langchain-fundamentals

Build LangChain agents with create_agent(), tools, and middleware.

Updated Nov 16, 2025
One-click install
npx skills add https://github.com/daniel-dihardja/menuyukti --skill langchain-fundamentals-daniel-dihardja
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: langchain-fundamentals
Source: https://github.com/daniel-dihardja/menuyukti/tree/main/.agents/skills/langchain-fundamentals
Command: npx skills add https://github.com/daniel-dihardja/menuyukti --skill langchain-fundamentals-daniel-dihardja

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Provide a structured guide to building robust LangChain agents using create_agent(), tools, prompts, and middleware for reliable loop control and state management across sessions.

Core Features & Use Cases

  • Agent creation and orchestration with create_agent() to manage the agent loop, tool calls, and state
  • Tool definitions using the @tool decorator (Python) or tool() (TypeScript) with clear descriptions
  • Middleware integration for human-in-the-loop approval, error handling, and custom hooks
  • Persistence patterns via checkpointer/memory to maintain context across invocations
  • Structured output options for typed responses and model-level structured outputs

Quick Start

Instantiate an agent with create_agent(), register tools, and enable middleware for human-in-the-loop and error handling.

Frequently Asked Questions about langchain-fundamentals

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I build production LangChain agents with human-in-the-loop control?

Build production LangChain agents by using create_agent() to manage the agent loop, registering tools, and applying middleware for human-in-the-loop approval and error handling.

How does middleware work in LangChain agents?

Middleware in LangChain agents integrates custom hooks for human-in-the-loop approval, error handling, and loop control, ensuring safe and repeatable agent workflows.

What is the best way to define tools for LangChain agents in Python and TypeScript?

Define LangChain agent tools using the @tool decorator in Python or the tool() function in TypeScript, ensuring clear descriptions and best practices for error handling.

Can I persist LangChain agent context across multiple sessions?

Persist LangChain agent context across sessions by implementing persistence patterns via checkpointer and memory configurations to maintain state across invocations.

How do I get structured output from a LangChain agent?

Get structured output from LangChain agents by configuring structured output options for typed responses and applying model-level structured outputs in Python or TypeScript.

Why should I use create_agent for LangChain workflows instead of custom loops?

Use create_agent for LangChain workflows to manage the agent loop, tool calls, and state automatically, enforcing best practices for safe and repeatable agent operations.