Nous Research is an open-source AI lab behind Hermes Agent, the most widely used open-source AI agent harness. Hermes Agent learns from use—it saves effective workflows as reusable skills, remembers projects across sessions, and lets users choose which underlying model to run (including local models). The Hermes model series (Hermes 3, Hermes 4, Hermes 4.3) are steerable, fine-tuned models built on Llama and Seed-OSS bases, available on Hugging Face for local inference. Nous Research raised $90M in October 2026 (investors include NVIDIA, Microsoft M12, Samsung, YC) to expand Hermes for Businesses. Hermes Agent is MIT-licensed and free to self-host; cloud-hosted subscriptions and API access are paid.