Cover

Identity and routing metadata for events and commands. The Cover tells the system where something belongs and how to route it.

Structure

message Cover {
  string domain = 1;        // Bounded context name
  UUID root = 2;            // Aggregate root identifier
  string correlation_id = 3; // Cross-domain workflow ID
  Edition edition = 4;      // Timeline/branch identifier
}

Fields

Field	Purpose	Example
domain	Bounded context	"order", "inventory"
root	Aggregate instance	UUID
correlation_id	Workflow tracking	"checkout-123"
edition	Timeline branching	Main or diverged

Addressing Patterns

By root: Single aggregate instance

Cover { domain: "order", root: <uuid> }

By correlation: All aggregates in a workflow

Cover { domain: "order", correlation_id: "checkout-123" }

Both: Specific instance within workflow

Cover { domain: "order", root: <uuid>, correlation_id: "checkout-123" }

Default Values

When not specified, Angzarr uses defaults:

• Event ID: {domain}:{root_id}:{sequence}
• Event source: angzarr/{domain}