tech-leads-club/domain-identification-grouping
Groups existing components into logical business domains to plan service-based architecture. Use when asking "which components belong together?", "group these into services", "organize by domain", "component-to-domain mapping", or planning service extraction from an existing codebase. Do NOT use for identifying new domains from scratch (use domain-analysis) or analyzing coupling (use coupling-analysis).
This is a copy. The original lives at christophacham/domain-identification-grouping.
npx skills add https://github.com/tech-leads-club/agent-skills --skill domain-identification-groupingThis skill groups architectural components into logical domains (business areas) to prepare for creating domain services in a service-based architecture.
Request analysis of your codebase:
Example 1: Domain Identification
User: "Group components into logical domains"
The skill will:
1. Analyze component responsibilities and relationships
2. Identify business domains based on functionality
3. Group components into domains
4. Create domain diagrams
5. Suggest namespace refactoring for domain alignment
Example 2: Domain Analysis
User: "Which domain should the billing components belong to?"
The skill will:
1. Analyze billing component functionality
2. Check relationships with other components
3. Identify appropriate domain (e.g., Customer or Financial)
4. Recommend domain assignment
Example 3: Domain Refactoring
User: "What namespace refactoring is needed to align components with domains?"
The skill will:
1. Compare current component namespaces to identified domains
2. Identify misaligned components
3. Suggest namespace changes
4. Create refactoring plan
Apply this skill when:
A domain is a logical grouping of components that:
Examples:
One-to-Many: A single domain contains multiple components
Domain: Customer
├── Component: Customer Profile
├── Component: Billing Payment
├── Component: Billing History
└── Component: Support Contract
Domains are physically manifested through namespace structure:
Before Domain Alignment:
services/billing/payment
services/billing/history
services/customer/profile
services/supportcontract
After Domain Alignment:
services/customer/billing/payment
services/customer/billing/history
services/customer/profile
services/customer/supportcontract
Notice how all customer-related functionality is grouped under .customer domain.
Analyze the codebase to identify distinct business domains:
Example Domain Identification:
## Identified Domains
1. **Ticketing Domain** (ss.ticket)
- Ticket creation, assignment, routing, completion
- Customer surveys
- Knowledge base
2. **Customer Domain** (ss.customer)
- Customer profile
- Billing and payment
- Support contracts
3. **Reporting Domain** (ss.reporting)
- Ticket reports
- Expert reports
- Financial reports
4. **Admin Domain** (ss.admin)
- User maintenance
- Expert profile management
5. **Shared Domain** (ss.shared)
- Login
- Notification
Assign each component to an appropriate domain:
Example Component Grouping:
## Component Domain Assignment
### Ticketing Domain (ss.ticket)
- Ticket Shared (ss.ticket.shared)
- Ticket Maintenance (ss.ticket.maintenance)
- Ticket Completion (ss.ticket.completion)
- Ticket Assign (ss.ticket.assign)
- Ticket Route (ss.ticket.route)
- KB Maintenance (ss.ticket.kb.maintenance)
- KB Search (ss.ticket.kb.search)
- Survey (ss.ticket.survey)
### Customer Domain (ss.customer)
- Customer Profile (ss.customer.profile)
- Billing Payment (ss.customer.billing.payment)
- Billing History (ss.customer.billing.history)
- Support Contract (ss.customer.supportcontract)
### Reporting Domain (ss.reporting)
- Reporting Shared (ss.reporting.shared)
- Ticket Reports (ss.reporting.tickets)
- Expert Reports (ss.reporting.experts)
- Financial Reports (ss.reporting.financial)
Ensure components fit well in their assigned domains:
Validation Checklist:
Align component namespaces with identified domains:
services/billing/paymentservices/customer/billing/payment.customer domain nodeExample Namespace Refactoring:
## Namespace Refactoring Plan
### Customer Domain Alignment
| Component | Current Namespace | Target Namespace | Action |
| ---------------- | ------------------- | --------------------------- | ------------- |
| Billing Payment | ss.billing.payment | ss.customer.billing.payment | Add .customer |
| Billing History | ss.billing.history | ss.customer.billing.history | Add .customer |
| Customer Profile | ss.customer.profile | ss.customer.profile | No change |
| Support Contract | ss.supportcontract | ss.customer.supportcontract | Add .customer |
### Ticketing Domain Alignment
| Component | Current Namespace | Target Namespace | Action |
| -------------- | ----------------- | ------------------------ | ----------- |
| KB Maintenance | ss.kb.maintenance | ss.ticket.kb.maintenance | Add .ticket |
| KB Search | ss.kb.search | ss.ticket.kb.search | Add .ticket |
| Survey | ss.survey | ss.ticket.survey | Add .ticket |
Visualize domain structure and component groupings:
Example Domain Map:
## Domain Map
┌─────────────────────────────────────┐
│ Ticketing Domain (ss.ticket) │
├─────────────────────────────────────┤
│ • Ticket Shared │
│ • Ticket Maintenance │
│ • Ticket Completion │
│ • Ticket Assign │
│ • Ticket Route │
│ • KB Maintenance │
│ • KB Search │
│ • Survey │
└─────────────────────────────────────┘
│
│ uses
▼
┌─────────────────────────────────────┐
│ Customer Domain (ss.customer) │
├─────────────────────────────────────┤
│ • Customer Profile │
│ • Billing Payment │
│ • Billing History │
│ • Support Contract │
└─────────────────────────────────────┘
## Output Format
### Domain Identification Report
Business Capability: Manages customer relationships, billing, and support contracts
Components:
Component Count: 4
Total Size: ~15,000 statements (18% of codebase)
Domain Cohesion: ✅ High
Boundaries:
### Component Domain Assignment Table
| Component | Current Namespace | Assigned Domain | Target Namespace |
| ------------------ | --------------------- | --------------- | --------------------------------- |
| Customer Profile | ss.customer.profile | Customer | ss.customer.profile (no change) |
| Billing Payment | ss.billing.payment | Customer | ss.customer.billing.payment |
| Ticket Maintenance | ss.ticket.maintenance | Ticketing | ss.ticket.maintenance (no change) |
| KB Maintenance | ss.kb.maintenance | Ticketing | ss.ticket.kb.maintenance |
| Reporting Shared | ss.reporting.shared | Reporting | ss.reporting.shared (no change) |
### Namespace Refactoring Plan
Customer Domain Alignment
Components to Refactor:
ss.billing.payment → ss.customer.billing.paymentss.billing.history → ss.customer.billing.historyss.supportcontract → ss.customer.supportcontractSteps:
Expected Impact:
.customer domain
### Domain Map Visualization
Customer Domain (ss.customer)
├── Customer Profile
├── Billing Payment
├── Billing History
└── Support Contract
Ticketing Domain (ss.ticket)
├── Ticket Shared
├── Ticket Maintenance
├── Ticket Completion
├── Ticket Assign
├── Ticket Route
├── KB Maintenance
├── KB Search
└── Survey
Reporting Domain (ss.reporting)
├── Reporting Shared
├── Ticket Reports
├── Expert Reports
└── Financial Reports
Admin Domain (ss.admin)
├── User Maintenance
└── Expert Profile
Shared Domain (ss.shared)
├── Login
└── Notification
Ticketing Domain
│ uses
├─→ Shared Domain (Login, Notification)
└─→ Customer Domain (Customer Profile)
Customer Domain
│ uses
└─→ Shared Domain (Login, Notification)
Reporting Domain
│ uses
├─→ Ticketing Domain (Ticket data)
├─→ Customer Domain (Customer data)
└─→ Shared Domain (Login)
## Analysis Checklist
**Domain Identification**:
- [ ] Analyzed component responsibilities
- [ ] Identified business capabilities
- [ ] Identified distinct business domains
- [ ] Validated domains with stakeholders
**Component Grouping**:
- [ ] Assigned each component to a domain
- [ ] Analyzed component relationships
- [ ] Ensured components fit domain vocabulary
- [ ] Handled edge cases (shared components, unclear assignments)
**Domain Validation**:
- [ ] Checked cohesion within domains
- [ ] Verified domain boundaries are clear
- [ ] Ensured all components assigned
- [ ] Validated with stakeholders
**Namespace Refactoring**:
- [ ] Compared current vs target namespaces
- [ ] Identified components needing refactoring
- [ ] Created refactoring plan
- [ ] Prioritized refactoring work
**Domain Mapping**:
- [ ] Created domain diagram
- [ ] Documented domain structure
- [ ] Created domain inventory table
- [ ] Documented domain relationships
## Implementation Notes
### For Node.js/Express Applications
Domains typically organized in `services/` directory:
services/
├── customer/ ← Customer Domain
│ ├── profile/
│ ├── billing/
│ │ ├── payment/
│ │ └── history/
│ └── supportcontract/
├── ticket/ ← Ticketing Domain
│ ├── shared/
│ ├── maintenance/
│ ├── assign/
│ └── route/
└── reporting/ ← Reporting Domain
├── shared/
├── tickets/
└── experts/
### For Java Applications
Domains identified by package structure:
com.company.customer ← Customer Domain
├── profile
├── billing
│ ├── payment
│ └── history
└── supportcontract
com.company.ticket ← Ticketing Domain
├── shared
├── maintenance
├── assign
└── route
### Domain Identification Strategies
**Strategy 1: Business Capability Analysis**
- Identify what business capabilities the system provides
- Group components by capability
- Example: "Customer Management" capability → Customer Domain
**Strategy 2: Vocabulary Analysis**
- Identify business vocabulary used by components
- Group components sharing same vocabulary
- Example: Components using "billing", "payment", "invoice" → Financial Domain
**Strategy 3: Relationship Analysis**
- Identify components frequently used together
- Group components with strong relationships
- Example: Components that share data/workflows → Same Domain
**Strategy 4: Stakeholder Collaboration**
- Work with product owners/business analysts
- Use their understanding of business areas
- Validate domain boundaries with them
## Fitness Functions
After creating domains, create automated checks:
### Domain Namespace Governance
// Ensure components belong to correct domain
function validateDomainNamespaces(components, domainRules) {
const violations = []
components.forEach((comp) => {
const domain = identifyDomain(comp.namespace)
const expectedDomain = domainRules[comp.name]
if (domain !== expectedDomain) {
violations.push({
component: comp.name,
currentDomain: domain,
expectedDomain: expectedDomain,
namespace: comp.namespace,
})
}
})
return violations
}
### Domain Boundary Enforcement
// Prevent components from accessing other domains directly
function enforceDomainBoundaries(components) {
const violations = []
components.forEach((comp) => {
comp.imports.forEach((imp) => {
const importedDomain = identifyDomain(imp)
const componentDomain = identifyDomain(comp.namespace)
if (importedDomain !== componentDomain && importedDomain !== 'shared') {
violations.push({
component: comp.name,
domain: componentDomain,
importsFrom: imp,
importedDomain: importedDomain,
issue: 'Cross-domain direct dependency',
})
}
})
})
return violations
}
## Best Practices
### Do's ✅
- Collaborate with business stakeholders to identify domains
- Group components by business capability, not technical layers
- Ensure domains represent distinct business areas
- Validate domain boundaries with stakeholders
- Refactor namespaces to align with domains
- Create clear domain documentation
- Use business language in domain names
### Don'ts ❌
- Don't create domains based on technical layers (services, controllers, models)
- Don't force components into domains where they don't fit
- Don't skip stakeholder validation
- Don't create too many small domains (aim for 3-7 domains)
- Don't create domains that are too large (monolithic domains)
- Don't ignore components that don't fit (analyze why)
- Don't skip namespace refactoring (critical for clarity)
## Common Domain Patterns
### Typical Domains in Business Applications
- **Customer Domain**: Customer management, profiles, relationships
- **Product Domain**: Product catalog, inventory, pricing
- **Order Domain**: Order processing, fulfillment, shipping
- **Billing Domain**: Invoicing, payments, financial transactions
- **Reporting Domain**: Reports, analytics, dashboards
- **Admin Domain**: User management, system configuration
- **Shared Domain**: Common functionality (login, notification, utilities)
### Domain Size Guidelines
- **Small Domain**: 2-4 components
- **Medium Domain**: 5-8 components
- **Large Domain**: 9-15 components
- **Too Large**: >15 components (consider splitting)
## Next Steps
After creating component domains:
1. **Apply Create Domain Services Pattern** - Extract domains to separate services
2. **Plan Service Extraction** - Create migration plan for domain services
3. **Implement Domain Services** - Move domains to separately deployed services
4. **Monitor Domain Boundaries** - Use fitness functions to enforce boundaries
## Notes
- Domains should represent business capabilities, not technical layers
- Domain identification requires collaboration with business stakeholders
- Namespace refactoring is critical for domain clarity
- Domains prepare the codebase for service-based architecture
- Well-formed domains make service extraction easier
- Domain boundaries should be clear and well-documented
Take tech-leads-club/domain-identification-grouping from the repository into ~/.claude/skills for personal
use, or into .claude/skills inside a project.
The agent identifies a skill by the name field in its header. Two skills with the
same name cannot sit side by side — one of them will be ignored.