最小循环 · 一个 Agent 只需要什么The Minimal Loop · What an Agent Really Needs.

import anthropic
 
client = anthropic.Anthropic()   # 读环境变量 ANTHROPIC_API_KEY
 
TOOLS = [{
    "name": "web_search",
    "description": "按查询搜索网页，返回标题和摘要的列表。要查资料时调用。",
    "input_schema": {
        "type": "object",
        "properties": {"query": {"type": "string"}},
        "required": ["query"],
    },
}]
 
def run_tool(name, args):                       # 工具的真正执行
    if name == "web_search":
        return search_web(args["query"])        # 真实场景接一个搜索 API
    return f"未知工具: {name}"
 
def agent(question, max_steps=10):
    messages = [{"role": "user", "content": question}]
    for _ in range(max_steps):                  # 停止条件：步数上限
        resp = client.messages.create(
            model="claude-opus-4-8", max_tokens=1024,
            tools=TOOLS, messages=messages,
        )
        messages.append({"role": "assistant", "content": resp.content})
        if resp.stop_reason != "tool_use":      # 模型给出最终回答
            return "".join(b.text for b in resp.content if b.type == "text")
        results = [{
            "type": "tool_result", "tool_use_id": b.id,
            "content": run_tool(b.name, b.input),
        } for b in resp.content if b.type == "tool_use"]
        messages.append({"role": "user", "content": results})
    return "stopped: 达到 max_steps"