Routing with Google ADK - Agent Development Kit

The Agent Development Kit (ADK) is a framework for engineering agentic systems, providing a structured environment for defining an agent's capabilities and behaviours. In contrast to architectures based on explicit computational graphs, routing within the ADK paradigm is typically implemented by defining a discrete set of "tools" that represent the agent's functions. The selection of the appropriate tool in response to a user query is managed by the framework's internal logic, which leverages an underlying model to match user intent to the correct functional handler.

This Python code demonstrates an example of an Agent Development Kit (ADK) application using Google's ADK library. It sets up a "Coordinator" agent that routes user requests to specialized sub-agents ("Booker" for bookings and "Info" for general information) based on defined instructions. The sub-agents then use specific tools to simulate handling the requests, showcasing a basic delegation pattern within an agent system

The script consists of a main Coordinator agent and two specialized sub_agents: Booker and Info. Each specialized agent is equipped with a FunctionTool that wraps a Python function simulating an action. The booking_handler function simulates handling flight and hotel bookings, while the info_handler function simulates retrieving general information. The unclear_handler is included as a fallback for requests the coordinator cannot delegate, although the current coordinator logic doesn't explicitly use it for delegation failure in the main run_coordinator function.

The Coordinator agent's primary role, as defined in its instruction, is to analyze incoming user messages and delegate them to either the Booker or Info agent. This delegation is handled automatically by the ADK's Auto-Flow mechanism because the Coordinator has sub_agents defined. The run_coordinator function sets up an InMemoryRunner, creates a user and session ID, and then uses the runner to process the user's request through the coordinator agent. The runner.run method processes the request and yields events, and the code extracts the final response text from the event.content.

The main function demonstrates the system's usage by running the coordinator with different requests, showcasing how it delegates booking requests to the Booker and information requests to the Info agent.

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