Agent Systems: Choosing and Composing Patterns

Outline

1. Start with the simplest deterministic structure that meets the task’s needs.
2. Add a pattern only when it addresses a named source of complexity or uncertainty.
3. Compare patterns by latency, cost, observability, reliability, and ease of revision.
4. Discuss useful combinations: chaining + reflection; router + specialized tools; plan + memory; parallelization + aggregation + human review.
5. Include a decision table: task shape, recommended pattern, main failure mode.
6. End with three questions:
   • What is the task’s main source of uncertainty?
   • Which interface makes that uncertainty observable?
   • What is the simplest pattern that provides that interface?