as const;
-
-function serverUrl(port: number): string {
-  return `http://localhost:${port}/mcp`;
-}
-
-// Cache server connections to avoid reconnecting when switching between servers
-const serverInfoCache = new Map<number, Promise<ServerInfo>>();
-
-function getServerInfo(port: number): Promise<ServerInfo> {
-  let promise = serverInfoCache.get(port);
-  if (!promise) {
-    promise = connectToServer(new URL(serverUrl(port)));
-    // Remove from cache on failure so retry is possible
-    promise.catch(() => serverInfoCache.delete(port));
-    serverInfoCache.set(port, promise);
-  }
-  return promise;
-}
-
-
 // Wrapper to track server name with each tool call
 interface ToolCallEntry {
   serverName: string;
   info: ToolCallInfo;
 }
 
-// Host just manages tool call results - no server dependency
-function Host() {
+// Host receives connected servers via promise, uses single use() call
+interface HostProps {
+  serversPromise: Promise<ServerInfo[]>;
+}
+function Host({ serversPromise }: HostProps) {
+  const servers = use(serversPromise);
   const [toolCalls, setToolCalls] = useState<ToolCallEntry[]>([]);
 
+  if (servers.length === 0) {
+    return <p>No servers configured. Set SERVERS environment variable.</p>;
+  }
+
   return (
     <>
       {toolCalls.map((entry, i) => (
         <ToolCallInfoPanel key={i} serverName={entry.serverName} toolCallInfo={entry.info} />
       ))}
       <CallToolPanel
+        servers={servers}
         addToolCall={(serverName, info) => setToolCalls([...toolCalls, { serverName, info }])}
       />
     </>
   );
 }
 
 
-// CallToolPanel includes server selection with its own Suspense boundary
+// CallToolPanel manages server selection from already-connected servers
 interface CallToolPanelProps {
+  servers: ServerInfo[];
   addToolCall: (serverName: string, info: ToolCallInfo) => void;
 }
-function CallToolPanel({ addToolCall }: CallToolPanelProps) {
-  const [selectedServer, setSelectedServer] = useState(SERVERS[0]);
-  const [serverInfoPromise, setServerInfoPromise] = useState(
-    () => getServerInfo(selectedServer.port)
-  );
-
-  const handleServerChange = (port: number) => {
-    const server = SERVERS.find(s => s.port === port) ?? SERVERS[0];
-    setSelectedServer(server);
-    setServerInfoPromise(getServerInfo(port));
-  };
+function CallToolPanel({ servers, addToolCall }: CallToolPanelProps) {
+  const [selectedIndex, setSelectedIndex] = useState(0);
+  const selectedServer = servers[selectedIndex];
 
   return (
     <div className={styles.callToolPanel}>
       <label>
         Server
         <select
-          value={selectedServer.port}
-          onChange={(e) => handleServerChange(Number(e.target.value))}
+          value={selectedIndex}
+          onChange={(e) => setSelectedIndex(Number(e.target.value))}
         >
-          {SERVERS.map(({ name, port }) => (
-            <option key={port} value={port}>
-              {name} (:{port})
+          {servers.map((server, i) => (
+            <option key={i} value={i}>
+              {server.name}
             </option>
           ))}
         </select>
       </label>
-      <ErrorBoundary>
-        <Suspense fallback={<p className={styles.connecting}>Connecting to {serverUrl(selectedServer.port)}...</p>}>
-          <ToolCallForm
-            key={selectedServer.port}
-            serverName={selectedServer.name}
-            serverInfoPromise={serverInfoPromise}
-            addToolCall={addToolCall}
-          />
-        </Suspense>
-      </ErrorBoundary>
+      <ToolCallForm
+        key={selectedIndex}
+        serverName={selectedServer.name}
+        serverInfo={selectedServer}
+        addToolCall={addToolCall}
+      />
     </div>
   );
 }
 
 
-// ToolCallForm renders inside Suspense - needs serverInfo for tool list
+// ToolCallForm receives already-resolved serverInfo
 interface ToolCallFormProps {
   serverName: string;
-  serverInfoPromise: Promise<ServerInfo>;
+  serverInfo: ServerInfo;
   addToolCall: (serverName: string, info: ToolCallInfo) => void;
 }
-function ToolCallForm({ serverName, serverInfoPromise, addToolCall }: ToolCallFormProps) {
-  const serverInfo = use(serverInfoPromise);
+function ToolCallForm({ serverName, serverInfo, addToolCall }: ToolCallFormProps) {
   const toolNames = Array.from(serverInfo.tools.keys());
   const [selectedTool, setSelectedTool] = useState(toolNames[0] ?? "");
   const [inputJson, setInputJson] = useState("{}");
@@ -263,8 +230,18 @@ class ErrorBoundary extends Component<ErrorBoundaryProps, ErrorBoundaryState> {
 }
 
 
+async function connectToAllServers(): Promise<ServerInfo[]> {
+  const serverUrlsResponse = await fetch("/api/servers");
+  const serverUrls = (await serverUrlsResponse.json()) as string[];
+  return Promise.all(serverUrls.map((url) => connectToServer(new URL(url))));
+}
+
 createRoot(document.getElementById("root")!).render(
   <StrictMode>
-    <Host />
+    <ErrorBoundary>
+      <Suspense fallback={<p className={styles.connecting}>Connecting to servers...</p>}>
+        <Host serversPromise={connectToAllServers()} />
+      </Suspense>
+    </ErrorBoundary>
   </StrictMode>,
 );

examples/basic-server-react/server.ts

@@ -12,7 +12,7 @@ const DIST_DIR = path.join(import.meta.dirname, "dist");
 
 
 const server = new McpServer({
-  name: "MCP App Server",
+  name: "Basic MCP App Server (React-based)",
   version: "1.0.0",
 });
 
@@ -85,7 +85,7 @@ app.post("/mcp", async (req: Request, res: Response) => {
   }
 });
 
-const httpServer = app.listen(PORT, err => {
+const httpServer = app.listen(PORT, (err) => {
   if (err) {
     console.error("Error starting server:", err);
     process.exit(1);

examples/basic-server-vanillajs/server.ts

@@ -12,7 +12,7 @@ const DIST_DIR = path.join(import.meta.dirname, "dist");
 
 
 const server = new McpServer({
-  name: "MCP App Server",
+  name: "Basic MCP App Server (Vanilla JS)",
   version: "1.0.0",
 });
 
@@ -85,7 +85,7 @@ app.post("/mcp", async (req: Request, res: Response) => {
   }
 });
 
-const httpServer = app.listen(PORT, err => {
+const httpServer = app.listen(PORT, (err) => {
   if (err) {
     console.error("Error starting server:", err);
     process.exit(1);

examples/run-all.ts

@@ -0,0 +1,120 @@
+#!/usr/bin/env bun
+/**
+ * Orchestration script for running all example servers.
+ *
+ * Usage:
+ *   bun examples/run-all.ts start  - Build and start all examples
+ *   bun examples/run-all.ts dev    - Run all examples in dev/watch mode
+ *   bun examples/run-all.ts build  - Build all examples
+ */
+
+import { readdirSync, statSync, existsSync } from "fs";
+import { spawn, type ChildProcess } from "child_process";
+
+const BASE_PORT = 3101;
+const BASIC_HOST = "basic-host";
+
+// Find all example directories except basic-host that have a package.json,
+// assign ports, and build URL list
+const servers = readdirSync("examples")
+  .filter(
+    (d) =>
+      d !== BASIC_HOST &&
+      statSync(`examples/${d}`).isDirectory() &&
+      existsSync(`examples/${d}/package.json`),
+  )
+  .sort() // Sort for consistent port assignment
+  .map((dir, i) => ({
+    dir,
+    port: BASE_PORT + i,
+    url: `http://localhost:${BASE_PORT + i}/mcp`,
+  }));
+
+const COMMANDS = ["start", "dev", "build"];
+
+const command = process.argv[2];
+
+if (!command || !COMMANDS.includes(command)) {
+  console.error(`Usage: bun examples/run-all.ts <${COMMANDS.join("|")}>`);
+
+  process.exit(1);
+}
+
+const processes: ChildProcess[] = [];
+
+// Handle cleanup on exit
+function cleanup() {
+  for (const proc of processes) {
+    proc.kill();
+  }
+}
+process.on("SIGINT", cleanup);
+process.on("SIGTERM", cleanup);
+
+// Spawn a process and track it
+function spawnProcess(
+  cmd: string,
+  args: string[],
+  env: Record<string, string> = {},
+  prefix: string,
+): ChildProcess {
+  const proc = spawn(cmd, args, {
+    env: { ...process.env, ...env },
+    stdio: ["ignore", "pipe", "pipe"],
+  });
+
+  proc.stdout?.on("data", (data) => {
+    const lines = data.toString().trim().split("\n");
+    for (const line of lines) {
+      console.log(`[${prefix}] ${line}`);
+    }
+  });
+
+  proc.stderr?.on("data", (data) => {
+    const lines = data.toString().trim().split("\n");
+    for (const line of lines) {
+      console.error(`[${prefix}] ${line}`);
+    }
+  });
+
+  proc.on("exit", (code) => {
+    if (code !== 0 && code !== null) {
+      console.error(`[${prefix}] exited with code ${code}`);
+    }
+  });
+
+  processes.push(proc);
+  return proc;
+}
+
+// Build the SERVERS environment variable (JSON array of URLs)
+const serversEnv = JSON.stringify(servers.map((s) => s.url));
+
+console.log(`Running command: ${command}`);
+console.log(
+  `Server examples: ${servers.map((s) => `${s.dir}:${s.port}`).join(", ")}`,
+);
+console.log("");
+
+// If dev mode, also run the main library watcher
+if (command === "dev") {
+  spawnProcess("npm", ["run", "watch"], {}, "lib");
+}
+
+// Run each server example
+for (const { dir, port } of servers) {
+  spawnProcess(
+    "npm",
+    ["run", "--workspace", `examples/${dir}`, command],
+    { PORT: String(port) },
+    dir,
+  );
+}
+
+// Run basic-host with the SERVERS env var
+spawnProcess(
+  "npm",
+  ["run", "--workspace", `examples/${BASIC_HOST}`, command],
+  { SERVERS: serversEnv },
+  BASIC_HOST,
+);