---
name: event-sourcing-architect
type: reference
description: "Designs event-sourced systems with CQRS, event stores, projections, and eventual consistency patterns. Use when architecting event-driven systems or when the user mentions event sourcing, CQRS, event store, or domain events."
effort: 4
allowed-tools: Read, Glob, Grep, Write, Edit, Bash
user-invocable: true
when_to_use: "When designing event-sourced systems, CQRS patterns, event stores, or systems requiring full audit trail"
Event Sourcing Architect
Expert in event sourcing, CQRS, and event-driven architecture patterns. Masters event store design, projection building, saga orchestration, and eventual consistency patterns. Use PROACTIVELY for event-sourced systems, audit trail requirements, or complex domain modeling with temporal queries.
Capabilities
- Event store design and implementation
- CQRS (Command Query Responsibility Segregation) patterns
- Projection building and read model optimization
- Saga and process manager orchestration
- Event versioning and schema evolution
- Snapshotting strategies for performance
- Eventual consistency handling
Use this skill when
- Building systems requiring complete audit trails
- Implementing complex business workflows with compensating actions
- Designing systems needing temporal queries ("what was state at time X")
- Separating read and write models for performance
- Building event-driven microservices architectures
- Implementing undo/redo or time-travel debugging
Do not use this skill when
- The domain is simple and CRUD is sufficient
- You cannot support event store operations or projections
- Strong immediate consistency is required everywhere
Instructions
- Identify aggregate boundaries and event streams
- Design events as immutable facts
- Implement command handlers and event application
- Build projections for query requirements
- Design saga/process managers for cross-aggregate workflows
- Implement snapshotting for long-lived aggregates
- Set up event versioning strategy
Safety
- Never mutate or delete committed events in production.
- Rebuild projections in staging before running in production.
Best Practices
- Events are facts - never delete or modify them
- Keep events small and focused
- Version events from day one
- Design for eventual consistency
- Use correlation IDs for tracing
- Implement idempotent event handlers
- Plan for projection rebuilding
- Use durable execution for process managers and sagas — frameworks like DBOS persist workflow state automatically, making cross-aggregate orchestration resilient to crashes
Related Skills
Works well with: saga-orchestration, architecture-patterns, dbos-*
When to Use
- Use when Expert in event sourcing, CQRS, and event-driven architecture patterns. Masters event store design, projection building, saga orchestration, and eventual consistency patterns. Use PROACTIVELY for e...
1---2name: event-sourcing-architect3description: ---4---5---6name: event-sourcing-architect7type: reference8description: "Designs event-sourced systems with CQRS, event stores, projections, and eventual consistency patterns. Use when architecting event-driven systems or when the user mentions event sourcing, CQRS, event store, or domain events."9effort: 410allowed-tools: Read, Glob, Grep, Write, Edit, Bash11user-invocable: true12when_to_use: "When designing event-sourced systems, CQRS patterns, event stores, or systems requiring full audit trail"13---1415# Event Sourcing Architect1617Expert in event sourcing, CQRS, and event-driven architecture patterns. Masters event store design, projection building, saga orchestration, and eventual consistency patterns. Use PROACTIVELY for event-sourced systems, audit trail requirements, or complex domain modeling with temporal queries.1819## Capabilities2021- Event store design and implementation22- CQRS (Command Query Responsibility Segregation) patterns23- Projection building and read model optimization24- Saga and process manager orchestration25- Event versioning and schema evolution26- Snapshotting strategies for performance27- Eventual consistency handling2829## Use this skill when3031- Building systems requiring complete audit trails32- Implementing complex business workflows with compensating actions33- Designing systems needing temporal queries ("what was state at time X")34- Separating read and write models for performance35- Building event-driven microservices architectures36- Implementing undo/redo or time-travel debugging3738## Do not use this skill when3940- The domain is simple and CRUD is sufficient41- You cannot support event store operations or projections42- Strong immediate consistency is required everywhere4344## Instructions45461. Identify aggregate boundaries and event streams472. Design events as immutable facts483. Implement command handlers and event application494. Build projections for query requirements505. Design saga/process managers for cross-aggregate workflows516. Implement snapshotting for long-lived aggregates527. Set up event versioning strategy5354## Safety5556- Never mutate or delete committed events in production.57- Rebuild projections in staging before running in production.5859## Best Practices6061- Events are facts - never delete or modify them62- Keep events small and focused63- Version events from day one64- Design for eventual consistency65- Use correlation IDs for tracing66- Implement idempotent event handlers67- Plan for projection rebuilding68- Use durable execution for process managers and sagas — frameworks like DBOS persist workflow state automatically, making cross-aggregate orchestration resilient to crashes6970## Related Skills7172Works well with: `saga-orchestration`, `architecture-patterns`, `dbos-*`7374## When to Use7576- Use when Expert in event sourcing, CQRS, and event-driven architecture patterns. Masters event store design, projection building, saga orchestration, and eventual consistency patterns. Use PROACTIVELY for e...
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