Agent skill
symfony-domain-modeling
Symfony domain modeling — entities, value objects, domain events, aggregates, domain exceptions. Triggers on: entity, value object, domain event, aggregate, domain exception, domain model, domain logic, business rule, invariant
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/symfony-domain-modeling
SKILL.md
Symfony Domain Modeling
You are an expert in Domain-Driven Design within Symfony hexagonal architecture. Use this skill when users need to create or modify domain model elements.
When to Activate
- User wants to create an entity or aggregate root
- User asks about value objects
- User needs domain events
- User mentions domain exceptions or business rules
- User discusses aggregates or invariants
Entity Patterns
Rules
- Private constructor + static factory method(s)
- No Doctrine annotations/attributes — mapping is in Infrastructure
- Record domain events on state changes
- Protect invariants in methods, not in external validators
- Use value objects for typed properties (no primitive obsession)
Template
namespace App\Domain\{Module}\Entity;
final class {Entity}
{
private array $domainEvents = [];
private function __construct(
private {EntityId} $id,
// typed properties using value objects
) {
}
public static function create(/* params */): self
{
// validate invariants
$entity = new self(/* params */);
$entity->recordEvent(new {Entity}Created(/* event data */));
return $entity;
}
// Business methods that protect invariants
public function doAction(/* params */): void
{
// guard clause / invariant check
// state change
$this->recordEvent(new {ActionDone}(/* event data */));
}
public function pullDomainEvents(): array
{
$events = $this->domainEvents;
$this->domainEvents = [];
return $events;
}
private function recordEvent(object $event): void
{
$this->domainEvents[] = $event;
}
}
Value Object Patterns
Rules
- Always
final readonly class - Self-validating in constructor (throw domain exception if invalid)
- Immutable — no setters
- Implement
equals()for comparison - Use for: IDs, email, money, dates, status enums
Template
namespace App\Domain\{Module}\ValueObject;
use App\Domain\{Module}\Exception\Invalid{ValueObject}Exception;
final readonly class {ValueObject}
{
public function __construct(
public string $value,
) {
if (/* validation fails */) {
throw new Invalid{ValueObject}Exception($value);
}
}
public function equals(self $other): bool
{
return $this->value === $other->value;
}
public function __toString(): string
{
return $this->value;
}
}
Domain Event Patterns
Rules
- Past-tense naming:
UserRegistered,OrderPlaced,PaymentFailed - Immutable (
final readonly class) - Carry only the data needed by handlers (IDs, not full entities)
- Created inside entities on state changes
Template
namespace App\Domain\{Module}\Event;
final readonly class {PastTenseEvent}
{
public function __construct(
public string $entityId,
public \DateTimeImmutable $occurredAt = new \DateTimeImmutable(),
// additional event-specific data
) {
}
}
Domain Exception Patterns
namespace App\Domain\{Module}\Exception;
final class {DomainException} extends \DomainException
{
public static function because{Reason}(/* context */): self
{
return new self(sprintf('Descriptive message: %s', $context));
}
}
References
See references/ for detailed patterns:
entity-patterns.md— Full entity examples with aggregatesvalue-object-patterns.md— Common value object implementationsdomain-event-patterns.md— Event design and dispatch patterns
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
majiayu000/claude-skill-registry
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
majiayu000/claude-skill-registry
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
majiayu000/claude-skill-registry
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
majiayu000/claude-skill-registry
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
majiayu000/claude-skill-registry
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
majiayu000/claude-skill-registry
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
Didn't find tool you were looking for?