create-event-model

A guide for creating Mermaid diagrams that show how a Cratis feature works over time. The diagrams connect commands, events, read models, and automated reactions in a business flow.

In plain words
What is it for?
Use it when adding, renaming, moving, or removing Cratis modules, features, slices, commands, events, read models, automations, translations, or cross-module flows.
Why use it?
It keeps the visual description of a feature aligned with changes to its modules and event-driven behavior.

Skill for Claude CodeCodex

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/cratis/ai/create-event-model
Any agent
npx skills add Cratis/AI --skill create-event-model
Clone the repo
git clone --depth 1 https://github.com/Cratis/AI

Made for: Claude Code, Codex.

Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,435 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 $0.00069 $0.01435
Opus 5 $0.00034 $0.00718
Sonnet 5 $0.00014 $0.00287
Haiku 4.5 $0.00007 $0.00144

Measured 2d ago against content hash 620e9d13a8e2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-event-model 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 2d 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:

.ai/skills/create-event-model/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.

Create Event Model Diagram

Use this skill when adding a module/feature, or when any slice within it is added, renamed, or removed — the EventModel.md for the affected area is updated in the same change. If the event vocabulary/stream boundaries aren't decided yet, use event-modeling first; this skill renders an already-chosen model.

Diagrams use Mermaid's native eventmodeling diagram type (v11.15+). The full grammar is at https://mermaid.js.org/syntax/eventmodeling.html; that page wins when in doubt.

What an event model is

It arranges a module's commands, events, read models, and automations on a left-to-right business-flow timeline — answering "what happens in this module, and in what order?" One file per module (or feature), in a fenced ```mermaid block, alongside the code: <Module>/EventModel.md; a system-overview at the source root shows only cross-module flows.

Mermaid eventmodeling cheat sheet

Frame prefix: tf (timeframe — auto-connects to the previous frame) · rf (resetframe — breaks the chain; start each independent flow with it). rf replaces tf; tf N rf Name is invalid.

Frame: <prefix> <number> <type> <EntityName>. Number is unique (order of declaration doesn't matter — frames position by reference). Type is one of:

Type Swimlane Represents
ui UI / Automation the persona interacting (persona name only — not a screen name)
pcr UI / Automation a reactor / automation processor
cmd Command / Read Model a [Command] record
rmo Command / Read Model a [ReadModel] record
evt Events an [EventType] record — use the exact, self-describing C# name

Multiple sources (->>): a read model or fan-in reactor fed by several frames references them by frame number: tf 10 rmo Profile ->> 03 ->> 06 ->> 09. Namespaces: a Module. prefix (tf 04 pcr Billing.CreateInvoice) creates a sub-swimlane — use it for cross-module entities and in the system overview. Comments: %% ── Section ── (don't use a frame as a section header).

Read the full file on GitHub · 81 lines

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. 2d ago First seen · 81 lines · 69 tokens per session scan A 620e9d13a8e2

Subscribe to this mod's changes

create-event-model is a skill published in the GitHub repository Cratis/AI (2 stars, last pushed 4d ago), licensed MIT. It adds 69 tokens to every session and 1,435 once invoked, about $0.0003 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 2026-08-31.

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