Aaron Weiker
b72c14f370
Based on actual review findings: - Replay determinism: DateTime.utc_now() in apply, random in state - Event design: OrderUpdated with changes map (CRUD-in-disguise) - Projections as source of truth - Suggesting event 'fixes' instead of compensating events - Missing idempotency in handlers Added Elixir/OTP specific patterns (handle_continue for replay, Process dictionary for test isolation). Anti-patterns table for quick flagging.
DDD & Event Sourcing Patterns
What LLMs get subtly wrong in event-sourced systems. Based on actual code review findings.
Why This Exists
LLMs know the textbook definitions of event sourcing and DDD. But they make subtle mistakes:
- Adding
DateTime.utc_now()in apply functions (breaks replay determinism) - Creating
OrderUpdatedevents with a changes map (CRUD-in-disguise) - Treating projections as source of truth
- Suggesting "fixes" to immutable events
- Making aggregates too large (data grouping vs consistency boundary)
- Multi-aggregate coordination in services without saga patterns
This checklist catches those mistakes.
Contents
DDD-CHECKLIST.md- Review prompts covering:- Replay Determinism (CRITICAL)
- Event Design
- Aggregate Boundaries
- Projections
- Idempotency
- Process Managers / Sagas
- Elixir/OTP Specific
- Anti-patterns table
Integration
# In your review workflow
patterns-repo: rodin/ddd-patterns
patterns-files: '.'
License
MIT