zod-google-genai-schema

Convert between Zod schemas and @google/genai Schema definitions.

Useful when you want to define validation in Zod and reuse it for Google GenAI tool/function schemas, or convert GenAI schemas back into Zod validators.

Installation

npm install zod-google-genai-schema

zod and @google/genai are peer dependencies. If they are not already in your app, install them with:

npm install zod @google/genai

Usage

import { Type } from "@google/genai";
import { z } from "zod";
import { genAIToZodSchema, zodToGenAISchema } from "zod-google-genai-schema";

// Zod -> Google GenAI Schema
const userInput = z.object({
  name: z.string().describe("Customer name"),
  age: z.number().optional(),
  tags: z.array(z.string()),
});

const schema = zodToGenAISchema(userInput);
// {
//   type: Type.OBJECT,
//   properties: { ... },
//   required: ["name", "tags"]
// }

// Google GenAI Schema -> Zod
const genaiSchema = {
  type: Type.OBJECT,
  properties: {
    action: { type: Type.STRING, enum: ["create", "update"] },
    customerId: { type: Type.STRING },
  },
  required: ["action"],
};

const zodSchema = genAIToZodSchema(genaiSchema);
zodSchema.parse({ action: "create" });

API

zodToGenAISchema(schema)

Converts a Zod schema into a Google GenAI Schema. z.discriminatedUnion(...) is intentionally not supported and throws an error. z.union(...) is supported for nested properties (anyOf), but top-level anyOf output is rejected. For top-level parameters, provide a merged object schema.

genAIToZodSchema(schema)

Converts a Google GenAI Schema into a Zod schema.

Development

npm run build
npm test

License

MIT