apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
metadata:
  name: story-crater-backend-rules
  namespace: story-crater-backend
spec:
  groups:
    - name: story-crater-backend.rules
      interval: 15s
      rules:
        - alert: StoryCraterBackendHighErrorRate
          expr: |
            (
              sum(rate(story_crater_app_metric_total{severity="error"}[5m]))
              /
              sum(rate(story_crater_messages_handled_total[5m]))
            ) > 0.05
          for: 10m
          labels:
            severity: warning
          annotations:
            summary: "High application error rate on story-crater-backend"
            description: "Error events exceeded 5% of message volume for 10 minutes. Value: {{ $value | humanizePercentage }}"

        - alert: StoryCraterBackendCheckLatencySLOBreach
          expr: |
            histogram_quantile(0.95, sum(rate(story_crater_check_latency_ms_bucket[5m])) by (le)) > 1200
          for: 10m
          labels:
            severity: critical
          annotations:
            summary: "CheckScene p95 latency breaching NFR-01 (1200ms SLO)"
            description: "p95 CheckScene latency has exceeded 1200ms for 10 minutes. Value: {{ $value }}ms"