Stores your application state as an immutable sequence of events instead of just the current state, which means you can rebuild state at any point in time, run temporal queries, and get full audit trails for free. The skill covers event stores, aggregates, CQRS projections, and includes practical implementations in TypeScript and PostgreSQL. Use this when you need audit compliance, are building financial systems, or want to debug by replaying past states. The concurrency control and snapshot examples are solid, though you'll need to think hard about event schema evolution before you're in production. Fair warning that querying gets more complex since you're reading from projections instead of your source of truth.
npx skills add https://github.com/aj-geddes/useful-ai-prompts --skill event-sourcing