playbook/antigravity-awesome-skills/plugins/agentic-bundle-ddd-evented-architecture/skills/event-store-design/resources/implementation-playbook.md

Event Store Design Playbook

Schema and stream strategy

• Use append-only writes with optimistic concurrency.
• Keep per-stream ordering and global ordering indexes.
• Include metadata fields for causation and correlation IDs.

Operational guardrails

• Never mutate historical events in production.
• Version event schema with explicit upcasters/downcasters policy.
• Define retention and archival strategy by stream type.

Subscription and projection safety

• Track per-subscriber checkpoint positions.
• Make handlers idempotent and replay-safe.
• Support projection rebuild from a clean checkpoint.

Performance checklist

• Index stream id + version.
• Index global position.
• Add snapshot policy for long-lived aggregates.