Business Rules Extractor

Overview

Identifies and catalogs business rules embedded in code — validation constraints, domain invariants, guards, authorization rules, and business policies. Translates technical implementations into business language.

Rule Categories

Category	Code Pattern	Business Meaning
Validation	Assert, validate, check	Input requirements
Invariant	Guard clause in constructor/method	Business constraint
Authorization	isAllowed, canPerform, Policy	Access control
Business Policy	If/match with domain logic	Business decision
State Guard	Status check before transition	Workflow rule
Limit/Threshold	Comparison with constant/config	Business limit

Detection Patterns

Validation Rules

# Symfony validation attributes
Grep: "#\\[Assert\\\\" --glob "**/*.php"
Grep: "#\\[(NotBlank|NotNull|Length|Range|Email|Regex|Valid|Choice)" --glob "**/*.php"

# Laravel validation
Grep: "'required|'email|'min:|'max:|'unique:" --glob "**/*.php"
Grep: "\\$rules|->validate\\(" --glob "**/*.php"

# Custom validation
Grep: "function validate|function isValid|function check" --glob "**/Domain/**/*.php"
Grep: "throw.*Invalid|throw.*Validation" --glob "**/*.php"

# Value Object self-validation
Grep: "private function (validate|ensure|assert|guard)" --glob "**/*.php"

Domain Invariants

# Guard clauses in constructors
Grep: "__construct" --glob "**/Domain/**/*.php" -A 20
# Look for: if (...) throw, match with exceptions

# Guard methods
Grep: "private function (ensure|guard|assert|verify)" --glob "**/Domain/**/*.php"

# Invariant enforcement
Grep: "throw new.*Exception" --glob "**/Domain/**/*.php"

# Business constraint patterns
Grep: "if.*<=.*0|if.*<.*0|if.*>.*MAX|if.*>=.*LIMIT" --glob "**/Domain/**/*.php"
Grep: "if.*empty|if.*null|if.*count.*==.*0" --glob "**/Domain/**/*.php"

Authorization Rules

# Symfony voters
Grep: "extends Voter|implements VoterInterface" --glob "**/*.php"
Grep: "function voteOnAttribute" --glob "**/*.php"

# Laravel policies
Grep: "class.*Policy" --glob "**/*.php"
Grep: "function (view|create|update|delete|restore|forceDelete)" --glob "**/Policy/**/*.php"

# Custom authorization
Grep: "->isAllowed|->can\\(|->authorize\\(|->isGranted" --glob "**/*.php"
Grep: "#\\[IsGranted\\(|@IsGranted\\(" --glob "**/*.php"

# Role-based checks
Grep: "hasRole|isAdmin|isModerator|ROLE_" --glob "**/*.php"

Business Policies

# Pricing rules
Grep: "discount|price|tax|fee|commission|markup" --glob "**/Domain/**/*.php"
Grep: "calculatePrice|calculateTotal|applyDiscount" --glob "**/*.php"

# Status/workflow transitions
Grep: "canTransitionTo|allowedTransitions|validTransitions" --glob "**/*.php"
Grep: "function (approve|reject|cancel|complete|archive|activate|deactivate)" --glob "**/Domain/**/*.php"

# Time-based rules
Grep: "isExpired|isActive|isWithin|deadline|expiresAt" --glob "**/*.php"
Grep: "new \\\\DateTimeImmutable|Carbon::" --glob "**/Domain/**/*.php"

# Quantity/limit rules
Grep: "MAX_|MIN_|LIMIT_|THRESHOLD" --glob "**/Domain/**/*.php"
Grep: "maxAttempts|maxRetries|maxItems|minAmount" --glob "**/*.php"

State Guards

# Status checks before operations
Grep: "if.*status.*===|if.*state.*===" --glob "**/Domain/**/*.php"
Grep: "match.*status|match.*state" --glob "**/Domain/**/*.php"

# Enum-based state management
Grep: "enum.*Status|enum.*State" --glob "**/*.php"
Grep: "->status === |->getStatus\\(\\) ===" --glob "**/*.php"

Analysis Process

1. Scan — Find all business rule patterns in code
2. Extract — Read each rule's implementation details
3. Classify — Categorize by type (validation, invariant, auth, policy)
4. Translate — Convert technical code to business language
5. Map — Connect rules to business entities/processes

Translation Rules

Technical Pattern	Business Translation
if ($amount <= 0) throw	"Order amount must be positive"
if ($user->getRole() !== 'admin')	"Only administrators can perform this action"
if ($order->status !== 'pending')	"Order can only be modified while pending"
if (count($items) > 100)	"Maximum 100 items per order"
if ($age < 18)	"Customer must be at least 18 years old"

Output Format

## Business Rules Catalog

### Summary
| Category | Count | Critical |
|----------|-------|----------|
| Validation Rules | 15 | 3 |
| Domain Invariants | 8 | 5 |
| Authorization Rules | 12 | 4 |
| Business Policies | 6 | 2 |
| State Guards | 4 | 3 |
| **Total** | **45** | **17** |

### Domain Invariants (Business Constraints)

| # | Rule (Business Language) | Location | Enforcement |
|---|--------------------------|----------|-------------|
| INV-1 | Order amount must be positive | Order.php:25 | Constructor guard |
| INV-2 | Order must have at least one item | Order.php:30 | Constructor guard |
| INV-3 | Customer email must be valid format | Email.php:15 | Value Object |
| INV-4 | Payment cannot exceed order total | Payment.php:22 | Method guard |

### Validation Rules (Input Requirements)

| # | Field | Rule | Location |
|---|-------|------|----------|
| VAL-1 | email | Required, valid format | CreateUserRequest.php |
| VAL-2 | name | Required, 2-100 chars | CreateUserRequest.php |
| VAL-3 | amount | Required, positive integer | CreateOrderDTO.php |

### Authorization Rules (Access Control)

| # | Action | Who Can | Where Enforced |
|---|--------|---------|----------------|
| AUTH-1 | View orders | Owner or Admin | OrderPolicy::view |
| AUTH-2 | Cancel order | Owner (if pending) | OrderPolicy::cancel |
| AUTH-3 | Manage users | Admin only | UserVoter |

### Business Policies

| # | Policy | Rule | Location |
|---|--------|------|----------|
| POL-1 | Free shipping | Orders over $100 | ShippingCalculator.php:45 |
| POL-2 | Loyalty discount | 10% for VIP customers | PriceCalculator.php:30 |
| POL-3 | Order expiry | Unpaid orders expire in 24h | OrderExpiryPolicy.php |

### State Transition Rules

| Entity | From State | To State | Condition |
|--------|-----------|----------|-----------|
| Order | pending | confirmed | Payment received |
| Order | confirmed | shipped | Items packed |
| Order | any | cancelled | By owner if not shipped |

Integration

This skill is used by:

• business-logic-analyst — catalogs all business rules
• explain-business-process — references rules in process descriptions
• extract-domain-concepts — connects rules to domain entities