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`.