Worked on the yugabyte/yugabyte-db repository to enhance the reliability of XCluster replication setup by addressing a critical validation issue. Developed an early rejection mechanism for the sequences_data table during manual universe replication, ensuring that attempts to replicate this table are blocked with clear error messages. This approach, implemented in C++ with a focus on backend development and rigorous testing, included the addition of targeted end-to-end tests to verify correct handling and maintain the stability of existing replication workflows. The fix prevents data duplication or misconfiguration, ultimately reducing operational support needs and improving the clarity of error reporting for operators.