Letta is an AI research lab and agent framework founded by the creators of MemGPT at UC Berkeley's Sky Computing Lab. The core product, Letta Agent, is a self-improving agent runtime in which memory, identity, and capabilities evolve with experience via programmatic context management, git-based memory versioning, and continual learning in token space. The framework ships as an npm package (@letta-ai/letta-code) and is designed to support long-horizon, stateful agents that persist knowledge across sessions. Research concepts such as sleep-time compute, context repositories, and context constitution directly inform the production software.