February 2026

LangChain

framework

GitHub · October 2022

  • Framework for composing LLM calls with tools, memory, and retrieval into multi-step chains and agents
  • Popularized the “chain” abstraction — sequential LLM calls where each step’s output feeds the next — and the “agent” pattern with dynamic tool selection
  • Useful as a reference for what complexity emerges when tool loops scale; argues for the shell thesis by showing what happens without simplicity constraints