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 rules/b-fontaine/devoxx-2026/rust-hexagonalgit clone --depth 1 https://github.com/b-fontaine/devoxx-2026What 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 | $0.00000 | $0.00369 |
| Opus 5 | $0.00000 | $0.00185 |
| Sonnet 5 | $0.00000 | $0.00074 |
| Haiku 4.5 | $0.00000 | $0.00037 |
Grade A, and why
rust-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 2d 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.
What it actually says
Rust Architecture Hexagonale
Structure
backend/src/
├── domain/ # Ports (traits) + entités + erreurs
├── application/ # Use cases (orchestration)
└── infrastructure/ # Adaptateurs gRPC + persistence
Domain (le cœur, zéro dépendance externe)
- Entités : structs simples, dérivant Clone, Debug, PartialEq
- Ports : traits async définissant les contrats
- Erreurs : enum DomainError avec thiserror
#[async_trait]
pub trait AnomalyRepository: Send + Sync {
async fn save(&self, report: AnomalyReport) -> Result<ReportId, DomainError>;
async fn find_by_id(&self, id: &ReportId) -> Result<Option<AnomalyReport>, DomainError>;
}
Application (use cases)
- Un struct par use case, injecte les ports via constructeur
- Retourne Result<T, DomainError>
- Pas de dépendance vers infrastructure
Infrastructure (adaptateurs)
- gRPC : implémentation des services tonic, conversion proto ↔ domain via From/Into
- Persistence : implémentation des traits Repository avec sea-orm
- Chaque adaptateur dans son propre module
Conventions
- Pas d'unwrap() en dehors des tests
- cargo clippy -- -D warnings doit passer sans erreur
- Tests unitaires dans le même fichier (#[cfg(test)] mod tests)
- Tests d'intégration dans tests/
- Mocking avec mockall : #[automock] sur les traits du domain
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.
- 2d ago First seen · 46 lines · 0 tokens per session scan A d4c8612a0f58
rust-hexagonal is a cursor rule published in the GitHub repository b-fontaine/devoxx-2026 (5 stars, last pushed 4mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 369 tokens. 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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