A callable interface to the page
On Try WebMCP, search_products filters the visible product list and add_to_cart updates the same cart as the product buttons. Tool inputs have a JSON Schema; the handler validates them and returns a structured result. The website stays the shared workspace for the person and the agent.
WebMCP versus MCP
Use WebMCP when the task depends on the current page and its interactive state. A remote MCP server is useful for backend integrations and work outside an open page. They can complement one another. Publishing a WebMCP page does not turn its URL into a remote MCP endpoint you can paste into every AI client.
Chrome: When to use WebMCP and MCP ↗
Try the smallest useful workflow
Open the commerce playground. Run search_products with a $100 limit, then add one backpack. Inspect get_demo_state: it reports the same $89 cart you can see on the page. Prepare checkout to see how a tool can stage a review without completing a purchase.
An evolving proposal
The September 4, 2026 Community Group draft defines document.modelContext. It is not a W3C Standard. Browser implementation and documentation are changing, so use capability detection and date your implementation notes.
WebMCP draft specification · September 4, 2026 ↗
See it in a working example.
Inspect the schema, run a call and observe the result in the page.
Open the playground