Carlos Fu enhanced observability in distributed systems by developing and documenting new Sentinel telemetry features for both the valkey-io/valkey and redis/redis repositories. He introduced the sentinel_total_tilt metric, exposing cumulative tilt events through the Sentinel INFO command, which enables administrators to monitor system stability and respond proactively to anomalies. His work involved system programming in C and comprehensive documentation in Markdown, ensuring that operational metrics were both robustly implemented and clearly communicated. By focusing on monitoring and Redis Sentinel internals, Carlos delivered features that improved incident response and administrative decision-making, demonstrating depth in distributed systems engineering and cross-repository collaboration.