# Eric Domain Modeling

> Apply when designing or reviewing business models, state machines, business rules, domain ownership, or side-effect boundaries in any language.

- Skill: `akarachen/eric-domain-modeling` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add akarachen/eric-domain-modeling`
- Raw SKILL.md: https://api.skillmd.com/api/skills/akarachen/eric-domain-modeling/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: akarachen (https://skillmd.com/u/akarachen)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/akarachen/eric-domain-modeling

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# Eric Domain Modeling

- Model business states and legal transitions explicitly. Commands produce plans/effects, events update state, and adapters perform external work.
- Organize code by feature slice: keep each business feature's models, rules, and use cases together rather than splitting the whole project into technical-layer folders. Within each slice, keep business decisions in the core and side effects in adapters.
- Introduce abstractions only for a real second implementation, test boundary, or ownership boundary.