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core-engineering marketplace

core-engineering marketplace is a plugin for Claude Code from JustineDevs/premortem. Its token cost is not measured, scanned A, original, Apache-2.0.

A software-design guide covering object-oriented programming ideas and rules for writing maintainable code, with TypeScript examples.

In plain words
What is it for?
Use it when planning classes, choosing between inheritance and composition, or reviewing code against principles such as SOLID, DRY, KISS, and YAGNI.
Why use it?
It helps explain common design choices and reduce repeated, tightly connected, or unnecessarily complex code.

Plugin for Claude Code

Written for Claude Code: a Claude Code plugin manifest. Also seen: installed under .agents/ (shared by several agents).

not rated 2repo 3mo ago A scan tokens not measured original Apache-2.0

Good fit Use it when planning classes, choosing between inheritance and composition, or reviewing code against principles such as SOLID, DRY, KISS, and YAGNI.

Compare 6 plugins from other repositories ↓
Install in Claude Code
/plugin marketplace add JustineDevs/premortem
/plugin install core-engineering marketplace
View source ↗ JustineDevs/premortem premortem.jstn.site
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/JustineDevs/premortem

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 core-engineering marketplace

README.md
[![agentmods](https://agentmods.dev/badge/plugins/justinedevs/premortem/marketplace/github.svg)](https://agentmods.dev/plugins/justinedevs/premortem/marketplace)
Your own site
<a href="https://agentmods.dev/plugins/justinedevs/premortem/marketplace"><img src="https://agentmods.dev/badge/plugins/justinedevs/premortem/marketplace/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 core-engineering marketplace

Your own site · 80×15
<a href="https://agentmods.dev/plugins/justinedevs/premortem/marketplace"><img src="https://agentmods.dev/badge/plugins/justinedevs/premortem/marketplace.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session not measured What this adds to a session before it is invoked.
When invoked not measured Not applicable: nothing here is loaded into a session.
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.
Security

Grade A, and why

core-engineering marketplace 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 2mo 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/skills/core-engineering/.claude-plugin/marketplace.json · 20 lines

What it actually says

{
  "name": "core-engineering",
  "owner": {
    "name": "JustineDevs",
    "email": "[email protected]"
  },
  "metadata": {
    "description": "OOP four pillars, SOLID, clean code (DRY, KISS, YAGNI, Law of Demeter), composition over inheritance, and relationship types (association, aggregation, composition) with example code for AI agents and developers.",
    "pluginRoot": "."
  },
  "plugins": [
    {
      "name": "core-engineering",
      "source": ".",
      "description": "Core Engineering skill: Object-Oriented Design (Abstraction, Encapsulation, Inheritance, Polymorphism), SOLID principles, composition over inheritance, DRY/KISS/YAGNI/LoD, and association vs aggregation vs composition. Each principle includes how it looks and TypeScript examples.",
      "category": "Software Design"
    }
  ]
}
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. 2mo ago First seen · 20 lines scan A 350100b00a22

Subscribe to this mod's changes

core-engineering marketplace is a plugin published in the GitHub repository JustineDevs/premortem (2 stars, last pushed 3mo ago), licensed Apache-2.0. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.

aigithubgitlabpredictive-modelingsecurity-tools
Related

core-engineering marketplace compared with plugins from other repositories

core-engineering marketplace next to 6 plugins from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
core-engineering marketplaceJustineDevs/premortemPlugin23mo agoApache-2.0A—Claude Code
code-gauntletliatrio-labs/claude-code-gauntletPlugin13yesterdayApache-2.0A—Claude Code
pr-comments-resolverDropelikeit/pr-comments-resolverPlugin23mo agoMITA—Claude Code
claude-settings marketplacefcakyon/claude-codex-settingsPlugin1.2kyesterdayApache-2.0A—Claude Code
gcloud-toolsfcakyon/claude-codex-settingsPlugin1.2kyesterdayApache-2.0A—Claude Code
github-to-mcpnirholas/github-to-mcpPlugin342d agononeA—Claude Code
humanizerblader/humanizerPlugin68k3d agoMITA—Claude Code