Royal MCP Protocol Insights

What Model Context Protocol is

Model Context Protocol (MCP) is an open specification, originally proposed by Anthropic and now maintained as a public standard, that defines how an AI client (Claude Desktop, ChatGPT, Cursor, VS Code, any other host) discovers and invokes tools exposed by a server. It uses JSON-RPC 2.0 as the message format and supports two transports: HTTP (the primary transport for hosted servers like Royal MCP) and stdio (for locally-installed servers a client launches as a subprocess).

Royal MCP runs as an HTTP transport server at /wp-json/royal-mcp/v1/mcp on your WordPress site. Every MCP-compliant client speaks to that endpoint using the same JSON-RPC message shapes, so setup is the same three values across every client: URL, authentication, and (for HTTP) a header name.

Supported MCP revisions

MCP is versioned by dated revisions. Royal MCP implements two active revisions and negotiates the right one per client during the initialize handshake:

Clients negotiate the highest mutually-supported revision at connect time, so you don’t choose one manually. If your client is on the older revision, Royal MCP responds in the older shape automatically.

Client compatibility matrix

Which MCP revision each major client speaks as of publication:

Tool inventory

Royal MCP exposes 209 tools organized into a WordPress core layer that is always available, plus conditional plugin-integration layers that auto-register when the underlying plugin is active.

Core layer (always available): posts, pages, media, taxonomies (categories, tags, terms), site info and system, users, comments, and search. Roughly 60 tools.

Plugin integration layers (conditional):

• Elementor — 11 tools for page cloning, widget management, template library, bulk replacements.
• Divi — 9 tools for D4 shortcode and D5 block editing with layout validation.
• WooCommerce — 29 tools for products, variations, attributes, orders, coupons, customers, store stats.
• Advanced Custom Fields — 4 tools with type-aware writes and Return-Format-respecting reads.
• GuardPress, SiteVault, ForgeCache, Royal AI Firewall, Redirection, Royal Links, Royal Ledger — smaller integration layers that register when the sibling plugin is active.

Tools appear automatically the moment the sibling plugin is detected on the site. No configuration is required and no restart is needed after activating a supported plugin.

WordPress Abilities API integration

Every Royal MCP tool automatically registers as a WordPress Ability on WordPress 6.9 and above. Same 209 tools, three access paths. Choose whichever fits your workflow. Added in v1.4.38.

The three access paths

1. Native MCP endpoint at /wp-json/royal-mcp/v1/mcp. Full MCP protocol with OAuth 2.0 discovery and session management. Used by Claude Desktop, ChatGPT, Cursor, Windsurf, and every other MCP-compliant client.
2. WP Abilities REST API at /wp-json/wp-abilities/v1/*. Standard WordPress REST endpoints, so any WordPress developer familiar with the REST API can enumerate and invoke tools without knowing MCP. Uses standard WP authentication (Application Passwords, cookies, or JWT via a plugin).
3. WordPress MCP Adapter. Automattic’s official MCP-adapter plugin bridges the WP Abilities API to the MCP protocol. If you already use the WordPress MCP Adapter for other WP-native tools, Royal MCP’s abilities auto-appear alongside them with no additional configuration.

Why three paths, not just one

Different clients need different transports. The native MCP endpoint is optimized for the OAuth-flavored, session-based flow Claude Desktop and ChatGPT use. The WP Abilities REST API is optimized for programmatic WordPress work such as scripts, cron jobs, and third-party plugins that don’t want to speak MCP. The WordPress MCP Adapter path is optimized for teams standardized on the Automattic adapter as a single MCP surface for a fleet of WordPress sites. All three paths hit the same tool implementations under the hood, so nothing is duplicated or diverged.

Ability categories

Royal MCP registers a set of ability categories so tools are discoverable by domain: royal-mcp/core, royal-mcp/woocommerce, royal-mcp/elementor, royal-mcp/divi, royal-mcp/acf, royal-mcp/guardpress, royal-mcp/sitevault, royal-mcp/forgecache, royal-mcp/raif, royal-mcp/redirection, royal-mcp/royal-links, and royal-mcp/royal-ledger. AI agents and standard WordPress consumers can enumerate abilities by category to find just the tools relevant to a task.

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