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 helmedeiros/clean-code-skills --skill hexagonal-domain-isolationgit clone --depth 1 https://github.com/helmedeiros/clean-code-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/helmedeiros/clean-code-skills/hexagonal-domain-isolation)<a href="https://agentmods.dev/skills/helmedeiros/clean-code-skills/hexagonal-domain-isolation"><img src="https://agentmods.dev/badge/skills/helmedeiros/clean-code-skills/hexagonal-domain-isolation.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 | $0.00051 | $0.00860 |
| Opus 5 | $0.00026 | $0.00430 |
| Sonnet 5 | $0.00010 | $0.00172 |
| Haiku 4.5 | $0.00005 | $0.00086 |
Grade A, and why
hexagonal-domain-isolation 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 7d 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.
How it starts
The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Hexagonal Architecture: Domain Isolation
Protect the domain model from infrastructure, framework, and external system concerns by enforcing strict boundaries that keep business logic pure and independent.
When This Skill Applies
- Domain objects contain serialization annotations, ORM decorators, or framework dependencies
- Business logic changes when an external API contract changes
- The domain model mirrors a database schema instead of business concepts
- The user mentions domain isolation, anti-corruption layer, or clean domain
- Framework upgrades require modifying business logic
Core Principle
The domain model represents business concepts and rules in their purest form. It must not be contaminated by infrastructure concerns like database schemas, serialization formats, API contracts, or framework conventions. An anti-corruption layer (ACL) translates between the domain's language and external systems' languages, ensuring the domain remains stable even when external systems change.
Workflow
Step 1: Audit Domain Dependencies
Check what the domain module imports. Any import from an infrastructure, framework, or external library is a boundary violation. The domain should depend only on the language's standard library and its own types.
Step 2: Identify Contamination
Look for: ORM annotations on domain entities, JSON serialization attributes, framework base classes, external API types used in domain logic, database column names influencing domain field names.
Step 3: Introduce Translation Layers
Create separate models for each boundary:
- Domain model: pure business objects.
- Persistence model: ORM entities that map to database tables.
- API model: DTOs that match external API contracts.
Mappers translate between these models at the boundary.
Step 4: Build the Anti-Corruption Layer
For external systems whose model differs from yours, create an ACL that translates their concepts into your domain language. The ACL adapter implements a domain port.
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.
- 7d ago First seen · 103 lines · 51 tokens per session scan A 3ac9599fe5d5
hexagonal-domain-isolation is a skill published in the GitHub repository helmedeiros/clean-code-skills (2 stars, last pushed 6mo ago), licensed MIT. It adds 51 tokens to every session and 860 once invoked, about $0.0003 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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