@roostjs/schema

Fluent JSON Schema builder for defining tool parameters and validation schemas.

Part of Roost — the Laravel of Cloudflare Workers.

Installation

bun add @roostjs/schema

Quick Start

import { schema } from '@roostjs/schema';

const params = schema.object()
  .property('email', schema.string().description('User email').minLength(5).maxLength(100), true)
  .property('age', schema.integer().min(0).max(120), false)
  .build();

// { type: 'object', properties: { email: {...}, age: {...} }, required: ['email'] }

Features

• Builders for string, integer, number, boolean, object, array, and enum
• Immutable — each modifier returns a new instance, so you can safely fork and reuse base schemas
• Fluent chainable API that produces plain JSON Schema objects via .build()
• Used by @roostjs/ai and @roostjs/mcp for agent tool parameter definitions

API

schema.string()           // StringSchemaBuilder — .minLength(n), .maxLength(n)
schema.integer()          // IntegerSchemaBuilder — .min(n), .max(n)
schema.number()           // NumberSchemaBuilder  — .min(n), .max(n)
schema.boolean()          // BooleanSchemaBuilder
schema.object()           // ObjectSchemaBuilder  — .property(name, builder, required?)
schema.array()            // ArraySchemaBuilder   — .items(builder), .minItems(n), .maxItems(n)
schema.enum(values[])     // SchemaBuilder with enum constraint

// All builders share:
.description(text)        // Sets JSON Schema description
.default(value)           // Sets default value
.build()                  // Returns plain JsonSchemaOutput object

Documentation

Full documentation at roost.birdcar.dev/docs/reference/schema

License

MIT