Developed the MetricChangeAnalysisTool for the opensearch-project/skills repository, enabling percentile-based detection of metric changes between baseline and selection periods. The tool analyzes metrics using Java and OpenSearch, ranking fields by relative change and supporting configurable parameters such as topN selection. To streamline data retrieval and analysis, a reusable DataFetchingHelper was implemented and integrated into both the new tool and the existing DataDistributionTool, reducing code duplication and maintaining prior functionality. Comprehensive test coverage was achieved with 16 new unit tests and successful execution of the full 97-test suite, ensuring CI stability and the seamless introduction of enhanced analytics capabilities.