# Specs Horizontal Instructions
## Purpose
The Specs horizontal defines the functional and non-functional requirements, business rules, and acceptance criteria for each vertical component. It serves as the authoritative specification that guides development, testing, and validation across all system layers.
## Content Requirements
### Required Sections
1. **Functional Requirements**
- User stories and use cases
- Business process flows
- Feature specifications
- Input/output requirements
2. **Non-Functional Requirements**
- Performance requirements (latency, throughput)
- Scalability requirements (concurrent users, data volume)
- Security requirements (authentication, authorization, encryption)
- Availability requirements (uptime, disaster recovery)
3. **Business Rules**
- Domain-specific constraints
- Validation rules and logic
- Workflow rules and approvals
- Compliance and regulatory requirements
4. **Acceptance Criteria**
- Definition of done for features
- Quality gates and checkpoints
- User acceptance test scenarios
- Success metrics and KPIs
5. **Constraints and Assumptions**
- Technical constraints and limitations
- Business assumptions and dependencies
- Resource constraints (time, budget, personnel)
- External dependencies and integrations
### Documentation Format
```yaml
feature:
name: "User Registration"
epic: "User Management"
priority: "high"
user_stories:
- id: "US001"
title: "As a new user, I want to register an account"
description: |
As a potential customer visiting the website,
I want to create a new account with my email and password,
So that I can access personalized features and make purchases.
acceptance_criteria:
- "Given I am on the registration page"
- "When I enter a valid email and secure password"
- "Then I should receive a confirmation email"
- "And my account should be created in pending status"
- "And I should be redirected to the email verification page"
business_rules:
- "Email must be unique across the system"
- "Password must meet security policy requirements"
- "Account activation required within 24 hours"
- "Duplicate registrations should be prevented"
performance_requirements:
- "Registration should complete within 3 seconds"
- "System should handle 100 concurrent registrations"
- "Confirmation email should be sent within 30 seconds"
security_requirements:
- "Passwords must be hashed using bcrypt with salt"
- "Email verification token must expire in 24 hours"
- "Rate limiting: 5 registration attempts per IP per hour"
```
## Validation Rules
### Quality Control
1. **Completeness**
- All user stories must have acceptance criteria
- All features must have defined business rules
- All requirements must be testable and measurable
- All dependencies must be identified and documented
2. **Clarity and Consistency**
- Requirements must be unambiguous and specific
- Terminology must be consistent across documents
- Requirements must not contradict each other
- Acceptance criteria must be clearly defined
3. **Traceability**
- Requirements must trace to business objectives
- Features must trace to user needs
- Test cases must trace to requirements
- Implementation must trace to specifications
4. **Feasibility**
- Requirements must be technically achievable
- Performance targets must be realistic
- Resource estimates must be accurate
- Timeline expectations must be feasible
### Automated Checks
- Requirement completeness validation
- Consistency checking across specifications
- Traceability matrix generation
- Requirements change impact analysis
- Acceptance criteria coverage verification
## Evolution Rules
### Across Verticals (Left to Right)
1. **Foundation → Core**
- Basic requirements evolve into detailed business logic
- Simple use cases become complex workflow specifications
- Generic requirements become domain-specific rules
2. **Core → Integration**
- Internal requirements expand to external interface specs
- Single-system requirements become multi-system orchestration
- Synchronous requirements include asynchronous patterns
3. **Integration → Extension**
- Fixed requirements become configurable specifications
- Standard requirements include customization points
- Monolithic requirements become modular and pluggable
### Specification Maturity Levels
- **Level 1**: Basic user stories with minimal acceptance criteria
- **Level 2**: Detailed requirements with business rules and constraints
- **Level 3**: Comprehensive specifications with performance and security requirements
- **Level 4**: Dynamic specifications with AI-assisted requirement generation
## Dependencies
### Upstream Dependencies
1. **Business Strategy**
- Business objectives and goals
- Market requirements and competition analysis
- User research and personas
- Revenue and cost models
2. **Stakeholder Input**
- User feedback and requirements
- Product management priorities
- Technical architecture constraints
- Compliance and regulatory requirements
### Downstream Dependencies
1. **Schema Horizontal**
- Data model requirements
- Validation rule specifications
- Relationship constraints
2. **API Horizontal**
- Interface requirement specifications
- Authentication and authorization requirements
- Performance and rate limiting requirements
3. **Tests Horizontal**
- Test scenario generation
- Acceptance criteria validation
- Performance benchmark requirements
4. **Frontend Horizontal**
- User experience requirements
- Accessibility specifications
- Browser compatibility requirements
5. **Backend Horizontal**
- Performance and scalability requirements
- Security implementation requirements
- Integration specifications
## Best Practices
### Requirements Engineering
1. **User-Centered Design**
- Focus on user needs and goals
- Use personas and user journey mapping
- Validate requirements with actual users
- Prioritize based on user value
2. **Agile Requirements**
- Write requirements as user stories
- Use acceptance criteria for validation
- Maintain a prioritized product backlog
- Refine requirements iteratively
3. **Behavior-Driven Development**
- Use Given-When-Then format for scenarios
- Focus on behavior rather than implementation
- Collaborate with stakeholders on examples
- Maintain living documentation
4. **Requirements Traceability**
- Link requirements to business objectives
- Trace features to user needs
- Connect test cases to requirements
- Track implementation to specifications
### Common Specification Patterns
```gherkin
# User Story Pattern
Feature: User Authentication
As a registered user
I want to log into my account
So that I can access my personal information
Background:
Given I am a registered user with email "user@example.com"
And my password is "SecurePassword123"
Scenario: Successful login with valid credentials
Given I am on the login page
When I enter my email "user@example.com"
And I enter my password "SecurePassword123"
And I click the "Login" button
Then I should be redirected to the dashboard
And I should see a welcome message "Welcome back, John"
And my session should be established
Scenario: Failed login with invalid password
Given I am on the login page
When I enter my email "user@example.com"
And I enter an incorrect password "WrongPassword"
And I click the "Login" button
Then I should see an error message "Invalid email or password"
And I should remain on the login page
And my failed login attempt should be logged
Scenario: Account lockout after multiple failed attempts
Given I have failed to login 4 times in the last hour
When I attempt to login with incorrect credentials again
Then my account should be temporarily locked
And I should see a message "Account locked due to multiple failed attempts"
And I should receive an email notification about the lockout
```
```yaml
# Business Rules Pattern
business_rules:
user_registration:
- rule_id: "BR001"
description: "Email uniqueness constraint"
logic: "Each email address can only be associated with one active account"
validation: "System must reject registration if email already exists"
exception: "Soft-deleted accounts may reuse email after 30 days"
- rule_id: "BR002"
description: "Password security policy"
logic: |
Password must contain:
- Minimum 8 characters
- At least one uppercase letter
- At least one lowercase letter
- At least one number
- At least one special character
validation: "System must validate password on client and server side"
exception: "Legacy users may keep existing passwords until next change"
account_verification:
- rule_id: "BR003"
description: "Email verification requirement"
logic: "All new accounts must verify email within 24 hours"
validation: "Unverified accounts cannot access protected features"
exception: "Admin-created accounts may bypass verification"
```
## Non-Functional Requirements
### Performance Requirements
```yaml
performance:
response_times:
page_load: "< 2 seconds (95th percentile)"
api_response: "< 500ms (95th percentile)"
database_query: "< 100ms (average)"
search_results: "< 1 second (95th percentile)"
throughput:
concurrent_users: 1000
requests_per_second: 500
transactions_per_minute: 10000
scalability:
horizontal_scaling: "Auto-scale from 2 to 20 instances"
database_scaling: "Read replicas for geographic distribution"
cdn_usage: "Static assets served via CDN"
resource_limits:
memory_usage: "< 512MB per instance"
cpu_usage: "< 70% under normal load"
disk_usage: "< 80% of allocated space"
```
### Security Requirements
```yaml
security:
authentication:
methods: ["email_password", "oauth_google", "oauth_github"]
session_timeout: "24 hours inactive, 7 days absolute"
password_policy: "As defined in BR002"
multi_factor: "Optional for users, required for admins"
authorization:
model: "Role-Based Access Control (RBAC)"
roles: ["user", "moderator", "admin", "super_admin"]
permissions: "Fine-grained resource-based permissions"
inheritance: "Role hierarchy with permission inheritance"
data_protection:
encryption_at_rest: "AES-256 for sensitive data"
encryption_in_transit: "TLS 1.3 for all communications"
pii_handling: "GDPR and CCPA compliant data processing"
data_retention: "User data retained for 7 years after deletion"
compliance:
standards: ["OWASP Top 10", "ISO 27001", "SOC 2"]
auditing: "All user actions logged and retained for 2 years"
vulnerability_scanning: "Weekly automated security scans"
penetration_testing: "Annual third-party security assessment"
```
### Availability Requirements
```yaml
availability:
uptime:
target: "99.9% (8.76 hours downtime per year)"
measurement: "Monthly uptime calculation"
exclusions: "Planned maintenance windows"
disaster_recovery:
rto: "4 hours (Recovery Time Objective)"
rpo: "1 hour (Recovery Point Objective)"
backup_frequency: "Real-time replication + daily snapshots"
geographic_distribution: "Multi-region deployment"
maintenance:
planned_maintenance: "Monthly 2-hour window, off-peak hours"
emergency_maintenance: "As needed with 1-hour notice"
rollback_capability: "Ability to rollback within 15 minutes"
```
## Integration Guidelines
### Requirements Management
1. **Version Control**
- Track all requirement changes
- Maintain requirement baselines
- Document change rationale
- Link changes to business justification
2. **Stakeholder Collaboration**
- Regular requirement review sessions
- Stakeholder sign-off on major changes
- Feedback loop with development teams
- User validation of requirements
3. **Requirements Testing**
- Every requirement must be testable
- Acceptance criteria must be verifiable
- Performance requirements must be measurable
- Business rules must be validatable
### Tools and Standards
- **Requirements Management**: Jira, Azure DevOps, Confluence
- **Documentation**: Markdown, AsciiDoc, Sphinx
- **Behavior Specification**: Gherkin, Cucumber, SpecFlow
- **Modeling**: UML, BPMN, ArchiMate
- **Prototyping**: Figma, Sketch, InVision
- **Validation**: User testing platforms, A/B testing tools
## Quality Assurance
### Requirements Review Checklist
- [ ] All requirements are clearly defined and unambiguous
- [ ] Acceptance criteria are specific and testable
- [ ] Business rules are documented and validated
- [ ] Performance requirements are measurable
- [ ] Security requirements are comprehensive
- [ ] Dependencies are identified and managed
- [ ] Constraints and assumptions are documented
- [ ] Requirements trace to business objectives
- [ ] Stakeholders have reviewed and approved
- [ ] Technical feasibility has been confirmed
### Continuous Improvement
- Regular retrospectives on requirements quality
- Metrics tracking on requirement changes and defects
- User feedback integration into requirement refinement
- Automated validation of requirement completeness
- Best practice sharing across teams and projects
