[Server] Compatibility of Capabilities with Symfony's Container

Passing container and using ->get() won't work with Symfony by default since services are private.

The \"App\\Tools\\PythonTool\" service or alias has been removed or inlined when the container was compiled. You should either make it public, or stop using the container directly and use dependency injection instead.

only way to make it work is to set service public.

It's slightly different from what was in PHP-MCP package (for some reason I was using it before swapping to this one), but it still persists.

 "exception": {
        "class": "ArgumentCountError",
        "message": "Too few arguments to function App\\Tools\\SearchTool::__construct(), 0 passed in /home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/Capability/Registry/ReferenceHandler.php on line 75 and exactly 1 expected",
        "code": 0,
        "file": "/home/ineersa/mcp-servers/browser-mcp/src/Tools/SearchTool.php:17",
        "trace": [
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/Capability/Registry/ReferenceHandler.php:75",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/Capability/Registry/ReferenceHandler.php:36",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/Capability/Registry.php:232",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/Server/RequestHandler/CallToolHandler.php:47",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/JsonRpc/Handler.php:160",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/JsonRpc/Handler.php:106",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/mcp/sdk/src/Server.php:50",
            "/home/ineersa/mcp-servers/browser-mcp/src/Command/BrowserMcpCommand.php:91",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/console/Command/Command.php:318",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/console/Application.php:1110",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/framework-bundle/Console/Application.php:123",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/console/Application.php:359",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/framework-bundle/Console/Application.php:77",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/console/Application.php:194",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/symfony/runtime/Runner/Symfony/ConsoleApplicationRunner.php:49",
            "/home/ineersa/mcp-servers/browser-mcp/vendor/autoload_runtime.php:29",
            "/home/ineersa/mcp-servers/browser-mcp/bin/browser-mcp:15"
        ]
    }

When we try to resolve how to get tool handler we will call ->container->has(CLASSNAME)

private function getClassInstance(string $className): object
{
    if (null !== $this->container && $this->container->has($className)) {
        return $this->container->get($className);
    }

    return new $className();
}

While this will work with containers like PHP-DI for example, it won't work with Symfony.
All services inside Symfony container are private, so ->container->has(CLASSNAME) will return false unless it explicitly set as public.

I don't really see how to fix it, since it's not a bug.
Maybe there should be Symfony specific documentation which will explicitly say that Tools/Resources/Prompts must be public if they have any dependencies:

For example this in services.yaml will fix those issues

services:
    ...
    # Make ALL services in App\Tools\ public
    App\Tools\:
        resource: '../src/Tools'
        public: true

That's alright, we can use a locator build with the services that have the attributes on them - that'll work :)
I'll take care while patching up the mcp-bundle

@ineersa

This should be solved with the bundle - fair to close @ineersa?

This should be solved with the bundle - fair to close @ineersa?

Sure! I need to try bundle =)

Closing for now - feel free to re-open if there are issues with the bundle.

Hi,
I'm facing the same error, for others reading this, I think the discussion mentions the "bundle".

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[Server] Compatibility of Capabilities with Symfony's Container #67

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[Server] Compatibility of Capabilities with Symfony's Container #67

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ineersa commented on Sep 14, 2025

chr-hertel commented on Sep 14, 2025

chr-hertel commented on Nov 11, 2025

ineersa commented on Nov 12, 2025

chr-hertel commented on Nov 14, 2025

axi commented on Nov 18, 2025

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