hughpearse/langchain-react-agent

1import os2import gradio as gr3import json4from gradio import ChatMessage5from huggingface_hub import login6from langchain.agents import AgentExecutor, create_react_agent7from langchain.tools import BaseTool, StructuredTool, tool8from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder9from langchain_core.prompts import PromptTemplate10from langchain_huggingface import ChatHuggingFace, HuggingFaceEndpoint11 12login(os.environ['HUGGINGFACE_HUB_API_KEY'])13 14@tool15def add(a: float, b: float) -> float:16    """Add two numbers: a+b"""17    try:18        return a + b19    except ValueError:20        raise ValueError(f"Inputs must be floats, but got: a={a}, b={b}")21 22@tool23def subtract(a: float, b: float) -> float:24    """Subtract two numbers: a-b"""25    try:26        return a - b27    except ValueError:28        raise ValueError(f"Inputs must be floats, but got: a={a}, b={b}")29 30@tool31def multiply(a: float, b: float) -> float:32    """Multiply two numbers: a*b"""33    try:34        return a * b35    except ValueError:36        raise ValueError(f"Inputs must be floats, but got: a={a}, b={b}")37 38@tool39def divide(a: float, b: float) -> float:40    """Divide two numbers: a/b"""41    try:42        return a // b43    except ValueError:44        raise ValueError(f"Inputs must be floats, but got: a={a}, b={b}")45 46@tool47def square(a: float) -> float:48    """Square a number: a^a"""49    try:50        return a * a51    except ValueError:52        raise ValueError(f"Input must be a float, but got: a={a}")53 54def get_llm():55    endpoint = HuggingFaceEndpoint(56        repo_id="mistralai/Mistral-7B-Instruct-v0.3",57        huggingfacehub_api_token=os.environ['HUGGINGFACE_HUB_API_KEY'],58        temperature=0.0,59        task="text-generation",60        max_new_tokens=102461    )62    model = ChatHuggingFace(llm=endpoint)63    return model64 65template = '''Answer the following questions as best you can. You have access to the following tools:66{tools}67Use the following format:68Question: the input question you must answer69Thought: you should always think about what to do70Action: the action to take, should be one of [{tool_names}]71Action Input: the numeric input to the action (must be a number)72Observation: the result of the action73... (this Thought/Action/Action Input/Observation can repeat N times)74Thought: I now know the final answer75Final Answer: the final answer to the original input question76Begin!77Question: {input}78Thought:{agent_scratchpad}'''79tools = [add, subtract, multiply, divide, square]80prompt = PromptTemplate.from_template(template=template).partial(81    tools="\n".join([f"{t.name}: {t.description}" for t in tools]),82    tool_names=", ".join([t.name for t in tools])83)84llm = get_llm()85agent = create_react_agent(llm, tools, prompt)86agent_executor = AgentExecutor(agent=agent, tools=tools, verbose=True)87 88def chat(message, history):89    response = agent_executor.invoke({"input": message})90    return ChatMessage(role="assistant", content=response['output'])91 92gr.ChatInterface(93    chat, 94    type="messages",95    title="Natural language calculator",96    description="Transform a prompt to a number.",97    examples=["what's five times 18 and add a million plus a billion?", "What is 13 multiplied 15 minus 3?"]98).launch()99