# Craft Model State

> Crafting model states. Explicit state machines.

- Skill: `attac-t/craft-model-state` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add attac-t/craft-model-state`
- Raw SKILL.md: https://api.skillmd.com/api/skills/attac-t/craft-model-state/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: attac-t (https://skillmd.com/u/attac-t)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/attac-t/craft-model-state

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# Skill: Craft Model State

> "States are not strings. They are behavior."

## The Standard

1. **Abstract Base**: One per entity. Defines `config()` with transitions.
2. **Concrete States**: One class per state. Behavior lives here.
3. **Custom Transitions**: Side effects in transition classes, not models.
4. **Co-location**: `Domain/Entity/States/`, not `App/States/`.

## The Anti-Patterns

| ❌ Don't | ✅ Do | Why |
|----------|-------|-----|
| Enum for stateful behavior | State classes | Behavior belongs with state |
| Transitions in model | Custom transition classes | Single responsibility |
| Fat abstract state | Thin base, behavior in concrete | Each state is unique |

## Real-World Examples

See [examples.md](examples.md).