Patterns and problems in multiagent systems \ Anthropic<br>Try Claude

Frontier Red Team<br>Patterns and problems in emerging multiagent systems<br>Aug 13, 2026

Models are improving and AI agents are taking on more tasks in shared codebases, markets, and other social systems. As a result, an increase in real-world interactions between agents is imminent. We've already begun studying this, but still have a lot of uncertainty regarding what this looks like at scale. The trajectory is easy to imagine and hard to slow: current institutions are designed by and for people, resting on assumptions about the sufficiency of oversight at human speed. Some institutions will become human-AI hybrids; others where agents outcompete on speed or cost will become agent-only. The volume of agent-agent interaction could plausibly exceed that of human-human and human-agent interactions before the world understands the conditions for making such interactions go well.<br>Agents are unlike people in many ways. They can work for longer, instantly grasp large bodies of information, and exhibit a breadth of knowledge surpassing any person. Yet they are also susceptible to confabulation and reward hacking, and despite progress in alignment, we know very little about how they behave in complex, real-world, multiagent environments. Moreover, benign behavioral quirks at the individual level might compound into unwanted global outcomes. Here, we identify a few examples of behavioral tendencies in current frontier models and show how they can produce unexpected systemic failures, in hopes of starting a conversation about mitigating these risks.<br>Measuring coordination<br>True multiagent systems are still in their infancy. For some time now, agents have excelled at tool use, and insofar as they are able to treat other agents as tool invocations—that is, with well-defined inputs (prompts) and outputs (responses and artifacts)—they can work together efficiently. Where agents currently stumble, however, is in treating each other as more like distinct, long-lived peers, with their own goals and behaviors, and no clear hierarchy between them. As autonomous agents become more and more prevalent in the world and operate in ever-more demanding settings, it is crucial that they learn how to effectively coordinate.<br>There are situations where we can make good use of simple multiagent swarms today. This is particularly true for problems that are highly parallelizable by default (i.e., problems that can be broken into many independent sub-problems) but where agents still have opportunities to specialize or learn from each other. One such problem is software vulnerability detection. The easiest way to use agents to find software vulnerabilities is to point individual agents at individual codebases (or individual files or modules within codebases), and ask them to find vulnerabilities in the code. This can then be run in parallel for many independent agents. This is an approach we use ourselves—in, for example, our work scanning open-source software as part of Project Glasswing.<br>But could multiagent cooperation make this process more effective? To find out, we tried a different approach: we initiated 45 different agents and gave each one its own virtual machine, a shared forum on which they could coordinate, and an identical prompt that asked them to find vulnerabilities in a set of 15 open-source software projects. We asked the agents to peer-review each other's findings, and initiated a separate arbiter agent to make final decisions on whether or not a submitted vulnerability submitted by the agent team was both new and valid.<br>The graph below shows how this method (in the solid lines) compares against the standard parallel approach (stars) for two models: Claude Mythos Preview and Opus 4.8. The coordinating swarm of agents was allowed to run for a long time, and found new vulnerabilities at a roughly constant rate. The fully independent parallel agents, in contrast, were directed to find vulnerabilities in a limited set of locations. There is no clear ordering to the parallel agents’ findings, so we report only the total number of tokens spent for them.<br>Cumulative vulnerabilities found via a coordinating swarm of agents (solid lines) compared to vulnerabilities found via independent agents each pointed at different sections of code (stars). Dashed lines show the cumulative vulnerabilities found by the swarm that were also found by the independent agents. The dotted line (Mythos Preview only) shows only vulnerabilities in the core code of each project where the independent agents were told to look.<br>For Mythos Preview, the simple independent parallelized method produces 21 vulnerabilities over a 6.5 million token run, while the coordinating agent swarm found 266 vulnerabilities over a 27 million token run. However, roughly half of these vulnerabilities were found outside of the core directories in which the simple independent parallel agents (stars in the above plot)...