# Pure
## Purpose
Pure functional components implementing business logic without side effects, enabling maximum testability, thread safety, and mathematical verification.
## Key Components
- **functional_core.py**: Pure functions for agent lifecycle, session management, security validation, message processing, and performance calculation with comprehensive mathematical properties
## Architecture & Dependencies
**External**: datetime, pathlib, typing, decimal for precise calculations and type safety
**Internal**: Types system for domain objects and validation, no circular dependencies
**Patterns**:
- Functional Core, Imperative Shell pattern for clean architecture
- Result type for functional error handling without exceptions
- Pure functions with immutable data for thread safety and predictability
- Mathematical properties for property-based testing verification
## Critical Considerations
- **Security**: All functions implement security validation through pure computation without side effects
- **Performance**: O(1) to O(log n) operations with deterministic complexity and no hidden state mutations
- **Integration**: Pure functions compose seamlessly with imperative shell components for complete system integration
## Related Documentation
- [Functional Programming Guide](../../docs/patterns/functional_programming.md) - Functional programming principles and patterns
- [Property-Based Testing](../../tests/properties/README.md) - Mathematical property verification approach
