# Implementation Plan
- [x] 1. Set up project structure and core dependencies
- Initialize Node.js TypeScript project with proper configuration
- Install MCP SDK, AWS SDK v3, authentication libraries, and testing frameworks
- Configure build system, linting, and development environment
- Set up SQLite database schema for billing data caching
- _Requirements: 1.1, 2.1, 4.1, 7.1_
- [x] 1.1 Write property test for project initialization
- **Property 13: Comprehensive logging**
- **Validates: Requirements 7.1**
- [x] 2. Implement AWS credential management and validation
- Create credential storage with encryption at rest
- Implement AWS credential validation against AWS APIs
- Add support for multiple AWS account configurations
- Build credential rotation and refresh mechanisms
- _Requirements: 1.1, 1.2, 1.3, 1.4, 1.5_
- [x] 2.1 Write property test for credential validation
- **Property 1: Credential validation consistency**
- **Validates: Requirements 1.1, 1.3**
- [x] 2.2 Write property test for credential encryption
- **Property 2: Credential encryption at rest**
- **Validates: Requirements 1.4**
- [x] 2.3 Write property test for multi-account management
- **Property 3: Multi-account unique identification**
- **Validates: Requirements 1.5**
- [x] 3. Build AWS billing data integration
- Implement AWS Cost Explorer API client with retry logic
- Create billing data retrieval and parsing functionality
- Build data caching layer with SQLite storage
- Add automatic data refresh scheduling (24-hour intervals)
- _Requirements: 2.1, 2.2, 2.3, 2.4, 2.5_
- [x] 3.1 Write property test for data structure consistency
- **Property 4: Data structure consistency**
- **Validates: Requirements 2.2, 2.5**
- [x] 3.2 Write property test for retry logic
- **Property 5: Retry logic consistency**
- **Validates: Requirements 2.3, 6.1**
- [x] 4. Implement Google SSO authentication system
- Set up Google OAuth2 integration with proper scopes
- Create JWT session token management
- Build user permission and authorization system
- Implement session expiration and refresh logic
- _Requirements: 4.1, 4.2, 4.3, 4.4, 4.5_
- [x] 4.1 Write property test for authentication state management
- **Property 9: Authentication state management**
- **Validates: Requirements 4.2, 4.3, 4.4**
- [x] 4.2 Write property test for authorization validation
- **Property 10: Authorization validation**
- **Validates: Requirements 4.5**
- [x] 5. Create billing analysis and query engine
- Implement cost analysis algorithms for filtering and aggregation
- Build usage comparison and percentage calculation functions
- Create trend analysis and anomaly detection algorithms
- Add cost ranking and top driver identification
- _Requirements: 3.2, 3.3, 3.4, 3.5, 5.1, 5.2, 5.3, 5.4_
- [x] 5.1 Write property test for query filtering
- **Property 6: Query filtering accuracy**
- **Validates: Requirements 3.2, 5.1, 5.2**
- [x] 5.2 Write property test for cost calculations
- **Property 7: Cost calculation accuracy**
- **Validates: Requirements 3.3, 5.3**
- [x] 5.3 Write property test for anomaly detection
- **Property 8: Anomaly detection consistency**
- **Validates: Requirements 3.5**
- [x] 6. Build MCP server and tool registry
- Implement MCP protocol server using official SDK
- Create tool registry for billing analysis functions
- Build tool parameter validation and routing
- Add structured JSON response formatting for LLM consumption
- _Requirements: 3.1, 5.5_
- [x] 6.1 Write property test for response formatting
- **Property 11: Response format consistency**
- **Validates: Requirements 5.5**
- [x] 7. Implement comprehensive error handling
- Add rate limiting and exponential backoff for AWS APIs
- Create network failure handling with cached data fallback
- Build parameter validation with descriptive error messages
- Implement resource management and priority handling
- _Requirements: 6.1, 6.2, 6.3, 6.4, 6.5_
- [x] 7.1 Write property test for error handling
- **Property 12: Error handling consistency**
- **Validates: Requirements 6.1, 6.2, 6.3**
- [x] 8. Add logging and monitoring infrastructure
- Implement structured logging for all operations
- Add request/response logging with performance metrics
- Create security event logging for authentication
- Build metrics exposure for monitoring integration
- _Requirements: 7.1, 7.2, 7.3, 7.4, 7.5_
- [x] 8.1 Write property test for comprehensive logging
- **Property 13: Comprehensive logging**
- **Validates: Requirements 7.1, 7.2, 7.3, 7.4**
- [x] 9. Checkpoint - Ensure all tests pass
- Ensure all tests pass, ask the user if questions arise.
- [x] 10. Create MCP tool implementations
- Implement cost analysis tool with filtering capabilities
- Build usage comparison tool with percentage calculations
- Create trend analysis tool with pattern recognition
- Add anomaly detection tool with baseline comparison
- Build top cost drivers tool with ranking functionality
- _Requirements: 3.1, 3.2, 3.3, 3.4, 3.5_
- [x] 10.1 Write unit tests for MCP tools
- Create unit tests for cost analysis tool
- Write unit tests for usage comparison tool
- Add unit tests for trend analysis tool
- Build unit tests for anomaly detection tool
- Create unit tests for cost ranking tool
- _Requirements: 3.1, 3.2, 3.3, 3.4, 3.5_
- [x] 11. Integrate authentication with MCP server
- Add authentication middleware to MCP server
- Implement session validation for tool access
- Create user permission checking for billing data access
- Build secure error responses without information leakage
- _Requirements: 4.1, 4.2, 4.3, 4.4, 4.5_
- [x] 11.1 Write integration tests for authenticated MCP access
- Test authenticated tool access flows
- Verify session validation and expiration handling
- Test permission-based access control
- Validate secure error responses
- _Requirements: 4.1, 4.2, 4.3, 4.4, 4.5_
- [x] 12. Final integration and configuration
- Wire together all components into main server application
- Create configuration management for deployment settings
- Add startup validation and health check endpoints
- Implement graceful shutdown and cleanup procedures
- _Requirements: All requirements integration_
- [x] 12.1 Write end-to-end integration tests
- Test complete billing query workflows
- Verify AWS integration with authentication
- Test error scenarios and recovery
- Validate performance under load
- _Requirements: All requirements integration_
- [x] 13. Final Checkpoint - Ensure all tests pass
- Ensure all tests pass, ask the user if questions arise.
- [x] 14. Simplify for Claude Desktop Personal Use
- Remove complex credential database storage and encryption
- Implement direct environment variable credential access
- Remove HTTP health check endpoint to eliminate port conflicts
- Disable authentication by default for personal use
- Update documentation and configuration for simplified setup
- Clean up unnecessary test and diagnostic files
- _Requirements: Simplified architecture for Claude Desktop_
- [x] 14.1 Update specifications and documentation
- Update requirements document to reflect simplified approach
- Modify design document for Claude Desktop optimization
- Update deployment guide with simplified setup instructions
- Clean up project files and remove unnecessary complexity
- _Requirements: Documentation consistency_
