event-store-design

event-store-design is a skill for Claude Code from wshobson/agents. It costs 33 tokens per session (780 once invoked), scanned A, original, MIT.

A guide to designing event stores, databases that keep a history of events rather than only the latest state. It covers event-sourcing infrastructure, storage choices, schemas, retrieval, and scaling.

In plain words
What is it for?
Use it when choosing or building an event store, designing event streams and schemas, improving event retrieval, or planning storage growth.
Why use it?
It helps preserve a complete record of changes and provides a structured way to store and rebuild application state from events.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the backend-development plugin — 9 skills, 1 command, 5 agents shipped together

About the project

Agentic Plugin Marketplace is a collection of reusable plugins, agents, skills, commands, and rules for coding-agent tools including Claude Code, Codex CLI, Cursor, OpenCode, Antigravity CLI, and GitHub Copilot. It is for developers assembling agentic workflows across multiple harnesses from shared Markdown sources, and the catalogue entries are examples or subsets of those workflow components.

wshobson/agents · 39,449 stars · on GitHub · sethhobson.com

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.

agentmods
npx agentmods add skills/wshobson/agents/event-store-design
Any agent
npx skills add wshobson/agents --skill event-store-design
Clone the repo
git clone --depth 1 https://github.com/wshobson/agents

Made for: Claude Code.

Or install backend-development, the plugin that ships this one along with the rest of its 9 skills, 1 command, 5 agents.

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-store-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/wshobson/agents/event-store-design.svg)](https://agentmods.dev/skills/wshobson/agents/event-store-design)
Your own site
<a href="https://agentmods.dev/skills/wshobson/agents/event-store-design"><img src="https://agentmods.dev/badge/skills/wshobson/agents/event-store-design.svg" alt="Measured on agentmods" height="20"></a>
Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 780 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00033 $0.00780
Opus 5 $0.00016 $0.00390
Sonnet 5 $0.00007 $0.00156
Haiku 4.5 $0.00003 $0.00078

Measured 3d ago against content hash 66bcb9ad668a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

event-store-design 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 3d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

plugins/backend-development/skills/event-store-design/SKILL.md · 81 lines

How it starts

The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Event Store Design

Comprehensive guide to designing event stores for event-sourced applications.

When to Use This Skill

  • Designing event sourcing infrastructure
  • Choosing between event store technologies
  • Implementing custom event stores
  • Optimizing event storage and retrieval
  • Setting up event store schemas
  • Planning for event store scaling

Core Concepts

1. Event Store Architecture

┌─────────────────────────────────────────────────────┐
│                    Event Store                       │
├─────────────────────────────────────────────────────┤
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐ │
│  │   Stream 1   │  │   Stream 2   │  │   Stream 3   │ │
│  │ (Aggregate)  │  │ (Aggregate)  │  │ (Aggregate)  │ │
│  ├─────────────┤  ├─────────────┤  ├─────────────┤ │
│  │ Event 1     │  │ Event 1     │  │ Event 1     │ │
│  │ Event 2     │  │ Event 2     │  │ Event 2     │ │
│  │ Event 3     │  │ ...         │  │ Event 3     │ │
│  │ ...         │  │             │  │ Event 4     │ │
│  └─────────────┘  └─────────────┘  └─────────────┘ │
├─────────────────────────────────────────────────────┤
│  Global Position: 1 → 2 → 3 → 4 → 5 → 6 → ...     │
└─────────────────────────────────────────────────────┘

2. Event Store Requirements

Requirement Description
Append-only Events are immutable, only appends
Ordered Per-stream and global ordering
Versioned Optimistic concurrency control
Subscriptions Real-time event notifications
Idempotent Handle duplicate writes safely

Technology Comparison

Technology Best For Limitations
EventStoreDB Pure event sourcing Single-purpose
PostgreSQL Existing Postgres stack Manual implementation
Kafka High-throughput streaming Not ideal for per-stream queries
DynamoDB Serverless, AWS-native Query limitations
Marten .NET ecosystems .NET specific

Read the full file on GitHub · 81 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 3d ago First seen · 81 lines · 33 tokens per session scan A 66bcb9ad668a

Subscribe to this mod's changes

event-store-design is a skill published in the GitHub repository wshobson/agents (39,449 stars, last pushed 4d ago), licensed MIT. It adds 33 tokens to every session and 780 once invoked, about $0.0002 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 2026-09-03.