register-mcp-resources.md

RegisterMcpResources API Documentation

The RegisterMcpResources API allows you to register and manage resources that provide data to AI models in WordPress.

Overview

Resources are data sources that can be accessed by AI models. They are registered using the RegisterMcpResource class and provide structured data in various formats.

Basic Usage

use Automattic\WordpressMcp\Core\RegisterMcpResource;

// Register a simple resource
new RegisterMcpResource(
    [
        'uri'         => 'WordPress://my-resource',
        'name'        => 'my-resource',
        'description' => 'A custom resource for providing data',
        'mimeType'    => 'application/json',
    ],
    function($params) {
        // Resource implementation
        return ['data' => 'example'];
    }
);

Resource Registration Parameters

Parameter	Type	Required	Description
uri	string	Yes	Unique URI identifier for the resource
name	string	Yes	Human-readable name of the resource
description	string	Yes	Description of the resource's purpose
mimeType	string	Yes	MIME type of the resource content (e.g., 'application/json')
callback	callable	Yes	Function that provides the resource data

Resource Types

Resources can provide different types of data:

1. JSON Resources

   • MIME type: application/json
   • Used for structured data
   • Example: Plugin information, site settings

2. Text Resources

   • MIME type: text/plain
   • Used for unstructured text data
   • Example: Log files, configuration files

Example: Plugin Information Resource

use Automattic\WordpressMcp\Core\RegisterMcpResource;
use Automattic\WordpressMcp\Utils\PluginsInfo;

class McpPluginInfoResource {
    private $plugins_info;

    public function __construct() {
        $this->plugins_info = new PluginsInfo();
        add_action('wordpress_mcp_init', [$this, 'register_resource']);
    }

    public function register_resource() {
        new RegisterMcpResource(
            [
                'uri'         => 'WordPress://plugin-info',
                'name'        => 'plugin-info',
                'description' => 'Provides detailed information about active WordPress plugins',
                'mimeType'    => 'application/json',
            ],
            [$this, 'get_plugin_info']
        );
    }

    public function get_plugin_info($params = []) {
        return $this->plugins_info->get_plugins_info();
    }
}

Resource Subscription

Resources can be subscribed to for real-time updates:

// Subscribe to a resource
$subscription = wp_mcp_subscribe_resource('WordPress://plugin-info');

// Unsubscribe from a resource
wp_mcp_unsubscribe_resource($subscription['subscriptionId']);

Error Handling

Resources should handle errors appropriately:

new RegisterMcpResource(
    [
        'uri'         => 'WordPress://my-resource',
        'name'        => 'my-resource',
        'description' => 'A resource with error handling',
        'mimeType'    => 'application/json',
    ],
    function($params) {
        try {
            // Resource implementation
            return [
                'success' => true,
                'data'    => $this->get_resource_data($params)
            ];
        } catch (Exception $e) {
            return [
                'success' => false,
                'error'   => $e->getMessage()
            ];
        }
    }
);

Best Practices

1. Unique URIs: Ensure resource URIs are unique across all registered resources
2. Clear Descriptions: Provide detailed descriptions of the resource's data
3. Proper MIME Types: Use appropriate MIME types for the resource content
4. Error Handling: Include proper error handling in callbacks
5. Data Validation: Validate and sanitize resource data
6. Caching: Implement caching for frequently accessed resources
7. Documentation: Document the resource's data structure and available parameters

Example: Complete Resource Implementation

use Automattic\WordpressMcp\Core\RegisterMcpResource;

class MyCustomResource {
    public function __construct() {
        add_action('wordpress_mcp_init', [$this, 'register_resource']);
    }

    public function register_resource() {
        new RegisterMcpResource(
            [
                'uri'         => 'WordPress://my-custom-resource',
                'name'        => 'my-custom-resource',
                'description' => 'A custom resource for providing custom data',
                'mimeType'    => 'application/json',
            ],
            [$this, 'resource_callback']
        );
    }

    public function resource_callback($params) {
        try {
            return [
                'success' => true,
                'data'    => $this->get_resource_data($params)
            ];
        } catch (Exception $e) {
            return [
                'success' => false,
                'error'   => $e->getMessage()
            ];
        }
    }

    private function get_resource_data($params) {
        // Implementation details
        return [
            'example' => 'data',
            'timestamp' => time()
        ];
    }
}