Worked on improving analytics reliability in the elastic/elasticsearch repository by addressing a bug in the CuckooFilter merge method that previously led to false positives in rare terms aggregations. Applied Java and backend development skills to correct the merge logic, ensuring accurate results across large datasets. Added comprehensive unit and regression tests to validate the fix and prevent future regressions, thereby enhancing the robustness of analytics pipelines. The work focused on maintaining code quality and reliability, with careful attention to analytics accuracy and test coverage. This contribution strengthened the foundation for dependable rare terms queries in Elasticsearch’s analytics features.