工具调用 Function Calling，让 Agent 真正能动手

import OpenAI from "openai";
import "dotenv/config";

const client = new OpenAI({
  baseURL: process.env.OPENAI_BASE_URL,
  apiKey: process.env.OPENAI_API_KEY,
});

// 工具定义
const tools = [
  {
    type: "function",
    function: {
      name: "getCurrentTime",
      description: "获取当前的日期和时间",
      parameters: {
        type: "object",
        properties: {},
        required: [],
      },
    },
  },
];

const messages = [
  { role: "user", content: "现在几点了？" },
];

const res = await client.chat.completions.create({
  model: process.env.MODEL,
  messages,
  tools,
});

const msg = res.choices[0].message;
console.log(msg);

node --experimental-strip-types index.ts

{
  content: '',
  reasoning_content: 'The user is asking what time it is now. I should use the getCurrentTime function to get the current date and time.',
  role: 'assistant',
  tool_calls: [
    {
      function: [Object],
      id: 'call_3f98e3257d3842e486021961',
      type: 'function'
    }
  ]
}

import OpenAI from "openai";
import "dotenv/config";

const client = new OpenAI({
  baseURL: process.env.OPENAI_BASE_URL,
  apiKey: process.env.OPENAI_API_KEY,
});

const tools = [
  {
    type: "function",
    function: {
      name: "getCurrentTime",
      description: "获取当前的日期和时间，当用户询问现在几点、今天几号时使用",
      parameters: {
        type: "object",
        properties: {},
        required: [],
      },
    },
  },
];

function getCurrentTime() {
  return new Date().toLocaleString("zh-CN");
}

const toolMap: Record<string, (...args: any[]) => string> = {
  getCurrentTime,
};

const messages: any[] = [
  { role: "user", content: "现在几点了？" },
];

const MAX_ROUNDS = 5;

for (let round = 0; round < MAX_ROUNDS; round++) {
  const res = await client.chat.completions.create({
    model: process.env.MODEL!,
    messages,
    tools,
  });

  const msg = res.choices[0].message;

  // 只保留标准字段，不要把供应商特有字段原样塞回上下文
  const assistantMessage = {
    role: "assistant" as const,
    content: msg.content ?? null,
    ...(msg.tool_calls ? { tool_calls: msg.tool_calls } : {}),
  };
  messages.push(assistantMessage);

  // 没有 tool_calls，就是最终回答
  if (!msg.tool_calls?.length) {
    console.log(msg.content);
    break;
  }

  // 如果模型要调用工具，逐个执行并回填
  for (const call of msg.tool_calls) {
    const fn = toolMap[call.function.name];

    if (!fn) {
      messages.push({
        role: "tool",
        tool_call_id: call.id,
        content: `未知工具：${call.function.name}`,
      });
      continue;
    }

    let args: any;
    try {
      args = JSON.parse(call.function.arguments || "{}");
    } catch (e) {
      messages.push({
        role: "tool",
        tool_call_id: call.id,
        content: `参数解析失败：${(e as Error).message}`,
      });
      continue;
    }

    let result: string;
    try {
      result = fn(args);
    } catch (e) {
      result = `工具执行失败：${(e as Error).message}`;
    }

    messages.push({
      role: "tool",
      tool_call_id: call.id,
      content: result,
    });
  }
}

const tools = [
  {
    type: "function",
    function: {
      name: "getCurrentTime",
      description: "获取当前的日期和时间",
      parameters: {
        type: "object",
        properties: {},
        required: [],
      },
    },
  },
  {
    type: "function",
    function: {
      name: "calculate",
      description: "执行基础数学计算，支持加减乘除",
      parameters: {
        type: "object",
        properties: {
          expression: {
            type: "string",
            description: "要计算的数学表达式，如 2 + 3 * 4",
          },
        },
        required: ["expression"],
      },
    },
  },
];

function calculate({ expression }: { expression: string }) {
  // 安全起见，只允许数字和运算符
  if (!/^[\d\s+\-*/().]+$/.test(expression)) return "不支持的表达式";
  return String(eval(expression));
}

const toolMap = { getCurrentTime, calculate };

const messages = [
  { role: "user", content: "现在几点了？另外帮我算一下 128 乘以 256 等于多少" },
];