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/fmflurry/settings-opencode/dotnet-dddnpx skills add fmflurry/settings-opencode --skill dotnet-dddgit clone --depth 1 https://github.com/fmflurry/settings-opencodeWhat 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 | $0.00112 | $0.01712 |
| Opus 5 | $0.00056 | $0.00856 |
| Sonnet 5 | $0.00022 | $0.00342 |
| Haiku 4.5 | $0.00011 | $0.00171 |
Grade A, and why
dotnet-ddd 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.
How it starts
The opening of the file, as written. The whole thing — 109 lines — stays where its author put it; the contents beside it link to each section on GitHub.
dotnet-ddd
Domain-Driven Design guidance for .NET domain code. Makes DDD principles explicit and enforceable for the coder and code-reviewer agents.
When to Activate
- Creating or modifying domain models (entities, value objects, aggregates)
- Adding repositories, factories, or domain services
- Defining or refactoring bounded contexts
- Reviewing domain code for DDD compliance
- Refactoring anemic models toward rich behavior
- Enforcing aggregate invariants or encapsulation rules
Provenance
Content is synthesized from established DDD literature:
- Eric Evans, Domain-Driven Design: Tackling Complexity in the Heart of Software (2003) — "Blue Book"
- Vaughn Vernon, Implementing Domain-Driven Design (2013) — "Red Book"
- Microsoft .NET Architecture guidance (eShop, microservices e-book, CQRS docs)
- Martin Fowler, bliki articles on Anemic Domain Model, Domain Event, etc.
This is a practitioner synthesis, not a verbatim reproduction. Where sources disagree, the Red Book's pragmatic guidance takes precedence for implementation details.
Core Principles
- The domain model is the software. Business logic lives in domain objects, not in services or controllers. (Evans, ch. 1)
- Ubiquitous Language. Code names match the domain expert's vocabulary. No translation layer between business and code. (Evans, ch. 2)
- Bounded Contexts define boundaries. Each context owns its model. Shared types across contexts are a design smell. (Evans, ch. 14)
- Aggregates enforce invariants. All mutations go through the aggregate root. External code never reaches inside. (Vernon, ch. 10)
- Value Objects are immutable and identity-free. They describe characteristics, not things. (Evans, ch. 5)
- Repositories return aggregates, not tables. Persistence is an infrastructure concern. (Vernon, ch. 12)
Tactical Patterns (summary)
| Pattern | One-liner | Reference |
|---|---|---|
| Entity | Has identity; equality by ID, not attributes | tactical-patterns.md § Entity |
| Value Object | No identity; immutable; equality by attributes | tactical-patterns.md § Value Object |
| Aggregate + Root | Consistency boundary; root is sole entry point | tactical-patterns.md § Aggregate |
| Repository | Collection-like abstraction over aggregates | tactical-patterns.md § Repository |
| Factory | Encapsulates complex creation logic | tactical-patterns.md § Factory |
| Specification | Reusable, composable query/predicate logic | tactical-patterns.md § Specification |
| Domain Service | Stateless logic that doesn't belong to an entity | tactical-patterns.md § Domain Service |
| Rich vs Anemic | Behavior lives with data, not in external services | tactical-patterns.md § Rich vs Anemic |
What ships with it
3 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.
- 2d ago First seen · 109 lines · 112 tokens per session scan A 556633ee6b5b
dotnet-ddd is a skill published in the GitHub repository fmflurry/settings-opencode (171 stars, last pushed 20d ago), licensed MIT. It adds 112 tokens to every session and 1,712 once invoked, about $0.0006 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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