An MIT-licensed LangGraph template ships 13 domain packs, per-run USD budgets with HTTP 402 enforcement, canary routing, and 800+ tests — the production parts tutorials skip.
LangSmith, Langfuse, Phoenix, Braintrust, and Galileo all score LLM responses after serving. None block bad answers in the moment. Here's how they compare.
A r/LangChain post argues most multi-agent LangGraph systems are architecture theater — orchestration overhead that doesn't beat a single agent with tools on eval.
Vercel's AI SDK LangChain adapter v2.0.215 fixes a bug where citation metadata from RAG and web search was silently discarded instead of surfaced as UI message parts.
Microsoft released a free, open-source LangChain.js course with 70+ TypeScript examples covering agents, MCP, and agentic RAG for JavaScript developers.