Monolithic AI applications are out. Collaborative Multi-Agent Systems (MAS) are in! 🚀 As AI challenges grow more complex, trying to cram everything into a single, giant agent becomes a maintenance nightmare. That's why the Agent Development Kit (ADK) is designed for building sophisticated applications by composing multiple, specialized agents that collaborate towards a larger goal.

Think of it like building a high-performing team, where each member (agent) has a specific role, but they all work together. This approach brings huge advantages: enhanced modularity, specialization, reusability, and much cleaner control flows.

Here’s what you need to know about building MAS with ADK:

▶️ The Agent Types

  • LLM Agents: The brains, powered by models like GPT or Gemini, capable of reasoning and generating.
  • Workflow Agents: The orchestrators like SequentialAgent, ParallelAgent, and LoopAgent that manage execution flow among sub-agents.
  • Custom Agents: Your own specialized agents with non-LLM logic for unique tasks.

▶️ Core Primitives for Composition

  • Agent Hierarchy: Structuring parent-child relationships for clear delegation.
  • Shared Session State: Passive communication where agents read/write to a common context.
  • LLM-Driven Delegation: Dynamic routing where an LLM agent intelligently hands off tasks to the best-suited sub-agent.
  • Explicit Invocation (AgentTool): Treating another agent as a callable tool, integrating its capabilities directly.

▶️ Common Multi-Agent Patterns

From Coordinator/Dispatcher to Sequential Pipelines, Parallel Fan-Out/Gather, Hierarchical Task Decomposition, Review/Critique, Iterative Refinement, and even Human-in-the-Loop — ADK's primitives let you implement powerful, established collaboration patterns.

This is the future of building robust, scalable AI applications. Understanding how to compose these systems is becoming a critical skill for any aspiring AI developer. What's the most complex task you think a Multi-Agent System could tackle? Share your thoughts below!