JSON Chat Agent

Some language models are particularly good at writing JSON. This agent uses JSON to format its outputs, and is aimed at supporting Chat Models.

from langchain import hub
from langchain.agents import AgentExecutor, create_json_chat_agent
from langchain_community.tools.tavily_search import TavilySearchResults
from langchain_openai import ChatOpenAI

Initialize Tools

We will initialize the tools we want to use

tools = [TavilySearchResults(max_results=1)]

Create Agent

# Get the prompt to use - you can modify this!
prompt = hub.pull("hwchase17/react-chat-json")

# Choose the LLM that will drive the agent
llm = ChatOpenAI()

# Construct the JSON agent
agent = create_json_chat_agent(llm, tools, prompt)

Run Agent

# Create an agent executor by passing in the agent and tools
agent_executor = AgentExecutor(
    agent=agent, tools=tools, verbose=True, handle_parsing_errors=True
)

agent_executor.invoke({"input": "what is LangChain?"})

> Entering new AgentExecutor chain...
{
    "action": "tavily_search_results_json",
    "action_input": "LangChain"
}[{'url': 'https://www.ibm.com/topics/langchain', 'content': 'LangChain is essentially a library of abstractions for Python and Javascript, representing common steps and concepts  LangChain is an open source orchestration framework for the development of applications using large language models  other LangChain features, like the eponymous chains.  LangChain provides integrations for over 25 different embedding methods, as well as for over 50 different vector storesLangChain is a tool for building applications using large language models (LLMs) like chatbots and virtual agents. It simplifies the process of programming and integration with external data sources and software workflows. It supports Python and Javascript languages and supports various LLM providers, including OpenAI, Google, and IBM.'}]{
    "action": "Final Answer",
    "action_input": "LangChain is an open source orchestration framework for the development of applications using large language models. It simplifies the process of programming and integration with external data sources and software workflows. It supports Python and Javascript languages and supports various LLM providers, including OpenAI, Google, and IBM."
}

> Finished chain.

{'input': 'what is LangChain?',
 'output': 'LangChain is an open source orchestration framework for the development of applications using large language models. It simplifies the process of programming and integration with external data sources and software workflows. It supports Python and Javascript languages and supports various LLM providers, including OpenAI, Google, and IBM.'}

Using with chat history

from langchain_core.messages import AIMessage, HumanMessage

agent_executor.invoke(
    {
        "input": "what's my name?",
        "chat_history": [
            HumanMessage(content="hi! my name is bob"),
            AIMessage(content="Hello Bob! How can I assist you today?"),
        ],
    }
)

> Entering new AgentExecutor chain...
Could not parse LLM output: It seems that you have already mentioned your name as Bob. Therefore, your name is Bob. Is there anything else I can assist you with?Invalid or incomplete response{
    "action": "Final Answer",
    "action_input": "Your name is Bob."
}

> Finished chain.

{'input': "what's my name?",
 'chat_history': [HumanMessage(content='hi! my name is bob'),
  AIMessage(content='Hello Bob! How can I assist you today?')],
 'output': 'Your name is Bob.'}