Implementation:Openai Openai node ZodFunction

Knowledge Sources	openai-node OpenAI Function Calling
Domains	Function_Calling, Schema_Validation
Last Updated	2026-02-15 00:00 GMT

Overview

Concrete tool for creating typed, auto-parseable tool definitions from Zod schemas provided by the openai-node SDK.

Description

The zodFunction helper creates an AutoParseableTool for the Chat Completions API, and zodResponsesFunction creates an AutoParseableResponseTool for the Responses API. Both accept a Zod schema for parameters, an optional implementation callback, and produce a tool specification with automatic argument parsing.

When used with runTools(), the SDK automatically: (1) sends the tool to the API, (2) parses the model's arguments via the Zod schema, (3) calls the implementation function, and (4) sends the result back to the model.

Usage

Use zodFunction with client.chat.completions.runTools() for automatic tool execution, or with client.chat.completions.parse() for auto-parsed tool call arguments without automatic execution.

Code Reference

Source Location

• Repository: openai-node
• File: src/helpers/zod.ts
• Lines: L123-180 (zodFunction: L123-152, zodResponsesFunction: L154-180)

Signature

export function zodFunction<Parameters extends z3.ZodType | z4.ZodType>(options: {
  name: string;
  parameters: Parameters;
  function?: ((args: InferZodType<Parameters>) => unknown | Promise<unknown>) | undefined;
  description?: string | undefined;
}): AutoParseableTool<{
  arguments: Parameters;
  name: string;
  function: (args: InferZodType<Parameters>) => unknown;
}>;

export function zodResponsesFunction<Parameters extends z3.ZodType | z4.ZodType>(options: {
  name: string;
  parameters: Parameters;
  function?: ((args: InferZodType<Parameters>) => unknown | Promise<unknown>) | undefined;
  description?: string | undefined;
}): AutoParseableResponseTool<{
  arguments: Parameters;
  name: string;
  function: (args: InferZodType<Parameters>) => unknown;
}>;

Import

import { zodFunction, zodResponsesFunction } from 'openai/helpers/zod';

I/O Contract

Inputs

Name	Type	Required	Description
name	string	Yes	Tool function name (sent to the model)
parameters	ZodType (v3 or v4)	Yes	Zod schema defining the function arguments
function	(args: T) => unknown	No	Implementation callback (required for runTools)
description	string	No	Description helping the model understand when to use this tool

Outputs

Name	Type	Description
(zodFunction)	AutoParseableTool	Tool spec for Chat Completions with JSON Schema and auto-parsing
(zodResponsesFunction)	AutoParseableResponseTool	Tool spec for Responses API with JSON Schema and auto-parsing

Usage Examples

Defining Tools with zodFunction

import { z } from 'zod';
import { zodFunction } from 'openai/helpers/zod';

const getWeather = zodFunction({
  name: 'get_weather',
  description: 'Get the current weather for a location',
  parameters: z.object({
    location: z.string().describe('City name'),
    unit: z.enum(['celsius', 'fahrenheit']).optional(),
  }),
  function: async ({ location, unit }) => {
    // Call weather API
    return { temperature: 22, condition: 'sunny', location };
  },
});

Using with runTools

import OpenAI from 'openai';

const client = new OpenAI();

const runner = client.chat.completions.runTools({
  model: 'gpt-4o',
  messages: [{ role: 'user', content: 'What is the weather in Paris?' }],
  tools: [getWeather],
});

const result = await runner.finalChatCompletion();
console.log(result.choices[0].message.content);

Related Pages

Implements Principle

• Principle:Openai_Openai_node_Tool_Definition