Worked on the vercel/vercel repository to enhance observability of caching behavior by introducing cacheReason visibility in log outputs. Implemented changes in TypeScript to ensure that both cache status and the underlying reason for cache MISS, BYPASS, or STALE events are included in vc logs, improving transparency for developers. Mapped cacheReason into RequestLogEntry types and ensured the data flowed correctly through backend and frontend logging systems. Coordinated with related services to surface this information in production logs, supporting consistent issue tracing. Added unit tests to verify correct propagation of cacheReason, strengthening troubleshooting capabilities and enabling more informed performance tuning.