Added Compiler Pass to build ToolChain

Author: tom-hart-sky-uk

demo/composer.json

@@ -5,6 +5,20 @@
     "license": "MIT",
     "minimum-stability": "dev",
     "prefer-stable": true,
+    "repositories": [
+        {
+            "type": "path",
+            "url": "../src/mcp-bundle"
+        },
+        {
+            "type": "path",
+            "url": "../src/ai-bundle"
+        },
+        {
+            "type": "path",
+            "url": "../src/mcp-sdk"
+        }
+    ],
     "require": {
         "php": ">=8.4",
         "ext-ctype": "*",
@@ -14,7 +28,7 @@
         "mrmysql/youtube-transcript": "^0.0.5",
         "php-http/discovery": "^1.20",
         "runtime/frankenphp-symfony": "^0.2.0",
-        "symfony/ai-bundle": "@dev",
+        "symfony/ai-bundle": "dev-main",
         "symfony/asset": "7.3.*",
         "symfony/asset-mapper": "7.3.*",
         "symfony/clock": "7.3.*",
@@ -25,7 +39,8 @@
         "symfony/flex": "^2.5",
         "symfony/framework-bundle": "7.3.*",
         "symfony/http-client": "7.3.*",
-        "symfony/mcp-bundle": "@dev",
+        "symfony/mcp-sdk": "dev-main",
+        "symfony/mcp-bundle": "dev-main",
         "symfony/monolog-bundle": "^3.10",
         "symfony/runtime": "7.3.*",
         "symfony/twig-bundle": "7.3.*",

demo/config/services.yaml

@@ -19,10 +19,6 @@ services:
             - '../src/Entity/'
             - '../src/Kernel.php'
 
-    Symfony\AI\McpSdk\Capability\Tool\ToolExecutorInterface:
-        class: Symfony\AI\McpSdk\Capability\ToolChain
-        arguments:
-            - ['@App\MCP\Tools\CurrentTimeTool']
-
-    Symfony\AI\McpSdk\Capability\Tool\CollectionInterface:
-        alias: Symfony\AI\McpSdk\Capability\Tool\ToolExecutorInterface
+    App\MCP\Tools\CurrentTimeTool:
+        tags:
+            - { name: 'mcp_tool' }

src/mcp-bundle/CHANGELOG.md

@@ -1,6 +1,7 @@
 CHANGELOG
 =========
 
+
 0.1
 ---
 
@@ -17,4 +18,6 @@ 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
+ * Added `\Symfony\AI\McpBundle\DependencyInjection\ContainerBuilder\MCPToolChainCompilerPass`
+   to find services tagged `mcp_tool` and register them in the MCP tool chain.

src/mcp-bundle/doc/index.rst

@@ -63,6 +63,14 @@ Configuration
                 sse:
                     url: 'http://localhost:8000/sse' # URL to SSE endpoint of MCP server
 
+To add your tools to the MCP server, add the tag:
+
+.. code-block:: yaml
+
+    App\MCP\Tools\MyCustomTool:
+        tags:
+            - { name: 'mcp_tool' }
+
 .. _`Model Context Protocol`: https://modelcontextprotocol.io/
 .. _`symfony/mcp-sdk`: https://github.com/symfony/mcp-sdk
 .. _`Claude Desktop`: https://claude.ai/download

src/mcp-bundle/src/DependencyInjection/ContainerBuilder/MCPToolChainCompilerPass.php

@@ -0,0 +1,50 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\AI\McpBundle\DependencyInjection\ContainerBuilder;
+
+use Symfony\AI\McpSdk\Capability\Tool\CollectionInterface;
+use Symfony\AI\McpSdk\Capability\Tool\ToolExecutorInterface;
+use Symfony\AI\McpSdk\Capability\ToolChain;
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Definition;
+
+/**
+ * @author Tom Hart <[email protected]>
+ */
+class MCPToolChainCompilerPass implements CompilerPassInterface
+{
+    use PriorityTaggedServiceTrait;
+
+    public function process(ContainerBuilder $container): void
+    {
+        // If the user has already defined this service, don't override it.
+        if ($container->hasDefinition(ToolExecutorInterface::class)) {
+            return;
+        }
+
+        $definition = new Definition(ToolChain::class);
+
+        $taggedServices = $this->findAndSortTaggedServices('mcp_tool', $container);
+
+        $definition->setArgument(0, $taggedServices);
+
+        $container->setDefinition(ToolExecutorInterface::class, $definition);
+
+        if (!$container->hasDefinition(CollectionInterface::class)) {
+            $container->setAlias(CollectionInterface::class, ToolExecutorInterface::class);
+        }
+    }
+}

src/mcp-bundle/src/McpBundle.php

@@ -13,6 +13,7 @@
 
 use Symfony\AI\McpBundle\Command\McpCommand;
 use Symfony\AI\McpBundle\Controller\McpController;
+use Symfony\AI\McpBundle\DependencyInjection\ContainerBuilder\MCPToolChainCompilerPass;
 use Symfony\AI\McpBundle\Routing\RouteLoader;
 use Symfony\Component\Config\Definition\Configurator\DefinitionConfigurator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -21,6 +22,13 @@
 
 final class McpBundle extends AbstractBundle
 {
+    public function build(ContainerBuilder $container): void
+    {
+        parent::build($container);
+
+        $container->addCompilerPass(new MCPToolChainCompilerPass());
+    }
+
     public function configure(DefinitionConfigurator $definition): void
     {
         $definition->import('../config/options.php');