ddd

ddd is a skill for Claude Code, Codex from svngoku/coding-agents-skills. It costs 137 tokens per session (1,334 once invoked), scanned A, original, MIT.

A software design guide based on Domain-Driven Design, an approach that structures code around the real business concepts and processes it represents.

In plain words
What is it for?
Designing systems, refactoring code, creating entities and data-access structures, mapping parts of a business, running Event Storming workshops, and reviewing domain-focused code.
Why use it?
It helps prevent business rules from becoming scattered or unclear as a system grows, and gives teams a shared way to divide and name the software.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Install

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.

agentmods
npx agentmods add skills/svngoku/coding-agents-skills/ddd
Any agent
npx skills add svngoku/coding-agents-skills --skill ddd
Clone the repo
git clone --depth 1 https://github.com/svngoku/coding-agents-skills

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for ddd

README.md
[![agentmods](https://agentmods.dev/badge/skills/svngoku/coding-agents-skills/ddd.svg)](https://agentmods.dev/skills/svngoku/coding-agents-skills/ddd)
Your own site
<a href="https://agentmods.dev/skills/svngoku/coding-agents-skills/ddd"><img src="https://agentmods.dev/badge/skills/svngoku/coding-agents-skills/ddd.svg" alt="Measured on agentmods" height="20"></a>
Per session 137 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,334 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00137 $0.01334
Opus 5 $0.00068 $0.00667
Sonnet 5 $0.00027 $0.00267
Haiku 4.5 $0.00014 $0.00133

Measured 5d ago against content hash 90b9411e7e62, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

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 5d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (graders/check.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/ddd/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Domain-Driven Design Skill

Apply DDD to build software that reflects deep understanding of the business domain.

Quick Reference

Task Reference
Bounded contexts, subdomains, context maps strategic-design.md
Entities, value objects, aggregates, repositories tactical-design.md
Hexagonal, CQRS, Event Sourcing, Clean Architecture architecture-patterns.md
Event Storming facilitation & documentation event-storming.md
Python implementations (Pydantic, SQLAlchemy, FastAPI) python-patterns.md
TypeScript implementations (NestJS, TypeORM, Prisma) typescript-patterns.md
DDD code review criteria code-review.md

Core Workflow

1. Identify the Task Type

Designing new system? → Start with strategic design, then tactical Refactoring existing code? → Assess current state, identify bounded contexts, refactor incrementally Generating scaffolding? → Determine patterns needed, generate code Event Storming? → Follow facilitation guide Code review? → Apply DDD checklist

2. Strategic Before Tactical

Always establish strategic design first:

  1. Identify subdomains (Core, Supporting, Generic)
  2. Define bounded contexts and their boundaries
  3. Map context relationships (upstream/downstream, conformist, ACL, etc.)
  4. Establish ubiquitous language per context

3. Select Architecture Pattern

Choose based on domain complexity and requirements:

Pattern When to Use
Layered Simple CRUD, low complexity
Hexagonal Need to isolate domain from infrastructure
Clean Architecture Complex business rules, multiple delivery mechanisms
CQRS Different read/write models, complex queries
Event Sourcing Audit trail required, temporal queries, event-driven

Read the full file on GitHub · 130 lines

Changes

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.

  1. 5d ago First seen · 130 lines · 137 tokens per session scan A 90b9411e7e62

Subscribe to this mod's changes

ddd is a skill published in the GitHub repository svngoku/coding-agents-skills (9 stars, last pushed 23d ago), licensed MIT. It adds 137 tokens to every session and 1,334 once invoked, about $0.0007 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.