poolAI: Skill for Claude Code

.agents/skills/system-design/SKILL.md

system-design is a skill for Claude Code, Codex from platinoff/poolAI. It costs 55 tokens per session (283 once invoked), scanned A, a copy of system-design, MIT.

A guide for planning software systems, including their parts, data, APIs, storage, and service boundaries. It also examines requirements such as speed, scale, reliability, cost, and team constraints.

In plain words
What is it for?
It helps design APIs, data models, caches, queues, error handling, monitoring, and scaling plans, with diagrams and documented assumptions.
Why use it?
It gives developers a structured way to make architecture decisions and understand their trade-offs before implementation.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is platinoff/poolAI's own configuration. It tells Claude Code and Codex how to work on poolAI itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything poolAI configures →

Reuse

Borrowing it

Nothing to install: this file belongs to platinoff/poolAI. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/platinoff/poolAI/main/.agents/skills/system-design/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/platinoff/poolAI

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 system-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/platinoff/poolai/system-design/github.svg)](https://agentmods.dev/skills/platinoff/poolai/system-design)
Your own site
<a href="https://agentmods.dev/skills/platinoff/poolai/system-design"><img src="https://agentmods.dev/badge/skills/platinoff/poolai/system-design/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 system-design

Your own site · 80×15
<a href="https://agentmods.dev/skills/platinoff/poolai/system-design"><img src="https://agentmods.dev/badge/skills/platinoff/poolai/system-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 283 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 100% copy Near-identical to another mod 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 $0.00055 $0.00283
Opus 5.5 $0.00022 $0.00113
Sonnet 5.5 $0.00011 $0.00057
Haiku 4.5 $0.00006 $0.00028

Measured 1mo ago against content hash 8f28eca99f22, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

system-design 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 1mo 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

This is a copy

100% identical to system-design — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/system-design/SKILL.md · 43 lines

What it actually says

System Design

Help design systems and evaluate architectural decisions.

Framework

1. Requirements Gathering

  • Functional requirements (what it does)
  • Non-functional requirements (scale, latency, availability, cost)
  • Constraints (team size, timeline, existing tech stack)

2. High-Level Design

  • Component diagram
  • Data flow
  • API contracts
  • Storage choices

3. Deep Dive

  • Data model design
  • API endpoint design (REST, GraphQL, gRPC)
  • Caching strategy
  • Queue/event design
  • Error handling and retry logic

4. Scale and Reliability

  • Load estimation
  • Horizontal vs. vertical scaling
  • Failover and redundancy
  • Monitoring and alerting

5. Trade-off Analysis

  • Every decision has trade-offs. Make them explicit.
  • Consider: complexity, cost, team familiarity, time to market, maintainability

Output

Produce clear, structured design documents with diagrams (ASCII or described), explicit assumptions, and trade-off analysis. Always identify what you'd revisit as the system grows.

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. 1mo ago First seen · 43 lines · 55 tokens per session scan A 8f28eca99f22

Subscribe to this mod's changes

system-design is a skill published in the GitHub repository platinoff/poolAI (4 stars, last pushed 3d ago), licensed MIT. It adds 55 tokens to every session and 283 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to system-design, differing in 0 lines, and is treated as a copy.

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