php-server-implementation

PHP MCP Server Implementation Guide

High-Level McpServer Class

The McpServer class provides a simplified API for creating MCP servers. It wraps the lower-level Server class.

Basic Server Structure

namespace MCP\Server;

use MCP\Types\Implementation;
use MCP\Shared\Transport;
use React\Promise\Promise;

class McpServer {
    private Server $server;
    private array $registeredTools = [];
    private array $registeredResources = [];
    private array $registeredResourceTemplates = [];
    private array $registeredPrompts = [];

    public function __construct(Implementation $serverInfo, ?ServerOptions $options = null) {
        $this->server = new Server($serverInfo, $options);
    }

    public function connect(Transport $transport): Promise {
        return $this->server->connect($transport);
    }
}

Registering Tools

/**
 * Register a tool with validation schema and handler
 */
public function registerTool(
    string $name,
    array $config,
    callable $handler
): RegisteredTool {
    // Tool configuration includes:
    // - title: Display name
    // - description: Tool description
    // - inputSchema: Input validation schema
    // - outputSchema: Optional output schema
    // - annotations: Tool hints

    $tool = new RegisteredTool($name, $config, $handler);
    $this->registeredTools[$name] = $tool;

    // Emit list changed notification if connected
    if ($this->server->isConnected()) {
        $this->server->sendNotification([
            'method' => 'notifications/tools/list_changed'
        ]);
    }

    return $tool;
}

Registering Resources

/**
 * Register a static resource
 */
public function registerResource(
    string $name,
    string $uri,
    array $metadata,
    callable $handler
): RegisteredResource {
    $resource = new RegisteredResource($name, $uri, $metadata, $handler);
    $this->registeredResources[$uri] = $resource;
    return $resource;
}

/**
 * Register a resource template for dynamic resources
 */
public function registerResourceTemplate(
    string $name,
    UriTemplate $template,
    array $metadata,
    callable $handler
): RegisteredResourceTemplate {
    $resourceTemplate = new RegisteredResourceTemplate($name, $template, $metadata, $handler);
    $this->registeredResourceTemplates[$name] = $resourceTemplate;
    return $resourceTemplate;
}