Magentic Marketplace: Testing societies of agents at scale

As AI agents move from isolated tools to active participants in multi-agent ecosystems, their success depends on more than task competence—it requires strategic behavior under misaligned incentives and imperfect information. Using Magentic Marketplace, an open-source simulation of two-sided agent markets, we show that while frontier models can achieve strong welfare outcomes in ideal settings, performance degrades at scale and reveals emergent failure modes such as manipulation and speed bias, motivating a shift toward training agents for social reasoning. ArXiv: https://arxiv.org/abs/2510.25779 GitHub: https://github.com/microsoft/multi-agent-marketplace Blog: https://www.microsoft.com/en-us/research/blog/magentic-marketplace-an-open-source-simulation-environment-for-studying-agentic-markets/ This session aired on March 3, 2026, at Microsoft Research Forum, Season 2 Episode 3. Register for the series to learn about future episodes: https://events.microsoft.com/flow/ms/researchforum/register/page/microsoftresearchforumreg/?OCID=msr_researchforum_YTDescription Explore all previous episodes: https://aka.ms/researchforumYTplaylist