domain-events

domain-events is a skill for Claude Code, Codex from garrettw/php-arch-skills. It costs 48 tokens per session (905 once invoked), scanned A, original, MPL-2.0.

A guide to domain events in PHP applications. A domain event is a record that something important in the business has already happened, allowing other parts of an application to react separately.

In plain words
What is it for?
Deciding whether events are appropriate, naming events and their data, and implementing record-then-publish workflows across application areas.
Why use it?
It helps reduce tight connections between one business action and side effects such as notifications, synchronisation, or audit history.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Deciding whether events are appropriate, naming events and their data, and implementing record-then-publish workflows across application areas.

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Install with agentmods
npx agentmods add skills/garrettw/php-arch-skills/domain-events
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.

Any agent
npx skills add garrettw/php-arch-skills --skill domain-events
Clone the repo
git clone --depth 1 https://github.com/garrettw/php-arch-skills

Made for: Claude Code, Codex.

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 domain-events

README.md
[![agentmods](https://agentmods.dev/badge/skills/garrettw/php-arch-skills/domain-events/github.svg)](https://agentmods.dev/skills/garrettw/php-arch-skills/domain-events)
Your own site
<a href="https://agentmods.dev/skills/garrettw/php-arch-skills/domain-events"><img src="https://agentmods.dev/badge/skills/garrettw/php-arch-skills/domain-events/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.

agentmods 80×15 button for domain-events

Your own site · 80×15
<a href="https://agentmods.dev/skills/garrettw/php-arch-skills/domain-events"><img src="https://agentmods.dev/badge/skills/garrettw/php-arch-skills/domain-events.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 905 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 $0.00048 $0.00905
Opus 5 $0.00024 $0.00452
Sonnet 5 $0.00010 $0.00181
Haiku 4.5 $0.00005 $0.00090

Measured 10d ago against content hash 6cd35078cadc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

domain-events 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 10d 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.

skills/domain-events/SKILL.md · 64 lines

How it starts

The opening of the file, as written. The whole thing — 64 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Domain Events in PHP Applications

When to Use Domain Events (and When NOT to)

Domain Events add indirection that must justify its cost. Use them when you need eventual consistency, decoupled downstream reactions, or a history of changes. Skip them for single-action uses where direct method calls suffice.

Use Domain Events For Use Direct Calls For
Decoupled side effects (email, notifications, sync) Single-step operations without downstream reactions
Cross-bounded-context communication Same-context synchronous updates
Audit trail or event replay requirements Stateless operations with no history needed
Multiple downstream triggers from one change One downstream reaction

Start without events. Introduce them only when coupling becomes a real maintenance or reliability problem.

System Overview

Domain Events represent facts that have already happened in the business. They decouple side effects from the primary transaction and serve as contracts between bounded contexts. This skill covers the implementation of the Record-Then-Publish pattern and the rules for defining events.

Numbered Workflows

1. Deciding to Introduce an Event

If evaluating whether a new behavior should be triggered by an event:

  1. Check for downstream needs. Does another bounded context need to know that a fact occurred? If yes, use an event.
  2. Check for non-blocking side effects. Must a side effect (like sending an email or syncing to a third party) happen without blocking the primary business transaction? If yes, use an event.
  3. Check for multiple triggers. Do you need to trigger multiple downstream actions from a single domain change without tightly coupling the orchestrating handler? If yes, use an event.
  4. If the goal is just logging or a synchronous internal call, do NOT use an event.

Read the full file on GitHub · 64 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. 10d ago First seen · 64 lines · 48 tokens per session scan A 6cd35078cadc

Subscribe to this mod's changes

domain-events is a skill published in the GitHub repository garrettw/php-arch-skills (12 stars, last pushed 1mo ago), licensed MPL-2.0. It adds 48 tokens to every session and 905 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 2026-08-31.

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