PHP MCP Demo

Simple demo gluing together MCP with Symfony and LLM Chain - heavily inspired by @lyrixx MCP blog post.

Requirements

• PHP 8.4
• Composer
• Symfony CLI
• NPX

Installation

Setting up the Symfony project:

git clone [email protected]:php-llm/mcp-demo.git
cd mcp-demo
composer install
symfony serve -d --no-tls

Running the MCP Inspector:

npx -y @modelcontextprotocol/inspector

Usage

Open the MCP Inspector in your browser, for example at http://localhost:5173/.

For STDIO use:

• Transport Type: STDIO
• Command: /path/to/mcp-demo/bin/console
• Arguments: mcp

For SSE use:

• Transport Type: SSE
• URL: http://localhost:8000/mcp/sse (port might differ)

Click Connect and you should be able to use the tools of the Symfony app via the MCP Inspector.

SDK

Server integration points for are tailored to Symfony Console and HttpFoundation (Laravel compatible).

Example Console Command for STDIO

#[AsCommand('mcp', 'Starts an MCP server')]
class McpCommand extends Command
{
    public function __construct(
        private readonly Server $server,
    ) {
        parent::__construct();
    }

    protected function execute(InputInterface $input, OutputInterface $output): int
    {
        $this->server->connect(
            new SymfonyConsoleTransport($input, $output)
        );

        return Command::SUCCESS;
    }
}

See McpCommand.php for the full example.

Example Controller for Server-Sent Events

#[AsController]
#[Route('/mcp', name: 'mcp_')]
final readonly class McpController
{
    public function __construct(
        private Server $server,
        private CachePoolStore $store,
        private UrlGeneratorInterface $urlGenerator,
    ) {
    }

    #[Route('/sse', name: 'sse', methods: ['GET'])]
    public function sse(): StreamedResponse
    {
        $id = Uuid::v4();
        $endpoint = $this->urlGenerator->generate('mcp_messages', ['id' => $id], UrlGeneratorInterface::ABSOLUTE_URL);
        $transport = new StreamTransport($endpoint, $this->store, $id);

        return new StreamedResponse(fn() => $this->server->connect($transport), headers: [
            'Content-Type' => 'text/event-stream',
            'Cache-Control' => 'no-cache',
            'X-Accel-Buffering' => 'no',
        ]);
    }

    #[Route('/messages/{id}', name: 'messages', methods: ['POST'])]
    public function messages(Request $request, Uuid $id): Response
    {
        $this->store->push($id, $request->getContent());

        return new Response();
    }
}

See McpController.php for the full example.