Google ADK Tutorial 3: Function Tools, ToolContext, Long-Running Tasks & Agent-as-Tool

This tutorial covers Function Tools in Google ADK, the core mechanism for enabling agents to perform actions. It explains ToolContext for managing tool execution state, handling long-running tasks with async patterns, and composing agents as reusable tools within larger agent systems. The video demonstrates practical implementation patterns for building functional, action-capable agents.

Key Points

• •Function Tools are the fundamental building block that enables Google ADK agents to execute actions and interact with external systems
• •ToolContext provides state management and execution context for tools, allowing tools to access shared resources and maintain execution state
• •Async/await patterns enable handling of long-running tasks without blocking agent execution
• •Tools can be composed and chained together to create complex workflows within agent systems
• •Agents themselves can be wrapped as tools, enabling hierarchical agent-as-tool architecture for modular agent design
• •Proper error handling and timeout management are critical for reliable long-running task execution
• •Tool definitions require clear input schemas and output specifications for agent understanding
• •Context passing between tools enables data flow and state sharing across tool invocations

Workflow Diagram

Concepts