Klaviyo MCP Server

# Enhanced JSON Error Handling for Klaviyo MCP This documentation covers the advanced JSON error handling implementation for the Klaviyo MCP Server. The solution addresses JSON parsing errors that were being displayed to users as popup warnings, creating a more seamless and professional experience. ## Background The previous implementation used a basic error handler that suppressed errors but did not fully resolve the underlying issues with JSON parsing in the MCP communication. This led to error popups appearing in the UI despite the server continuing to function. ## Implementation Overview The enhanced error handling system follows a vertical slice architecture and consists of three main components: 1. **JSON Parser** (`json_parser.js`) - Provides utilities for sanitizing and safely parsing potentially malformed JSON 2. **MCP Handler** (`mcp_handler.js`) - Enhances the MCP transport layer to better handle JSON errors 3. **Integration Module** (`index.js`) - Ties everything together and provides a clean API ## Key Features ### JSON Sanitization The system can automatically repair common JSON syntax issues: - Missing closing braces and brackets - Unmatched quotes - Single quotes used instead of double quotes - Trailing commas - Missing commas between properties - Unescaped control characters - Trailing content after valid JSON ### Safe Buffer Processing The enhanced MCP handler implements: - Recovery from parsing errors without crashing - Skipping of malformed messages to prevent getting stuck - Buffer sanitization to handle partial or corrupted inputs - Custom error handling to prevent error popups ### Error Logging All errors are properly logged with: - Debug-level logging for non-critical errors - Detailed information about the error type and location - Success messages when recovery is successful ## Integration The error handling system is integrated into the MCP server through the `initErrorHandling` function, which patches the transport layer to use our enhanced error handling. ```javascript import { initErrorHandling } from './features/error_handling/index.js'; // When setting up the server: const transport = new StdioServerTransport(); initErrorHandling(server, transport); ``` ## Testing A dedicated test script (`test-json-error-handling.js`) is provided to validate the error handling capabilities against various types of malformed JSON inputs. To run the tests: ```bash node test-json-error-handling.js ``` This will run a series of test cases and report on the success rate of the JSON sanitization. ## Edge Cases Handled The implementation handles many edge cases: 1. **Partial JSON** - When a message is cut off mid-transmission 2. **Invalid Characters** - When non-JSON characters appear in the stream 3. **Recovery Failures** - Graceful handling when sanitization fails 4. **Buffer Management** - Preventing buffer bloat from corrupted inputs ## Performance Considerations The enhanced error handling system is designed to be lightweight: - Sanitization only occurs when an error is detected (not on every message) - Buffer operations are optimized to avoid unnecessary copying - Successful parses bypass the error handling logic entirely ## Further Improvements Potential future enhancements: 1. **Machine Learning** - Implement a learning system that improves sanitization over time 2. **Protocol Negotiation** - Detect client capabilities and adjust error handling accordingly 3. **Error Metrics** - Track error rates and patterns for better debugging ## Conclusion The enhanced JSON error handling system significantly improves the user experience by eliminating error popups while maintaining the full functionality of the Klaviyo MCP Server. It follows a clean architecture pattern that makes it easy to maintain and extend as needed.