Overview
WebMCP stands for Web Model Context Protocol. It is a proposed browser-level standard co-developed by Google and Microsoft that allows websites to expose their functionality as structured, callable tools specifically for AI agents.
Technical Overview
WebMCP is designed to provide a standardized way for AI agents to interact with web applications. It defines a set of protocols and data formats that enable agents to discover, understand, and invoke the capabilities of web services in a consistent manner.
WebMCP is an extension of the Model Context Protocol (MCP), originally introduced by Anthropic. While the standard MCP connects AI models to local data and tools, WebMCP is a browser-native implementation that enables AI agents to interact directly with the frontend and DOM of a live website through a secure sandbox.
Key Features and Implementation
WebMCP allows web developers to define structured APIs for their web applications, which can be consumed by AI agents. This includes:
Navigator API: The protocol is accessed via a new JavaScript API, navigator.modelContext, which allows developers to register site-specific actions.
Structured Interaction: It replaces fragile methods like screen scraping with a reliable contract, allowing agents to call specific functions—such as searchProducts or addToCart—instead of guessing actions via screenshots.
Browser Support: Introduced in early preview with Chrome 146, it is currently available for testing in Chrome Canary.
Standardization: It is currently a W3C Draft Community Group specification, intended to become a cross-browser standard for the "agent-ready web."
How it Differs from MCP
While MCP typically functions at the server level or as a local integration, WebMCP acts as a client-side MCP server. This allows the AI to perform actions within the user's current session and security context, enabling a more seamless and interactive browsing experience.
Official Definitions and Technical Standards
This W3C Draft specification enables websites to act as client-side MCP servers through the JavaScript navigator.modelContext API.
WebMCP Websites
WebMCP Videos