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.
npx skills add hoangatg/ai-agent-toolkit --skill event-sourcing-architectgit clone --depth 1 https://github.com/hoangatg/ai-agent-toolkitWrote 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.
[](https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/event-sourcing-architect)<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/event-sourcing-architect"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/event-sourcing-architect/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/event-sourcing-architect"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/event-sourcing-architect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00034 | $0.00707 |
| Opus 5 | $0.00017 | $0.00353 |
| Sonnet 5 | $0.00007 | $0.00141 |
| Haiku 4.5 | $0.00003 | $0.00071 |
Grade A, and why
event-sourcing-architect 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.
How it starts
The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Event Sourcing Architect
Store what happened, not where you are. Reconstruct any state at any point in time.
1. Core Concepts
| Concept | Description |
|---|---|
| Event | Immutable fact that happened (past tense) |
| Event Store | Append-only log of all events |
| Projection | Materialized view from events |
| Snapshot | Periodic state checkpoint |
| CQRS | Separate command (write) and query (read) models |
When to Use
| ✅ Good Fit | ❌ Bad Fit |
|---|---|
| Audit requirements | Simple CRUD apps |
| Temporal queries | Low complexity domains |
| Complex business logic | Real-time requirements only |
| Event-driven architecture | Team unfamiliar with patterns |
2. Event Design
Event Principles
| Principle | Application |
|---|---|
| Past tense naming | OrderPlaced, not PlaceOrder |
| Self-contained | All relevant data included |
| Immutable | Never modify, only append |
| Versioned | Schema evolution support |
Event Schema
Event {
id: UUID
type: "OrderPlaced"
aggregateId: "order-123"
version: 3
timestamp: ISO-8601
data: { ... }
metadata: { userId, correlationId }
}
3. CQRS Pattern
Separation
| Side | Responsibility | Model |
|---|---|---|
| Command | Validate + write events | Domain model (aggregates) |
| Query | Read optimized views | Projections (denormalized) |
Benefits
- Read and write scale independently
- Optimized models for each use case
- Multiple read models from same events
- Clear separation of concerns
4. Projections
| Type | Use Case |
|---|---|
| Synchronous | Strong consistency needed |
| Asynchronous | Performance, eventual consistency |
| Catch-up | Rebuild from event history |
Design Principles
- One projection per read use case
- Idempotent event handlers
- Track last processed event position
- Rebuild capability is mandatory
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.
- 7d ago First seen · 125 lines · 34 tokens per session scan A 1284cae63975
event-sourcing-architect is a skill published in the GitHub repository hoangatg/ai-agent-toolkit (1 stars, last pushed 5mo ago), licensed MIT. It adds 34 tokens to every session and 707 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.
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