Entities & Fields

Entities are persistent domain objects that form the backbone of your product's data model. They have identity, exist over time, and are referenced by workflows, surfaces, and rules. Alongside entities, you can define value objects, enums, actors, rules, and other domain constructs.

Defining an Entity

billing.prd
entity invoice {
  invoice_id: uuid
  customer: crm.customer
  total: money
  status: invoice_status = draft
  notes: optional<string>
  line_items: list
  created_at: datetime
}

enum invoice_status {
  draft
  issued
  paid
  overdue
  cancelled
}

Field Types

CategoryTypes
Primitivesstring, integer, decimal, boolean, datetime, date, uuid
Rich typesmoney, email, phone, url, binary
Genericsoptional<T>, list<T>
Referencescrm.customer (cross-module entity ref)
Defaultsstatus: invoice_status = draft

Value Objects

Value objects are structured types without identity - they are compared by value, not by reference. Use them for addresses, money, coordinates, and other composite types. 

value address {
  street: string
  city: string
  state: string
  zip: string
  country: string
}

value line_item {
  description: string
  quantity: integer
  unit_price: money
}

Enums

Enums define a closed set of named values. Members can carry optional metadata for priority, labeling, or other properties. 

enum priority {
  low { label: "Low Priority" }
  medium { label: "Medium Priority" }
  high { label: "High Priority" }
  critical { label: "Critical", escalation: true }
}

Actors & Capabilities

Actors represent user roles or system identities. Capabilities group related permissions that actors can be granted. 

actor customer {
  title: "Customer"
  description: "External customer who places orders"
}

actor accountant {
  title: "Accountant"
  description: "Internal staff managing invoices"
}

capability invoicing {
  title: "Invoice Management"
  actors: [accountant]
}

Rules

Rules express business constraints that are enforced across workflows and surfaces. 

rule customer_must_exist {
  entity: invoice
  condition: customer != null
  message: strings.customer_required
}

rule total_positive {
  entity: invoice
  condition: total > 0
  message: strings.total_must_be_positive
}

Entity Lifecycle

Entity lifecycle is modeled through enums and workflow transitions. Define an enum for the entity's states, then use workflow transitions blocks to declare valid state changes. The compiler validates that all transitions are reachable and valid. 

workflow issue_invoice {
  transitions {
    invoice.status: draft -> issued
  }
}

workflow pay_invoice {
  transitions {
    invoice.status: issued -> paid
  }
}

workflow cancel_invoice {
  transitions {
    invoice.status: draft -> cancelled
    invoice.status: issued -> cancelled
  }
}