# Specification: [FEATURE_NAME]

**Version:** [X.Y.Z]  
**Created:** [YYYY-MM-DD]  
**Last Updated:** [YYYY-MM-DD]  
**Status:** [Draft | Review | Approved | Implemented]  
**Owner:** [OWNER_NAME]  

## Purpose

Clear statement of what this specification defines and its business/technical value.

## Requirements

### Functional Requirements

#### FR1: [Requirement Name]
**Priority:** [Critical | High | Medium | Low]  
**Description:** Detailed description of the requirement.

**Acceptance Criteria:**
- [ ] Criterion 1 (testable condition)
- [ ] Criterion 2 (testable condition)
- [ ] Criterion 3 (testable condition)

**Constitutional Alignment:**
- Testing: [How this will be tested per Principle 2]
- UX Impact: [User-facing implications per Principle 3]
- Performance: [Performance considerations per Principle 4]

#### FR2: [Requirement Name]
[Repeat structure above]

### Non-Functional Requirements

#### NFR1: Performance
Per Constitutional Principle 4:
- Response time: [target, e.g., <200ms for p95]
- Throughput: [target, e.g., >1000 req/s]
- Resource limits: [memory/CPU bounds]
- Scalability: [expected load ranges]

#### NFR2: Quality
Per Constitutional Principle 1:
- Code coverage: ≥80% (Principle 2 requirement)
- Linting: Zero errors/warnings
- Type safety: Full type hints on public APIs
- Documentation: All public APIs documented

#### NFR3: User Experience
Per Constitutional Principle 3:
- Accessibility: WCAG 2.1 AA compliance
- Error handling: User-friendly messages
- Consistency: Follows existing design patterns
- Response feedback: <200ms or progress indicators

#### NFR4: Maintainability
Per Constitutional Principle 1:
- Complexity: Cyclomatic complexity <10 per function
- Dependencies: Explicit versioning, security audit
- Modularity: Clear separation of concerns

## Design

### Architecture Overview
[Diagram or description of system components and their interactions]

### Data Models
```python
# Example data structures with type hints
class ExampleModel:
    """Clear docstring explaining purpose."""
    field1: str
    field2: int
    field3: Optional[List[str]]
```

### API/Interface Specifications

#### Endpoint/Method: [Name]
```python
def example_function(param1: str, param2: int) -> ResultType:
    """
    Clear description of what this does.
    
    Args:
        param1: Description of parameter
        param2: Description of parameter
        
    Returns:
        Description of return value
        
    Raises:
        ValueError: When validation fails
    """
    pass
```

**Error Handling:**
- Error case 1: Response/behavior
- Error case 2: Response/behavior

### Testing Strategy

#### Unit Tests
- Component A: [Test scenarios]
- Component B: [Test scenarios]
- Edge cases: [List critical edge cases]

#### Integration Tests
- Integration point 1: [Test scenario]
- Integration point 2: [Test scenario]

#### Performance Tests
- Benchmark 1: [Target metric]
- Load test: [Expected traffic pattern]

## Implementation Considerations

### Performance Analysis
- Algorithmic complexity: [Big-O analysis]
- Database queries: [Query plans, indexes needed]
- Caching strategy: [What, when, invalidation]
- Bottleneck prevention: [Known risks and mitigations]

### Security Considerations
- Authentication/Authorization requirements
- Input validation requirements
- Data protection measures

### Migration Path
If this changes existing functionality:
- Backward compatibility strategy
- User migration steps
- Rollback plan

## Dependencies

### Internal Dependencies
- Module/Service A: [Why needed]
- Module/Service B: [Why needed]

### External Dependencies
```python
# New dependencies to add (with justification)
package-name==X.Y.Z  # Why: specific reason for this dependency
```

## Rollout Plan

1. **Development:** [Timeline and milestones]
2. **Testing:** [QA approach and environments]
3. **Staging:** [Validation steps]
4. **Production:** [Deployment strategy - canary/blue-green/etc]
5. **Monitoring:** [Key metrics to watch]

## Success Metrics

Post-deployment validation:
- [ ] All acceptance criteria met
- [ ] Performance benchmarks achieved
- [ ] Zero critical bugs in first week
- [ ] User feedback collected and positive
- [ ] Test coverage ≥80% maintained

## Open Issues

- [ ] Issue 1 requiring resolution
- [ ] Issue 2 needing decision

## Appendix

### References
- Related specifications
- External documentation
- Research materials

### Change Log
| Version | Date | Author | Changes |
|---------|------|--------|---------|
| 1.0.0 | YYYY-MM-DD | Name | Initial specification |