Added browser open in prod launcher, cleanup up port in use error in prod, removed vestigial client launcher.

Author: BobDickinson

package-lock.json

@@ -112,33 +112,40 @@ async function startProdClient(clientOptions) {
   } = clientOptions;
   const honoServerPath = resolve(__dirname, "../dist/server.js");
 
-  // Inspector API server (Hono) serves static files + /api/* endpoints
-  // Pass Inspector API auth token and config values explicitly via env vars (read-only, server reads them)
-  await spawnPromise("node", [honoServerPath], {
-    env: {
-      ...process.env,
-      CLIENT_PORT,
-      ...(dangerouslyOmitAuth
-        ? {}
-        : { [API_SERVER_ENV_VARS.AUTH_TOKEN]: inspectorApiToken }),
-      // Pass config values for HTML injection
-      ...(command ? { MCP_INITIAL_COMMAND: command } : {}),
-      ...(mcpServerArgs && mcpServerArgs.length > 0
-        ? { MCP_INITIAL_ARGS: mcpServerArgs.join(" ") }
-        : {}),
-      ...(transport ? { MCP_INITIAL_TRANSPORT: transport } : {}),
-      ...(serverUrl ? { MCP_INITIAL_SERVER_URL: serverUrl } : {}),
-      ...(headers && Object.keys(headers).length > 0
-        ? { MCP_INITIAL_HEADERS: JSON.stringify(headers) }
-        : {}),
-      ...(envVars && Object.keys(envVars).length > 0
-        ? { MCP_ENV_VARS: JSON.stringify(envVars) }
-        : {}),
-      ...(cwd ? { MCP_INITIAL_CWD: cwd } : {}),
-    },
-    signal: abort.signal,
-    echoOutput: true,
-  });
+  // Inspector API server (Hono) serves static files + /api/*; it logs and opens browser when listening
+  try {
+    await spawnPromise("node", [honoServerPath], {
+      env: {
+        ...process.env,
+        CLIENT_PORT,
+        ...(dangerouslyOmitAuth
+          ? {}
+          : { [API_SERVER_ENV_VARS.AUTH_TOKEN]: inspectorApiToken }),
+        ...(command ? { MCP_INITIAL_COMMAND: command } : {}),
+        ...(mcpServerArgs && mcpServerArgs.length > 0
+          ? { MCP_INITIAL_ARGS: mcpServerArgs.join(" ") }
+          : {}),
+        ...(transport ? { MCP_INITIAL_TRANSPORT: transport } : {}),
+        ...(serverUrl ? { MCP_INITIAL_SERVER_URL: serverUrl } : {}),
+        ...(headers && Object.keys(headers).length > 0
+          ? { MCP_INITIAL_HEADERS: JSON.stringify(headers) }
+          : {}),
+        ...(envVars && Object.keys(envVars).length > 0
+          ? { MCP_ENV_VARS: JSON.stringify(envVars) }
+          : {}),
+        ...(cwd ? { MCP_INITIAL_CWD: cwd } : {}),
+      },
+      signal: abort.signal,
+      echoOutput: true,
+    });
+  } catch (err) {
+    // Child already printed the message (e.g. PORT IS IN USE); exit cleanly without stack
+    const code = err?.code ?? err?.exitCode;
+    if (typeof code === "number" && code !== 0) {
+      process.exit(code);
+    }
+    throw err;
+  }
 }
 
 async function main() {

web/bin/client.js

@@ -53,9 +53,9 @@
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-simple-code-editor": "^0.14.1",
-    "serve-handler": "^6.1.6",
     "tailwind-merge": "^2.5.3",
     "zod": "^3.25.76",
+    "open": "^10.1.0",
     "pino": "^9.6.0"
   },
   "devDependencies": {
@@ -66,7 +66,6 @@
     "@types/prismjs": "^1.26.5",
     "@types/react": "^18.3.23",
     "@types/react-dom": "^18.3.0",
-    "@types/serve-handler": "^6.1.4",
     "@vitejs/plugin-react": "^5.0.4",
     "autoprefixer": "^10.4.20",
     "co": "^4.6.0",

web/bin/start.js

@@ -2,6 +2,7 @@ import { readFileSync } from "node:fs";
 import { join, dirname } from "node:path";
 import { fileURLToPath } from "node:url";
 import { randomBytes } from "node:crypto";
+import open from "open";
 import { serve } from "@hono/node-server";
 import { serveStatic } from "@hono/node-server/serve-static";
 import { Hono } from "hono";
@@ -139,9 +140,12 @@ const httpServer = serve(
     hostname: host,
   },
   (info) => {
-    console.log(
-      `\n🚀 MCP Inspector Web is up and running at:\n   http://${host}:${info.port}\n`,
-    );
+    const baseUrl = `http://${host}:${info.port}`;
+    const url =
+      dangerouslyOmitAuth || !authToken
+        ? baseUrl
+        : `${baseUrl}?${API_SERVER_ENV_VARS.AUTH_TOKEN}=${authToken}`;
+    console.log(`\n🚀 MCP Inspector Web is up and running at:\n   ${url}\n`);
     const sandboxUrl = sandboxController.getUrl();
     if (sandboxUrl) {
       console.log(`   Sandbox (MCP Apps): ${sandboxUrl}\n`);
@@ -151,5 +155,20 @@ const httpServer = serve(
     } else {
       console.log(`   Auth token: ${authToken}\n`);
     }
+    if (process.env.MCP_AUTO_OPEN_ENABLED !== "false") {
+      console.log("🌐 Opening browser...");
+      open(url);
+    }
   },
 );
+
+httpServer.on("error", (err: Error) => {
+  if (err.message.includes("EADDRINUSE")) {
+    console.error(
+      `❌  MCP Inspector PORT IS IN USE at http://${host}:${port} ❌ `,
+    );
+    process.exit(1);
+  } else {
+    throw err;
+  }
+});