WebMCP declarative API

Why it matters

WebMCP is the W3C proposal for exposing website functionality directly to AI agents. Declarative tool annotations on forms let agents perform actions (search, purchase, book) without screen scraping.

How to fix it

Annotate your main forms with WebMCP toolname and tooldescription attributes.

1. Add toolname and tooldescription to each form that agents may use.

   <form toolname="search" tooldescription="Search products by keyword">
     <input name="q" toolparamdescription="Search keywords">
   </form>

2. Or register tools in JavaScript with document.modelContext.registerTool().

   document.modelContext.registerTool({
     name: "search",
     description: "Search products",
     inputSchema: {type: "object", properties: {q: {type: "string"}}},
     execute: async ({q}) => ({content: []})
   });

Verify

Run a new scan for this checkpoint: