domain-modeling

Files (4)

• ADR-FORMAT.md
• GLOSSARY-FORMAT.md
• SKILL.md
• visual-glossary.html · resources/

SKILL.md (first lines)

# Domain Modeling

Actively build and sharpen the project's domain model as you design. This is the *active* discipline — challenging terms, inventing edge-case scenarios, and writing the glossary and decisions down the moment they crystallise. (Merely *reading* `docs/glossary.md` for vocabulary is not this skill — that's a one-line habit any skill can do. This skill is for when you're changing the model, not just consuming it.)

## File structure

Most repos have a single context:

```
/
├── docs/
│   ├── glossary.md
│   ├── visual-glossary.html
│   └── adr/
│       ├── 0001-event-sourced-orders.md
│       └── 0002-postgres-for-write-model.md
└── src/
```

If a `docs/glossary-map.md` exists, the repo has multiple contexts. The map points to where each one lives:

```
/
├── docs/
│   ├── glossary-map.md
│   ├── adr/                          ← system-wide decisions
│   └── ordering/
│       ├── glossary.md
│       └── adr/                      ← context-specific decisions
```

Create files lazily — only when you have something to write. If no `docs/glossary.md` exists, create one when the first term is resolved. If no `docs/adr/` exists, create it when the first ADR is needed.

## During the session

### Challenge against the glossary

When the user uses a term that conflicts with the existing language in `docs/glossary.md`, call it out immediately. "Your glossary defines 'cancellation' as X, but you seem to mean Y — which is it?"

### Sharpen fuzzy language

When the user uses vague or overloaded terms, propose a precise canonical term. "You're saying 'account' — do you mean the Customer or the User? Those are different things."

### Discuss concrete scenarios

When domain relationships are being discussed, stress-test them with specific scenarios. Invent scenarios that probe edge cases and force the user to be precise about the boundaries between concepts.

### Cross-reference with code

When the user states how something works, check whether the code agrees. If you find a contradiction, surface it: "Your code cancels entire Orders, but you just said partial cancellation is possible — which is right?"

### Update docs/glossary.md inline

When a term is resolved, update `docs/glossary.md` right there. Don't batch these up — capture them as they happen. Use the format in [GLOSSARY-FORMAT.md](./GLOSSARY-FORMAT.md).

After updating `docs/glossary.md` or adding/modifying any ADR in `docs/adr/`, you MUST also update the global visual glossary (`docs/visual-glossary.html`) to sync with the changes:
1. Copy `skills/domain-modeling/resources/visual-glossary.html` (located relative to repository root) to `docs/visual-glossary.html`.
2. Format all current terms and ADRs into their respective placeholder markers (`<!-- VG:GLOSSARY -->` and `<!-- VG:ADR -->`).
3. Dual-write the updated HTML directly to system artifacts directory as `01_visual-glossary.html` (making it visible in the Artifacts tab).

`docs/glossary.md` should be totally devoid of implementation details. Do not treat `docs/glossary.md` as a spec, a scratch pad, or a repository for implementation decisions. It is a glossary and nothing else.

### Offer ADRs sparingly

Only offer to create an ADR when all three are true:

1. **Hard to reverse** — the cost of changing your mind later is meaningful
2. **Surprising without context** — a future reader will wonder "why did they do it this way?"
3. **The result of a real trade-off** — there were genuine alternatives and you picked one for specific reasons

If any of the three is missing, skip the ADR. Use the format in [ADR-FORMAT.md](./ADR-FORMAT.md).

From sapientcoffee/bean-roaster, Apache-2.0.

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