Executive Summary
The field of Artificial Intelligence is in a constant state of evolution. For years, the focus was on building a single, powerful model capable of tackling any task thrown its way. But as the complexity of our problems grows, it's becoming clear that a lone genius, no matter how brilliant, can be outmatched by a well-coordinated team of specialists. This is the paradigm shift that brings us to multi-agent AI systems.
A Multi-Agent System (MAS) is a team of specialized AI agents that collaborate to tackle complex problems. Use a multi-agent system when your challenge involves multiple tasks, dynamic environments, or specialized expertise that require agent coordination and agent communication. For simpler or well-defined workflows, a single intelligent agent or structured agentic workflow is often a better, faster, and more cost-efficient choice. The golden rule is to use the simplest setup that effectively solves your problem.
Alphabet, OpenAI, and other AI pioneers already rely on multi-agent systems - and the question for most teams now is: should you? In recent months, AI agents and multi-agent architectures have dominated Artificial intelligence discussions, rapidly translating into real-world value. Influential voices such as Bill Gates, Jensen Huang, and McKinsey have named AI agents and multi-agent systems among the next big leaps in Artificial Intelligence.
Before diving in, it's important to understand that agentic systems and architectures exist on a spectrum- from structured workflows that handle a single user query, to fully autonomous multi-agent setups.
Some of you may be wondering, “What are AI agents, really, and how do they differ from traditional AI models?” - and if you’d like to dive deeper, feel free to explore our earlier post: Unlocking the Power of AI Agents: When LLMs Can Do More Than Just Talk, where we break down how individual agents operate, interact with data, and use tools to go beyond simple text generation.
For others, the question might be, “What exactly is a multi-agent system - and do I actually need one for my use case?” This article tackles that very question, offering a practical lens on when multi-agent systems make sense and when a single-agent setup is more efficient.
In the sections that follow, we’ll explore:
Imagine an AI system where multiple agents work together, each with a specialized role — like a well-coordinated team rather than a solo performer. That’s the essence of multi-agent systems: collaboration, scalability, and adaptability across complex AI workflows.
Think of a modern digital assistant powered by multiple AI agents (Figure 1) that helps manage your day - navigating traffic, playing music, scheduling meetings, sending emails, checking the weather, and even assisting with online shopping.
Instead of a single large model attempting to handle every request from start to finish, a coordinated team of specialized agents works together, each one designed to perform a specific task with higher accuracy, context, and efficiency.
Together, these AI agents form an interconnected system that mirrors a collaborative human team, where each expert focuses on their strength while maintaining constant communication and shared situational awareness. The result is a fluid, intelligent experience that feels proactive rather than reactive, capable of handling multi-step, real-world scenarios like planning a day out, organizing an online event, or managing household logistics. Each agent operates independently within its domain, while the system ensures smooth coordination across tasks — just like a team of specialists working under one shared goal.
These agents collaborate behind the scenes through a process known as message passing, by sharing data, coordinating actions, and adapting continuously to your preferences and priorities in real time. But how do you know when a MAS is actually needed? Let’s explore that next.
To decide whether you need a multi-agent system, consider two guiding principles:
A Multi-Agent System is ideal when the overall challenge is too complex to be solved by a fixed sequence of steps, and instead requires continuous, adaptive breakdown into sub-problems.
A single agent, even an autonomous one, is limited by the size and complexity of its knowledge base and toolset. A MAS allows you to overcome this limitation by distributing the load.
One powerful example of MAS in action is collaborative and multidisciplinary medical decision support.
In complex settings like tumor boards, agents specialized in diagnostics, vital-sign monitoring, patient history retrieval, and treatment planning can work together. They synchronize their recommendations to help clinicians in real time.
Isolated systems, like single agents, can analyze individual data points. Only a coordinated multi-agent setup can combine insights dynamically and support medical reasoning across different fields.
At ML6, we proposed and developed the AI Tumor Board, a multi-agent framework built to demonstrate how specialized AI agents can collaborate seamlessly in high-stakes, real-world scenarios. This setup brings together agents dedicated to diagnostics, medical imaging analysis, patient history retrieval, and treatment planning, all working in harmony under a coordinated decision-making layer.
The AI Tumor Board showcases how agent coordination can transform complex clinical discussions into data-driven, evidence-backed decisions, supporting healthcare professionals with faster insights, reduced cognitive load, and improved consistency across cases.
The following video illustrates the AI Tumor Board in action, highlighting how each agent contributes unique expertise and how their collaboration leads to more informed, transparent, and efficient medical decision-making.
Virtual Tumor Board
Other real-world applications of multi-agent systems include:
A single AI agent can be fast, effective, and easy to manage—ideal for focused, repeatable and well-defined tasks. When challenges are multi-layered, data-rich, or interdependent, a multi-agent system offers a more flexible approach.
With MAS, you gain:
That said, more flexibility also means more complexity. Unlike structured agent workflows, MAS don’t always follow a predictable path. If information doesn’t flow properly between agents, or goals aren’t aligned, the system can drift - leading to inefficiencies or unpredictable results. MAS architecture demands strong coordination, observability, and evaluation layers to avoid error cascades.
So while multi-agent systems unlock powerful new frontiers in AI collaboration and problem-solving, they’re not always the most efficient or necessary solution. In some cases - especially for lightweight, repeatable, or clearly defined tasks such as personal digital assistants, automated reporting, or simple customer-support workflows - a single, well-orchestrated agentic workflow remains simpler to design, easier to maintain, and often just as effective. A streamlined, single-agent architecture backed by strong prompt engineering and tool integration can deliver equal or better outcomes with fewer moving parts.
This principle echoes ML6’s Superintelligence Solutions (Unum)— our approach to building systems that move beyond individual models toward collective intelligence. It’s not just about creating more capable AI, but about enabling human and artificial intelligence to evolve together with purpose and alignment. The key insight is that complexity should serve purpose, not novelty.
The bottom line: Whether it’s multi-agent systems, single agents, or structured workflows, the smartest move isn’t picking the most advanced - it’s choosing the setup that best fits your problem’s complexity and desired outcome.