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 ccheney/robust-skills --skill clean-ddd-hexagonalgit clone --depth 1 https://github.com/ccheney/robust-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/ccheney/robust-skills/clean-ddd-hexagonal)<a href="https://agentmods.dev/skills/ccheney/robust-skills/clean-ddd-hexagonal"><img src="https://agentmods.dev/badge/skills/ccheney/robust-skills/clean-ddd-hexagonal/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/ccheney/robust-skills/clean-ddd-hexagonal"><img src="https://agentmods.dev/badge/skills/ccheney/robust-skills/clean-ddd-hexagonal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector 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 | $0.00049 | $0.00748 |
| Opus 5.5 | $0.00020 | $0.00299 |
| Sonnet 5.5 | $0.00010 | $0.00150 |
| Haiku 4.5 | $0.00005 | $0.00075 |
Grade A, and why
clean-ddd-hexagonal 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.
How it starts
The opening of the file, as written. The whole thing — 49 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Clean Architecture, DDD, and Hexagonal Architecture
Use these related patterns to solve a concrete domain or dependency problem. This is an opinionated synthesis, not a mandatory folder layout. The user's explicit instructions take precedence over this skill's guidelines.
Choose the scope
Start from the requested behavior, existing domain model, and current dependencies. Preserve the project's language and architecture unless changing them is part of the task. Simple CRUD can remain simple; team size, entity count, and file length do not determine whether DDD is appropriate.
| Design question | Relevant pattern |
|---|---|
| What language and consistency rules describe the business? | DDD, bounded contexts, aggregates |
| Which way should source dependencies point? | Clean/Onion Architecture |
| How can the application use different interfaces or infrastructure? | Hexagonal ports and adapters |
| Do reads and writes need different models? | CQRS |
| Must state be reconstructed from an event history? | Event Sourcing |
If a business invariant is unknown, identify the specific missing rule and continue work that does not depend on it. Do not invent business behavior or require a discovery workshop for a local fix.
Preserve the boundaries that matter
- Keep domain behavior independent of HTTP, persistence, and messaging implementations. Put orchestration in application use cases and external I/O in adapters.
- Model entity identity separately from value-object equality. Choose aggregate boundaries from transactional invariants and contention.
- Prefer transactions contained within an aggregate. When a requirement needs cross-aggregate atomicity, make that tradeoff explicit rather than silently replacing it with eventual consistency.
- Use an outbox when a committed database change and external event delivery must be reliable together.
- Treat CQRS, Event Sourcing, repository interfaces, and separate presentation folders as choices justified by the task. Adapt example naming and directories to the project.
What ships with it
7 files 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.
- 1mo ago Changed · -164 lines · -71 tokens per session 6b719ae95e3b
- 1mo ago First seen · 213 lines · 120 tokens per session scan A 5b7dcd3f34d5
clean-ddd-hexagonal is a skill published in the GitHub repository ccheney/robust-skills (61 stars, last pushed 21d ago), licensed MIT. It adds 49 tokens to every session and 748 once invoked, about $0.0002 per session on Opus 5.5. 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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