# layers-domain

A technique library for mapping real-world domain concepts, terminology clashes, and bounded contexts before shaping a product.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1900 installs · ★ 313
- Author: jamiemill
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/jamiemill/layers-skills/tree/HEAD/skills/layers-domain/SKILL.md
- Updated: 2026-05-30
- HTML: https://affpapa.org/en/nevibecode/skills/layers-domain

## What it does

The skill outlines methods for examining how a domain works independently of any software. It details techniques such as concept maps, terminology audits, bounded-context mapping, and noun harvesting. The goal is observation rather than product design.

Its core discipline requires recording contradictions instead of resolving them early. When two teams use the same term for different concepts, the skill documents that polysemy as raw data. It also separates true objects from mere instances.

Working with the skill requires loading `/layers-intro` first. In projects where the domain is already uncontested, teams skip this layer to move straight ahead. The resulting noun harvest feeds directly into `/layers-conceptual-model`.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add jamiemill/layers-skills --skill layers-domain -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/layers-domain/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/layers-domain/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add jamiemill/layers-skills --skill layers-domain -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/layers-domain/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add jamiemill/layers-skills --skill layers-domain -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/layers-domain/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install jamiemill/layers-skills layers-domain
```

2. **Manually: put the files in place**
- File: `.github/skills/layers-domain/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add jamiemill/layers-skills --skill layers-domain -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/jamiemill/layers-skills --path skills/layers-domain
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/layers-domain/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add jamiemill/layers-skills --skill layers-domain -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/jamiemill/layers-skills/tree/HEAD/skills/layers-domain/SKILL.md

## When to use it
- audit domain vocabulary for synonyms and polysemy
- map relationships between concepts without forcing premature structure
- isolate bounded contexts across different user groups
- compile a classified noun harvest for conceptual modeling
- trace process sequences using domain event storming

## Example prompts
- Load /layers-domain and help me run a terminology audit for our domain
- Use /layers-domain to build a concept map and extract candidate nouns
- Run domain event storming with /layers-domain for our order fulfillment flow

## Source text · SKILL.md · MIT

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BEGIN THIRD-PARTY FILE f097fe5b3b14ba2f
```text
---
name: layers-domain
description: Techniques for mapping a domain's concepts, terminology conflicts, and bounded contexts — the raw material the conceptual model is built from
---

# /layers-domain

*Assumes `/layers-intro` has been loaded. This skill is a library of techniques, not a script — see "How to use these skills" there.*

The domain layer maps what exists in the real world independently of any product: the concepts, terminology, processes, relationships, and mental models users bring with them. This is observation, not design.

---

## The decisions this layer makes

- What the key concepts in this domain are, and how they relate
- What language people use — and where it conflicts or diverges
- Where the natural seams are: communities that use the same words differently
- What events and processes structure the domain's activity over time

If the domain is already well understood and uncontested, you may not need this layer — go straight to the conceptual model.

---

## Disciplines — what keeps domain work honest

- **Don't resolve contradictions — record them.** Messy, inconsistent domain language is *data*: it signals where communities have diverged and where the product will later have to choose. Resolution belongs to the conceptual model, not here. Capture **synonyms** (same thing, different names) and **polysemy** (same name, different things in different contexts) as findings, not problems.
- **Stay in the real world.** Push back whenever answers drift toward product or interface decisions. The question is always how the domain works *before* your product enters it.
- **Real objects vs instances** (for the noun harvest). A true object is *instanceable* (you can have many), *structured* (has its own attributes), and *useful* (people care about it in its own right). Watch for instances mistaken for objects: "CAC", "ROAS", "LTV" aren't objects, they're instances of one object, **Metric**. Mark each noun *object / attribute / instance-or-value / unclear* — and don't filter aggressively; the conceptual model does the sorting.
- **Beliefs vs reality.** If you're mapping what the team believes rather than researched fact, say so throughout — it's the team's model, not necessarily how users experience the domain.

---

## Techniques

Pick what fits — concept mapping plus a terminology audit is the usual core.

| Technique | Use it when |
|---|---|
| **Concept maps / bubble diagrams** (`graph TD`/`LR`) | The domain is complex and poorly understood. Informal nodes-and-lines show how concepts relate without forcing premature structure. |
| **Terminology audit** | Capture, per concept: the names used, who uses which and when, and whether the conflict is synonymy or polysemy. Don't pick a winner. |
| **Bounded-context mapping** | Communities share vocabulary internally but diverge across groups. Name and describe each seam — it will matter when the model is defined. |
```
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