ice-lfernandes Available specs
!find docs/use-cases -mindepth 1 -maxdepth 1 -type d -name 'UC-*' 2>/dev/null | sort
Empty above → none yet, run /use-case-design first. (find, not an ls glob: under zsh an unmatched glob
aborts the command before any fallback runs.)
Target
$ARGUMENTS
Domain Modeling
Details the interior of a use case: what the mother spec named, this skill gives shape to. Signatures, types, invariants, and where each lives.
Entry rule: without a mother spec, there's nothing to detail. This skill reads
docs/use-cases/UC-NNN-<slug>/00-caso-de-uso.md and treats it as a contract. Without
that file, it stops and tells you to run /use-case-design — modeling a domain from a
loose request reinvents the boundary the mother spec exists to fix.
Exit rule: it doesn't write code. It emits 10-dominio.md. The Java classes come
from the executor agent, which reads the partial and the templates/ exemplars.
How it's invoked
Two paths, and both matter: /domain-modeling by hand, or chained by /new-feature once
that orchestrator exists. That's why it does not carry
disable-model-invocation — that field hides the skill from the model, and a skill the
model can't see is a skill the orchestrator can't call.
The guard against out-of-order firing isn't the frontmatter: it's the entry rule
above. Without the previous partial, the skill stops and says what needs to run first.
Recorded in @.claude/decisions/0007-pipeline-skills-invocation.md.
Why this isn't a subagent
It's a procedure whose step 3 goes back to the user to ask what the mother spec left
open — the exact type of each value object, which invariant lives in the constructor. A
subagent doesn't see the conversation. Decision recorded in
@.claude/decisions/0003-skill-domain-modeling.md.
Boundary with neighboring skills
Three pieces touch domain and application. Overlapping would be an ownership bug, so the division is by moment, not by folder:
| Piece | When it acts | What it produces |
|---|---|---|
use-case-design |
Before the domain exists | Canonical names and boundary — 00-caso-de-uso.md |
| this skill | After the mother spec, before code exists | Signatures and invariants — 10-dominio.md |
java-patterns |
After code exists, and only with a symptom | Refactor of real code (file:line that hurts) |
If the code already exists and the problem is a growing chain of ifs, it isn't this
skill — it's java-patterns. If there's no mother spec, it also isn't this skill.
Procedure
Read the mother spec. Without
00-caso-de-uso.mdin the given folder, stop and report. Extract: canonical names, trigger, effects, listed invariants, error table, and the component-table rows markedDetailed by: domain-modeling.Read the existing code.
Glob/Grepthe project for the canonical names. The aggregate might already exist and the use case be just a new method. Confirm or correct the mother spec's NEW/CHANGE/REUSE state — and if you correct it, say so in the report: the mother spec is now stale and someone needs to review it.Ask only what's missing.
AskUserQuestionfor what the mother spec didn't fix:Typical gap Why it matters Type of each field — Stringor value objectemail: Stringspreads validation everywhere;Emailconcentrates it in one place. The criterion isn't opinion:@.claude/rules/value-objects.mdInvariant in the constructor or in a method Constructor = always true. Method = only for that transition Does the aggregate emit an event? Decides whether there's a sibling UC to consume it, and whether messaging-architectcomes inAggregate boundary — what's inside and what's a reference by id An aggregate that's too big is an unnecessary lock Command with a single field Sometimes the record is ceremony; sometimes it's cheap extensibility Don't ask what the mother spec already answered. Repeating an already-answered question is the sign you didn't read step 1.
Fix the signatures. Names from
@.claude/rules/naming.md§ Architecture vocabulary — they already come from the mother spec, don't change them. Exception names are this skill's: the mother spec only describes the situation and its kind. Zero framework types in signatures (@.claude/rules/architecture-ddd.md). Zeronullcrossing a boundary;Optionalonly on query return (@.claude/rules/code-quality.md). Every primitive field goes through the@.claude/rules/value-objects.mdcriterion before staying a primitive — a field with a formation rule that staysStringis a decision to justify in the partial, not a default.Flag which fields are sensitive. The same pass that decides a field's value object (document, phone, email —
@.claude/rules/value-objects.md's catalog) is the natural signal for@.claude/rules/logging.md's masking rule: a field with a formation rule that identifies a person (CPF/CNPJ, phone, email, a document number) is a candidate for@MaskSensitiveData. List these fields in the aggregate block —rest-api-architectreads this to decide which DTO fields implementLogMask; it doesn't re-derive sensitivity from field names on its own.Map each invariant to its exception. Typed family from
@.claude/rules/error-handling.mdanderrorCodeinUPPER_SNAKE_CASE. An invariant without a named exception is an invariant nobody will implement.The exception family belongs to this skill, and this is where it enters the project.
project-bootstrapdoesn't write it — it has no invariant to tie it to (@.claude/decisions/0011-bootstrap-without-business-code.md). So: search forDomainExceptionin the project withGrep. If it doesn't exist, the partial's invariants block opens with the line "Exception family: NEW — five classes in thedomain.exceptionpackage", and names the five. If it already exists, write REUSE and name only the missing ones. Once per project, not once per use case — the second spec finds them and reuses them.The form exemplars are
templates/DomainException.java.exampleand the four typed ones. Don't invent categories beyond the four: the taxonomy belongs to the rule, not this skill.Default every invariant to the plain typed family + a string
errorCode. Promote to a named subclass (OrderAlreadyPaidException extends ConflictException, no new state) only when the entry bar in@.claude/rules/error-handling.md§ Shape of the base classes is met: theerrorCodealready repeats across ≥ 2 call sites, or a caller needs tocatchit specifically rather than branch onerrorCode(). A first occurrence never gets its own class — the same disciplinejava-patternsapplies to when a symptom earns a design pattern.A second call site found in a later use case promotes the exception here, in this case's
10-dominio.md, under## Impact on approved use cases— never by editing the earlier case's partial or spec, which are approved and immutable.Generate from
templates/domain-spec.md.exampletodocs/use-cases/UC-NNN-<slug>/10-dominio.md.Report and stop. File path, divergences found against the mother spec, and what's missing for the folder to be complete (
20-persistencia.md,30-rest.md,40-testes.md). Don't invoke anyone.
What the partial contains
Four blocks, all mandatory. An empty block is written as "none" — deleting it hides a question nobody asked.
| Block | Details | Form exemplar |
|---|---|---|
| Aggregate and value objects | Root, fields, types, which VOs exist and why, which fields are sensitive (masking candidates) | Aggregate.java.example · ValueObject.java.example · ValueObjectCatalog.java.example |
| Invariants | Each rule, where it's enforced, which exception it raises; and the state of the exception family (NEW or REUSE) | DomainGuards.java.example · DomainException.java.example and the four typed ones · @.claude/rules/error-handling.md |
| Ports | Input (<Verb><Noun>UseCase), command, output — complete signatures |
UseCasePort.java.example · Command.java.example |
| Events | Which event, which payload, which UC consumes it | DomainEvent.java.example |
The exemplars in templates/ are reference for form, not files to copy: they show a
record with a compact constructor, a static of factory, and total absence of
framework. It's the executor that reads them when generating code.
Twelve exemplars, and the five of the exception family (DomainException, NotFound,
Validation, BusinessRuleViolation, Conflict) arrived here when project-bootstrap
stopped emitting business code. This skill owns the shape of the domain, and the
exception is domain: transport-agnostic, no framework, with a stable errorCode.
Record: @.claude/decisions/0011-bootstrap-without-business-code.md.
Contract
Reads docs/use-cases/UC-NNN-<slug>/00-caso-de-uso.md (mandatory — stops without
it), @.claude/rules/architecture-ddd.md (Domain and Application sections),
@.claude/rules/value-objects.md (criterion for which field becomes a value object),
@.claude/rules/naming.md, @.claude/rules/error-handling.md,
@.claude/rules/code-quality.md, @.claude/rules/logging.md (which fields to flag as
masking candidates), and the active blueprint's packages.map.
Writes docs/use-cases/UC-NNN-<slug>/10-dominio.md. Only that file.
Does not write Java code. The classes in domain/** and application/** come from
the executor agent — the exception family included: this skill owns the shape (the
templates/ exemplars) and the state (NEW or REUSE, in the partial), not the
writing. Does not touch 00-caso-de-uso.md (use-case-design), the other partials, or
.claude/rules/**.
Does not collide with java-patterns, which writes domain code from a symptom in
existing code. This skill produces a spec before code exists; that one refactors code
that already hurts. Different moments, different artifacts.
Does not decide persistence, mapping, or transport technology —
20-persistencia.md and 30-rest.md have their own owners.