A multi-agent system is a setup where several AI agents, each with its own role, split a piece of work between them, usually with one lead agent directing the others. It suits broad tasks that can run in parallel, such as wide research. It costs more and fails in more ways, so most businesses are better served by simpler workflows.
Key takeaways
- A multi-agent system divides a task between several agents, often a lead that plans and workers that each handle one part.
- According to Anthropic, its multi-agent research system beat a single agent by 90.2% on an internal research test, while using about 15 times the tokens of a chat.
- Multi-agent setups suit wide, parallel work; they suit tightly linked work, where every step depends on the last, poorly.
- Researchers who studied over 1,600 multi-agent runs identified 14 distinct ways these systems fail.
- Most growing businesses need well-built workflows and a few narrow agents, not a swarm.
What is a multi-agent system?
It is a group of AI agents that work on one task together, each with a defined role. One agent might plan, several might research different questions, and another might check the result. They pass work between them, either through a lead agent that directs the rest or through a fixed sequence of hand-offs.
Think of it like a small project team. A single agent is one capable generalist doing every step alone. A multi-agent system is a lead who breaks the job down, hands pieces to specialists, and assembles what comes back.
The analogy has limits, though. Human teams share years of context, a culture and the ability to ask a quick question across the desk. Agents share only what they are explicitly given. That difference explains most of what goes wrong. If agents themselves are new to you, start with the guide to what AI agents are.
How do multiple AI agents work together?
There are four common patterns. A lead agent can direct workers. Agents can hand work along a fixed line, like an assembly line. A writer agent can be paired with a reviewer agent. Or several agents can tackle parts of a question at once and merge their findings. Each pattern suits a different kind of job.
| Pattern | How it works | Suits |
|---|---|---|
| Lead and workers | One agent plans, others carry out parts, the lead combines results | Broad research with many angles |
| Hand-off line | Each agent does one stage and passes it on | Fixed processes such as draft, check, format |
| Writer and reviewer | One drafts, another critiques against rules | Work with clear quality criteria |
| Parallel search | Several agents explore at once, then results merge | Questions with many independent parts |
The hand-off line is often not really multi-agent at all. It is a workflow with several AI steps, which is usually easier to build and to trust. The comparison of agentic workflows and agents explains the difference.
When does a multi-agent system beat a single agent?
When the work is broad, splits into independent parts, and holds more information than one agent can keep in view. Wide research is the clearest case: separate agents can each explore one line of enquiry with a clean slate, then report back. Where every step depends on the previous one, a single agent usually does better.
Anthropic's engineers published their own results in June 2025. Their multi-agent research system, with a lead model directing sub-agents, "outperformed single-agent Claude Opus 4 by 90.2%" on an internal research evaluation.
The same write-up is candid about limits. It says domains where agents must "share the same context" are a poor fit. It also notes that coding involves "fewer truly parallelizable tasks than research". In business terms, writing one proposal is a single-agent job; surveying fifty competitors might not be.
Why do multi-agent systems fail?
Because coordination is hard, and agents coordinate badly. Instructions get lost between agents, one agent's assumption contradicts another's, and nobody checks the combined result properly. Costs climb too, since every agent consumes its own share of model usage. Each extra agent adds a new place for a misunderstanding to start.
The failures have been catalogued. According to a 2025 study led by researchers at UC Berkeley, which annotated more than 1,600 runs across seven multi-agent frameworks, there are 14 distinct failure modes. They fall into three groups: system design issues, misalignment between agents, and weak checking of the final result.
Cost is the other issue. Anthropic found agents use about four times the tokens of a chat, and multi-agent systems about 15 times. One developer of coding agents, Cognition, went further in a June 2025 post, arguing that running multiple agents in collaboration "only results in fragile systems". The guide to why AI agents fail covers the single-agent version.
Does a growing business need a multi-agent system?
Usually not. Most business jobs, such as reports, proposals, follow-ups and research briefs, follow known steps and suit a workflow with AI inside it. A multi-agent system makes sense for genuinely broad, open-ended work where parallel exploration pays for the extra cost. Start simple and add agents only when a simpler setup demonstrably falls short.
That is also the guidance from the people who build the models. According to Anthropic's "Building effective agents", the right approach is "the simplest solution possible, and only increasing complexity when needed". Its authors add that agents bring "higher costs, and the potential for compounding errors".
What a growing business often does need is several narrow agents that each do one job well. They can share the same company knowledge and run as separate workflows, each stopping for a person before anything goes out. That looks like a team of agents, but it avoids most of the coordination risk, because the agents do not depend on talking to each other.
What should you ask before building a multi-agent system?
Ask whether the task really splits into independent parts, whether a single agent or a workflow has been tried and fallen short, what the extra cost buys, and who checks the combined output. If the answers are vague, the system will be too. A clear yes to the first two is the minimum.
- Does the work split? Independent parts that can run at once, not a chain of dependent steps.
- Has simpler failed? A workflow or single agent tried and measured first.
- What does it cost? Model usage multiplied by the number of agents, every run.
- What do agents share? The same business facts, or each a different version.
- Who checks the result? A named person approves anything that goes out.
- Who owns it? One person accountable for access, failures and retirement.
Skein builds narrow agents that each do one job, read the same shared company knowledge and stop at their approval point; the agents page shows what each one reads and produces. That suits a growing business wanting several agents that work from one version of the facts. A team with a genuine large-scale research need may justify a true multi-agent setup.
Frequently asked questions
What is a multi-agent system in simple terms?
It is several AI agents working on one task together, each with a defined role. Typically a lead agent breaks the work into parts, hands them to other agents, and combines what comes back. It resembles a small project team, except the agents share only the information they are explicitly given.
What is the difference between a single agent and multi-agent AI?
A single agent handles every step of a task itself. A multi-agent system splits the task between several agents that plan, research, write or check separately. Multi-agent setups can cover broader ground in parallel, but they cost more, need careful coordination and fail in more ways, so they suit only certain jobs.
When should a business use multiple AI agents?
Use them when the work is broad, splits into independent parts and exceeds what one agent can keep in view, such as surveying many competitors at once. For jobs with known, linked steps, like reports or proposals, a workflow with AI inside it is cheaper and more reliable. Try the simpler option first.
Why are multi-agent systems expensive?
Every agent consumes its own model usage, and they often repeat context to each other. Anthropic reported that its multi-agent research system used about 15 times the tokens of a normal chat. That can be worth it for high-value research, but for routine business work the cost rarely pays back against a simpler workflow.
Are multi-agent systems reliable enough for business?
For narrow, well-tested uses, they can be. In general, they fail more often than simpler setups, because agents lose instructions, contradict each other's assumptions and rarely check the combined result well. Businesses get more reliability from separate narrow agents that share the same knowledge, each with a person approving its output.
Related reading
- Anthropic Engineering. "How we built our multi-agent research system." Anthropic, 13 June 2025. https://www.anthropic.com/engineering/multi-agent-research-system
- Cemri, Mert, et al. "Why Do Multi-Agent LLM Systems Fail?" arXiv 2503.13657, March 2025, revised October 2025. https://arxiv.org/abs/2503.13657
- Yan, Walden. "Don't Build Multi-Agents." Cognition, 12 June 2025. https://cognition.com/blog/dont-build-multi-agents
- Anthropic Engineering. "Building effective agents." Anthropic, 19 December 2024. https://www.anthropic.com/engineering/building-effective-agents