Google's Agent Development Kit for Python is an open-source, code-first framework for building, evaluating, and deploying sophisticated AI agents. ADK provides abstractions for defining agent instructions, tools, behavior, sessions, and orchestration while keeping the application logic in normal Python code.

ADK 2.0 adds a graph-based workflow runtime for deterministic agentic flows, including routing, loops, retries, fan-out and fan-in, state management, nested workflows, and human-in-the-loop steps. It also includes structured task delegation for agent-to-agent collaboration and local development interfaces such as an interactive CLI and web UI.

The framework is intended for developers who want more control than a purely visual agent builder while still receiving a structured runtime for multi-agent and workflow applications. It can be used from local experimentation through production-oriented agent services, with Google's samples and documentation providing patterns for progressively more complex systems.