Magentic-One is a general-purpose multi-agent system developed by Microsoft Research, designed to tackle open-ended internet and file tasks. This system represents an important step in the evolution of artificial intelligence towards agent systems that can handle complex, multi-step tasks encountered in various work and life situations. Magentic-One utilizes a main agent called the Orchestrator, responsible for planning, tracking progress, and replanning when necessary, while guiding other specialized agents to perform tasks such as operating a web browser, navigating local files, or writing and executing Python code. Magentic-One demonstrates performance comparable to state-of-the-art technologies across various challenging agent benchmarks without requiring modifications to its core capabilities or architecture.