feature #168 [McpBundle] Compiler pass for tools (tom-hart-sky-uk)

This PR was merged into the main branch.

Discussion
----------

[McpBundle] Compiler pass for tools

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Docs?         | yes
| Issues        | N/A
| License       | MIT

Add a Compiler Pass to find tools and register them in the ToolChain

Commits
-------

0a77af8 Added Compiler Pass to build ToolChain

Author: chr-hertel

demo/config/services.yaml

@@ -18,11 +18,3 @@ services:
             - '../src/DependencyInjection/'
             - '../src/Entity/'
             - '../src/Kernel.php'
-
-    mcp.tool_executor:
-        class: Symfony\AI\McpSdk\Capability\ToolChain
-        arguments:
-            - ['@App\MCP\Tools\CurrentTimeTool']
-
-    mcp.tool_collection:
-        alias: mcp.tool_executor

src/mcp-bundle/CHANGELOG.md

@@ -17,4 +17,6 @@ CHANGELOG
  * Add `McpCommand` providing STDIO interface
  * Add bundle configuration for enabling/disabling transports
  * Add cache-based SSE message storage
- * Add service configuration for MCP server setup
+ * Add service configuration for MCP server setup
+ * Classes extending `\Symfony\AI\McpSdk\Capability\Tool\IdentifierInterface` automatically
+   get the `mcp.tool` tag for MCP tool discovery

src/mcp-bundle/config/services.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\DependencyInjection\Loader\Configurator;
 
+use Symfony\AI\McpSdk\Capability\ToolChain;
 use Symfony\AI\McpSdk\Message\Factory;
 use Symfony\AI\McpSdk\Server;
 use Symfony\AI\McpSdk\Server\JsonRpcHandler;
@@ -66,5 +67,11 @@
             ->args([
                 service('cache.app'),
             ])
+        ->set('mcp.tool_chain', ToolChain::class)
+            ->args([
+                tagged_iterator('mcp.tool'),
+            ])
+            ->alias('mcp.tool_executor', 'mcp.tool_chain')
+            ->alias('mcp.tool_collection', 'mcp.tool_chain')
     ;
 };

src/mcp-bundle/src/McpBundle.php

@@ -14,6 +14,7 @@
 use Symfony\AI\McpBundle\Command\McpCommand;
 use Symfony\AI\McpBundle\Controller\McpController;
 use Symfony\AI\McpBundle\Routing\RouteLoader;
+use Symfony\AI\McpSdk\Capability\Tool\IdentifierInterface;
 use Symfony\AI\McpSdk\Server\NotificationHandlerInterface;
 use Symfony\AI\McpSdk\Server\RequestHandlerInterface;
 use Symfony\Component\Config\Definition\Configurator\DefinitionConfigurator;
@@ -42,6 +43,11 @@ public function loadExtension(array $config, ContainerConfigurator $container, C
         if (isset($config['client_transports'])) {
             $this->configureClient($config['client_transports'], $builder);
         }
+
+        $builder
+            ->registerForAutoconfiguration(IdentifierInterface::class)
+            ->addTag('mcp.tool')
+        ;
     }
 
     /**

src/mcp-sdk/src/Capability/ToolChain.php

@@ -30,7 +30,7 @@ public function __construct(
         /**
          * @var IdentifierInterface[] $items
          */
-        private readonly array $items,
+        private readonly iterable $items,
     ) {
     }