fix: add error handling for server startup failures

Previously, if app.listen() failed (e.g., port already in use), the
server would fail silently. This adds proper error handling to log
the error and exit with a non-zero status code.

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ochafik

examples/basic-server-preact/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/basic-server-react/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/basic-server-solid/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/basic-server-svelte/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/basic-server-vanillajs/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/basic-server-vue/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/budget-allocator-server/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/cohort-heatmap-server/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/customer-segmentation-server/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });
 

examples/integration-server/server-utils.ts

@@ -54,7 +54,11 @@ export async function startServer(
     }
   });
 
-  const httpServer = app.listen(port, () => {
+  const httpServer = app.listen(port, (err) => {
+    if (err) {
+      console.error("Failed to start server:", err);
+      process.exit(1);
+    }
     console.log(`${name} listening on http://localhost:${port}/mcp`);
   });