The suite’s ground truth. Every service declares itself in a catalogue — how to probe it, how to restart it, what secrets it consumes — and Watchdog holds the estate to a measured durability SLO against that declaration. Its diagnostic module does deep rounds across ports, processes, certificates and drift, grounded in a local knowledge bank of past incidents. Its hardest-won lesson: alert noise fails exactly like silence, so the taxonomy of what pings the keeper is engineered as carefully as the monitoring itself.