· 4 min read
Quartermaster (QM): YC's Open-Source Multiplayer Agent Harness
YC open-sourced QM (Quartermaster) in July 2026. Its launch note describes starting with a Ruby agent loop that could reach internal data, adding crons and webhooks, and later giving individual employees more than 50 Hermes personal agents. Those agents were flexible, but managing the fleet became difficult.
QM is the result of that experience. It aims to retain the flexibility of a personal agent while giving an organization a way to manage models, permissions, and the runtime. Employees and projects get agents as needed; collaboration happens in Slack channels, group messages, and projects, rather than by handing one person's environment to the entire company.
