langchain-fundamentals

Create LangChain agents with create_agent, tools, and middleware.

Updated Mar 7, 2026
One-click install
npx skills add https://github.com/tivon-x/deep-research --skill langchain-fundamentals-tivon-x
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: langchain-fundamentals
Source: https://github.com/tivon-x/deep-research/tree/main/.agents/skills/langchain-fundamentals
Command: npx skills add https://github.com/tivon-x/deep-research --skill langchain-fundamentals-tivon-x

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill provides the essential building blocks and best practices for creating robust LangChain agents, ensuring they are production-ready with features like human-in-the-loop and state persistence.

Core Features & Use Cases

  • Agent Creation: Use create_agent() for streamlined agent development.
  • Tool Definition: Define custom tools using @tool (Python) or tool() (TypeScript).
  • Middleware Integration: Implement human-in-the-loop, error handling, and custom logic with middleware.
  • State Management: Ensure conversation memory with checkpointers and thread_id.
  • Use Case: Develop an agent that can answer user questions, but requires human approval before executing potentially sensitive tools like making a purchase.

Quick Start

Create a basic LangChain agent that can respond to user queries using a specified model and tools.

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 capabilities?

Build production LangChain agents by using the `create_agent` function and integrating middleware to implement human-in-the-loop controls. This approach ensures robust error handling and allows human approval before executing sensitive tools like purchases.

What is the best way to define custom tools for LangChain agents?

The best way to define custom tools for LangChain agents is by using the `@tool` decorator in Python or the `tool()` function in TypeScript. This allows your agent to execute specific, tailored actions based on user queries.

How do I manage conversation state and memory in LangChain agents?

Manage conversation state in LangChain agents by configuring checkpointers and utilizing a `thread_id`. This state management mechanism ensures conversation memory persistence across multiple interactions.

Can I use middleware to handle errors and custom logic in LangChain?

Yes, you can use middleware integration in LangChain to handle errors, implement custom logic, and establish advanced control flows. This middleware architecture provides the robust error handling needed for production-grade agent development.

Does this approach support generating structured output from LLM agents?

Yes, creating LangChain agents with the `create_agent` function supports structured output generation. This allows you to configure your model and tools to return data in predictable, structured formats.

When do I need to use checkpointers for LLM agent development?

You need to use checkpointers for LLM agent development when your application requires state persistence and conversation memory. Checkpointers ensure continuity by saving the agent's state using a designated `thread_id`.