architecture-anti-patterns

architecture-anti-patterns is a skill for Claude Code from sethdford/claude-skills. It costs 28 tokens per session (757 once invoked), scanned A, original, MIT.

A guide to architectural anti-patterns—recurring design choices that make software fragile, tangled, or difficult to change.

In plain words
What is it for?
Use it when reviewing a system design, diagnosing growing complexity, or learning how to avoid common structural failures.
Why use it?
It helps reviewers recognize problems such as one class doing too much, circular dependencies, shared database schemas, and premature scaling.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the architect-toolkit plugin — 7 skills shipped together

Good fit Use it when reviewing a system design, diagnosing growing complexity, or learning how to avoid common structural failures.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sethdford/claude-skills/architecture-anti-patterns
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 sethdford/claude-skills --skill architecture-anti-patterns
Clone the repo
git clone --depth 1 https://github.com/sethdford/claude-skills

Made for: Claude Code.

Or install architect-toolkit, the plugin that ships this one along with the rest of its 7 skills.

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 architecture-anti-patterns

README.md
[![agentmods](https://agentmods.dev/badge/skills/sethdford/claude-skills/architecture-anti-patterns/github.svg)](https://agentmods.dev/skills/sethdford/claude-skills/architecture-anti-patterns)
Your own site
<a href="https://agentmods.dev/skills/sethdford/claude-skills/architecture-anti-patterns"><img src="https://agentmods.dev/badge/skills/sethdford/claude-skills/architecture-anti-patterns/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 architecture-anti-patterns

Your own site · 80×15
<a href="https://agentmods.dev/skills/sethdford/claude-skills/architecture-anti-patterns"><img src="https://agentmods.dev/badge/skills/sethdford/claude-skills/architecture-anti-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 757 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 $0.00028 $0.00757
Opus 5 $0.00014 $0.00378
Sonnet 5 $0.00006 $0.00151
Haiku 4.5 $0.00003 $0.00076

Measured 11d ago against content hash 7b8d6785cf98, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

architecture-anti-patterns 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.

architect/architect-toolkit/skills/architecture-anti-patterns/SKILL.md · 53 lines

How it starts

The opening of the file, as written. The whole thing — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Architecture Anti-Patterns

Recognize and avoid common architectural mistakes that lead to fragility, complexity, or failure.

Context

You are reviewing an architecture and want to spot common anti-patterns. Patterns of failure repeat across organizations. Learn them, recognize them, guide teams away from them.

Domain Context

Based on architecture and design anti-patterns research:

  • God Object: One class/service responsible for too much. Hard to change, test, understand.
  • Big Ball of Mud: No clear architecture. Code accretion with no structure. Hard to modify without breaking things.
  • Circular Dependency: A depends on B, B depends on A. Can't use A without B, vice versa. Breaks modularity.
  • Database as Integration Point: Services share database schema. Schema changes break all services. No independence.
  • Premature Optimization: Design for 10x scale when you have 1x. Overcomplex, unmaintainable.

Instructions

  1. Common Anti-Patterns and Recognition:

    • Monolith Bloat: Hundreds of thousands of lines in one service. Deploys take 30 min. Hard to test. Fix: decompose into services by business domain.
    • Tight Coupling: Service A calls Service B calls Service C synchronously. Cascade failure: A down → B unavailable → C affected. Fix: async, timeouts, circuit breakers, fallbacks.
    • No Logging/Monitoring: Don't know what's happening in production. Outage takes hours to debug. Fix: structured logging, metrics, distributed tracing, alerts.
    • Cache Invalidation Chaos: Cache stale data, inconsistency everywhere. Fix: cache strategy with TTL, event-driven invalidation, don't cache mutable shared state.
    • N+1 Query Problem: Loop calls database for each item. 1000 items = 1000 queries. Fix: batch queries, join tables, fetch aggregates.
  2. Diagnose When Present:

    • Performance issues in service you don't touch? Likely tight coupling or cascade failure.
    • Hard to understand request path? Likely circular dependencies or god objects.
    • Frequent outages from unrelated changes? Likely shared database or tight coupling.

Read the full file on GitHub · 53 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 · 53 lines · 28 tokens per session scan A 7b8d6785cf98

Subscribe to this mod's changes

architecture-anti-patterns is a skill published in the GitHub repository sethdford/claude-skills (40 stars, last pushed 6mo ago), licensed MIT. It adds 28 tokens to every session and 757 once invoked, about $0.0001 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 2026-08-30.