<?php
/**
* WordPress MCP Registry - Main class for managing multiple MCP servers.
*
* @package WP\MCP\Core
*/
declare( strict_types=1 );
namespace WP\MCP\Core;
use WP\MCP\Abilities\DiscoverAbilitiesAbility;
use WP\MCP\Abilities\ExecuteAbilityAbility;
use WP\MCP\Abilities\GetAbilityInfoAbility;
use WP\MCP\Cli\McpCommand;
use WP\MCP\Infrastructure\ErrorHandling\Contracts\McpErrorHandlerInterface;
use WP\MCP\Infrastructure\ErrorHandling\NullMcpErrorHandler;
use WP\MCP\Infrastructure\Observability\Contracts\McpObservabilityHandlerInterface;
use WP\MCP\Infrastructure\Observability\NullMcpObservabilityHandler;
use WP\MCP\Servers\DefaultServerFactory;
/**
* WordPress MCP Registry - Main class for managing multiple MCP servers.
*/
final class McpAdapter {
public const VERSION = '0.4.1';
/**
* Registry instance
*
* @var \WP\MCP\Core\McpAdapter
*/
private static self $instance;
/**
* Registered servers
*
* @var \WP\MCP\Core\McpServer[]
*/
private array $servers = array();
/**
* Track if adapter has been initialized to prevent duplicate initialization
*
* @var bool
*/
private static bool $initialized = false;
/**
* Get the registry instance
*
* @return \WP\MCP\Core\McpAdapter
*/
public static function instance(): self {
if ( ! isset( self::$instance ) ) {
self::$instance = new self();
// In WP-CLI context, initialize immediately so commands have access to servers
if ( defined( 'WP_CLI' ) && constant( 'WP_CLI' ) ) {
add_action( 'init', array( self::$instance, 'init' ), 20 );
} else {
// Initialize for REST API requests with reasonable priority
add_action( 'rest_api_init', array( self::$instance, 'init' ), 15 );
}
}
return self::$instance;
}
/**
* Initialize the registry
*
* @internal For use by instance initialization only.
*/
public function init(): void {
if ( self::$initialized ) {
return;
}
$this->maybe_create_default_server();
do_action( 'mcp_adapter_init', $this );
$this->register_wp_cli_commands();
self::$initialized = true;
}
/**
* Create and register a new MCP server.
*
* @param string $server_id Unique identifier for the server.
* @param string $server_route_namespace Server route namespace.
* @param string $server_route Server route.
* @param string $server_name Server name.
* @param string $server_description Server description.
* @param string $server_version Server version.
* @param array $mcp_transports Array of classes that extend the BaseTransport.
* @param class-string<\WP\MCP\Infrastructure\ErrorHandling\Contracts\McpErrorHandlerInterface> $error_handler The error handler class name. If null, NullMcpErrorHandler will be used.
* @param class-string<\WP\MCP\Infrastructure\Observability\Contracts\McpObservabilityHandlerInterface> $observability_handler The observability handler class name. If null, NullMcpObservabilityHandler will be used.
* @param array $tools Ability names to register as tools.
* @param array $resources Resources to register.
* @param array $prompts Prompts to register.
* @param callable|null $transport_permission_callback Optional custom permission callback for transport-level authentication. If null, defaults to is_user_logged_in().
*
* @return \WP\MCP\Core\McpAdapter|\WP_Error McpAdapter instance on success, WP_Error on failure.
*/
public function create_server( string $server_id, string $server_route_namespace, string $server_route, string $server_name, string $server_description, string $server_version, array $mcp_transports, ?string $error_handler, ?string $observability_handler = null, array $tools = array(), array $resources = array(), array $prompts = array(), ?callable $transport_permission_callback = null ) {
// Use NullMcpErrorHandler if no error handler is provided.
if ( ! $error_handler ) {
$error_handler = NullMcpErrorHandler::class;
}
// Validate error handler class exists and implements McpErrorHandlerInterface.
if ( ! class_exists( $error_handler ) ) {
return new \WP_Error(
'invalid_error_handler',
sprintf(
/* translators: %s: error handler class name */
esc_html__( 'Error handler class "%s" does not exist.', 'mcp-adapter' ),
esc_html( $error_handler )
)
);
}
if ( ! in_array( McpErrorHandlerInterface::class, class_implements( $error_handler ) ?: array(), true ) ) {
return new \WP_Error(
'invalid_error_handler',
sprintf(
/* translators: %s: error handler class name */
esc_html__( 'Error handler class "%s" must implement the McpErrorHandlerInterface.', 'mcp-adapter' ),
esc_html( $error_handler )
)
);
}
// Use NullMcpObservabilityHandler if no observability handler is provided.
if ( ! $observability_handler ) {
$observability_handler = NullMcpObservabilityHandler::class;
}
// Validate observability handler class exists and implements McpObservabilityHandlerInterface.
if ( ! class_exists( $observability_handler ) ) {
return new \WP_Error(
'invalid_observability_handler',
sprintf(
/* translators: %s: observability handler class name */
esc_html__( 'Observability handler class "%s" does not exist.', 'mcp-adapter' ),
esc_html( $observability_handler )
)
);
}
if ( ! in_array( McpObservabilityHandlerInterface::class, class_implements( $observability_handler ) ?: array(), true ) ) {
return new \WP_Error(
'invalid_observability_handler',
sprintf(
/* translators: %s: observability handler class name */
esc_html__( 'Observability handler class "%s" must implement the McpObservabilityHandlerInterface interface.', 'mcp-adapter' ),
esc_html( $observability_handler )
)
);
}
if ( ! doing_action( 'mcp_adapter_init' ) ) {
_doing_it_wrong(
__FUNCTION__,
esc_html__( 'MCP Servers must be created during the "mcp_adapter_init" action. Hook into "mcp_adapter_init" to register your server.', 'mcp-adapter' ),
'0.1.0'
);
return new \WP_Error(
'invalid_timing',
esc_html__( 'MCP Server creation must be done during mcp_adapter_init action.', 'mcp-adapter' )
);
}
if ( isset( $this->servers[ $server_id ] ) ) {
_doing_it_wrong(
__FUNCTION__,
sprintf(
// translators: %s: server ID
esc_html__( 'Server with ID "%s" already exists. Each server must have a unique ID.', 'mcp-adapter' ),
esc_html( $server_id )
),
'0.1.0'
);
return new \WP_Error(
'duplicate_server_id',
// translators: %s: server ID.
sprintf( esc_html__( 'Server with ID "%s" already exists.', 'mcp-adapter' ), esc_html( $server_id ) )
);
}
// Create server with tools, resources, and prompts - let server handle all registration logic.
$server = new McpServer(
$server_id,
$server_route_namespace,
$server_route,
$server_name,
$server_description,
$server_version,
$mcp_transports,
$error_handler,
$observability_handler,
$tools,
$resources,
$prompts,
$transport_permission_callback
);
// Track server creation.
$server->get_observability_handler()->record_event(
'mcp.server.created',
array(
'status' => 'success',
'server_id' => $server_id,
'transport_count' => count( $mcp_transports ),
'tools_count' => count( $tools ),
'resources_count' => count( $resources ),
'prompts_count' => count( $prompts ),
)
);
// Add server to registry.
$this->servers[ $server_id ] = $server;
return $this;
}
/**
* Get a server by ID.
*
* @param string $server_id Server ID.
*
* @return \WP\MCP\Core\McpServer|null
*/
public function get_server( string $server_id ): ?McpServer {
return $this->servers[ $server_id ] ?? null;
}
/**
* Get all registered servers
*
* @return \WP\MCP\Core\McpServer[]
*/
public function get_servers(): array {
return $this->servers;
}
/**
* Conditionally create the default server based on filter.
*
* @internal For use by adapter initialization only.
*/
private function maybe_create_default_server(): void {
// Allow disabling default server creation
if ( ! apply_filters( 'mcp_adapter_create_default_server', true ) ) {
return;
}
// Register category before abilities
add_action( 'wp_abilities_api_categories_init', array( $this, 'register_default_category' ) );
add_action( 'wp_abilities_api_init', array( $this, 'register_default_abilities' ) );
add_action( 'mcp_adapter_init', array( DefaultServerFactory::class, 'create' ) );
}
/**
* Register the default MCP category.
*
* @return void
*/
public function register_default_category(): void {
wp_register_ability_category(
'mcp-adapter',
array(
'label' => 'MCP Adapter',
'description' => 'Abilities for the MCP Adapter',
)
);
}
/**
* Register the default MCP abilities.
*
* @return void
*/
public function register_default_abilities(): void {
// Register the three core MCP abilities
DiscoverAbilitiesAbility::register();
GetAbilityInfoAbility::register();
ExecuteAbilityAbility::register();
}
/**
* Register WP-CLI commands if WP-CLI is available
*
* @internal For use by adapter initialization only.
*/
private function register_wp_cli_commands(): void {
// Only register if WP-CLI is available
if ( ! defined( 'WP_CLI' ) || ! constant( 'WP_CLI' ) ) {
return;
}
if ( ! class_exists( 'WP_CLI' ) ) {
return;
}
\WP_CLI::add_command(
'mcp-adapter',
McpCommand::class,
array(
'shortdesc' => 'Manage MCP servers via WP-CLI.',
'longdesc' => 'Commands for managing and serving MCP servers, including STDIO transport.',
)
);
}
}