WebMCP

More and more people shop with an AI assistant open. In ChatGPT’s built-in browser, and soon in Chrome and Edge, the assistant can act on the page for them - and without help, it has to guess: find the right variant dropdown, hunt for the add-to-cart button, hope the theme behaves.

Every Jumpseller store now tells the assistant what it can do, using the W3C WebMCP standard. Instead of guessing, the assistant calls your store’s real commerce tools.

There is nothing to install or configure. It works on every Jumpseller store, on every theme, including custom ones.

Why This Matters for Your Sales

When an AI assistant fails halfway through, that shopper leaves. WebMCP removes the guesswork:

• Adding to cart works on every theme - no matter how customized your design is
• The assistant works in the shopper’s real cart - the same cart they see on screen, with their currency, prices, and discounts
• It can answer with live data - real stock and real prices, not a stale feed
• It can suggest related products - your own cross-sell recommendations, which an assistant reading the page would never find
• It can apply your coupons - so shoppers use your promotion instead of hunting for a code elsewhere

What the Assistant Can Do

Your store offers eleven tools:

Tool	What it does
search_catalog	Search your products by keyword, with name, price, stock and a link
browse_store	List the categories in your store menu, then the products inside one
get_product	Full detail for one product, and which options it comes in
show_variant	Show one variant on the page, picked by its options, with its price and stock
get_cart	Read what is currently in the shopper’s cart
add_to_cart	Add a product, choosing the right variant
update_cart_item	Change a quantity, or remove a line
apply_coupon	Apply a discount code
cancel_cart	Empty the cart
get_recommended_products	Your cross-sell suggestions for what is already in the cart
proceed_to_checkout	Open checkout so the shopper can review and pay

If a product comes in many combinations - sizes across colours, say - the assistant is told which options exist rather than every combination, then asks the shopper which they want and shows that one. So a product with a hundred variants works as smoothly as one with two.

The Shopper Always Pays

No tool can place an order or handle payment. proceed_to_checkout opens your checkout page and hands control back to the person, who reviews and pays exactly as they always have. Inside checkout, no tools are offered at all.

This is deliberate. The assistant helps a shopper find and choose. The purchase stays theirs.

Customer Data Is Not Shared

The assistant never receives the shopper’s personal details. When it reads the cart, it sees products, quantities, discounts, shipping and totals - never the name, email, phone or address.

Everything else it can see is already public on your website: product names, descriptions, prices, images, stock availability and categories. It has no access to your orders, your customers, your costs or your settings.

Make Browsing Work Better

browse_store offers the categories you put in your store menu. If your menu links only to a generic products page, an assistant can still search your catalog, but it cannot offer your categories by name.

To get the most from it, add your real categories to your navigation menu in Themes > Menus. A shopper asking “what kind of lamps do you have?” then gets your actual category, instead of a general search.

Trying It Yourself

1. Open your store in ChatGPT’s built-in browser, where this works today.
2. Ask it something a shopper would ask - “find me a blue dress under 40 euros and add a medium to my cart”.
3. Watch your cart update on the page as it works.

If you want to confirm the tools loaded, open your browser console on any page of your store and type window.JumpsellerWebMCP. It lists the tools your store is offering.

Where it works today: ChatGPT’s built-in browser supports WebMCP and calls these tools on its own - an arrow appears in its address bar when a site offers them. Chrome and Edge are running origin trials, and Brave has experimental support in Leo. Firefox and Safari are still reviewing the standard.

Where a browser does not support WebMCP yet, nothing changes for your store and normal shoppers are unaffected.

WebMCP vs the MCP Servers

Jumpseller offers three ways for AI to work with your store. They complement each other:

	WebMCP	Storefront MCP	Admin MCP
Where it runs	In the shopper’s browser tab	On our servers	On our servers
Who uses it	The shopper’s own AI browser	Any AI agent or app you connect	You, or your tools
Authentication	None - it is the shopper’s session	None (public)	API Token or OAuth 2.0
Cart	The shopper’s real cart	No cart	No cart
Access	Browse and fill a cart	Read-only catalog	Read and write, full management
Setup	None, always on	None, always on	Requires credentials

In short: WebMCP helps the shopper who is already on your store, Storefront MCP helps agents discover your products from anywhere, and Admin MCP helps you run your store.