sky-computing-lab
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Letta
Letta is a San Francisco AI research lab and platform for building stateful agents - AI that remembers, learns, and improves itself over time. Spun out of UC Berkeley's Sky Computing Lab from the viral MemGPT project, Letta gives developers an open framework, API, and cloud service where agent state (memories, messages, reasoning, tool calls) is persisted in a database rather than lost when it falls out of the context window. The company positions itself as the open alternative for developers who want to build agents that behave less like stateless chatbots and more like continuously learning digital collaborators.
Charles Packer
Charles Packer is the co-founder and CEO of Letta, the San Francisco startup building the memory layer for AI agents. He is the original author of MemGPT, the viral research project that reframed large language models as operating systems that manage their own memory. A UC Berkeley computer science PhD out of the BAIR and Sky Computing labs, Packer walked away from offers at OpenAI and Google DeepMind to build stateful agents that remember, learn, and improve after deployment - the layer he argues sits above the base models and separates a real agent from a chatbot with a nice interface.
Simon Mo
Simon Mo is the CEO and co-founder of Inferact, the startup commercializing vLLM, the open-source inference engine he helped create and now leads as lead maintainer. A PhD student at UC Berkeley's Sky Computing Lab advised by Ion Stoica and Joseph Gonzalez, Mo has spent roughly eight years building high-throughput, memory-efficient model-serving systems, from Ray Serve at Anyscale to vLLM, which now powers inference for companies including Amazon. In January 2026 he and his vLLM co-maintainers raised a $150M seed round at an $800M valuation, co-led by Andreessen Horowitz and Lightspeed.