# Principle Model The Domain

> Replace scattered state booleans, repeated shape assumptions, and branching with the smallest structure that encodes the real domain and its invariants.

- Skill: `njs14/principle-model-the-domain` (Agent Skill)
- Install (CLI): `npx skillmds@latest add njs14/principle-model-the-domain`
- Raw SKILL.md: https://api.skillmd.com/api/skills/njs14/principle-model-the-domain/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: njs14 (https://skillmd.com/u/njs14)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/njs14/principle-model-the-domain

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# Encode the domain

Treat the request text that activated this skill as the domain behavior to model.

Apply [model the domain](../pkstack-principles/references/catalog.md#model-the-domain). List valid states,
transitions, and access patterns, then choose a state machine, variant type, registry, command model,
or simpler local structure that makes invalid combinations difficult to construct. Return the model
and the branches or synchronized flags it replaces.