Test incident response signals and thresholds

You own a citation-producing RAG API at POST /v1/research. The goal is to coordinate detection, severity, roles, mitigation, evidence, and communication during a user-visible correctness incident. The measurable target is declare SEV-1 within 8 minutes when more than 5% of answers cite nonexistent documents, assign commander/comms/operations roles, disable the faulty reranker within 12 minutes, and preserve a timestamped evidence bundle. The known production tension is fast rollback limits harm but may erase runtime evidence; broad shutdown is simple but denies service to unaffected tenants that could safely remain online.

Convert the Incident response objective into tests, not screenshots. The target is declare SEV-1 within 8 minutes when more than 5% of answers cite nonexistent documents, assign commander/comms/operations roles, disable the faulty reranker within 12 minutes, and preserve a timestamped evidence bundle. Write one assertion for the exact boundary, one immediately inside it, and one immediately outside it. Include denominator behavior when traffic is zero, missing, duplicated, delayed, or partially sampled.

The telemetry contract is citation_validation_failures_total, affected_answers_total{tenant}, incident_mttd_seconds, incident_mttm_seconds, deployment_version, and feature_flag_state. For every series, verify metric type, unit, label allowlist, ownership, and retention. Counters must only rise; histograms need buckets around the target; gauges require staleness handling. Confirm dashboards display demand, successful or protected outcomes, user latency or age, saturation, and version context together. A green ratio without its event count is not sufficient evidence.

Run the test workflow:

pytest -q tests/test_incident_policy.py
./ops/game-day assert SIM-CITATIONS --mitigated-under 720 --evidence-complete

Store machine-readable output as a build artifact. Seed deterministic time or fixtures where possible, but keep at least one integration test against the actual collector and rule engine. Tests must fail when the threshold expression, label name, or alert receiver is intentionally broken. A test that remains green after its signal is disconnected is worse than no test because it creates false confidence.

Use the configured contract:

severity_rules:
  sev1:
    any:
      - citation_failure_rate: "> 0.05 for 5m"
      - regulated_tenant_affected: true
roles: [incident_commander, operations, communications, scribe]
mitigations:
  - disable_flag: reranker_v2
  - rollback: reranker
evidence_retention_days: 90

Replay the controlled scenario—deploy a reranker that reverses relevance scores for one tenant and introduces fabricated citation IDs; responders must distinguish correctness failure from availability and roll back only the implicated component.—and measure time from fault start to metric visibility, alert pending, alert firing, delivery, acknowledgement where relevant, mitigation, and stable recovery. Compare those times with the operational objective. Verify short benign blips do not page if the policy says they should not, while sustained or fast-burning impact does.

Check telemetry loss separately from service loss. Stop or misconfigure one scrape target and prove the system reports missing data rather than silently treating it as healthy. Verify logs and drill artifacts redact secrets and private payloads. Bound label cardinality using a representative workload and set an alert or budget for unexpected series growth.

Use the prior incident—reranker v2.7 sorted ascending scores, producing 11.8% invalid citations for legal-research users while HTTP latency and status dashboards remained green.—to ask which test would have detected the problem earlier. Remove or demote signals that do not lead to a decision. The production tradeoff is fast rollback limits harm but may erase runtime evidence; broad shutdown is simple but denies service to unaffected tenants that could safely remain online. Quantify the cost of collection and paging against the risk reduction it buys.

This page passes only when contract tests, failure tests, alert-path tests, and recovery assertions all run from a clean environment and produce retained evidence linked to the configuration revision.