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This course is about Getting Started with LangGraph for Large Model Agents
Getting Started with LangGraph for Large Model Agents

Getting Started with LangGraph for Large Model Agents
LangGraph, as a powerful framework, provides strong support for building and expanding applications based on large model agents. Whether you are a beginner or a developer with some experience, you can achieve complex task automation using LangGraph. This article will take you through the basics of LangGraph and demonstrate its powerful features through practical cases.
1. Introduction to LangGraph
(1) Framework Overview
LangGraph is a framework for building and deploying language agents, allowing developers to construct and deploy language agents in the form of graphs. These agents can be used to create chatbots, retrieval-augmented generation (RAG) systems, SQL agents, planning agents, and various other applications. LangGraph supports multiple control flows, human-machine collaboration, streaming processing, and various deployment options, enabling it to handle complex tasks.
(2) Core Concepts
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Node: Nodes in LangGraph can be agent nodes or tool nodes. Agent nodes determine what action to take, while tool nodes are called when an agent node chooses to execute a certain action.
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Edge: Edges are used to define connections between nodes, including conditional edges and regular edges. Conditional edges are used to define the direction of the graph, such as selecting the next node based on the agent’s decision; regular edges are used to return to the agent node after calling a tool, allowing the agent to decide the next action.
(3) Quick Start
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Install Dependencies: Before starting, you need to install LangGraph and related dependencies. For example, if you need to use the Tavily search API, you can install it using
<span>pip install -U langchain-community tavily-python</span>
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Define the Graph: Defining the graph is a key step in using LangGraph. First, you need to define the nodes and edges in the graph. For example, you can define a simple graph that includes agent nodes and tool nodes and set their connections.
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Run the Graph: After defining the graph, you can run it by calling the graph’s
<span>stream</span>
method. During the execution, you can handle user input as needed and obtain the outputs from the agent and tools.
2. LangGraph Practical Cases
(1) Case 1: Creating a Simple Chatbot
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Define the Agent and Tools: First, define an agent node to handle user input and generate replies. At the same time, define a tool node to perform specific tasks, such as searching for information.
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Build the Graph: Create a graph and add the agent node and tool node to it. Set the agent node as the entry point and define the conditional edge from the agent node to the tool node, as well as the regular edge from the tool node back to the agent node.
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Run and Interact: Compile and run the graph, inputting user queries to observe the interaction process between the agent and tools, ultimately generating replies.
(2) Case 2: Implementing an Agent with Search Functionality
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Integrate Search Tool: Use the Tavily search API to define a search tool node that searches for relevant information when the user queries.
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Update the Graph Structure: Add the search tool node to the existing graph structure and update the conditional and regular edges to ensure the search tool is called at the appropriate time.
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Test and Optimize: Run the graph, inputting search queries to observe the integration of search results and the agent’s replies. Adjust search parameters and the agent’s logic based on actual results to optimize performance.
3. Advanced Applications
(1) Multi-Agent Collaboration
LangGraph supports multi-agent collaboration, allowing the creation of complex systems with multiple agents. For example, in a project management scenario, multiple agents can be defined, each responsible for task allocation, progress tracking, and resource coordination. By designing nodes and edges effectively, efficient collaboration between agents can be achieved, improving overall project efficiency.
(2) State Management and Persistence
In some application scenarios, managing and persisting the state of agents is necessary. LangGraph provides state management features, allowing for the definition of state schemas and state reducers to achieve precise control and persistent storage of agent states. For example, in a customer service chatbot, user conversation history and preferences can be recorded to provide more personalized service.
(3) Dynamic Graph Editing and Breakpoints
LangGraph also supports dynamic graph editing and breakpoints. Developers can edit the graph structure at runtime, adding or removing nodes and edges, allowing for dynamic adjustments to agent behavior. Additionally, by setting breakpoints, the execution of the graph can be paused at specific nodes for debugging and analysis. This is very helpful for developing and optimizing complex agent applications.
4. Conclusion
LangGraph, as a powerful framework, provides rich features and flexible control for the development of applications based on large model agents. Through this article, you should have a preliminary understanding of LangGraph and be able to start using it to build your own agent applications. Whether it’s a simple chatbot or a complex multi-agent system, LangGraph can meet your needs. I hope you continue to explore and innovate while using LangGraph, developing more valuable applications.
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