Component Boundary Identifier

Identify and analyze boundaries between software components to ensure proper architectural separation.

Quick Start

When a user requests boundary analysis:

1. Understand the goal: Identify boundaries, detect violations, or both
2. Analyze structure: Examine package/module organization and dependencies
3. Identify boundaries: Determine component boundaries based on structure
4. Detect violations: Find improper cross-boundary dependencies
5. Report findings: Present boundaries and violations with severity levels

What This Skill Does

Boundary Identification

Identify component boundaries based on:

• Package/module structure
• Namespace organization
• Architectural patterns (layered, hexagonal, clean)
• Naming conventions
• Dependency clusters

Violation Detection

Detect boundary violations including:

• Upward dependencies (lower layers depending on higher layers)
• Circular dependencies between components
• Layer skipping (bypassing intermediate layers)
• Domain depending on infrastructure
• Accessing private/internal implementations
• Concrete type dependencies across boundaries

Analysis Methods

Static Code Analysis

Analyze code structure without execution.

Python:

• Parse import statements
• Analyze package structure
• Identify dependency directions
• Detect circular imports

Java:

• Parse import statements
• Analyze package hierarchy
• Check access modifiers
• Identify dependency directions

Script: Use scripts/analyze_boundaries.py for automated Python analysis

Manual Code Review

Review code for boundary patterns.

Process:

1. Identify top-level packages/modules
2. Map dependencies between components
3. Check against architectural rules
4. Find violations

See: boundary-indicators.md for patterns

Architectural Patterns

Layered Architecture

Layers (top to bottom):

1. Presentation/API
2. Application/Service
3. Domain/Business
4. Infrastructure/Data

Rules:

• Dependencies flow downward only
• No layer skipping
• No upward dependencies

Violations:

• Domain imports from API
• Infrastructure imports from Domain
• API directly uses Infrastructure (skips Service)

Hexagonal Architecture

Boundaries:

• Core: Domain logic (center)
• Ports: Interfaces for external interaction
• Adapters: Implementations (outside)

Rules:

• Core has no dependencies on adapters
• Adapters depend on ports
• All external access through ports

Violations:

• Core imports adapter implementations
• Core depends on frameworks
• Direct adapter-to-adapter dependencies

Clean Architecture

Boundaries (inside to outside):

1. Entities (domain models)
2. Use Cases (business rules)
3. Interface Adapters
4. Frameworks & Drivers

Dependency Rule:

• Dependencies point inward only
• Inner layers independent of outer layers

Violations:

• Inner layer imports outer layer
• Domain depends on UI/API
• Use cases depend on frameworks

Language-Specific Guidance

Python

Boundary indicators:

• Top-level packages (domain/, infrastructure/, api/)
• __init__.py with controlled exports
• Protocol/ABC definitions

Common violations:

• Domain imports from infrastructure
• Circular imports between modules
• Importing private members (_name)
• Direct implementation dependencies

See: boundary-indicators.md for details

Java

Boundary indicators:

• Package hierarchy (com.example.domain, com.example.infrastructure)
• Access modifiers (public, package-private, private)
• Interface definitions

Common violations:

• Domain imports infrastructure packages
• Accessing package-private from different package
• Static coupling across boundaries
• Framework annotations in domain

See: boundary-indicators.md for details

Workflow

1. Understand the Request

Questions to clarify:

• Identify boundaries or detect violations?
• Specific architectural pattern in use?
• Focus on specific components?
• Known problem areas?

2. Analyze Project Structure

For automated analysis:

python scripts/analyze_boundaries.py <project_directory>

For manual analysis:

1. List top-level packages/modules
2. Identify architectural layers
3. Note naming conventions
4. Understand intended architecture

3. Identify Boundaries

Look for:

• Package/module groupings
• Architectural layer separation
• Domain vs infrastructure separation
• API vs business logic separation

Document:

• Boundary names and purposes
• Components within each boundary
• Intended dependency directions

4. Detect Violations

Check for:

• Upward dependencies
• Circular dependencies
• Layer skipping
• Concrete type dependencies
• Private/internal access

See: violation-patterns.md for patterns

5. Report Findings

Structure:

IDENTIFIED BOUNDARIES
- boundary1/ (N modules)
- boundary2/ (M modules)

BOUNDARY VIOLATIONS
[CRITICAL] module_a depends on higher layer module_b
[HIGH] Circular dependency: module_c -> module_d -> module_c
[MEDIUM] module_e accesses private implementation

RECOMMENDATIONS
- Fix critical violations first
- Introduce interfaces for concrete dependencies
- Refactor circular dependencies

Violation Severity Levels

Critical

• Domain depends on infrastructure
• Upward dependencies in layered architecture
• Circular dependencies between major components

Impact: Breaks architectural principles, prevents proper separation

Priority: Fix immediately

High

• Layer skipping
• Concrete type dependencies across boundaries
• Framework coupling in domain

Impact: Reduces flexibility, complicates testing

Priority: Fix soon

Medium

• Accessing private/internal members
• Static coupling across boundaries
• Missing interfaces at boundaries

Impact: Breaks encapsulation, reduces maintainability

Priority: Fix when refactoring

Low

• Suboptimal package structure
• Inconsistent naming
• Missing documentation

Impact: Reduces code clarity

Priority: Fix opportunistically

Detection Patterns

Upward Dependency

Pattern:

# domain/services.py
from api.serializers import UserSerializer  # VIOLATION

Detection: Lower layer imports from higher layer

Fix: Move serialization to API layer

Circular Dependency

Pattern:

# module_a.py
from module_b import ClassB

# module_b.py
from module_a import ClassA  # VIOLATION

Detection: A imports B, B imports A

Fix: Extract shared interface, use dependency injection

Layer Skipping

Pattern:

# api/routes.py
from infrastructure.repositories import UserRepository  # VIOLATION

Detection: API directly uses infrastructure (skips service layer)

Fix: Use service layer as intermediary

Concrete Dependency

Pattern:

# domain/services.py
from infrastructure.email import SMTPEmailSender  # VIOLATION

class NotificationService:
    def __init__(self):
        self.sender = SMTPEmailSender()

Detection: Domain depends on concrete infrastructure class

Fix: Depend on interface, inject implementation

Best Practices

Boundary Definition

• Use clear package/module names
• Follow architectural patterns consistently
• Document boundary purposes
• Establish dependency rules

Dependency Management

• Depend on interfaces, not implementations
• Use dependency injection
• Follow dependency inversion principle
• Avoid static coupling

Violation Prevention

• Code reviews focusing on imports
• Automated dependency analysis in CI/CD
• Architecture decision records
• Team training on patterns

Refactoring Strategy

• Fix critical violations first
• Introduce interfaces gradually
• Extract shared code carefully
• Test after each change

Ex