# What is WebMCP? Let AI agents use your website

Source: https://busymate.ai/articles/what-is-webmcp
Last modified: 2026-09-07
Published: 2026-09-07 · Busymate AI team · 5 min read

> WebMCP lets an AI agent use your site's real actions — book, check an order — instead of guessing at your page. What it is, and how to expose your first one.

A customer asks an assistant to book a table, chase an order, or compare three plumbers. The assistant opens your website and does what a hurried person does: it reads the page and guesses which button means "book". **WebMCP** removes the guessing. Your site hands the agent a short list of things it can actually do — and the visitor still sees, and confirms, every one of them.

## What WebMCP is

WebMCP is "a proposed web standard to help you build and expose structured tools for AI agents" ([Chrome for Developers](https://developer.chrome.com/docs/ai/webmcp)). A tool is just a named action your page already offers — *bookAppointment*, *checkOrderStatus*, *addToCart* — described in a sentence, with its inputs named. The action runs on your page, in front of the visitor: "tools execute on your webpage visibly, so users gain trust that tasks are completed as expected."

| | Without WebMCP | With WebMCP |
|---|---|---|
| How the agent acts | Clicks around and guesses | Calls the action you named |
| What the visitor sees | Automation happening to them | Your page, your form, their confirmation |
| When it breaks | Any redesign | Only when you rename the tool |

There is no central registry: "clients and browsers must visit a site directly to know if it has callable tools." Being early is the whole advantage.

## Turn any form into an agent tool

The fastest version needs no JavaScript. Take the form you already have and add two attributes — `toolname` and `tooldescription` — plus one short note per field ([Chrome's declarative API](https://developer.chrome.com/docs/ai/webmcp/declarative-api)):

```html
<form action="/book" method="post"
      toolname="bookAppointment"
      tooldescription="Requests an appointment at [Business name].">
  <label for="service">Service</label>
  <input id="service" name="service"
         toolparamdescription="Which service, e.g. haircut or colour">
  <label for="date">Preferred date</label>
  <input id="date" name="date" type="date"
         toolparamdescription="The date the customer would like">
  <button type="submit">Request appointment</button>
</form>
```

When an agent invokes it, "the browser brings the form into focus and populates its field" — the visitor sees the filled form and presses the button. Only if you add `toolautosubmit` does it send by itself, so leave that off for anything that takes money or cancels something.

Then check your work: paste your address into the free [WebMCP check](https://busymate.ai/tools/webmcp-check), or open the [inspector](https://busymate.ai/webmcp/inspect) to see the tool list your site publishes, read-only actions marked. The full picture is on the [WebMCP page](https://busymate.ai/webmcp), the steps in order on [adopt](https://busymate.ai/webmcp/adopt), and the one-line hosted version in the [page tools guide](https://busymate.ai/docs/guides/page-tools).

## What is honestly supported today

- **Chrome**: an origin trial from Chrome 149, which opened on 9 June 2026 ([origin-trial announcement](https://developer.chrome.com/blog/ai-webmcp-origin-trial)); `chrome://flags/#enable-webmcp-testing` for local testing.
- **ChatGPT**: "site tools" work in the desktop app's built-in browser, ChatGPT Work and Codex — but **not** in Enterprise or Education workspaces, **not** for tools inside iframes, and **not** for the HTML form attributes above ([ChatGPT docs](https://learn.chatgpt.com/docs/webmcp)). Registered JavaScript tools are what reaches it.
- **Everyone else**: nothing changes. An annotated form is a normal form.

So annotate your forms for Chrome, and register real tools when you want ChatGPT's browser to reach them too. Both are gated by a `tools` permissions policy that defaults to your own origin, so a third-party iframe cannot expose actions in your name.

## Ask your assistant to do it

You do not have to hand-write any of this. Paste this into the AI assistant you already use for your site:

```text
My site is https://[your-site]. Find the main form (booking or contact) in my
templates and add declarative WebMCP attributes: toolname in camelCase,
tooldescription as one sentence a stranger would understand, and a
toolparamdescription on every input. Do NOT add toolautosubmit. Show me the diff
and mark anything you had to assume with [CHECK].
```

Read the diff, fix the `[CHECK]` marks, publish, and re-run the check.

## Where it fits with the rest

[llms.txt](https://busymate.ai/llms.txt) tells an assistant what your site *says*; WebMCP tells it what your site can *do*. Do both and an agent arriving from a chat app can answer a question and complete the job in one visit, instead of dropping your customer back into a search box. If you would rather see it before you build it, [try an assistant on your own address](https://busymate.ai/try) — it reads your public pages and answers from them — and [pricing](https://busymate.ai/pricing) starts where a small site starts.

## Questions

### Do I need a developer to add WebMCP?

Not for the simple case. If your booking or contact form already works, two extra HTML attributes on the form turn it into a tool an agent can use. Anything beyond that — actions that are not a form — is a small piece of JavaScript your web person can add in an afternoon.

### Can an agent buy or cancel something without asking me?

Not unless you build it that way. The browser fills your form in front of the visitor and they press the button themselves, unless you explicitly mark the tool to submit automatically. ChatGPT also applies its own confirmation step before consequential actions.

### Does WebMCP work in every browser today?

No. It is an origin trial in Chrome from version 149, and ChatGPT's built-in browser supports a subset of it. Treat it as an early advantage, not as a finished standard — the annotated form still works normally for people.

### Will WebMCP help my Google ranking?

There is no evidence that it does, and nobody should tell you otherwise. It changes what an assistant can DO on your site once a visitor is there, which is a conversion question rather than a ranking one.

### How do I check whether a site has any tools?

Run the free WebMCP check on any public address, or open the inspector and see the tool list a site publishes, with the read-only ones marked. Agents themselves have to visit a site to find out — there is no directory.