Google ADK 2.0 Review — Graph Workflows, Mobile Agents, and Where It Fits

Google launched Agent Development Kit 2.0 at Google I/O 2026, adding a graph-based Workflow Runtime, collaborative multi-agent modes, and — the real headline — ADK for Android with on-device Gemini Nano support. We cover the architecture, multi-language support, how it compares to LangGraph and CrewAI, and the real limitations before building production agents on it.