system-architect

system-architect is a skill for Claude Code, Codex from Aizaz-Noor/Agent-Startup-Skills. It costs 44 tokens per session (622 once invoked), scanned A, original, MIT.

A system-design guide that plans an application's technologies, folder structure, API contracts, and connections to outside services before coding begins.

In plain words
What is it for?
Use it when choosing a technology stack, designing APIs, planning project files, or mapping the flow of a key user action.
Why use it?
It helps prevent disorganized code by making deliberate architecture choices and explaining how the frontend, backend, database, and authentication fit together.

Skill for Claude CodeCodex

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

Good fit Use it when choosing a technology stack, designing APIs, planning project files, or mapping the flow of a key user action.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aizaz-noor/agent-startup-skills/system-architect
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 Aizaz-Noor/Agent-Startup-Skills --skill system-architect
Clone the repo
git clone --depth 1 https://github.com/Aizaz-Noor/Agent-Startup-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 system-architect

README.md
[![agentmods](https://agentmods.dev/badge/skills/aizaz-noor/agent-startup-skills/system-architect/github.svg)](https://agentmods.dev/skills/aizaz-noor/agent-startup-skills/system-architect)
Your own site
<a href="https://agentmods.dev/skills/aizaz-noor/agent-startup-skills/system-architect"><img src="https://agentmods.dev/badge/skills/aizaz-noor/agent-startup-skills/system-architect/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-architect

Your own site · 80×15
<a href="https://agentmods.dev/skills/aizaz-noor/agent-startup-skills/system-architect"><img src="https://agentmods.dev/badge/skills/aizaz-noor/agent-startup-skills/system-architect.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 622 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 $0.00044 $0.00622
Opus 5 $0.00022 $0.00311
Sonnet 5 $0.00009 $0.00124
Haiku 4.5 $0.00004 $0.00062

Measured 11d ago against content hash 2697489ae4fb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

system-architect 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 11d 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:

skills/system-architect/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.

System Architect — Design Agent

Purpose

Design a complete, justified system architecture before any code is written. Prevent "spaghetti architecture" by making deliberate, documented choices.

When to Use

  • After MVP scope is approved
  • When choosing a tech stack for a new project
  • When designing API contracts or system structure

Process

Step 1: Tech Stack Selection

For each layer, recommend a technology with a one-line justification:

Layer Choice Why
Frontend e.g., Next.js SSR for SEO, React ecosystem
Backend e.g., Next.js API Routes Unified codebase, serverless-ready
Database e.g., PostgreSQL Relational data, free tier on Supabase
Auth e.g., NextAuth.js Free, supports OAuth providers
Hosting e.g., Vercel Free tier, zero-config deploys

Constraint: Prefer free-tier-friendly technologies unless the user specifies a budget.

Step 2: System Architecture

Describe the architecture in plain text or a mermaid diagram:

  • How do the frontend, backend, and database connect?
  • What is the request flow for the core user action?
  • Where does authentication happen?

Step 3: Project File Structure

Present the complete folder/file tree:

project-root/
├── src/
│   ├── app/           # Pages and routes
│   ├── components/    # Reusable UI components
│   ├── lib/           # Business logic and utilities
│   ├── api/           # API route handlers
│   └── db/            # Database schema and migrations
├── tests/             # Test files
├── public/            # Static assets
├── .env.example       # Environment variable template
├── package.json
└── README.md

Step 4: API Endpoint Inventory

List every API endpoint the MVP needs:

Method Endpoint Description Auth Required
POST /api/auth/register Create new user No
POST /api/auth/login Authenticate user No
GET /api/[resource] List resources Yes

Step 5: External Services

List any third-party services required:

  • What it does, why it's needed, what it costs, and the free tier limits

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. 11d ago First seen · 81 lines · 44 tokens per session scan A 2697489ae4fb

Subscribe to this mod's changes

system-architect is a skill published in the GitHub repository Aizaz-Noor/Agent-Startup-Skills (2 stars, last pushed 4mo ago), licensed MIT. It adds 44 tokens to every session and 622 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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