Tool Node

name

• Type: string
• Required: Yes
• Description: Function name the AI will call. Must be a valid JavaScript identifier (alphanumeric + underscores, no spaces)
• Example: "get_weather", "searchDatabase"

description

• Type: string
• Required: Yes
• Description: Clear explanation of what the function does. The AI uses this to decide when to call it. Be specific and include when to use it
• Example: "Get current weather for a city. Use when user asks about weather conditions."

parameters

• Type: Record<string, any>
• Required: No
• Description: JSON Schema defining function parameters. Follows OpenAI function calling format. Defines parameter types, descriptions, required fields, and validation rules

code

• Type: string
• Required: No
• Description: JavaScript function body to execute when AI calls this tool. Has access to parameters passed by the AI. Can be async. Must return a value (string, object, or JSON)

Parameters Schema

{
  "type": "object",
  "properties": {
    "city": {
      "type": "string",
      "description": "The city name (e.g., 'San Francisco', 'London')"
    },
    "unit": {
      "type": "string",
      "enum": ["celsius", "fahrenheit"],
      "description": "Temperature unit"
    }
  },
  "required": ["city"]
}

Function Code

async function get_weather({ city, unit = "celsius" }) {
  const apiKey = process.env.WEATHER_API_KEY
  const url = `https://api.openweathermap.org/data/2.5/weather?q=${city}&units=${
    unit === "celsius" ? "metric" : "imperial"
  }&appid=${apiKey}`

  const response = await fetch(url)
  const data = await response.json()

  return {
    city: data.name,
    temperature: data.main.temp,
    conditions: data.weather[0].description,
    unit: unit
  }
}

Parameters Schema

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string",
      "description": "Search query (name, department, or project)"
    },
    "type": {
      "type": "string",
      "enum": ["employee", "project"],
      "description": "Type of search"
    }
  },
  "required": ["query", "type"]
}

Function Code

async function search_database({ query, type }) {
  const db = await getDatabase()

  if (type === "employee") {
    const results = await db.employees.find({
      $or: [
        { name: { $regex: query, $options: "i" } },
        { department: { $regex: query, $options: "i" } }
      ]
    }).limit(5)

    return results.map(emp => ({
      name: emp.name,
      department: emp.department,
      role: emp.role
    }))
  } else {
    const results = await db.projects.find({
      name: { $regex: query, $options: "i" }
    }).limit(5)

    return results.map(proj => ({
      name: proj.name,
      status: proj.status,
      team_size: proj.team.length
    }))
  }
}

Function Code

function calculate_returns({ principal, rate, years }) {
  if (principal <= 0 || rate < 0 || years <= 0) {
    return { error: "Invalid input: all values must be positive numbers" }
  }

  const finalAmount = principal * Math.pow(1 + rate, years)
  const totalGain = finalAmount - principal
  const percentageGain = (totalGain / principal) * 100

  return {
    initial: principal,
    final: finalAmount.toFixed(2),
    gain: totalGain.toFixed(2),
    percentage: percentageGain.toFixed(2),
    years: years
  }
}