Google WebMCP Review — Bringing MCP to the Browser

Google WebMCP is a proposed open web standard, announced at Google I/O 2026, that lets any website expose structured tools to in-browser AI agents without a backend. Two API surfaces — Declarative (HTML form annotations) and Imperative (navigator.modelContext) — let developers register MCP-style tools that Gemini in Chrome can call directly. The Chrome 149 origin trial is open to developers now. We cover what WebMCP is, how it compares to server-side MCP, who is backing it, its limitations, and whether it matters.