refactor(examples): use getPort() helper for transport selection

- Add getPort() helper that returns undefined for --stdio, else port
- Caller now explicitly passes port to startServer()
- port: undefined → stdio mode, port: number → HTTP mode

This makes the transport selection explicit at the call site.

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

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

Author: ochafik

examples/basic-server-react/server.ts

@@ -3,7 +3,7 @@ import type { CallToolResult, ReadResourceResult } from "@modelcontextprotocol/s
 import fs from "node:fs/promises";
 import path from "node:path";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -52,4 +52,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "Basic MCP App Server (React-based)" });
+startServer(server, { port: getPort(), name: "Basic MCP App Server (React-based)" });

examples/basic-server-vanillajs/server.ts

@@ -3,7 +3,7 @@ import type { CallToolResult, ReadResourceResult } from "@modelcontextprotocol/s
 import fs from "node:fs/promises";
 import path from "node:path";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -52,4 +52,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "Basic MCP App Server (Vanilla JS)" });
+startServer(server, { port: getPort(), name: "Basic MCP App Server (Vanilla JS)" });

examples/budget-allocator-server/server.ts

@@ -13,7 +13,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -292,4 +292,4 @@ server.registerResource(
 // Server Startup
 // ---------------------------------------------------------------------------
 
-startServer(server, { name: "Budget Allocator Server" });
+startServer(server, { port: getPort(), name: "Budget Allocator Server" });

examples/cohort-heatmap-server/server.ts

@@ -4,7 +4,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -201,4 +201,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "Cohort Heatmap Server" });
+startServer(server, { port: getPort(), name: "Cohort Heatmap Server" });

examples/customer-segmentation-server/server.ts

@@ -7,7 +7,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 import {
   generateCustomers,
   generateSegmentSummaries,
@@ -100,4 +100,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "Customer Segmentation Server" });
+startServer(server, { port: getPort(), name: "Customer Segmentation Server" });

examples/scenario-modeler-server/server.ts

@@ -7,7 +7,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -308,4 +308,4 @@ const server = new McpServer({
 // Server Startup
 // ============================================================================
 
-startServer(server, { name: "SaaS Scenario Modeler Server" });
+startServer(server, { port: getPort(), name: "SaaS Scenario Modeler Server" });

examples/shared/server-utils.ts

@@ -2,7 +2,7 @@
  * Shared utilities for running MCP servers with multiple transports.
  *
  * Supports:
- * - stdio transport (--stdio flag)
+ * - stdio transport (when port is undefined)
  * - Streamable HTTP transport (/mcp) - stateful sessions
  * - Legacy SSE transport (/sse, /messages) - backwards compatibility
  */
@@ -18,7 +18,7 @@ import { randomUUID } from "node:crypto";
 import type { Request, Response } from "express";
 
 export interface ServerOptions {
-  /** Port to listen on. Defaults to PORT env var or 3001. */
+  /** Port to listen on. If undefined, uses stdio transport. */
   port?: number;
   /** Server name for logging. */
   name?: string;
@@ -27,21 +27,18 @@ export interface ServerOptions {
 type Transport = StreamableHTTPServerTransport | SSEServerTransport;
 
 /**
- * Starts an MCP server with stdio and HTTP transports.
+ * Starts an MCP server.
  *
- * HTTP mode provides:
- * - /mcp (GET/POST/DELETE): Streamable HTTP with stateful sessions
- * - /sse (GET) + /messages (POST): Legacy SSE for older clients
+ * - If port is undefined: uses stdio transport
+ * - If port is provided: HTTP server with Streamable HTTP + legacy SSE
  */
 export async function startServer(
   server: McpServer,
   options: ServerOptions = {},
 ): Promise<void> {
-  const port =
-    options.port ?? (process.env.PORT ? parseInt(process.env.PORT, 10) : 3001);
-  const name = options.name ?? "MCP Server";
+  const { port, name = "MCP Server" } = options;
 
-  if (process.argv.includes("--stdio")) {
+  if (port === undefined) {
     await server.connect(new StdioServerTransport());
     console.error(`${name} running in stdio mode`);
     return;
@@ -51,7 +48,6 @@ export async function startServer(
   const sessions = new Map<string, Transport>();
 
   // Express app - bind to all interfaces for development/testing
-  // (allows connections from Android emulators, other devices, etc.)
   const app = createMcpExpressApp({ host: "0.0.0.0" });
   app.use(cors());
 
@@ -157,3 +153,9 @@ export async function startServer(
   process.on("SIGINT", shutdown);
   process.on("SIGTERM", shutdown);
 }
+
+/** Helper to get port from args/env, returns undefined for stdio mode */
+export function getPort(defaultPort = 3001): number | undefined {
+  if (process.argv.includes("--stdio")) return undefined;
+  return process.env.PORT ? parseInt(process.env.PORT, 10) : defaultPort;
+}

examples/system-monitor-server/server.ts

@@ -9,7 +9,7 @@ import path from "node:path";
 import si from "systeminformation";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 // Schemas - types are derived from these using z.infer
 const CpuCoreSchema = z.object({
@@ -171,4 +171,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "System Monitor Server" });
+startServer(server, { port: getPort(), name: "System Monitor Server" });

examples/threejs-server/server.ts

@@ -9,7 +9,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -181,4 +181,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "Three.js Server" });
+startServer(server, { port: getPort(), name: "Three.js Server" });

examples/wiki-explorer-server/server.ts

@@ -8,7 +8,7 @@ import fs from "node:fs/promises";
 import path from "node:path";
 import { z } from "zod";
 import { RESOURCE_MIME_TYPE, RESOURCE_URI_META_KEY } from "../../dist/src/app";
-import { startServer } from "../shared/server-utils.js";
+import { getPort, startServer } from "../shared/server-utils.js";
 
 const DIST_DIR = path.join(import.meta.dirname, "dist");
 
@@ -138,4 +138,4 @@ const server = new McpServer({
   );
 }
 
-startServer(server, { name: "Wiki Explorer" });
+startServer(server, { port: getPort(), name: "Wiki Explorer" });