[MCP Bundle] Add MCP profiler support to display server capabilities

[camilleislasse]

Q	A
Bug fix?	no
New feature?	yes
Docs?	no
Issues	Fix #529
License	MIT

Description

This PR adds a Web Profiler integration for the MCP Bundle that displays MCP server capabilities (tools, prompts, resources, resource templates) in the Symfony debug toolbar and profiler panel.

Features

• ProfilingLoader to capture Registry reference during server build
• DataCollector to collect and display MCP capabilities

Note: This implementation depends on the loader pattern. If MCP SDK PR #146 (direct Registry injection via DI) is merged, this approach may need adjustment.

[chr-hertel]

Thanks, this looks great already, but let's please switch to a TraceableRegistry once modelcontextprotocol/php-sdk#150 gets merged - makes sense?

[OskarStark]

Would love to see some infos around the MCP Profiler and the screenshot in the documentation

[chr-hertel]

We should be able to use/decorate the Registry directly now and skip the ProfilingLoader, right?

[chr-hertel]

Looks good & works with the demo - one last thing about the service registration tho 👍

Thanks already!

[chr-hertel]

let's shift that into McpBundle, make it conditional, drop the ai. prefix in favor of just mcp. and use the decoration feature of the container:

if ($container->getParameter('kernel.debug')) {
    $traceableRegistry = (new Definition('mcp.traceable_registry'))
        ->setClass(TraceableRegistry::class)
        ->setArguments([new Reference('.inner')])
        ->setDecoratedService('mcp.registry');
    $container->setDefinition('mcp.traceable_registry', $traceableRegistry);
}

[chr-hertel]

Thanks for kicking this off - we can build up on this now with more features :)

[chr-hertel]

Thank you @camilleislasse.