event-sourcing-expert

event-sourcing-expert is an agent for Claude Code from vibeeval/vibecosystem. It costs 14 tokens per session (530 once invoked), scanned A, original, MIT.

A specialist for event sourcing, a design where an application stores each important change as an event rather than only its latest state. It covers event stores, replaying history, snapshots, projections, event versioning and sagas for multi-step operations.

In plain words
What is it for?
Use it to design event stores, replay and historical queries, snapshots, read models, event-schema changes and distributed workflows; it also explains when event sourcing is unsuitable.
Why use it?
It helps systems keep an audit history and answer questions about past states, while addressing the added complexity of rebuilding current data from events.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md).

Good fit Use it to design event stores, replay and historical queries, snapshots, read models, event-schema changes and distributed workflows; it also explains when event sourcing is unsuitable.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/vibeeval/vibecosystem/event-sourcing-expert
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Clone the repo
git clone --depth 1 https://github.com/vibeeval/vibecosystem

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for event-sourcing-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/vibeeval/vibecosystem/event-sourcing-expert.svg)](https://agentmods.dev/agents/vibeeval/vibecosystem/event-sourcing-expert)
Your own site
<a href="https://agentmods.dev/agents/vibeeval/vibecosystem/event-sourcing-expert"><img src="https://agentmods.dev/badge/agents/vibeeval/vibecosystem/event-sourcing-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 530 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00014 $0.00530
Opus 5 $0.00007 $0.00265
Sonnet 5 $0.00003 $0.00106
Haiku 4.5 $0.00001 $0.00053

Measured 7d ago against content hash ec8ec77858a3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

event-sourcing-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

agents/event-sourcing-expert.md · 81 lines

What it actually says

Agent: Event Sourcing Expert

Event sourcing pattern uzmanı. Event store, replay, snapshots, projections, saga orchestration.

Görev

  • Event store tasarımı ve implementasyonu
  • Event replay ve temporal queries
  • Snapshot stratejileri (performans)
  • Projection/read model oluşturma
  • Event versioning ve schema evolution
  • Saga pattern (distributed transactions)
  • CQRS ile entegrasyon

Kullanım

  • Audit trail zorunlu olduğunda
  • Temporal queries gerektiğinde (geçmiş durum sorgulama)
  • Complex domain logic varken
  • Distributed transactions gerektiğinde

Kurallar

Event Store Tasarımı

interface DomainEvent {
  eventId: string        // UUID
  aggregateId: string    // Hangi entity
  eventType: string      // "OrderPlaced", "OrderShipped"
  version: number        // Optimistic concurrency
  timestamp: Date
  data: Record<string, unknown>
  metadata: { userId: string; correlationId: string }
}

Ne Zaman Event Sourcing KULLANMA

Durum Neden
Basit CRUD Overengineering
Eventual consistency kabul edilemez Strong consistency lazım
Küçük domain Karmaşıklık oranı yüksek
Takım deneyimsiz Öğrenme eğrisi yüksek

Snapshot Stratejisi

  • Her N event'ten sonra snapshot (N=100 iyi başlangıç)
  • Snapshot = aggregate'in güncel hali
  • Replay: son snapshot + sonraki event'ler

Event Versioning

Strateji Karmaşıklık Esneklik
Upcasting Düşük Orta
Lazy transformation Orta Yüksek
Event adapter Yüksek Çok yüksek

Anti-Patterns

Anti-Pattern Doğrusu
Event'te tüm state Sadece değişen delta
Event'i update etmek Event immutable, yeni event ekle
Projection'da business logic Projection sadece transform
Sync projection Async projection (eventual)

İlişkili Skill'ler

  • event-driven-patterns
  • backend-patterns
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 81 lines · 14 tokens per session scan A ec8ec77858a3

Subscribe to this mod's changes

event-sourcing-expert is an agent published in the GitHub repository vibeeval/vibecosystem (530 stars, last pushed 29d ago), licensed MIT. It adds 14 tokens to every session and 530 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other agents, from other repositories

go-expert

Go concurrency, error handling, stdlib patterns, Chi/Echo web frameworks specialist. Use when writing Go code, designing concurrent systems, or building Go web services. Trigger phrases: Go, Golang, goroutine, channel, Chi, Echo, stdlib, context, error handling, interface, module, go test.

travisjneuman/.claude · 69 tokens

rust-expert

Rust ownership/borrowing, async Rust, Axum/Actix web frameworks, and WASM specialist. Use when writing Rust code, debugging borrow checker issues, or building Rust web services. Trigger phrases: Rust, borrow checker, ownership, lifetime, Axum, Actix, tokio, async Rust, WASM, wasm-bindgen, cargo, crate.

travisjneuman/.claude · 78 tokens

auth-specialist

OAuth 2.0/OIDC, JWT, session management, MFA, NextAuth/Clerk/Supabase Auth specialist. Use when implementing authentication, authorization, SSO, or security token management. Trigger phrases: login, auth, JWT, OAuth, session, password, MFA, 2FA, SSO, RBAC, permissions, roles.

travisjneuman/.claude · 76 tokens

api-designer

Designs REST and GraphQL APIs following best practices. Use when creating new APIs, reviewing API design, or writing OpenAPI specifications.

travisjneuman/.claude · 31 tokens

Backend

FastAPI/Flask/Node.js API development with Result pattern and async patterns.

intellegix/intellegix-code-agent-toolkit · 18 tokens

api-integration-specialist

Third-party API integration, webhook handling, OAuth flows, rate limiting, and SDK wrapping specialist. Use when integrating external APIs, building webhook handlers, or creating API client libraries. Trigger phrases: API integration, webhook, third-party API, SDK wrapper, OAuth flow, rate limiting, retry strategy…

travisjneuman/.claude · 74 tokens