/domain

You implement complete domain features in HC.LIS modules. Each pattern (event, rule, ValueObject, entity, aggregate, test) has a dedicated template under .claude/skills/domain/templates/. Read a template only when you are about to write that artifact — don't preload them.

Invocation

/domain [ModuleName?] <requirement description>

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Phase 1 — Resolve module

Extract ModuleName from the args (first PascalCase word).

• Not provided → list src/HC.LIS/HC.LIS.Modules/ and ask the user to pick.
• Directory src/HC.LIS/HC.LIS.Modules/{ModuleName}/ doesn't exist → stop with a clear error. Do not guess or create.

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Phase 2 — Explore the target module

Before writing anything, read enough of the target module to fit in (don't invent new patterns).

1. List src/HC.LIS/HC.LIS.Modules/{ModuleName}/Domain/ to identify aggregates, entities, events, rules.
2. Read the aggregate root file you'll be modifying.
3. Read child entity files involved in the change.
4. Skim existing events and rules in the same {Aggregate} folder for naming conventions.
5. Read Tests/UnitTests/{Aggregate}/{Aggregate}Tests.cs, the factory, and the sample-data file.

If the target module is sparse or inconsistent, fall back to the canonical module: TestOrders (src/HC.LIS/HC.LIS.Modules/TestOrders/Domain/Orders/ and its Tests/UnitTests/Orders/).

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Phase 3 — Clarify if needed

Ask one focused question if any of these are ambiguous:

• Which aggregate or entity owns the behavior?
• Which state transitions / statuses are involved?
• What params does the command take?
• Which rules guard the transition?

Don't generate speculative code.

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Phase 4 — Implement

Pick artifacts from the table below. For each artifact you create, read its template first — the template has the file location, naming rules, full code shape, and the canonical reference file in TestOrders.

Artifact	Read this template
New domain event	.claude/skills/domain/templates/domain-event.md
Business rule (exception + rule)	.claude/skills/domain/templates/business-rule.md
Status ValueObject	.claude/skills/domain/templates/status-value-object.md
Data-grouping ValueObject (e.g., PatientInfo)	.claude/skills/domain/templates/value-object.md
Entity with strongly-typed ID	.claude/skills/domain/templates/entity.md
Aggregate root command + When()	.claude/skills/domain/templates/aggregate.md
Unit test (happy path + broken rule)	.claude/skills/domain/templates/unit-test.md

Cross-cutting rules (always apply, no template lookup needed)

• TDD: write the failing test first, then implement just enough to pass. Test commits (test:) precede feature commits (feat:).
• File-scoped namespaces — no {} blocks around namespaces.
• Private fields: _camelCase. Static: s_camelCase. Constants: PascalCase. 4-space indent.
• Domain events carry primitives only. Unwrap ValueObjects (.Value, .Prop) at the call site.
• ValueObjects → private ctor + static Of(...) factory; reconstruct with Of(...), never new.
• Integration event handlers that schedule a command live in the same folder as the command, not in a separate Handle{Event}/ folder. File: {Event}IntegrationEventHandler.cs. Class: {Event}IntegrationEventNotificationHandler (CA1711 forbids the EventHandler type-name suffix).

Analyzer rules (TreatWarningsAsErrors=true) — must not violate

• CA1002 never expose List<T> — use IReadOnlyCollection<T>
• CA1707 no underscores in public/test member names — PascalCase only
• CA1716 avoid reserved keywords in namespaces
• CA2007 .ConfigureAwait(false) on awaited tasks in infra/lib code
• CA2201 specific exception types, never new Exception()

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Phase 5 — Verify

dotnet build src/HC.LIS/HC.LIS.Modules/{ModuleName}/Tests/UnitTests/HC.LIS.Modules.{ModuleName}.UnitTests.csproj
dotnet test  src/HC.LIS/HC.LIS.Modules/{ModuleName}/Tests/UnitTests/HC.LIS.Modules.{ModuleName}.UnitTests.csproj

Fix any compile or test failure before reporting success.

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HC.Core base classes — read on demand

These are stable contracts. Read only if you need to confirm a method signature.

File	Provides
src/HC.Core/Domain/Entity.cs	Events, ClearEvents(), AddEvent(), CheckRule()
src/HC.Core/Domain/EventSourcing/AggregateRoot.cs	AddDomainEvent(), abstract Apply(), Load()
src/HC.Core/Domain/ValueObject.cs	reflection-based equality, ==/!=, CheckRule()
src/HC.Core/Domain/Id.cs	base Id (throws on Guid.Empty, value-equality)
src/HC.Core/Domain/IBusinessRule.cs	rule interface
src/HC.Core/Domain/BaseBusinessRuleException.cs	required exception ctor overloads
src/HC.Core/Domain/DomainEvent.cs / IDomainEvent.cs	event base + marker
src/HC.Core/Domain/SystemClock.cs	SystemClock.Now
src/HC.Core/Tests/UnitTests/TestBase.cs	AssertPublishedDomainEvent<T>(), AssertPublishedDomainEvents<T>(), AssertBrokenRule<TRule>()