# zod-to-mcp-json

> 🔁 Convert Zod schemas into MCP-compatible JSON effortlessly.

[![npm version](https://badge.fury.io/js/zod-to-mcp-json.svg)](https://www.npmjs.com/package/zod-to-mcp-json)
[![MIT License](https://img.shields.io/badge/license-MIT-blue.svg)](#license)

---

## 🧩 What is this?

`zod-to-mcp-json` is a small, fast, and powerful tool that converts [Zod](https://github.com/colinhacks/zod) schemas into a JSON format compatible with MCP (Model Configuration Protocol) or other schema-driven systems.

✅ Use it to:
- Export your Zod validation as JSON
- Share schemas between backend, frontend, or configuration tools
- Avoid duplicating type definitions manually

---

## 🚀 Installation

```bash
npm install zod-to-mcp-json
# or
yarn add zod-to-mcp-json

🛠️ Usage (Programmatic)

import { z } from "zod";
import { zodToMCP } from "zod-to-mcp-json";

const schema = z.object({
  id: z.string(),
  name: z.string(),
  age: z.number().default(18),
  status: z.enum(["active", "inactive"]),
  tags: z.array(z.string()),
  metadata: z.record(z.string())
});

const json = zodToMCP(schema);
console.log(JSON.stringify(json, null, 2));

✅ Output

{
  "type": "object",
  "properties": {
    "id": { "type": "string" },
    "name": { "type": "string" },
    "age": { "type": "number", "default": 18 },
    "status": { "type": "string", "enum": ["active", "inactive"] },
    "tags": { "type": "array", "items": { "type": "string" } },
    "metadata": { "type": "object", "additionalProperties": { "type": "string" } }
  },
  "required": ["id", "name", "status", "tags", "metadata"]
}

🔧 CLI Usage

npx zod-to-mcp-json ./example/schema.ts > schema.json

Your .ts file must:

• Use ESM module style (export default)
• Export a single Zod schema as the default export

Example:

// example/schema.ts
import { z } from "zod";

export default z.object({
  username: z.string(),
  age: z.number().optional()
});

📘 Supported Zod Types

| Zod Type | MCP Conversion | | --------------------- | ------------------------------ | | z.string() | type: "string" | | z.number() | type: "number" | | z.boolean() | type: "boolean" | | z.literal("x") | enum: ["x"] | | z.enum(["a", "b"]) | enum: [...] | | z.object({...}) | type: "object" | | z.array(z.string()) | type: "array" | | z.union([...]) | oneOf: [...] | | z.optional() | handled | | z.nullable() | anyOf: [..., {type: "null"}] | | z.default(...) | default: ... | | z.record() | additionalProperties: ... | | z.tuple([...]) | prefixItems |

📄 License

MIT License © [Your Name]

🙌 Contributing

PRs are welcome! If you'd like to support additional features like:

• Custom error messages
• CLI flags (--out, --pretty, etc.)
• VS Code integration

Feel free to contribute or open issues.

⭐️ Give it a Star

If you find this useful, please give it a ⭐️ on GitHub!