Worked on the percona/percona-server-mongodb repository, delivering a focused refactor of the ExpressionContext to improve maintainability and parameter correctness. The approach involved removing duplicate members and consolidating configuration and operational data into ExpressionContextParams, ensuring all necessary parameters were consistently passed and accessible during expression evaluation. This C++ development effort emphasized code cleanup and object-oriented design, resulting in a cleaner and more reliable core path for query expression evaluation. By centralizing data and streamlining parameter propagation, the changes reduced future maintenance risks and enabled safer refactoring, while also enhancing testability and extensibility for ongoing and future development needs.