08-LangGraph-Hierarchical-Multi-Agent-Teams

Hierarchical Multi-Agent Teams

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Overview

In this tutorial, we'll explore how to build a Hierarchical Agent Team.

We'll implement a hierarchical structure to break down complex tasks that are difficult to handle with a single agent or single-level supervisor. In this structure, each lower-level supervisor manages worker agents specialized in their respective domains.

This hierarchical approach helps efficiently solve complex tasks that would be overwhelming for a single worker or when there are too many workers to manage directly.

This example implements ideas from the AutoGen paper using LangGraph, demonstrating how to organize two distinct teams for web research and document writing, managed through top and mid-level supervisors to oversee the entire process.

Why Choose a Hierarchical Agent Team?

In our previous Supervisor example, we looked at how a single supervisor node assigns tasks to multiple worker nodes and consolidates their results. While this approach works well for simple cases, a hierarchical structure might be necessary in the following situations:

  • Increased Task Complexity: A single supervisor may not be able to handle specialized knowledge required across various sub-domains simultaneously.

  • Growing Number of Workers: When managing many workers, having a single supervisor directly command all workers can become overwhelming.

In such scenarios, we can create a hierarchical structure where higher-level supervisors delegate tasks to lower-level sub-supervisors, and each sub-supervisor then redistributes these tasks to their specialized worker teams.

Table of Contents

References


Environment Setup

Set up the environment. You may refer to Environment Setup for more details.

[Note]

  • langchain-opentutorial is a package that provides a set of easy-to-use environment setup, useful functions and utilities for tutorials.

  • You can checkout the langchain-opentutorial for more details.

LangChain provides built-in tools that make it easy to use the Tavily search engine as a tool in your applications.

To use Tavily Search, you'll need to obtain an API key.

Click here to sign up on the Tavily website and get your Tavily Search API key.

You can alternatively set API keys in a .env file and load it.

[Note] This is not necessary if you've already set API keys in previous steps.

Building Tools

Each team consists of one or more agents, and each agent is equipped with one or more tools. Below, we'll define all the tools that will be used by various teams. Let's first look at the research team.

ResearchTeam Tools

The ResearchTeam can use search engines and URL scrapers to find information on the web. You can freely add additional features below to enhance the ResearchTeam's performance.

Document Writing Team Tools

Next, we'll define the tools (file access tools) that the document writing team will use. These tools allow agents to access the file system, which may not be secure. Therefore, caution is needed when using them.

Finally, let's define the code execution tool, PythonREPLTool:

Implementing Utility Functions for Multiple Agents

Here's how we create utility functions to streamline our tasks.

We'll use the functools.partial function from our previous tutorial to create agent nodes, specifically for:

  1. Creating worker agents

  2. Creating supervisors for sub-graphs

Here's an example of creating an agent node using the AgentFactory. Let's look at how to create a search agent:

Next is the function for creating a Team Supervisor:

Defining Agent Teams

Let's define the Research Team and Doc Writing Team.

Research Team

The research team has two worker nodes: a search agent and a research_agent responsible for web scraping. Let's create these and set up their team supervisor:

Finally, let's define a function to select the next node for routing:

Creating Research Team Graph

Creates a workflow where a supervisor coordinates web search and scraping tasks.

png

Let's run the web_research_app:

Document Writing Team

Now let's create the document writing team. Here, we'll grant different file-writing tool access to each agent.

Creating Doc Writing Team Graph

Integrates document writing, note-taking, and chart generation into a unified flow.

Let's visualize the graph:

png

Now, let's run the graph and check the results:

Structuring a Super-Graph

This design implements a bottom-up planning policy. Although we've already created two graphs, we need to determine how to route tasks between them.

For this purpose, we'll define a Super-Graph to coordinate these two existing graphs and add connecting elements that define how this higher-level state is shared between different graphs. First, let's create the chief supervisor node:

Next, we'll define the state and nodes of the Super-Graph.

The Super-Graph primarily serves to route tasks between teams.

Defining the Super-Graph

Now, let's define a Super-Graph that connects the two teams.

Let's visualize the graph:

png

Display the final result in Markdown format:

Report on Multi-Agent Architecture for Complex Task Execution

Outline

  1. Introduction

    • Definition of multi-agent systems (MAS) and their significance in solving complex tasks.

    • Overview of the evolution of MAS and their applications in various fields.

    • Importance of collaboration among agents in achieving task objectives.

    • Brief mention of the structure of the report and what each section will cover.

    • Statement of the report's objectives and the relevance of the topic in current research.

  2. Background

    • Historical context of multi-agent systems and their development.

    • Key concepts in MAS, including agent autonomy, communication, and cooperation.

    • Overview of different types of agents and their roles in MAS.

    • Discussion of the theoretical frameworks that underpin MAS, such as game theory and distributed systems.

    • Summary of existing literature and research on MAS applications.

  3. Methodology

    • Description of the design and implementation of a multi-agent architecture.

    • Explanation of task decomposition and agent specialization.

    • Overview of communication protocols and mechanisms used in MAS.

    • Discussion of evaluation metrics for assessing the performance of MAS.

    • Case studies illustrating the application of the methodology in real-world scenarios.

  4. Applications

    • Exploration of various domains where MAS can be applied, such as robotics, healthcare, and smart cities.

    • Detailed examples of successful MAS implementations in industry and research.

    • Discussion of how MAS can enhance efficiency and effectiveness in complex task execution.

    • Analysis of the role of MAS in emerging technologies, such as AI and IoT.

    • Future trends and potential areas for further research in MAS applications.

  5. Challenges

    • Identification of common challenges faced in the development and deployment of MAS.

    • Discussion of issues related to agent coordination, communication, and conflict resolution.

    • Examination of ethical considerations and safety concerns in MAS.

    • Overview of technical limitations and scalability issues.

    • Strategies for overcoming these challenges and improving MAS performance.

  6. Conclusions

    • Summary of key findings from the report.

    • Reflection on the significance of multi-agent architecture in solving complex tasks.

    • Recommendations for future research directions in MAS.

    • Final thoughts on the potential impact of MAS on society and technology.

    • Call to action for researchers and practitioners to explore MAS further.

Detailed Content

1. Introduction

Multi-agent systems (MAS) are defined as systems composed of multiple interacting intelligent agents, capable of autonomous decision-making and task execution. The significance of MAS lies in their ability to collaboratively solve complex tasks that are beyond the capabilities of individual agents. Over the years, MAS have evolved from simple rule-based systems to sophisticated architectures that leverage advanced algorithms and machine learning techniques. The collaboration among agents is crucial, as it allows for the distribution of tasks, parallel processing, and the pooling of resources and knowledge. This report aims to provide a comprehensive overview of multi-agent architecture, focusing on its methodology, applications, challenges, and future directions.

2. Background

The historical context of multi-agent systems dates back to the early days of artificial intelligence, where researchers began exploring the potential of autonomous agents. Key concepts in MAS include agent autonomy, which refers to the ability of agents to operate independently, and communication, which is essential for coordination among agents. Different types of agents, such as reactive, deliberative, and hybrid agents, play distinct roles in MAS, contributing to their overall functionality. Theoretical frameworks, including game theory and distributed systems, provide the foundation for understanding agent interactions and decision-making processes. A review of existing literature reveals a growing interest in MAS applications across various domains, highlighting their versatility and effectiveness.

3. Methodology

The design and implementation of a multi-agent architecture involve several key steps, including task decomposition, where complex tasks are broken down into manageable subtasks assigned to specialized agents. Communication protocols, such as publish-subscribe mechanisms, facilitate information exchange among agents, ensuring that they remain informed about relevant developments. Evaluation metrics, such as task completion time and resource utilization, are essential for assessing the performance of MAS. Case studies, such as the deployment of MAS in disaster response scenarios, illustrate the practical application of these methodologies, showcasing how agents can work together to achieve common goals.

4. Applications

Multi-agent systems have found applications in diverse fields, including robotics, where they enable coordinated movements of robotic swarms, and healthcare, where they assist in patient monitoring and treatment planning. Successful implementations, such as autonomous vehicles and smart grid management, demonstrate the potential of MAS to enhance efficiency and effectiveness in complex task execution. The integration of MAS with emerging technologies, such as the Internet of Things (IoT) and artificial intelligence (AI), opens new avenues for innovation and problem-solving. Future trends indicate a growing reliance on MAS in various sectors, driven by the need for intelligent and adaptive systems.

5. Challenges

Despite their advantages, the development and deployment of multi-agent systems face several challenges. Coordination among agents can be difficult, especially in dynamic environments where tasks and conditions change rapidly. Communication issues, such as information overload and misinterpretation, can hinder agent collaboration. Ethical considerations, including privacy and security concerns, must be addressed to ensure responsible use of MAS. Technical limitations, such as scalability and computational complexity, pose additional hurdles. Strategies for overcoming these challenges include the development of robust algorithms, improved communication protocols, and ethical guidelines for agent behavior.

6. Conclusions

In conclusion, multi-agent architecture represents a powerful approach to solving complex tasks through collaboration and autonomy. The findings of this report highlight the significance of MAS in various applications and the potential for future research to address existing challenges. As technology continues to evolve, the impact of MAS on society and industry will likely grow, necessitating further exploration and innovation in this field. Researchers and practitioners are encouraged to delve deeper into the capabilities of MAS, fostering advancements that can lead to more efficient and effective solutions to real-world problems.

References

  • Fourney, A., Bansal, G., Mozannar, H., Dibia, V., & Amershi, S. (2024). Magentic-One: A Generalist Multi-Agent System for Solving Complex Tasks. Microsoft Research. Retrieved from Microsoft Research

  • Sharifi, N. (2024). Building a Multi-Agent System to Accomplish Complex Tasks. Towards AI. Retrieved from Towards AI

  • Pimentel, S. (2024). Architectures for AI Agents: From Basic to Multi-Agent Systems. DragonScale AI Blog. Retrieved from DragonScale AI

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