During November 2025, Quagsirus focused on backend stability for the tailscale/tailscale repository, addressing a regression in client metrics collection. They identified and resolved an issue where Metric.v was left uninitialized when building with the ts_omit_logtail flag, which risked missing telemetry in production dashboards. Using Go, Quagsirus implemented the fix within util/clientmetric, ensuring consistent metrics initialization across build configurations. Their work involved regression debugging, validation across affected builds, and collaboration through code review. While the period did not include new feature development, the targeted bug fix demonstrated depth in Go-based backend engineering and a strong focus on production observability.