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LangChain Agents

Open Source
Agent Frameworks Updated Jan 15, 2025
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Overview

LangChain Agents is a framework component that enables LLMs to use tools and take actions. It provides structured approaches for building agents that can reason about which tools to use and execute multi-step workflows.

Problem It Solves

Simplifies the development of AI agents by providing abstractions for tool use, memory management, and chain-of-thought reasoning. Reduces boilerplate code when building LLM applications that need to interact with external systems.

Target Audience: Software developers building LLM-powered applications, particularly those needing tool integration, retrieval augmentation, or multi-step reasoning capabilities.

Inputs

  • User query or task
  • Tool definitions and configurations
  • LLM provider credentials
  • Optional: Vector store for memory
  • Optional: Custom prompt templates

Outputs

  • Agent responses
  • Tool execution results
  • Intermediate reasoning steps
  • Structured data outputs

Example Workflow

  1. 1 Initialize agent with LLM and available tools
  2. 2 Receive user input or query
  3. 3 Agent reasons about which tool to use
  4. 4 Execute selected tool with generated parameters
  5. 5 Observe tool output and decide next action
  6. 6 Repeat until task complete or max iterations reached
  7. 7 Return final response to user

Sample System Prompt


              Answer the following questions as best you can. You have access to the following tools:

{tools}

Use the following format:

Question: the input question you must answer
Thought: you should always think about what to do
Action: the action to take, should be one of [{tool_names}]
Action Input: the input to the action
Observation: the result of the action
... (repeat Thought/Action/Observation as needed)
Thought: I now know the final answer
Final Answer: the final answer to the original question

            

Tools & Technologies

OpenAI API Anthropic API Various LLM providers FAISS Chroma Pinecone

Alternatives

  • LlamaIndex
  • Semantic Kernel
  • Haystack

FAQs

Is this agent open-source?
Yes
Can this agent be self-hosted?
Yes
What skill level is required?
Intermediate

LangChain is one of the most widely adopted frameworks for building LLM applications and provides extensive documentation and community support.