Building a Tool-Calling Agent from Scratch with LangChain.js

This tutorial walks through creating a fully functional Tool-Calling Agent using LangChain.js, covering tool definition, model binding, manual execution loops, the high‑level createReactAgent API, streaming responses, state management with thread IDs, common pitfalls, and a complete runnable example.

JavaScriptLangChain.jsOpenAI

0 likes · 20 min read

Building a Tool-Calling Agent from Scratch with LangChain.js

Rare Earth Juejin Tech Community

Sep 23, 2025 · Artificial Intelligence

How Front‑End Developers Can Build Powerful AI Agents with LangChain.js

This article guides front‑end developers through the evolution of AI agents—from early chatbots to modern multimodal agents—covering LLM fundamentals, prompt engineering, LangChain.js workflow creation, Retrieval‑Augmented Generation, model context protocols, and future multi‑agent technologies.

AI AgentFrontend DevelopmentLLM

0 likes · 11 min read

How Front‑End Developers Can Build Powerful AI Agents with LangChain.js