LangChain Ecosystem Guide

Build production-ready agents with LangGraph, from basic primitives to advanced context management.

Quick Start: Which Tool?

IMPORTANT: Use modern abstractions. Older helpers like create_sql_agent, create_tool_calling_agent, create_react_agent, etc. are outdated.

Simple tool-calling agent? → create_agent

from langchain.agents import create_agent
graph = create_agent(model="anthropic:claude-sonnet-4-5", tools=[search], system_prompt="...")

Use this for: Basic ReAct loops, tool-calling agents, simple Q&A bots.

Need planning + filesystem + subagents? → create_deep_agent

from deepagents import create_deep_agent
agent = create_deep_agent(model=model, tools=tools, backend=FilesystemBackend())