# Mailbox MCP Server - Improvement Roadmap
## **Immediate Next Steps (High Priority)**
### **Quick Wins (1-2 days)**
#### 1. **Add Structured Error Types**
**Goal**: Create custom error classes for better error handling and debugging
**Implementation**:
- Create `src/types/errors.ts` with custom error classes:
- `ConnectionError` - Network and connection issues
- `AuthenticationError` - Login and credential problems
- `RateLimitError` - API rate limiting issues
- `ValidationError` - Input validation failures
- `MailboxError` - Mailbox.org specific errors
**Benefits**:
- Better error categorization and handling
- Improved debugging experience
- More informative error messages to users
- Structured error logging
#### 2. **Implement Input Validation**
**Goal**: Add comprehensive input sanitization and validation using Zod schemas
**Implementation**:
- Create validation schemas for all tool inputs
- Add runtime validation in tool handlers
- Provide clear validation error messages
- Sanitize potentially dangerous inputs
**Benefits**:
- Enhanced security against malicious inputs
- Better user experience with clear error messages
- Type safety at runtime
- Consistent input handling across all tools
#### 3. **Enhanced Logging**
**Goal**: Add MCP-compliant structured logging with different levels and context
**Implementation**:
- Replace console.log with stderr logging for development/debugging
- Implement MCP logging notifications (`notifications/message`) for client integration
- Add log levels (debug, info, warn, error, critical) per RFC 5424
- Include request context and timing in structured log data
- Add performance metrics logging through MCP notifications
**Benefits**:
- MCP protocol compliance (stdout reserved for JSON-RPC)
- Better debugging capabilities with client-visible logs
- Production-ready logging through proper channels
- Performance monitoring accessible to clients
- Easier troubleshooting with structured log data
**Important Note**: MCP servers must use stderr for console output and MCP logging notifications for client-visible logs. stdout is reserved for JSON-RPC communication.
#### 4. **Configuration Validation**
**Goal**: Validate environment variables and configuration on startup
**Implementation**:
- Add Zod schema for configuration validation
- Validate all environment variables at startup
- Provide clear error messages for missing/invalid config
- Add configuration documentation generation
**Benefits**:
- Fail fast on misconfiguration
- Clear setup instructions
- Reduced runtime errors
- Better developer experience
---
## **Medium-term Goals (1-2 weeks)**
### **Feature Enhancements**
#### 1. **Email Composition Enhancements**
- Add email templates support
- Implement delayed/scheduled email sending
- Add rich text formatting options
- Support for email signatures
#### 2. **Calendar Event Creation**
- Implement full CRUD operations for calendar events
- Add meeting invitation handling
- Support for recurring event creation
- Calendar sharing and permissions
#### 3. **Contact Management (CardDAV)**
- Add CardDAV integration for contacts
- Implement contact search and retrieval
- Support for contact groups and categories
- Contact synchronization
#### 4. **Performance Monitoring**
- Add metrics collection endpoints
- Implement health check endpoints
- Create performance dashboards
- Add alerting for critical issues
---
## **Long-term Improvements (1+ months)**
### **Advanced Features**
#### 1. **OAuth2 Support**
- Add modern authentication methods
- Support for multiple OAuth providers
- Token refresh and management
- Enhanced security features
#### 2. **Background Synchronization**
- Implement intelligent background sync
- Delta synchronization for efficiency
- Offline capability improvements
- Real-time notifications
#### 3. **Advanced Search**
- Full-text search with indexing
- Search across multiple data types
- Advanced filtering and sorting
- Search result highlighting
#### 4. **Multi-account Support**
- Support multiple email/calendar accounts
- Account switching and management
- Cross-account operations
- Unified inbox and calendar views
---
## **Most Impactful Starting Points**
### **Recommended Implementation Order**
1. **🚀 Custom Error Types** - Foundation for all error handling improvements
2. **🔒 Input Validation** - Critical for security and reliability
3. **📊 Enhanced Logging** - Essential for debugging and monitoring
4. **⚙️ Configuration Validation** - Improves setup experience and reliability
### **Success Metrics**
- **Error Resolution Time**: Reduce debugging time by 50%
- **Security Incidents**: Zero input-related security issues
- **Setup Success Rate**: 95% successful first-time setups
- **Performance Visibility**: 100% operation visibility through logs
### **Implementation Notes**
- Start with error types as they provide foundation for other improvements
- Use TDD approach for all new features
- Maintain backward compatibility
- Add comprehensive tests for each improvement
- Update documentation alongside code changes
---
## **Getting Started**
To begin implementing these improvements:
1. **Review Current Error Handling**: Analyze existing error patterns
2. **Create Error Type Hierarchy**: Design the error class structure
3. **Implement Gradually**: Start with most critical error types first
4. **Add Tests**: Ensure comprehensive test coverage
5. **Update Documentation**: Keep docs current with changes
**Next Action**: Begin with creating `src/types/errors.ts` and implementing the base error classes.
