Scaffold a minimal local LangChain agent in TypeScript by following the official quickstart. Use when the user wants to quickly build or try a LangChain agent locally.

LangChain TypeScript quickstart Follow the live docs — do not invent an alternate API from memory: https://docs.langchain.com/oss/javascript/langchain/quickstart Fetch that page (Docs MCP or HTTP) and implement what it shows (weather agent + createAgent ). Requires Node 22+. 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 provider:model string — e.g. openai:gpt 5.5 , anthropic:claude sonnet 5 , google genai:gemini 2.5 flash lite . Default if you're unsure: anthropic:claude sonnet 5 . Swap the quickstart's model string for their choice (or the default). 2. Create a new directory (e.g. langchain agent/ ) and do all work there — do not pollute the open project. 3. Only secret: the provider API key in .env (gitignored). No LangSmith / Tavily unless they ask. Prefer they edit .env themselves — don't paste keys into chat. 4. Install the provider package needed for their model if the quickstart's base install isn't enough. 5. Run the example, show output, then stop. Point to langchain fundamentals for next steps.

langchain-typescript-quickstart