LANGSMITH

LangChain's June LangSmith updates point to a practical agent-ops pattern: Fleet templates, on-call triage, computer use, Slack interrupts, MCP auth, traces, and eval progress all belong in one operator loop.

Most popular LLM framework. 100K+ GitHub stars. Chains, RAG, vector stores, tool use. LangGraph adds stateful multi-agent workflows with cycles and persistence.