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.
npx skills add secondsky/claude-skills --skill architecture-patternsgit clone --depth 1 https://github.com/secondsky/claude-skillsWrote 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.
[](https://agentmods.dev/skills/secondsky/claude-skills/architecture-patterns)<a href="https://agentmods.dev/skills/secondsky/claude-skills/architecture-patterns"><img src="https://agentmods.dev/badge/skills/secondsky/claude-skills/architecture-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.
<a href="https://agentmods.dev/skills/secondsky/claude-skills/architecture-patterns"><img src="https://agentmods.dev/badge/skills/secondsky/claude-skills/architecture-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00040 | $0.02053 |
| Opus 5.5 | $0.00016 | $0.00821 |
| Sonnet 5.5 | $0.00008 | $0.00411 |
| Haiku 4.5 | $0.00004 | $0.00205 |
Grade A, and why
architecture-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 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.
This is a copy
91% identical to architecture-patterns — 217 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.
How it starts
The opening of the file, as written. The whole thing — 302 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Architecture Patterns
Master proven backend architecture patterns including Clean Architecture, Hexagonal Architecture, and Domain-Driven Design to build maintainable, testable, and scalable systems.
When to Use This Skill
- Designing new backend systems from scratch
- Refactoring monolithic applications for better maintainability
- Establishing architecture standards for your team
- Migrating from tightly coupled to loosely coupled architectures
- Implementing domain-driven design principles
- Creating testable and mockable codebases
- Planning microservices decomposition
Core Concepts
1. Clean Architecture (Uncle Bob)
Layers (dependency flows inward):
- Entities: Core business models
- Use Cases: Application business rules
- Interface Adapters: Controllers, presenters, gateways
- Frameworks & Drivers: UI, database, external services
Key Principles:
- Dependencies point inward
- Inner layers know nothing about outer layers
- Business logic independent of frameworks
- Testable without UI, database, or external services
2. Hexagonal Architecture (Ports and Adapters)
Components:
- Domain Core: Business logic
- Ports: Interfaces defining interactions
- Adapters: Implementations of ports (database, REST, message queue)
Benefits:
- Swap implementations easily (mock for testing)
- Technology-agnostic core
- Clear separation of concerns
3. Domain-Driven Design (DDD)
Strategic Patterns:
- Bounded Contexts: Separate models for different domains
- Context Mapping: How contexts relate
- Ubiquitous Language: Shared terminology
Tactical Patterns:
- Entities: Objects with identity
- Value Objects: Immutable objects defined by attributes
- Aggregates: Consistency boundaries
- Repositories: Data access abstraction
- Domain Events: Things that happened
Clean Architecture Pattern
Directory Structure
app/
├── domain/ # Entities & business rules
│ ├── entities/
│ ├── value_objects/
│ └── interfaces/ # Abstract interfaces
├── use_cases/ # Application business rules
├── adapters/ # Interface implementations
│ ├── repositories/
│ ├── controllers/
│ └── gateways/
└── infrastructure/ # Framework & external concerns
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.
- 1mo ago First seen · 302 lines · 40 tokens per session scan A eb5eda069baa
architecture-patterns is a skill published in the GitHub repository secondsky/claude-skills (237 stars, last pushed yesterday), licensed MIT. It adds 40 tokens to every session and 2,053 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 91% identical to architecture-patterns, differing in 217 lines, and is treated as a copy.
Other skills, from other repositories
decide
A reusable decision procedure, and a copyable prototype for the guard that encodes it — derive the population, set one threshold by what being wrong costs, name the offender, and break it once to prove it can fail. Use when writing a check, guard, gate or validation of any kind, or when deciding whether something is…
remember
Record why something is the way it is — a decision and its reasoning, a lesson that cost time, or a standing constraint. Use when the reasoning behind a choice would be expensive to reconstruct later.
bootstrap
Set up chamnan in this repository for the first time — build the architecture index, measure how well the code describes itself, fill in missing file comments, and record a baseline. Run once per repo.
resume
Write down where this stretch of work stopped, so the next session continues instead of restarting. Use at the end of a working session, or when handing the repository to someone else.
review
Review a change with what this repository knows about it — who depends on the file, which tests cover it, what broke here before, and what the repo has written down. Use before approving a diff, opening a PR, or when asked to review.
milestone
Record a change that reshaped the repository — what moved, why it was worth doing, and which areas it touched. Use after a migration, a rewrite, or a decision that changed how part of the system works.