Actors

Actors represent entities that interact with your system. There are three types: users, systems, and services.

Actor Types

User

Human users of your system:

actor user Customer
actor user Admin
actor user SupportAgent

System

External systems:

actor system PaymentGateway
actor system EmailService
actor system SMSProvider

Service

Internal services (actors from other bounded contexts):

actor service AnalyticsService
actor service AuditService

Single Actor Definition

actor user Customer
actor system PaymentGateway
actor service NotificationService

Multiple Actors Block

actors {
  user Customer
  user Admin
  system PaymentGateway
  system EmailService
  service AnalyticsService
}

Using Actors in Use Cases

Actors appear in external triggers:

actors {
  user Customer
  user Admin
  system EmailService
}

use_case "Order Management" {
  // User actor triggers
  when Customer places order
    Order creates order record

  // Admin actor triggers
  when Admin approves order
    Order updates status

  // System actor involvement
  when Order listens "Order Confirmed"
    Order asks EmailService to send confirmation
}

Best Practices

Name by Role, Not Person

✅ user Admin ❌ user JohnDoe

Use Specific Names

✅ system PaymentGateway ❌ system External

Group Related Actors

actors {
  // Human users
  user Customer
  user Admin

  // External systems
  system PaymentGateway
  system ShippingProvider

  // Internal services
  service AnalyticsService
}