Domain Modeling

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 the glossary 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.)

The domain model lives in two places:

• Glossary — docs/glossary/, one markdown file per term, in the format uvx disambiguate expects (see below). Never a root CONTEXT.md.
• Decisions — ADRs in docs/adr/, per the writing-adrs skill.

Glossary entries, ADRs, docs: as short as possible, caveman mode preferred (caveman skill) — precision and understandability must not suffer.

Create files lazily — only when you have something to write. If docs/glossary/ doesn't exist, create it when the first term is resolved.

During the session

Challenge against the glossary

When the user uses a term that conflicts with the existing language in docs/glossary/, 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 the glossary inline

When a term is resolved, write its glossary file right there. Don't batch these up — capture them as they happen.

Glossary entries must be totally devoid of implementation details. The glossary is not 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 the three-part bar in the writing-adrs skill is met (hard to reverse, surprising without context, the result of a real trade-off). Format, numbering, and location also come from writing-adrs.

Glossary entry format

One file per term in docs/glossary/, consumable by uvx disambiguate:

• Filename is the slug: lowercase letters, digits, single hyphens (order-line.md → slug order-line). Slugs must be unique.
• First H2 is the canonical name (mandatory): ## Order Line.
• Body is free-form markdown: one or two tight sentences defining what the term IS, not what it does. When multiple words exist for the same concept, pick the best one and list the others under _Avoid_:.
• Cross-reference related terms with standard markdown links by basename ([Customer](customer.md)) or wiki-style ([[customer]]). These links form the dependency graph disambiguate renders in topological order — a term that builds on another must link it.

Example docs/glossary/invoice.md:

## Invoice

A request for payment sent to a [Customer](customer.md) after delivery.

_Avoid_: Bill, payment request

Rules:

• Be opinionated. One canonical term per concept; competing words go under _Avoid_.
• Only include terms specific to this project's context. General programming concepts (timeouts, error types, utility patterns) don't belong even if the project uses them extensively.
• Validate with uvx disambiguate --lint after editing.