What you'll learn

• Signal naming patterns that remain stable as systems grow
• How routing decouples producers from downstream execution
• How to handle out-of-order, delayed, or duplicate events
• How to design idempotent communication flows

Prerequisites

• You can write validated action modules
• You know the difference between command and event messages
• You are comfortable with map-based payloads

Lesson Breakdown

1. Signal taxonomy: separate intent (*.command) from fact (*.changed).
2. Route design: keep routing tables small and explicit.
3. Payload discipline: include identifiers and timestamps consistently.
4. Idempotency: protect handlers with dedupe keys or monotonic checks.
5. Observability: emit telemetry around route hits and failures.

Hands-on Exercise

Model a two-agent workflow for order fulfillment:

1. OrderAgent emits order.approved.
2. InventoryAgent listens and reserves stock.
3. ShippingAgent listens for inventory.reserved.
4. Add idempotency key handling to prevent duplicate reservation.
5. Simulate duplicate order.approved events and verify safe behavior.

Validation Checklist

• [ ] Signal names follow a consistent domain prefix.
• [ ] Each consumer route is explicit and traceable.
• [ ] Duplicate delivery does not double-apply state changes.
• [ ] Telemetry exists for routing success and failure paths.

Next Module

Continue with Directives, Scheduling, and Time-Based Behavior.