Standalone Mode
If invoked directly (not via the orchestrator), you must first:
- Read
../codeprobe/shared-preamble.md for the output contract, execution modes, and constraints. - Load applicable reference files from
../codeprobe/references/ based on the project's tech stack. - Default to
full mode unless the user specifies otherwise.
SOLID Principles Auditor
Domain Scope
This sub-skill detects violations of the five SOLID principles:
- Single Responsibility Principle (SRP) — A class or module should have only one reason to change.
- Open/Closed Principle (OCP) — Software entities should be open for extension but closed for modification.
- Liskov Substitution Principle (LSP) — Subtypes must be substitutable for their base types without altering program correctness.
- Interface Segregation Principle (ISP) — Clients should not be forced to depend on interfaces they do not use.
- Dependency Inversion Principle (DIP) — High-level modules should not depend on low-level modules; both should depend on abstractions.
What It Does NOT Flag
- Simple DTOs/value objects with multiple fields — having many properties is not an SRP violation when the class represents a single data concept.
- Small scripts and CLIs that don't need dependency injection — proportional design matters.
- Enums used in switches where the enum is stable and closed (e.g., compass directions, days of the week) — OCP applies when variants are likely to grow.
- Framework-generated classes following framework conventions (e.g., Laravel migrations, Django admin classes, Rails ActiveRecord models with standard callbacks).
- Test helper classes that aggregate setup utilities — test infrastructure has different design constraints.
Detection Instructions
SRP — Single Responsibility Principle
| ID Prefix | Signal | How to Detect | Severity |
|---|
SRP | Class has 5+ public methods doing unrelated things | Count public methods. If 5+ exist, check whether they cluster around a single responsibility or span multiple concerns (e.g., authentication + email + database). Look for method name prefixes that suggest different domains. | Major |
SRP | Method exceeds 30 LOC doing multiple concerns | Count lines in each method (excluding blank lines and comments). If > 30 LOC, check whether the method handles multiple distinct steps (validation, transformation, persistence, notification) that could be extracted. | Minor |
SRP | Class name is vague | Flag classes named Manager, Handler, Utils, Helper, Processor, Service (when not domain-qualified) — these names suggest the class has no clear single purpose. Exception: if the class is small (< 5 methods, < 100 LOC), downgrade to suggestion. | Minor |
SRP | Constructor takes 5+ dependencies | Count constructor parameters or injected dependencies. 5+ dependencies suggest the class has too many responsibilities. Check whether dependencies serve different domains. | Major |
OCP — Open/Closed Principle
| ID Prefix | Signal | How to Detect | Severity |
|---|
OCP | Switch/if-else chains on type or status | Look for switch/if-else chains that branch on a type, status, role, or kind field — especially where adding a new variant requires modifying this block. Count the number of cases: 3+ cases on a growable type is a signal. | Major |
OCP | No extension point where variants are likely to grow | When a switch/if-else on type is found, check whether there is an interface, abstract class, strategy pattern, or plugin mechanism that would allow adding new variants without modifying the existing code. If absent, flag it. | Minor |
LSP — Liskov Substitution Principle
| ID Prefix | Signal | How to Detect | Severity |
|---|
LSP | Subclass overrides method but changes semantics | Check overridden methods: does the subclass return a fundamentally different type, change the meaning of the return value, or produce side effects the parent does not? Compare method signatures and doc comments. | Major |
LSP | Subclass throws exception parent doesn't declare | Look for overridden methods that throw exceptions not present in the parent's throws clause or documented contract. In dynamic languages, look for raise/throw in overrides where the parent method doesn't throw. | Major |
LSP | Subclass ignores or no-ops parent behavior | Look for overridden methods with empty bodies, pass, return null, return, or // not implemented comments. The subclass is refusing the parent's contract. | Minor |
LSP | instanceof/type checks after polymorphic call | Search for instanceof, is_a, typeof, type(), is checks on objects that should be used polymorphically. If code calls a method on a base type and then checks the concrete type, it signals broken substitutability. | Major |
ISP — Interface Segregation Principle
| ID Prefix | Signal | How to Detect | Severity |
|---|
ISP | Interface has 8+ methods | Count methods declared in each interface/abstract class/protocol. If 8+, the interface is likely too broad. Check whether the methods cluster into distinct groups. | Minor |
ISP | Class implements interface but leaves methods empty or throwing | Look for interface implementations where one or more methods are empty, return null, throw NotImplementedError/UnsupportedOperationException, or contain only pass/TODO comments. | Major |
ISP | Multiple unrelated method groups in one interface | Analyze the interface's methods: do they fall into 2+ distinct responsibility groups (e.g., read operations + write operations + notification methods)? If so, the interface should be split. | Major |
DIP — Dependency Inversion Principle
| ID Prefix | Signal | How to Detect | Severity |
|---|
DIP | new ConcreteClass() inside business logic | Search for direct instantiation (new ClassName(), direct constructor calls) of infrastructure or service classes inside business logic methods. Exclude: DTOs, value objects, exceptions, collections, factories, and DI container registrations. | Major |
DIP | High-level module imports from infrastructure layer directly | Check import statements: does a domain/business logic module import directly from database drivers, HTTP clients, file system libraries, or third-party SDKs without an abstraction layer? Look for patterns like import mysql, use Illuminate\Support\Facades\DB, from requests import. | Major |
DIP | No constructor injection — static method calls to concrete dependencies | Look for static method calls like Database::query(), Cache::get(), Logger.log() in business logic where no interface is injected. The class is tightly coupled to the concrete implementation via static access. | Minor |
ID Prefixes & Fix Prompt Examples
SRP- — Single Responsibility Principle violationsOCP- — Open/Closed Principle violationsLSP- — Liskov Substitution Principle violationsISP- — Interface Segregation Principle violationsDIP- — Dependency Inversion Principle violations
Number findings sequentially within each prefix: SRP-001, SRP-002, OCP-001, etc.
Fix Prompt Examples
- "Refactor
src/OrderService.php: extract payment logic (lines 45-78) into a new PaymentService class. Inject PaymentService via constructor into OrderService. Move methods calculateTotal(), applyDiscount(), and processPayment() to the new class." - "Replace the switch on
$type in NotificationSender (lines 30-65) with a Strategy pattern: create a NotificationChannel interface with a send(Message $message) method. Create EmailChannel, SmsChannel, and PushChannel implementations. Use a NotificationChannelFactory to resolve the correct channel by type." - "In
UserRepository.php, replace new MySqlConnection() at line 23 with constructor injection: add a DatabaseConnectionInterface $connection parameter to the constructor and use it instead of the concrete instantiation."
