Python实现简单AI Agent的两种方法详解

pip install openai python-dotenv

API_KEY=sk-xxx
BASE_URL=https://api.deepseek.com/v1
MODEL_NAME=deepseek-chat

import os
from dotenv import load_dotenv
from openai import OpenAI
import time
import math

load_dotenv()
client = OpenAI(api_key=os.getenv("API_KEY"), base_url=os.getenv("BASE_URL"))
MODEL = os.getenv("MODEL_NAME")

# ---------------------- 1、定义可用工具 ----------------------
def calculator(expr: str) -> str:
    """数学计算工具，输入数学表达式，例如 '2500 * 1.08' """
    try:
        return str(eval(expr, {"__builtins__": None}, {"math": math}))
    except Exception as e:
        return f"计算错误:{str(e)}"

def get_current_time() -> str:
    """获取当前时间"""
    return time.strftime("%Y‑%m‑%d %H:%M:%S")

# 工具注册表
tools = {
    "calculator": calculator,
    "get_current_time": get_current_time
}

# system提示词：告诉模型可用工具，输出格式要求
SYSTEM_PROMPT = """
你是AI Agent。你可以使用工具完成任务。
可用工具：
1. calculator(expr): 数学计算
2. get_current_time(): 获取当前时间

输出规则：
- 需要调用工具时严格输出格式：
ACTION:工具名|参数
示例：ACTION:calculator|1250*1.15
- 不需要工具，直接输出最终答案：ANSWER:你的最终回答
"""

def run_agent(user_query: str, max_loop=5):
    messages = [
        {"role":"system", "content": SYSTEM_PROMPT},
        {"role":"user", "content": user_query}
    ]
    for _ in range(max_loop):
        resp = client.chat.completions.create(model=MODEL, messages=messages, temperature=0)
        reply = resp.choices[0].message.content.strip()
        print(f"\n【模型输出】{reply}")

        if reply.startswith("ANSWER:"):
            return reply.replace("ANSWER:", "").strip()

        if reply.startswith("ACTION:"):
            # 解析动作
            parts = reply.replace("ACTION:", "").split("|", 1)
            tool_name, tool_arg = parts[0].strip(), parts[1].strip()
            print(f"【调用工具】{tool_name} 参数:{tool_arg}")
            func = tools[tool_name]
            tool_result = func(tool_arg) if tool_arg else func()
            print(f"【工具返回】{tool_result}")
            # 将工具观察结果放回对话，继续循环
            messages.append({"role":"assistant", "content": reply})
            messages.append({"role":"user", "content": f"OBSERVATION:{tool_result}"})
    return "达到最大循环次数，任务终止"

# 测试
if __name__ == "__main__":
    res = run_agent("现在时间是多少？365乘以47等于多少？")
    print("\n✅最终结果：", res)

pip install langchain langchain-openai python-dotenv

import os
from dotenv import load_dotenv
from langchain_openai import ChatOpenAI
from langchain_core.tools import tool
from langchain.agents import create_openai_tools_agent, AgentExecutor
from langchain_core.prompts import ChatPromptTemplate

load_dotenv()

llm = ChatOpenAI(
    model=os.getenv("MODEL_NAME"),
    api_key=os.getenv("API_KEY"),
    base_url=os.getenv("BASE_URL"),
    temperature=0
)

# 定义工具
@tool
def calculator_tool(expression: str) -> str:
    """用于数学运算，输入数学表达式字符串"""
    return str(eval(expression))

@tool
def time_tool() -> str:
    """获取当前系统时间"""
    import time
    return time.strftime("%Y‑%m‑%d %H:%M:%S")

tools = [calculator_tool, time_tool]

prompt = ChatPromptTemplate.from_messages([
    ("system", "你是AI智能助手，合理调用工具完成用户任务。"),
    ("user", "{input}"),
    ("agent_scratchpad", "{agent_scratchpad}")
])

agent = create_openai_tools_agent(llm, tools, prompt)
agent_executor = AgentExecutor(agent=agent, tools=tools, verbose=True)

if __name__ == "__main__":
    output = agent_executor.invoke({"input":"现在几点，1245除以7等于多少"})
    print("输出：", output["output"])