Protocol
LOWDeclarative WebMCP forms are valid
Any declarative WebMCP <form> carries a valid toolname, tooldescription, and well-formed parameters. If you expose WebMCP tools, browser agents call them directly instead of scraping — but a tool missing its name or description is unusable to the agent.
What this check looks for
WebMCP (W3C Web Machine Learning CG draft) lets a storefront expose structured tools to in-browser agents (Chrome Auto Browse, Copilot) by annotating <form> elements with `toolname`/`tooldescription` and form controls with `toolparamdescription`. We validate declared tools against the same rules Lighthouse's agentic audit surfaces. WebMCP is optional and near-zero-adoption today, so a store with no declarative WebMCP returns `na` (no score impact).
Which AI surfaces it affects
- Google AI Mode (UCP)50
- Microsoft Copilot50
- ChatGPT (ACP)15
- Perplexity15
- Meta AI10
Weighted against the live specs — ACP 2026-04-17, UCP 2026-04-08.
How to fix it
Give every declarative WebMCP form a toolname, tooldescription, and named, described parameters
Shopify
Developer- Edit the relevant section/snippet in your theme and add the `toolname`/`tooldescription` attributes to the <form>.
BigCommerce
Developer- Add the WebMCP attributes to the form in your Stencil theme template.
WooCommerce
Developer- Add the WebMCP attributes to the form in your theme template or a block override.
Custom / headless
Developer- Annotate the <form> with `toolname`/`tooldescription` and each control with `name` + `toolparamdescription`.
<form toolname="search-products" tooldescription="Search the product catalog">
<input name="q" toolparamdescription="Search query" />
</form>The spec it's pinned to
WebMCP — declarative form API
WebMCP lets a site expose <form>-based tools to browser agents via `toolname`/`tooldescription` attributes. When advertised, each tool must carry a name, a description, and well-formed parameters so agents can call it.
Does your store pass this check?
Run the full audit — 82 checks across five AI shopping surfaces. Most tools only check whether you get mentioned; we check whether an agent can buy from you.