WordPress AI Stack Summary: Abilities API, MCP Adapter & AI Client Recap

Seven lessons in, you now have every concept this whole track builds on. This lesson ties them together into one mental model, and points you at exactly where to go next.

You should now be able to

Name the four pieces of the stack

And explain what each one does without confusing them with each other.

Explain the two directions of AI traffic

Agents calling WordPress, versus WordPress calling an AI model.

Describe the anatomy of an ability

Name, schemas, permission_callback, execute_callback, and meta annotations.

Trace a full agent request

From connection through tool discovery, permission check, execution, and response.

Explain meta.mcp.public

And why it defaults to false rather than true.

The stack, one more time, as a single picture

Abilities API (core, WordPress 6.9+): you register what your site can do, as a named, schema-described, permission-checked unit called an ability.

MCP (open protocol, not WordPress-specific): defines how an AI client and a server communicate, tools, resources, and prompts, over stdio or Streamable HTTP.

MCP Adapter (plugin, github.com/WordPress/mcp-adapter): the bridge. Takes your abilities with meta.mcp.public set to true, converts them into MCP tools, and serves them to connecting AI clients, always running your permission_callback before execute_callback.

PHP AI Client SDK (core entry point since WordPress 7.0): the unrelated, opposite direction, your own PHP code calling out to Claude, GPT, or Gemini via wp_ai_client_prompt(), with no MCP or Abilities API involvement at all.

The one distinction worth over-remembering

If you remember nothing else from this course, remember this: an ability existing and an ability being exposed to an external AI agent are two separate, deliberate steps. Registration is not exposure. meta.mcp.public is the switch, and it defaults to off.

Where each later course in this track lives

This track’s courses, mapped to the stack you just learned
Course	Which direction, which piece
Build a WordPress MCP Server From Scratch	AI calling WordPress: registering abilities and serving them via the MCP Adapter, for real
Connect AI Assistants & Agents to WordPress	AI calling WordPress: real clients (Claude, Cursor, ChatGPT) using your server
WordPress MCP Security & Authentication	AI calling WordPress: hardening permission_callback, OAuth, auditing
LLM Integration in WordPress With the PHP AI Client SDK	WordPress calling AI: wp_ai_client_prompt() in depth
AI Content & SEO Automation, AI-Powered WooCommerce	Both directions combined, in real project builds
Advanced WordPress MCP Architecture & Enterprise AI	Scaling and productionizing everything above

Recap

You now have a working local environment (WordPress 6.9+, WP-CLI, the MCP Adapter installed) and a clear model of four distinct pieces: the Abilities API registers capabilities, MCP is the open protocol those capabilities get exposed through, the MCP Adapter is WordPress’s bridge to that protocol, and the PHP AI Client SDK is the separate, opposite-direction tool for calling AI from your own code. Every later course in this track is really just a deeper application of one or both directions.

Continue the track

Ready to build a real, working ability and serve it over MCP? Continue to Build a WordPress MCP Server From Scratch.

Resources & further reading

Abilities API reference, developer.wordpress.org
MCP Adapter repository, GitHub
PHP AI Client SDK repository, GitHub
Model Context Protocol specification, modelcontextprotocol.io