LangChain Python quickstart Follow the live docs — do not invent an alternate API from memory: https://docs.langchain.com/oss/python/langchain/quickstart Fetch that page (Docs MCP or HTTP) and implement what it shows (weather agent + ). Local setup constraints Apply these on top of the quickstart (they keep setup minimal and model-agnostic): 1. Ask which provider/model to use. Showcase that LangChain is model-agnostic. Suggested prompt: Which model should this agent use? Pass a string — e.g. , , . Default if you're unsure: . Swap the quickstart's model string for their choice (or the default)…