ERPNext MCP Server

# ERPNext MCP Server Analysis This document provides an analysis of the current ERPNext MCP server implementation and suggests improvements for better reliability, maintainability, and extensibility. ## Current Implementation Overview The ERPNext MCP server currently provides integration with the ERPNext/Frappe API through: - **Resource access**: Documents can be accessed via `erpnext://{doctype}/{name}` URIs - **Tools**: Several tools for authentication, document manipulation, and report running - **Single-file implementation**: All logic is contained in `src/index.ts` ## Areas for Improvement ### 1. Code Organization **Issues:** - The entire server implementation is in a single file, making it difficult to maintain as it grows - No separation of concerns between API client, MCP server, and request handlers - Mixed business logic and protocol handling **Recommendations:** - Restructure the codebase into multiple modules: ``` src/ ├── client/ │ └── erpnext-client.ts # ERPNext API client logic ├── handlers/ │ ├── resource-handlers.ts # Resource request handlers │ └── tool-handlers.ts # Tool request handlers ├── models/ │ └── types.ts # TypeScript interfaces and types ├── utils/ │ ├── error-handler.ts # Error handling utilities │ ├── logger.ts # Logging utilities │ └── config.ts # Configuration management └── index.ts # Server bootstrap ``` ### 2. Error Handling **Issues:** - Basic error handling with limited categorization - Inconsistent error response formats - No handling of network-specific errors vs. business logic errors **Recommendations:** - Create a dedicated error handling module - Map ERPNext API errors to appropriate MCP error codes - Implement consistent error logging with appropriate detail levels - Add correlation IDs to track errors across requests ### 3. Authentication **Issues:** - Only username/password authentication supported - No token refresh mechanism - API key/secret handling is basic **Recommendations:** - Support modern OAuth-based authentication - Implement token refresh strategy - Add secure credential storage options - Consider implementing session management ### 4. Caching **Issues:** - `doctypeCache` is defined but never used - No caching strategy for frequently accessed data - Each request makes a fresh API call **Recommendations:** - Implement in-memory cache for DocType metadata - Add time-based cache expiration - Consider using a dedicated cache library for more complex scenarios - Add cache invalidation when documents are updated ### 5. Testing **Issues:** - No test suite - No mocking of external dependencies **Recommendations:** - Add unit tests for core functionality - Implement integration tests for ERPNext client - Create mock ERPNext API for testing - Set up CI/CD pipeline with test automation ### 6. Logging **Issues:** - Basic console logging - No structured log format - No log levels for different environments **Recommendations:** - Implement structured logging - Add configurable log levels - Include request/response details for debugging - Consider using a dedicated logging library ### 7. Documentation **Issues:** - Basic README with limited examples - No JSDoc comments for most functions - No detailed API documentation **Recommendations:** - Add comprehensive JSDoc comments - Create detailed API reference - Add code examples for common scenarios - Document error codes and their meanings - Consider generating API docs with TypeDoc ### 8. Configuration **Issues:** - Environment variables handled in an ad-hoc way - No configuration validation - Limited configuration options **Recommendations:** - Create a dedicated configuration module - Add validation for required configuration - Support multiple configuration sources (env vars, config files) - Add configuration schema validation ### 9. Rate Limiting **Issues:** - No protection against excessive API calls - Potential for unintended DoS on ERPNext instance **Recommendations:** - Implement rate limiting for API calls - Add configurable limits per operation - Provide feedback on rate limit status ### 10. Tool Implementation **Issues:** - `get_doctype_fields` has a hacky implementation that loads a sample document - Limited error handling in tool implementations - No pagination support for large result sets **Recommendations:** - Use proper metadata APIs to get DocType fields - Implement pagination for list operations - Add better validation of tool inputs - Consider adding additional useful tools (e.g., bulk operations) ### 11. Security **Issues:** - Passwords are passed directly with no handling recommendations - No security headers or CORS configuration - No input sanitization **Recommendations:** - Add input validation and sanitization - Improve credential handling and provide secure usage guidelines - Document security best practices ### 12. Resource Management **Issues:** - Limited resource implementations compared to tools - No dynamic resource discovery **Recommendations:** - Expand resource capabilities - Implement more resource templates - Add resource discovery mechanism ### 13. Dependency Management **Issues:** - No dependency injection for better testability - Direct dependency on axios without abstraction **Recommendations:** - Implement dependency injection pattern - Create HTTP client abstraction to allow switching libraries - Centralize external dependency management ## Conclusion The ERPNext MCP server provides a solid foundation for integration with ERPNext but could benefit from several improvements to make it more maintainable, robust, and feature-rich. The recommendations provided above would help transform it into a production-ready solution that's easier to maintain and extend.