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 agentmods add skills/lexler/skill-factory/hexagonal-architecturenpx skills add lexler/skill-factory --skill hexagonal-architecturegit clone --depth 1 https://github.com/lexler/skill-factoryWrote 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/lexler/skill-factory/hexagonal-architecture)<a href="https://agentmods.dev/skills/lexler/skill-factory/hexagonal-architecture"><img src="https://agentmods.dev/badge/skills/lexler/skill-factory/hexagonal-architecture.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00047 | $0.00765 |
| Opus 5 | $0.00023 | $0.00382 |
| Sonnet 5 | $0.00009 | $0.00153 |
| Haiku 4.5 | $0.00005 | $0.00076 |
Grade A, and why
hexagonal-architecture 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 6d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- hexagonal-architecture — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Hexagonal Architecture
The Core Decision Rule
To decide if something belongs inside or outside the hexagon, ask:
"Does it do I/O or run out-of-process?"
- No → Inside the hexagon (domain or application layer)
- Yes → Outside (adapter)
Critical: Consider ALL dependencies. A component's dependencies disqualify it even if the component itself doesn't do I/O. If it depends on Spring, a database driver, or any framework—it's outside.
Layer Responsibilities
Common misconception: The hexagon is NOT just the domain. The hexagon contains both domain AND application layers. Adapters sit outside.
┌─────────────────────────────────────────┐
│ ADAPTERS (outside) │
│ Web, CLI, Database, External APIs │
│ ┌───────────────────────────────────┐ │
│ │ APPLICATION SERVICES │ │
│ │ ┌─────────────────────────────┐ │ │
│ │ │ DOMAIN │ │ │
│ │ └─────────────────────────────┘ │ │
│ └───────────────────────────────────┘ │
└─────────────────────────────────────────┘
Dependencies flow INWARD only
Domain — Business constraints (what CAN happen). Contains Entities, Value Objects, Domain Services.
Application — Orchestration (HOW things happen). Contains Use Cases, Application Services.
Adapters — Translation to/from external world. Contains Controllers, Repositories, API clients.
Domain defines ports (interfaces). Adapters implement them.
Naming Conventions
- Display/response:
*Viewor*Response→MemberView,OrderResponse - Incoming request:
*Request→CreateMemberRequest - Database entity:
*Dbo→MemberDbo - Domain → DTO:
static from(domain)→MemberView.from(member) - DTO → Domain:
as*()method →request.asMember()
Anti-Patterns
Brittle Interfaces
register(username, password) // Breaks when email required
Use wrapper objects that can evolve without breaking signatures.
Domain Scope Pollution
Third-party types (GoogleUser, StripePayment) leaking into domain. Keep external types in adapters; map to domain types at the boundary.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 6d ago First seen · 87 lines · 47 tokens per session scan A 98f0e5e4515a
hexagonal-architecture is a skill published in the GitHub repository lexler/skill-factory (232 stars, last pushed 10d ago), licensed Apache-2.0. It adds 47 tokens to every session and 765 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 2026-08-30.
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