Schema types#

Everything typed in Janux — component state, intent inputs, api() contracts, events — uses one small schema system from janux:

import { schema, str, int, num, bool, money, enums, list, obj } from 'janux';

const cart = schema({
  items: list({ productId: str(), qty: int().min(1), unitPrice: money() }),
  coupon: str().nullable(),
  status: enums(['open', 'paid']).default('open'),
  meta: obj({ note: str() }).optional(),
});

Builders#

Builder	Meaning
`str()`	string
`int()`	integer
`num()`	finite number
`bool()`	boolean
`money()`	integer amount in minor units (cents); marked `format: money-minor-units` in JSON Schema
`enums([...])`	one of a closed set
`list(shapeOrType)`	array; `list({...})` is shorthand for `list(obj({...}))`
`obj({...})` / `schema({...})`	object with a fixed shape

Modifiers#

Chainable and immutable: .optional(), .nullable(), .default(value), .min(n), .max(n) (length for strings, value for numbers).

Validation semantics#

Missing value: explicit .default() wins → optional passes undefined → nullable passes null → otherwise required error.
Unknown object keys are stripped, never passed through.
Errors carry precise paths: items[0].qty: below min 1.

Defaults#

buildDefault(type) produces initial state: explicit defaults, null for nullables, [] for lists, first value for enums, zero values for primitives ('', 0, false). This is how a component boots with no initial prop.

JSON Schema projection#

toJsonSchema(type) serializes any Janux type to standard JSON Schema — this is what the manifest publishes for every tool input and resource, so MCP clients and LLMs validate against the same contract your server enforces.