feat: add callable tool handler example

[skip ci]

Author: CodeWithKyrian

examples/02-discovery-http-userprofile/server.php

@@ -70,6 +70,48 @@ public function log($level, \Stringable|string $message, array $context = []): v
         ->withCapabilities(ServerCapabilities::make(completions: true, logging: true))
         ->withLogger($logger)
         ->withContainer($container)
+        ->withTool(
+            function (float $a, float $b, string $operation = 'add'): array {
+                $result = match ($operation) {
+                    'add' => $a + $b,
+                    'subtract' => $a - $b,
+                    'multiply' => $a * $b,
+                    'divide' => $b != 0 ? $a / $b : throw new \InvalidArgumentException('Cannot divide by zero'),
+                    default => throw new \InvalidArgumentException("Unknown operation: {$operation}")
+                };
+
+                return [
+                    'operation' => $operation,
+                    'operands' => [$a, $b],
+                    'result' => $result
+                ];
+            },
+            name: 'calculator',
+            description: 'Perform basic math operations (add, subtract, multiply, divide)'
+        )
+        ->withResource(
+            function (): array {
+                $memoryUsage = memory_get_usage(true);
+                $memoryPeak = memory_get_peak_usage(true);
+                $uptime = time() - $_SERVER['REQUEST_TIME_FLOAT'] ?? time();
+                $serverSoftware = $_SERVER['SERVER_SOFTWARE'] ?? 'CLI';
+
+                return [
+                    'server_time' => date('Y-m-d H:i:s'),
+                    'uptime_seconds' => $uptime,
+                    'memory_usage_mb' => round($memoryUsage / 1024 / 1024, 2),
+                    'memory_peak_mb' => round($memoryPeak / 1024 / 1024, 2),
+                    'php_version' => PHP_VERSION,
+                    'server_software' => $serverSoftware,
+                    'operating_system' => PHP_OS_FAMILY,
+                    'status' => 'healthy'
+                ];
+            },
+            uri: 'system://status',
+            name: 'system_status',
+            description: 'Current system status and runtime information',
+            mimeType: 'application/json'
+        )
         ->build();
 
     $server->discover(__DIR__, ['.']);