Kizuna.brand

Give a Zod schema a brand, so the handler and every generated client type its values as that brand.

pnpm add kizunajs@beta

import { Kizuna } from 'kizunajs';

Parameters

Kizuna.brand(brand: string, schema: ZodType): ZodType

Returns

The schema with .brand() applied and the brand recorded in its metadata. It validates exactly as schema does.

Example

import { Kizuna } from 'kizunajs';
import { z } from 'zod';

export const UserId = Kizuna.brand('UserId', z.string());

Why not .brand()

Zod's .brand() exists only in the types, so the generators cannot see it. Kizuna.brand also records the name in .meta(), which they read.

Effect on generators

• TypeScript: export type UserId = string & $brand<"UserId"> in the API namespace, and a toUserId('usr_k7f3q9') function beside createClient
• Swift: public struct UserId: RawRepresentable, Codable, Hashable, Sendable, encoded as the bare value
• Kotlin: @Serializable @JvmInline value class UserId(val value: String), serialized as the bare value
• OpenAPI: x-kizuna-brand: UserId on the schema
• MCP: nothing, a tool's input stays a plain string

A brand wraps a scalar, so Kizuna.brand throws on an object, an enum or a transform. Put .optional() or .nullable() on the brand rather than inside it:

parentId: UserId.nullable(),

See the Zod guide for using one in each client.