Implemented MCP logging specification with auto-injection

Author: Adebayo120

composer.json

@@ -60,6 +60,7 @@
       "Mcp\\Example\\StdioDiscoveryCalculator\\": "examples/stdio-discovery-calculator/",
       "Mcp\\Example\\StdioEnvVariables\\": "examples/stdio-env-variables/",
       "Mcp\\Example\\StdioExplicitRegistration\\": "examples/stdio-explicit-registration/",
+      "Mcp\\Example\\StdioLoggingShowcase\\": "examples/stdio-logging-showcase/",
       "Mcp\\Tests\\": "tests/"
     }
   },

examples/stdio-discovery-calculator/McpElements.php

@@ -13,8 +13,7 @@
 
 use Mcp\Capability\Attribute\McpResource;
 use Mcp\Capability\Attribute\McpTool;
-use Psr\Log\LoggerInterface;
-use Psr\Log\NullLogger;
+use Mcp\Capability\Logger\McpLogger;
 
 /**
  * @phpstan-type Config array{precision: int, allow_negative: bool}
@@ -29,27 +28,28 @@ final class McpElements
         'allow_negative' => true,
     ];
 
-    public function __construct(
-        private readonly LoggerInterface $logger = new NullLogger(),
-    ) {
-    }
-
     /**
      * Performs a calculation based on the operation.
      *
      * Supports 'add', 'subtract', 'multiply', 'divide'.
      * Obeys the 'precision' and 'allow_negative' settings from the config resource.
      *
-     * @param float  $a         the first operand
-     * @param float  $b         the second operand
-     * @param string $operation the operation ('add', 'subtract', 'multiply', 'divide')
+     * @param float     $a         the first operand
+     * @param float     $b         the second operand
+     * @param string    $operation the operation ('add', 'subtract', 'multiply', 'divide')
+     * @param McpLogger $logger    Auto-injected MCP logger
      *
      * @return float|string the result of the calculation, or an error message string
      */
     #[McpTool(name: 'calculate')]
-    public function calculate(float $a, float $b, string $operation): float|string
+    public function calculate(float $a, float $b, string $operation, McpLogger $logger): float|string
     {
-        $this->logger->info(\sprintf('Calculating: %f %s %f', $a, $operation, $b));
+        $logger->info('🧮 Calculate tool called', [
+            'operand_a' => $a,
+            'operand_b' => $b,
+            'operation' => $operation,
+            'auto_injection' => 'McpLogger auto-injected successfully',
+        ]);
 
         $op = strtolower($operation);
 
@@ -65,25 +65,48 @@ public function calculate(float $a, float $b, string $operation): float|string
                 break;
             case 'divide':
                 if (0 == $b) {
+                    $logger->warning('Division by zero attempted', [
+                        'operand_a' => $a,
+                        'operand_b' => $b,
+                    ]);
+
                     return 'Error: Division by zero.';
                 }
                 $result = $a / $b;
                 break;
             default:
+                $logger->error('Unknown operation requested', [
+                    'operation' => $operation,
+                    'supported_operations' => ['add', 'subtract', 'multiply', 'divide'],
+                ]);
+
                 return "Error: Unknown operation '{$operation}'. Supported: add, subtract, multiply, divide.";
         }
 
         if (!$this->config['allow_negative'] && $result < 0) {
+            $logger->warning('Negative result blocked by configuration', [
+                'result' => $result,
+                'allow_negative_setting' => false,
+            ]);
+
             return 'Error: Negative results are disabled.';
         }
 
-        return round($result, $this->config['precision']);
+        $finalResult = round($result, $this->config['precision']);
+        $logger->info('✅ Calculation completed successfully', [
+            'result' => $finalResult,
+            'precision' => $this->config['precision'],
+        ]);
+
+        return $finalResult;
     }
 
     /**
      * Provides the current calculator configuration.
      * Can be read by clients to understand precision etc.
      *
+     * @param McpLogger $logger Auto-injected MCP logger for demonstration
+     *
      * @return Config the configuration array
      */
     #[McpResource(
@@ -92,9 +115,12 @@ public function calculate(float $a, float $b, string $operation): float|string
         description: 'Current settings for the calculator tool (precision, allow_negative).',
         mimeType: 'application/json',
     )]
-    public function getConfiguration(): array
+    public function getConfiguration(McpLogger $logger): array
     {
-        $this->logger->info('Resource config://calculator/settings read.');
+        $logger->info('📊 Resource config://calculator/settings accessed via auto-injection!', [
+            'current_config' => $this->config,
+            'auto_injection_demo' => 'McpLogger was automatically injected into this resource handler',
+        ]);
 
         return $this->config;
     }
@@ -103,8 +129,9 @@ public function getConfiguration(): array
      * Updates a specific configuration setting.
      * Note: This requires more robust validation in a real app.
      *
-     * @param string $setting the setting key ('precision' or 'allow_negative')
-     * @param mixed  $value   the new value (int for precision, bool for allow_negative)
+     * @param string    $setting the setting key ('precision' or 'allow_negative')
+     * @param mixed     $value   the new value (int for precision, bool for allow_negative)
+     * @param McpLogger $logger  Auto-injected MCP logger
      *
      * @return array{
      *     success: bool,
@@ -113,18 +140,37 @@ public function getConfiguration(): array
      * } success message or error
      */
     #[McpTool(name: 'update_setting')]
-    public function updateSetting(string $setting, mixed $value): array
+    public function updateSetting(string $setting, mixed $value, McpLogger $logger): array
     {
-        $this->logger->info(\sprintf('Setting tool called: setting=%s, value=%s', $setting, var_export($value, true)));
+        $logger->info('🔧 Update setting tool called', [
+            'setting' => $setting,
+            'value' => $value,
+            'current_config' => $this->config,
+            'auto_injection' => 'McpLogger auto-injected successfully',
+        ]);
         if (!\array_key_exists($setting, $this->config)) {
+            $logger->error('Unknown setting requested', [
+                'setting' => $setting,
+                'available_settings' => array_keys($this->config),
+            ]);
+
             return ['success' => false, 'error' => "Unknown setting '{$setting}'."];
         }
 
         if ('precision' === $setting) {
             if (!\is_int($value) || $value < 0 || $value > 10) {
+                $logger->warning('Invalid precision value provided', [
+                    'value' => $value,
+                    'valid_range' => '0-10',
+                ]);
+
                 return ['success' => false, 'error' => 'Invalid precision value. Must be integer between 0 and 10.'];
             }
             $this->config['precision'] = $value;
+            $logger->info('✅ Precision setting updated', [
+                'new_precision' => $value,
+                'previous_config' => $this->config,
+            ]);
 
             // In real app, notify subscribers of config://calculator/settings change
             // $registry->notifyResourceChanged('config://calculator/settings');
@@ -138,10 +184,19 @@ public function updateSetting(string $setting, mixed $value): array
             } elseif (\in_array(strtolower((string) $value), ['false', '0', 'no', 'off'])) {
                 $value = false;
             } else {
+                $logger->warning('Invalid allow_negative value provided', [
+                    'value' => $value,
+                    'expected_type' => 'boolean',
+                ]);
+
                 return ['success' => false, 'error' => 'Invalid allow_negative value. Must be boolean (true/false).'];
             }
         }
         $this->config['allow_negative'] = $value;
+        $logger->info('✅ Allow negative setting updated', [
+            'new_allow_negative' => $value,
+            'updated_config' => $this->config,
+        ]);
 
         // $registry->notifyResourceChanged('config://calculator/settings');
         return ['success' => true, 'message' => 'Allow negative results set to '.($value ? 'true' : 'false').'.'];

examples/stdio-discovery-calculator/server.php

@@ -22,6 +22,7 @@
     ->setServerInfo('Stdio Calculator', '1.1.0', 'Basic Calculator over STDIO transport.')
     ->setContainer(container())
     ->setLogger(logger())
+    ->enableMcpLogging()  // Enable MCP logging capability and auto-injection!
     ->setDiscovery(__DIR__, ['.'])
     ->build();