system-design-skills plugin
A plugin with 22 skills for system design: from load estimates to failure analysis, a /design command and an orchestrator agent.
- 131 ★ on the repository
- Last commit
- MIT
Minimal access
Why this level
- Skills give recommendations and write a design document and diagram to `docs/design/`, running no commands.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add plugins/system-design-skillsDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewMinimal accessThe tool runs nothing and makes no network calls.
- Skills give recommendations and write a design document and diagram to `docs/design/`, running no commands.
This is third-party code. Review the repository files before installing.
What it does
The plugin builds system design out of blocks: an orchestrator, a diagram engine and 20 building-block skills arranged bottom-up. Layers run from framing and back-of-the-envelope sizing through DNS, load balancing and CDN, API design and service decomposition, storage, caches and search, queues and schedulers to consistency, resilience, observability and 10x and 100x growth. The `/design` command runs the full loop: clarify requirements, estimate numbers, compose blocks, weigh trade-offs, stress-test failures and iterate. The result lands in `docs/design/` as a scored document plus an HTML and SVG diagram. Each block follows one contract: when to reach for it, what to clarify, options, trade-offs, behavior under stress, numbers and provider choice (AWS, Azure, GCP, Temporal).
Who it is for. Developers and tech leads designing scalable services or preparing for a system design interview with Claude Code or Codex.
Good fit when
- You must design an API rate limiter across a hundred gateway nodes and justify each choice.
- You need to decide whether SQL or NoSQL suits a chat app and how to shard it.
- You need an order-of-magnitude load estimate: requests per second, storage size, network.
- An interview is coming and you want an architecture walk-through with trade-offs and failure scenarios.
Not a fit when
- You need a ready diagram from a single screenshot without discussion: the plugin is built for step-by-step reasoning.
- You are editing specific code: the blocks describe architecture and do not edit your files.
- You want the `/design` command in Codex: it and the orchestrator work only in Claude Code.
Example request
/design a rate limiter for our API across 100 gateway nodesLimitations
The `/design` command and the `system-design-orchestrator` agent exist only in Claude Code. Codex gets the skills and starts with a phrase like "use the system-design skill to design". Installing the plugin from the marketplace clones the repository over SSH, and without GitHub keys you must pass an HTTPS address. The one-command install form needs Claude Code 2.1.275 or newer. Skills give recommendations and order-of-magnitude numbers, and the final decision stays with you. The design document is written to `docs/design/` in your project.
How to disable. For Claude Code run `/plugin uninstall system-design-skills`. If you installed through `npx skills`, delete the skill folders from `.claude/skills/`.
FAQ
How do I install system-design-skills in Claude Code?
Add the marketplace with `/plugin marketplace add proyecto26/system-design-skills` and install with `/plugin install system-design-skills`. Without GitHub SSH keys pass the HTTPS repository URL.
What does the /design command do?
It runs the reasoning loop: clarifies requirements, estimates numbers, composes blocks, weighs trade-offs, tests failures and iterates. The result is written to `docs/design/` as a scored document with a diagram.
Does the plugin work in Codex?
The skills work. The `/design` command and orchestrator belong to Claude Code, so in Codex start by asking to use the system-design skill.
Which topics do the blocks cover?
Framing and load estimates, DNS, load balancing, CDN, API design, service decomposition, storage, caches, search, queues, schedulers, consistency, resilience, observability and 10x and 100x growth. A separate skill draws diagrams.
Are dependencies required?
No, the plugin is self-contained with no runtime dependencies. For development there are metadata checks in `meta/evals/run_checks.py` and an eval suite in `evals/`.
Discussion
No questions or reviews yet.
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README in short
The README argues that design is better composed from blocks than memorized as finished diagrams and shows the reasoning loop with layers L0 to L7. It continues with six install options, sample requests, the block contract and the Agent Plugins and Agent Skills packaging standards.