[MCP Bundle] autoconfigure, tag and inject registry loader

Author: soyuka

src/mcp-bundle/src/DependencyInjection/McpPass.php

@@ -12,18 +12,28 @@
 namespace Symfony\AI\McpBundle\DependencyInjection;
 
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
 use Symfony\Component\DependencyInjection\Compiler\ServiceLocatorTagPass;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Reference;
 
 final class McpPass implements CompilerPassInterface
 {
+    use PriorityTaggedServiceTrait;
+
     public function process(ContainerBuilder $container): void
     {
         if (!$container->hasDefinition('mcp.server.builder')) {
             return;
         }
 
+        $definition = $container->getDefinition('mcp.server.builder');
+
+        $loaderReferences = $this->findAndSortTaggedServices('mcp.loader', $container);
+        if ([] !== $loaderReferences) {
+            $definition->addMethodCall('addLoaders', $loaderReferences);
+        }
+
         $allMcpServices = [];
         $mcpTags = ['mcp.tool', 'mcp.prompt', 'mcp.resource', 'mcp.resource_template'];
 
@@ -42,8 +52,6 @@ public function process(ContainerBuilder $container): void
         }
 
         $serviceLocatorRef = ServiceLocatorTagPass::register($container, $serviceReferences);
-
-        $container->getDefinition('mcp.server.builder')
-            ->addMethodCall('setContainer', [$serviceLocatorRef]);
+        $definition->addMethodCall('setContainer', [$serviceLocatorRef]);
     }
 }

src/mcp-bundle/src/McpBundle.php

@@ -16,6 +16,7 @@
 use Mcp\Capability\Attribute\McpResource;
 use Mcp\Capability\Attribute\McpResourceTemplate;
 use Mcp\Capability\Attribute\McpTool;
+use Mcp\Capability\Registry\Loader\LoaderInterface;
 use Mcp\Server\Session\FileSessionStore;
 use Mcp\Server\Session\InMemorySessionStore;
 use Symfony\AI\McpBundle\Command\McpCommand;
@@ -58,6 +59,9 @@ public function loadExtension(array $config, ContainerConfigurator $container, C
 
         $this->registerMcpAttributes($builder);
 
+        $builder->registerForAutoconfiguration(LoaderInterface::class)
+            ->addTag('mcp.loader');
+
         if ($builder->getParameter('kernel.debug')) {
             $traceableRegistry = (new Definition('mcp.traceable_registry'))
                 ->setClass(TraceableRegistry::class)

src/mcp-bundle/tests/DependencyInjection/McpBundleTest.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\AI\McpBundle\Tests\DependencyInjection;
 
+use Mcp\Capability\Registry\Loader\LoaderInterface;
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\TestCase;
 use Symfony\AI\McpBundle\McpBundle;
@@ -349,6 +350,15 @@ public function testDiscoveryWithExcludeDirsOnly()
         $this->assertSame(['src/DataFixtures'], $container->getParameter('mcp.discovery.exclude_dirs'));
     }
 
+    public function testLoaderInterfaceAutoconfiguration()
+    {
+        $container = $this->buildContainer([]);
+        $autoconfigured = $container->getAutoconfiguredInstanceof();
+        $this->assertArrayHasKey(LoaderInterface::class, $autoconfigured);
+        $definition = $autoconfigured[LoaderInterface::class];
+        $this->assertTrue($definition->hasTag('mcp.loader'));
+    }
+
     private function buildContainer(array $configuration): ContainerBuilder
     {
         $container = new ContainerBuilder();

src/mcp-bundle/tests/DependencyInjection/McpPassTest.php

@@ -138,4 +138,37 @@ public function testHandlesPartialMcpServices()
         $this->assertInstanceOf(Reference::class, $services['tool_service']->getValues()[0]);
         $this->assertInstanceOf(Reference::class, $services['prompt_service']->getValues()[0]);
     }
+
+    public function testInjectsLoadersIntoBuilder()
+    {
+        $container = new ContainerBuilder();
+        $container->setDefinition('mcp.server.builder', new Definition());
+
+        $container->setDefinition('loader_one', (new Definition())->addTag('mcp.loader'));
+        $container->setDefinition('loader_two', (new Definition())->addTag('mcp.loader'));
+
+        $pass = new McpPass();
+        $pass->process($container);
+
+        $builderDefinition = $container->getDefinition('mcp.server.builder');
+        $methodCalls = $builderDefinition->getMethodCalls();
+
+        $addLoadersCall = null;
+        foreach ($methodCalls as $call) {
+            if ('addLoaders' === $call[0]) {
+                $addLoadersCall = $call;
+                break;
+            }
+        }
+
+        $this->assertNotNull($addLoadersCall, 'Builder should have addLoaders method call');
+
+        // Verify arguments are References
+        $args = $addLoadersCall[1];
+        $this->assertContainsOnlyInstancesOf(Reference::class, $args);
+
+        $ids = array_map(fn (Reference $ref) => (string) $ref, $args);
+        $this->assertContains('loader_one', $ids);
+        $this->assertContains('loader_two', $ids);
+    }
 }