For two years the way an AI agent used a website was the way a stranger uses a stranger's kitchen: open every cupboard, guess which button is the kettle, hope. Agents that browse on a person's behalf read the page, infer what the buttons do, click one, and read again. It works surprisingly often and fails in ways the site owner never sees. In August 2026 that changed for the agents that matter most, and the change is small enough to fit in a footer.
A page can now hand an agent a menu
WebMCP is an open web standard, backed by Google and Microsoft, that lets a page declare a short list of named tools the agent in the visitor's browser can call directly. The page says: here is what I am, here is how to send me a request, here is how to search my catalog. The agent no longer has to guess where those things live. It asks, gets a typed answer, and moves on.
What made this practical rather than academic is that OpenAI's ChatGPT desktop browser started consuming WebMCP tools in late August, alongside Codex and Chrome 150 and later. A meaningful set of the agents that visit real websites now enumerate a page's tools at load. The mechanism on the page side is a single object exposed by the browser:
if (document.modelContext) {
document.modelContext.registerTool({
name: 'describe_business',
description: 'What Acme Rentals is and offers ...',
inputSchema: { type: 'object', properties: {} },
execute: async () => fetch('/wp-json/vizwp/v1/mcp?tool=describe_business')
})
}If the browser does not expose that object, nothing happens. A page with WebMCP tools looks identical to a page without them for every visitor who is not an agent, which is still nearly all of them.
What a WordPress site registers with Viz
Since version 2.12, every page of a site running Viz registers a small set of tools, and since 2.13 a WooCommerce store registers nine. None of them are written by hand. They are generated from three things Viz already holds: the business profile it built by reading your site (what you sell, who you serve, how people convert), the fields of your contact form, and, on a store, your product catalog.
- describe_business returns what you are and offer, where a visitor can act, and which of the five questions an agent asks (describe, list, price, availability, act) your site can answer. Read-only, no input.
- contact_business sends a contact, quote or availability request on the visitor's behalf. It is the same request the /ai-contact/ form accepts, and it becomes a lead the same way. The tool description tells the agent to ask the person for their real name and email first, because a human replies.
- search_products, browse_products and get_product read the catalog: by query, by category or on-sale or featured listing, and one product in full with its variations, attributes, images and rating.
- get_cart, add_to_cart, update_cart and apply_coupon work on the visitor's own cart: the one they see on the site, with WooCommerce's usual session, exactly as if they had clicked “Add to cart” themselves.
The generated-not-written part matters more than it sounds. A site owner who has to write tool definitions will write them once, for the launch, and never again. Tools that are derived from the contact form and the catalog change when those change. Rename a form field and the tool follows. Publish a product and it is searchable by an agent that afternoon.
The agent prepares, the person confirms
The design line we held throughout is that the agent never checks out. It can search, browse, read, fill the cart, change a quantity and apply a coupon. The purchase itself is completed by the visitor, in their own session, on your normal checkout page. There are three reasons, and only one of them is caution.
The first is that this is what the visitor asked for. Someone who tells an agent to “find me a two-person tent under $200 on this site” wants a cart, not a charge. The second is that your existing checkout already does the hard, regulated parts: payment, tax, address validation, fraud checks. Reimplementing them for agents would be a worse copy of what you have. The third is attribution. A purchase that happens in the visitor's session, after an agent's tool call, is something Viz can credit honestly, because it already sits on the server-side hook where WooCommerce records the order.
How the credit works
Every tool call is logged as an agent request. That is the sentence that turns a feature into a measurement. Under AI Conversions → Agent tools you see each tool, how many times it was called and when; the calls also appear in the Intent view, in any segment that matches them, and in the daily digest on days when something happened.
- A contact_business call becomes a lead: emailed to you, stored only in your site's database, covered by the WordPress export and erase tools, never synced anywhere.
- A purchase that follows a tool call is credited to the agent, shown as “WebMCP agent” in Attribution, the same way a visit from ChatGPT is credited. Only with cookie consent, and never replacing an existing AI-referral credit if the visitor arrived from an assistant in the first place.
- Read-only calls are counted but credit nothing. Twenty calls to describe_business are twenty agents that asked; they are not twenty customers, and the dashboard never pretends otherwise.
One more piece of honesty is built in. A toggle can be on while a full-page cache or a strict content-security policy strips the script out of what visitors actually receive. So Viz checks. The weekly scan fetches your homepage the way an agent would and looks for the registered tools; the Agent tools tab shows a “Verified on homepage” pill when they are there, and tells you what to purge when they are not.
What we do not claim
The channel is early. We would rather write that plainly than have you find out from a dashboard. Agents fetching pricing, booking and contact pages on someone's behalf is already routine; we have watched it in server logs for a year. Agents calling a tool on a page is weeks old, and most of the browsers your visitors use do not support it yet. Across the sites we can see, the agent channel is real and small, and it is growing from a baseline you can watch in your own numbers rather than take from ours.
So we are not going to tell you that agents are already your customers, or quote a volume, or say the era of something has arrived. What we will say is that when an agent does come to act on your site, it should find tools rather than a wall, and that the sites ready when the channel stops being small will get the first requests. Both of those are true today.
If you are not on Viz
The standard is open and the principle travels. Two things are worth doing on any site. First, put the tool hints on your forms. WebMCP defines declarative attributes (toolname on the form, toolparamdescription on each field) that let an agent understand a plain HTML form without a script at all; Viz adds them to the /ai-contact/ form as progressive enhancement, and you can add them to yours by hand. Second, publish something an agent fetching from outside a browser can act on: a contact or quote form with every field named, typed and described, linked from your money pages with a rel="alternate" tag and a Link header. That is the /ai-contact/ pattern, and it needs no plugin, only discipline.
If you do register tools, keep three rules. Accept calls only from your own pages. Rate-limit everything and rate-limit coupons twice. And log every call as what it is, an agent request, so you can tell in a month whether any of this earned anything.
What to watch next
- The Verified on homepage pill under AI Conversions → Agent tools. Green means agents can see your tools; anything else means a cache or a policy is in the way.
- The call counts per tool. describe_business first, then search_products, then, some weeks later, the first contact_business and the first cart.
- A segment for agent requests that touched a money page. Put a bell on it and let the daily digest tell you the morning after the first one.
- Attribution, for the first order credited to WebMCP agent. Read the rate, not the count, and compare it with the assistant referrals you already have.
All of this is on by default on HTTPS sites running Viz 2.13 or later, on every plan including Free. The tools, the door at /ai-contact/, the verification and the credit are described on the Agent tools page, and the two-minute setup is in the docs. Install it, purge your cache, and check the pill.