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# MCP Adapter |
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Part of the [](https://make.wordpress.org/ai/2025/07/17/ai-building-blocks**AI Building Blocks for WordPress** initiative](https://make.wordpress.org/ai/2025/07/17/ai-building-blocks](https://make.wordpress.org/ai/2025/07/17/ai-building-blocks) |
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|
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The official WordPress package for MCP integration that exposes WordPress abilities as [](https://modelcontextprotocol.ioModel Context Protocol (MCP)](https://modelcontextprotocol.io](https://modelcontextprotocol.io) tools, resources, and prompts for AI agents. |
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[](https://deepwiki.com/WordPress/mcp-adapter](https://deepwiki.com/WordPress/mcp-adapter](https://deepwiki.com/WordPress/mcp-adapter) |
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## Overview |
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This adapter bridges WordPress's Abilities API with the [](https://modelcontextprotocol.io/specification/2025-11-25/MCP specification](https://modelcontextprotocol.io/specification/2025-11-25/](https://modelcontextprotocol.io/specification/2025-11-25/), providing a standardized way for AI agents to interact with WordPress functionality. It includes HTTP and STDIO transport support, comprehensive error handling, and an extensible architecture for custom integrations. |
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## Features |
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### Core Functionality |
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- **Ability-to-MCP Conversion**: Automatically converts WordPress abilities into MCP tools, resources, and prompts |
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- **Multi-Server Management**: Create and manage multiple MCP servers with unique configurations |
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- **Extensible Transport Layer**: |
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- **HTTP Transport**: Unified transport implementing [](https://modelcontextprotocol.io/specification/2025-11-25/basic/transportsMCP 2025-11-25 specification](https://modelcontextprotocol.io/specification/2025-11-25/basic/transports](https://modelcontextprotocol.io/specification/2025-11-25/basic/transports) for HTTP-based communication |
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- **STDIO Transport**: Process-based communication via standard input/output for local development and CLI integration |
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- **Custom Transport Support**: Implement `McpTransportInterface` to create specialized communication protocols |
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- **Multi-Transport Configuration**: Configure servers with multiple transport methods simultaneously |
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- **Flexible Error Handling**: |
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- **Built-in Error Handler**: Default WordPress-compatible error logging included |
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- **Custom Error Handlers**: Implement `McpErrorHandlerInterface` for custom logging, monitoring, or notification |
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systems |
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- **Server-specific Handlers**: Different error handling strategies per MCP server |
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- **Observability**: |
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- **Built-in Observability**: Default zero-overhead metrics tracking with configurable handlers |
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- **Custom Observability Handlers**: Implement `McpObservabilityHandlerInterface` for integration with monitoring |
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systems |
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- **Validation**: Built-in validation for tools, resources, and prompts with extensible validation rules |
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- **Permission Control**: Granular permission checking for all exposed functionality with configurable [](docs/guides/transport-permissions.mdtransport permissions](docs/guides/transport-permissions.md](docs/guides/transport-permissions.md) |
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### MCP Component Support |
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- **[](https://modelcontextprotocol.io/specification/2025-06-18/server/tools.mdTools](https://modelcontextprotocol.io/specification/2025-06-18/server/tools.md](https://modelcontextprotocol.io/specification/2025-06-18/server/tools.md)**: Convert WordPress abilities into executable MCP tools for AI agent interactions |
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- **[](https://modelcontextprotocol.io/specification/2025-06-18/server/resources.mdResources](https://modelcontextprotocol.io/specification/2025-06-18/server/resources.md](https://modelcontextprotocol.io/specification/2025-06-18/server/resources.md)**: Expose WordPress data as MCP resources for contextual information access |
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- **[](https://modelcontextprotocol.io/specification/2025-06-18/server/prompts.mdPrompts](https://modelcontextprotocol.io/specification/2025-06-18/server/prompts.md](https://modelcontextprotocol.io/specification/2025-06-18/server/prompts.md)**: Transform abilities into structured MCP prompts for AI guidance and templates |
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- **Server Discovery**: Automatic registration and discovery of MCP servers following MCP protocol standards |
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- **Built-in Abilities**: Core WordPress abilities for system introspection and ability management |
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- **CLI Integration**: WP-CLI commands supporting STDIO transport as defined in MCP specification |
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## Architecture |
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For a full breakdown of the component structure, see the [](docs/architecture/overview.mdArchitecture Overview](docs/architecture/overview.md](docs/architecture/overview.md). |
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## Dependencies |
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- **PHP**: >= 7.4 |
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- **WordPress**: >= 6.9 (includes the [](https://developer.wordpress.org/news/2025/11/introducing-the-wordpress-abilities-api/Abilities API](https://developer.wordpress.org/news/2025/11/introducing-the-wordpress-abilities-api/](https://developer.wordpress.org/news/2025/11/introducing-the-wordpress-abilities-api/) in core — no separate plugin) |
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- **[](https://github.com/WordPress/php-mcp-schemaphp-mcp-schema](https://github.com/WordPress/php-mcp-schema](https://github.com/WordPress/php-mcp-schema)** (`^0.1.0`): Typed DTOs for MCP protocol types — installed automatically via Composer |
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## Installation |
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### As a WordPress Plugin (Recommended) |
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MCP Adapter is designed to be installed as a WordPress plugin. To install you should download the latest stable release from the [](https://github.com/WordPress/mcp-adapter/releases/latestGitHub Releases page](https://github.com/WordPress/mcp-adapter/releases/latest](https://github.com/WordPress/mcp-adapter/releases/latest) and install it like any other WordPress plugin. |
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#### With WP-CLI |
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```bash |
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wp plugin install https://github.com/WordPress/mcp-adapter/releases/latest/download/mcp-adapter.zip --activate |
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``` |
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#### With WP-Env |
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```jsonc |
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// .wp-env.json |
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{ |
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"$schema": "https://schemas.wp.org/trunk/wp-env.json", |
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"plugins": [ |
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"https://github.com/WordPress/mcp-adapter/releases/latest/download/mcp-adapter.zip" |
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] |
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} |
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``` |
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### As a Composer Library (for plugin developers) |
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Plugin developers may wish to install MCP Adapter as a Composer dependency to integrate MCP functionality into their own plugins. |
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```bash |
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composer require wordpress/mcp-adapter |
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``` |
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#### Using Jetpack Autoloader (Highly Recommended) |
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When multiple plugins use the MCP Adapter, it's highly recommended to use the [](https://github.com/Automattic/jetpack-autoloaderJetpack Autoloader](https://github.com/Automattic/jetpack-autoloader](https://github.com/Automattic/jetpack-autoloader) to prevent version conflicts. The Jetpack Autoloader ensures that only the latest version of shared packages is loaded, eliminating conflicts when different plugins use different versions of the same dependency. |
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```bash |
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composer require automattic/jetpack-autoloader |
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``` |
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Then load it in your main plugin file instead of the standard Composer autoloader: |
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```php |
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<?php |
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require_once plugin_dir_path( __FILE__ ) . 'vendor/autoload_packages.php'; |
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``` |
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### Using MCP Adapter in Your Plugin |
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Check availability and initialize on `plugins_loaded` so all plugins are available before the adapter starts: |
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```php |
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add_action( 'plugins_loaded', function() { |
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if ( ! class_exists( 'WP\MCP\Core\McpAdapter' ) ) { |
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// MCP Adapter is not active — show an admin notice or return early. |
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return; |
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} |
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\WP\MCP\Core\McpAdapter::instance(); |
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} ); |
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``` |
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|
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## Basic Usage |
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The MCP Adapter automatically creates a default server that exposes registered WordPress abilities through a layered architecture. This provides immediate MCP functionality without requiring manual server configuration. |
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**How it works:** |
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- WordPress abilities registered via `wp_register_ability()` with `meta.public` set to `true` are discoverable and executable on the default server via its built-in adapter tools |
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- Set `meta.mcp.public` explicitly to override the high-level setting for MCP only; `false` opts a public ability out, while `true` exposes an otherwise private ability to MCP |
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- On the default server, public abilities are accessed through `mcp-adapter/discover-abilities`, `mcp-adapter/get-ability-info`, and `mcp-adapter/execute-ability` rather than being auto-registered individually in `tools/list` |
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- Alternatively, abilities can be explicitly listed when creating a [](#creating-custom-mcp-serverscustom MCP server](#creating-custom-mcp-servers](#creating-custom-mcp-servers); in that case, they can be exposed directly as MCP tools, resources, or prompts without requiring the `meta.mcp.public` flag |
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- The default server supports both HTTP and STDIO transports and supports multiple MCP protocol versions |
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- Built-in error handling and observability are included |
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- Access via HTTP: `/wp-json/mcp/mcp-adapter-default-server` |
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- Access via STDIO: `wp mcp-adapter serve --server=mcp-adapter-default-server` |
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<details> |
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<summary><strong>Create a new ability (click to expand)</strong></summary> |
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|
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```php |
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// Simply register a WordPress ability |
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add_action( 'wp_abilities_api_init', function() { |
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wp_register_ability( 'my-plugin/get-posts', [ |
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'label' => 'Get Posts', |
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'description' => 'Retrieve WordPress posts with optional filtering', |
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'category' => 'site', |
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'input_schema' => [ |
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'type' => 'object', |
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'properties' => [ |
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'numberposts' => [ |
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'type' => 'integer', |
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'description' => 'Number of posts to retrieve', |
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'default' => 5, |
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'minimum' => 1, |
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'maximum' => 100 |
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], |
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'post_status' => [ |
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'type' => 'string', |
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'description' => 'Post status to filter by', |
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'enum' => ['publish', 'draft', 'private'], |
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'default' => 'publish' |
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] |
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] |
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], |
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'output_schema' => [ |
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'type' => 'array', |
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'items' => [ |
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'type' => 'object', |
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'properties' => [ |
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'ID' => ['type' => 'integer'], |
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'post_title' => ['type' => 'string'], |
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'post_content' => ['type' => 'string'], |
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'post_date' => ['type' => 'string'], |
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'post_author' => ['type' => 'string'] |
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] |
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] |
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], |
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'execute_callback' => function( $input ) { |
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$args = [ |
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'numberposts' => $input['numberposts'] ?? 5, |
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'post_status' => $input['post_status'] ?? 'publish' |
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]; |
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return get_posts( $args ); |
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}, |
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'permission_callback' => function() { |
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return current_user_can( 'read' ); |
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}, |
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'meta' => [ |
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'public' => true, // Expose to clients, including the default MCP server |
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], |
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]); |
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}); |
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// With the meta.public flag, the ability is exposed through the default MCP server. |
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// In the default server configuration, discover it via `discover-abilities` |
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// and invoke it via `mcp-adapter/execute-ability` rather than expecting |
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// it to appear as its own entry in `tools/list`. |
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// To opt out of MCP while remaining public to other clients, explicitly set |
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// meta.mcp.public to false. |
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// To expose only through MCP, omit `meta.public` and set `meta.mcp.public` to true. |
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// Without either public flag, abilities are only accessible through custom MCP |
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// servers that explicitly list them. |
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// Note: how far `meta.public` reaches depends on the WordPress version. WordPress |
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// core starts applying `meta.public` to the REST API (`meta.show_in_rest`) in 7.1. On |
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// WordPress 6.9 and 7.0, this adapter honors `meta.public` for MCP, but REST API |
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// access still requires setting `meta.show_in_rest` to true. |
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``` |
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|
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</details> |
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For detailed information about creating WordPress abilities, see the [Abilities API developer documentation](https://developer.wordpress.org/news/2025/11/introducing-the-wordpress-abilities-api/). |
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### Connecting to MCP Servers |
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The MCP Adapter supports multiple connection methods. Here are examples for connecting with MCP clients: |
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#### STDIO Transport (Local Development) |
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For local development and testing, you can interact directly with MCP servers using WP-CLI commands: |
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```bash |
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# List all available MCP servers |
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wp mcp-adapter list |
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# Test the discover abilities tool to see all available WordPress abilities |
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echo '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"mcp-adapter-discover-abilities","arguments":{}}}' | wp mcp-adapter serve --user=admin --server=mcp-adapter-default-server |
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# Test listing available tools |
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echo '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}' | wp mcp-adapter serve --user=admin --server=mcp-adapter-default-server |
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``` |
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#### MCP Client Configuration |
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Configure MCP clients (Claude Desktop, Claude Code, VS Code, Cursor, etc.) to connect to your WordPress MCP servers. |
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<details> |
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<summary><strong>STDIO Transport Configuration for local sites (click to expand)</strong></summary> |
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```json |
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{ |
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"mcpServers": { |
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"wordpress-default": { |
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"command": "wp", |
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"args": [ |
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"--path=/path/to/your/wordpress/site", |
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"mcp-adapter", |
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"serve", |
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"--server=mcp-adapter-default-server", |
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"--user=admin" |
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] |
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}, |
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"wordpress-custom": { |
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"command": "wp", |
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"args": [ |
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"--path=/path/to/your/wordpress/site", |
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"mcp-adapter", |
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"serve", |
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"--server=your-custom-server-id", |
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"--user=admin" |
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] |
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} |
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} |
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} |
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``` |
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|
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</details> |
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|
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<details> |
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<summary><strong>HTTP Transport via Proxy (click to expand)</strong></summary> |
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The [](https://www.npmjs.com/package/@automattic/mcp-wordpress-remote`@automattic/mcp-wordpress-remote`](https://www.npmjs.com/package/@automattic/mcp-wordpress-remote](https://www.npmjs.com/package/@automattic/mcp-wordpress-remote) proxy runs locally and translates STDIO-based MCP communication from AI clients into HTTP REST API calls that WordPress understands. Authentication uses [](https://make.wordpress.org/core/2020/11/05/application-passwords-integration-guide/WordPress Application Passwords](https://make.wordpress.org/core/2020/11/05/application-passwords-integration-guide/](https://make.wordpress.org/core/2020/11/05/application-passwords-integration-guide/). |
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|
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```json |
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{ |
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"mcpServers": { |
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"wordpress-http-default": { |
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"command": "npx", |
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"args": [ |
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"-y", |
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"@automattic/mcp-wordpress-remote@latest" |
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], |
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"env": { |
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"WP_API_URL": "http://your-site.test/wp-json/mcp/mcp-adapter-default-server", |
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"LOG_FILE": "/path/to/logs/mcp-adapter.log", |
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"WP_API_USERNAME": "your-username", |
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"WP_API_PASSWORD": "your-application-password" |
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} |
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}, |
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"wordpress-http-custom": { |
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"command": "npx", |
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"args": [ |
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"-y", |
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"@automattic/mcp-wordpress-remote@latest" |
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], |
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"env": { |
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"WP_API_URL": "http://your-site.test/wp-json/your-namespace/your-route", |
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"LOG_FILE": "/path/to/logs/mcp-adapter.log", |
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"WP_API_USERNAME": "your-username", |
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"WP_API_PASSWORD": "your-application-password" |
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} |
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} |
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} |
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} |
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``` |
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|
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</details> |
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|
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## Advanced Usage |
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|
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### Creating Custom MCP Servers |
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For advanced use cases, you can create custom MCP servers with specific configurations: |
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```php |
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add_action( 'mcp_adapter_init', function( $adapter ) { |
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$adapter->create_server( |
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'my-server-id', // Unique server identifier |
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'my-namespace', // REST API namespace |
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'mcp', // REST API route |
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'My MCP Server', // Server name |
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'Description of my server', // Server description |
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'v1.0.0', // Server version |
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array( // Transport methods |
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\WP\MCP\Transport\HttpTransport::class, |
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), |
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\WP\MCP\Infrastructure\ErrorHandling\ErrorLogMcpErrorHandler::class, // Error handler |
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\WP\MCP\Infrastructure\Observability\NullMcpObservabilityHandler::class, // Observability handler |
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array( 'my-plugin/my-ability' ), // Abilities to expose as tools |
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array(), // Resources (optional) |
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array() // Prompts (optional) |
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); |
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} ); |
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``` |
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|
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### Custom Transport Implementation |
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The MCP Adapter includes production-ready HTTP transports. For specialized requirements like custom authentication, message queues, or enterprise integrations, you can create custom transport protocols. |
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See the [](docs/guides/custom-transports.mdCustom Transports Guide](docs/guides/custom-transports.md](docs/guides/custom-transports.md) for detailed implementation instructions. |
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|
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### Custom Transport Permissions |
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The MCP Adapter supports custom authentication logic through transport permission callbacks. Instead of the default `is_user_logged_in()` check, you can implement custom authentication for your MCP servers. |
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See the [](docs/guides/transport-permissions.mdTransport Permissions Guide](docs/guides/transport-permissions.md](docs/guides/transport-permissions.md) for detailed authentication patterns. |
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|
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### Custom Error Handler |
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The MCP Adapter includes a default WordPress-compatible error handler, but you can implement custom error handling to integrate with existing logging systems, monitoring tools, or meet specific requirements. |
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See the [](docs/guides/error-handling.mdError Handling Guide](docs/guides/error-handling.md](docs/guides/error-handling.md) for detailed implementation instructions. |
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### Custom Observability Handler |
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|
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The MCP Adapter includes built-in observability for tracking metrics and events. You can implement custom observability handlers to integrate with monitoring systems, analytics platforms, or performance tracking tools. |
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See the [](docs/guides/observability.mdObservability Guide](docs/guides/observability.md](docs/guides/observability.md) for detailed metrics tracking and custom handler implementation. |
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|
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## Migration |
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|
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- [](docs/migration/v0.5.0.mdMigration Guide: v0.5.0](docs/migration/v0.5.0.md](docs/migration/v0.5.0.md) — Breaking changes and upgrade instructions |
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- [](docs/migration/v0.3.0.mdMigration Guide: v0.3.0](docs/migration/v0.3.0.md](docs/migration/v0.3.0.md) — Transport, observability, and hook name changes |
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|
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## License |
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[](https://spdx.org/licenses/GPL-2.0-or-later.htmlGPL-2.0-or-later](https://spdx.org/licenses/GPL-2.0-or-later.html](https://spdx.org/licenses/GPL-2.0-or-later.html) |
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|
