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 xonovex/platform --skill ddd-guidegit clone --depth 1 https://github.com/xonovex/platformWrote 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/xonovex/platform/ddd-guide)<a href="https://agentmods.dev/skills/xonovex/platform/ddd-guide"><img src="https://agentmods.dev/badge/skills/xonovex/platform/ddd-guide/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/xonovex/platform/ddd-guide"><img src="https://agentmods.dev/badge/skills/xonovex/platform/ddd-guide.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00114 | $0.00856 |
| Opus 5.5 | $0.00046 | $0.00342 |
| Sonnet 5.5 | $0.00023 | $0.00171 |
| Haiku 4.5 | $0.00011 | $0.00086 |
Grade A, and why
ddd-guide 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 — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Domain-Driven Design
Find the boundaries in a domain, name everything inside them rigorously, and model each boundary with building blocks that keep business invariants honest. Strategic design draws the map; tactical design fills it in.
Essentials
- Build one ubiquitous language per context - bind agreed terms into both the model and the code, see references/strategic-design.md
- Draw bounded contexts before classes - each context is a boundary of model consistency where words mean exactly one thing, see references/strategic-design.md
- Map contexts and shield with an anti-corruption layer - translate foreign models both directions into your own terms, see references/strategic-design.md
- Distinguish entity from value object - identity-over-time versus defined-by-attributes-and-immutable, see references/tactical-building-blocks.md
- Keep aggregates small with one root - protect true invariants in a transaction, reference other aggregates by id, see references/tactical-building-blocks.md
- Hand whole aggregates through a repository - persistence-ignorant, collection-like access to roots only, see references/tactical-building-blocks.md
Gotchas
- A bounded context is not a microservice or a subdomain: it is a solution-space model boundary; a subdomain is a problem-space area; a service is a deployment unit. They often align but are not the same thing.
- Ubiquitous language is not "a glossary". It only counts when the agreed terms live in the model AND the code; a wiki nobody compiles against is not a ubiquitous language.
- A thin ORM/DAO wrapper is not a repository, and an upstream-API client is not an anti-corruption layer: a repository hands out whole aggregate roots and is persistence-ignorant; an ACL translates foreign concepts both directions, not just forwards calls.
- Code-level coupling metrics belong to connascence-guide, class/inheritance mechanics to oop-guide, and undo/serialization machinery to data-model-guide: DDD names the domain boundaries, not those.
What ships with it
6 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 First seen · 47 lines · 114 tokens per session scan A d386d2461646
ddd-guide is a skill published in the GitHub repository xonovex/platform (6 stars, last pushed 4d ago), licensed MIT. It adds 114 tokens to every session and 856 once invoked, about $0.0005 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 2026-09-08.
Other skills, from other repositories
harbor-daytona
Use Harbor's Daytona sandbox platform for computer use — creating sandboxes, taking screenshots, sending mouse/keyboard input, and building agent loops. Use when the user wants to interact with a GUI, automate a desktop, do computer use, control a browser visually, or run Claude computer use against a Daytona sandbox.
docker
Use when authoring or auditing a Dockerfile, shrinking a bloated image, hardening a container that runs as root, picking a base image, or wiring a Compose dev loop with hot reload. NOT CI builds or deploy-to-host (that is deployment), NOT k8s autoscaling (that is scaling), NOT app-level injection or secrets-in-code…
kastell
Server security auditing, hardening, and fleet management. 457 security checks across 30 categories (SSH, Firewall, Docker, TLS, HTTP Headers), CIS/PCI-DSS/HIPAA compliance mapping, 24-step production hardening, and 13 MCP tools. Supports Hetzner, DigitalOcean, Vultr, and Linode with Coolify, Dokploy, and bare VPS…
ilo
Run builds, tests, and other tooling inside a reproducible, containerized dev environment via the ilo CLI instead of on the host. Use this whenever a project relies on ilo, devcontainers, or container-based build environments — it has a .ilo.rc / .ilo/ilo.rc, dev/ argument files, a Containerfile/Dockerfile, a…
docker-compose-local-setup
Creates or updates local multi-service orchestration using docker compose. Covers compose.yaml design, service health checks, dependson readiness, env files, named volumes, migrations/seeds jobs, verification commands, and cleanup workflows for local development.
compose
A guide to Docker Compose, a tool for defining and running applications made of multiple containers, such as a web app, API, and database.