Google's A2UI (Agent-to-User Interface) protocol is now available as an open-source framework that transforms Google Apps Script into what developer Kanshi Tanaike calls an "Agent Hub." The implementation allows Gemini to generate dynamic HTML interfaces directly within Workspace applications, enabling multi-step workflows where the AI designs its own functional tools.
The architecture uses recursive UI logic. When a user interacts with a generated component like a file selector or metadata editor, that action becomes a "System Event" fed back to Gemini along with conversation history. The agent then generates the next interface based on current state, creating stateful workflows without manual context switching.
The practical advantage is Apps Script's native access to Drive and Spreadsheet APIs. Unlike external chat interfaces where users must bridge the gap between AI advice and actual files, this integration allows Gemini to act directly on Workspace data. Tanaike's demonstration shows the system guiding users through file organization, metadata editing, and approval workflows from within a Google Sheet.
Implementation Reality
The framework requires a Gemini API key and deployment through Apps Script's editor. Tanaike's GitHub repository includes sample code and a copyable Spreadsheet template. Developers should expect rate limit considerations with the free tier, particularly for batch operations across multiple Drive files.
Google's Product Manager Fred Jabbour positions A2UI as part of a broader shift toward "workflow acceleration" in enterprise environments. The protocol supports Model Context Protocol (MCP) for tool connections and Agent-to-Agent (A2A) communication, though real-world adoption of these features remains unproven.
What This Means in Practice
Organizations using Google Workspace gain a path to custom automation without leaving the platform. The trade-off is dependency on Apps Script's execution limits and Gemini's API quotas. For IT teams already managing Workspace deployments, this represents incremental capability rather than transformation. The real test comes when departments attempt production-scale implementations.