Schema Overview

Harness Kernel ships a small official schema primitive in @harness-kernel/core/schema. Official packages use it so @harness-kernel/core stays independent from Zod or any other external validator.

import { s, type InferInput, type InferOutput } from "@harness-kernel/core/schema";

const ticketSchema = s.object({
  id: s.string().min(1),
  priority: s.enum(["low", "normal", "high"] as const).default("normal"),
  tags: s.array(s.string()).default([]),
});

type TicketInput = InferInput<typeof ticketSchema>;
type Ticket = InferOutput<typeof ticketSchema>;

Primitives

Primitive	Example
s.string()	s.string().min(1).max(120)
s.number()	s.number().int().positive().max(100)
s.boolean()	s.boolean()
s.array(item)	s.array(s.string())
s.object(shape)	s.object({ name: s.string() })
s.record(value)	s.record(s.string())
s.enum(values)	s.enum(["read", "write"] as const)
s.literal(value)	s.literal("assistant")
s.unknown()	s.unknown()

Schemas support optional(), default(value), describe(text), parse(input), safeParse(input), and toJsonSchema().

Errors

Failed parsing throws SchemaError with normalized SchemaIssue[].

const result = ticketSchema.safeParse({});
if (!result.success) {
  console.log(result.error.issues);
}

Normalization

normalizeSchema() accepts Harness schemas, JSON Schema, Zod-like schemas with safeParse, Standard Schema values, and compatible custom schemas.

Use the official schema for docs and official package examples. Use normalized external schemas when application code already owns another validator.