An example of how to use zod (https://www.npmjs.com/package/zod) to get a structured result from OpenAI

example.ts

async function makeOpenAICall({ style, theme }: { style: string; theme: string }) {
  /**
   * set up a schema for the result using zod (https://www.npmjs.com/package/zod). we can then use this schema to tell open ai how to format the result
   * it will use the descriptions to figure our what to but in each property..
   * 
   */
  const resultSchema = z.object({
    name: z.string().describe('The name of the game'),
    backgroundPrompt: z.string().describe('A midjourney prompt for the game background image '),
  });

  const response = await openai.chat.completions.create({
    model: 'gpt-4o',
    tools: [
      {
        type: 'function',
        function: {
          name: 'classify',
          parameters: zodToJsonSchema(resultSchema),
        },
      },
    ],
    tool_choice: {
      type: 'function',
      function: {
        name: 'classify',
      },
    },
    messages: [
      {
        role: 'system',
        content: 'You are a creative director looking to create an amazing mobile game.',
      },
      {
        role: 'user',
        content: [
          {
            type: 'text',
            text: `create me a theme and style for a match 3 game screen based in the following theme and style: 
              Style: ${style}  
              Theme: ${theme}
          `,
          },
        ],
      },
    ],
  });

  const choice = response.choices[0]!;

  // parse the result using Zod schema. This will error out if the result does not fit the schema
  // will return {name:'...', backgroundPrompt:'...'}
  return resultSchema.parse(JSON.parse(choice.message.tool_calls![0]!.function.arguments));
}

// const result = async function makeOpenAICall({ style:'cartoon', theme:'space' });