# WebMCP WebMCP (Web Model Context Protocol) is a W3C Community Group standard that lets websites expose structured tools to AI agents running in the browser via the `navigator.modelContext` API. Jointly developed by [[Google]] and [[Microsoft]], it allows sites to tell AI agents exactly what actions are available instead of the agent guessing by scraping the UI or taking screenshots. Think of it as [[Model Context Protocol (MCP)]] but for the browser: where MCP connects AI to backend services, WebMCP connects AI to frontend web applications through well-defined interfaces. ## How It Works Websites register tools — JavaScript functions with natural language descriptions and structured schemas. When an agent loads a page implementing WebMCP, it discovers available tools and can invoke them directly. The user remains in control while the agent handles tedious tasks. ### Two APIs - **Declarative API**: Standard actions defined directly in HTML forms — no JavaScript needed - **Imperative API**: Complex, dynamic interactions requiring JavaScript execution ### Key Benefits - **89% token efficiency improvement** over screenshot-based agent methods - **Code reuse**: Developers leverage existing frontend logic, no separate backend API needed - **Unified interface**: One UI serves both human and agent users - **Shared context**: Agent and user see the same application state - **Accessibility**: Standardized tool access also benefits assistive technologies ## Status & Timeline - **August 2025**: Google and Microsoft converge on a unified spec (building on Amazon's earlier MCP-B work) - **September 2025**: Formally accepted as a W3C Community Group deliverable - **February 2026**: Early preview in Chrome 146 Canary behind the "WebMCP for testing" flag - **Mid-to-late 2026**: Broader browser rollout expected (Google Cloud Next / Google I/O) Edge support likely given Microsoft's co-authorship. Other browsers TBD. ## References - GitHub: https://github.com/webmachinelearning/webmcp - W3C spec: https://webmachinelearning.github.io/webmcp/ - Chrome early preview blog: https://developer.chrome.com/blog/webmcp-epp ## Related - [[AI Agents Web Browsing]] - [[Browser Use]] - [[Model Context Protocol (MCP)]] - [[AI Agents]] - [[Google]] - [[Microsoft]]