Multi-Agent Systems: When One AI Agent Isn't Enough
Multi-agent systems use specialized AI agents that collaborate like microservices. Here's how they work and when you need them.
Multi-agent systems use multiple specialized AI agents — each with a defined role — orchestrated by a coordinator. They map to Microservices Architecture in software engineering.
When a single agent isn't enough
A single AI agent works great for focused tasks. But some problems are too complex for one agent: writing a full research report (needs a researcher, analyst, and writer), building a software feature (needs a planner, coder, and reviewer), or handling a customer support escalation (needs a classifier, responder, and specialist). Multi-agent systems solve this by splitting the work across specialized agents.
The architecture
Every multi-agent system has three components. (1) Specialized agents — each with a role, a system prompt, and its own tools. A 'Researcher' agent has search tools. A 'Coder' agent has code execution. A 'Reviewer' agent has testing tools. (2) A coordinator — an orchestrator agent that assigns tasks, routes work, and decides when the job is done. (3) Communication protocol — how agents pass information to each other (structured messages, shared memory, or direct handoffs).
researcher = Agent(
role="Researcher",
tools=[web_search, arxiv_api],
prompt="Find the latest papers and data on {topic}"
)
writer = Agent(
role="Writer",
tools=[],
prompt="Write a clear summary from the research"
)
reviewer = Agent(
role="Reviewer",
tools=[],
prompt="Check facts, find gaps, suggest improvements"
)
coordinator = Coordinator(agents=[researcher, writer, reviewer])
report = coordinator.run("Produce a report on quantum computing trends")The SWE parallel: Microservices
If you've built microservices, you already understand multi-agent systems. Each agent is a microservice with a single responsibility. The coordinator is the service mesh or API gateway. Agent communication protocols are API contracts. Shared agent memory is the message bus. The benefits are the same: independent scaling, specialized expertise, fault isolation, and easier debugging.
When to use (and when not to)
Use multi-agent when: the task requires diverse expertise, different steps need different tools, you need parallel processing, or a single prompt can't capture the full complexity. Don't use it when: the task is simple enough for a single chain, you don't need specialization, or the coordination overhead isn't worth it. Start with a single agent and prompt chaining. Only move to multi-agent when you hit the ceiling.
Multi-agent systems are microservices for AI — specialized agents with defined roles, orchestrated by a coordinator. Use them when one agent can't handle the complexity.
This post covers the basics. The full curriculum page for Multi-Agent Collaboration includes the SWE mapping, code examples, production notes, and an interactive building exercise.
Multi-Agent Collaboration → Microservices Architecture