Run the on-call operations baseline

Code the narrow path that serves primary engineer receiving SEV2 after hours: accept → authorize/normalize → call dependency → validate → record. Keep stages named so a trace can show which boundary passed. Success must emit evidence useful to ack_minutes and pages_per_week, not only a 200 with prose. Predict the observable for PagerDuty schedule ai-answer-primary before running: game day: primary misses ACK → secondary owns INC-OC-554 in 15m with access grant.

Drive the path with recording fakes or local stubs. Assert call order and arguments. Idempotency keys or stable ids should keep retries from duplicating costly work where the product requires it. Product under test remains humane escalation path for production AI answer platform — resist adding unrelated features mid-path.

For On-call lab, paste the CLI/HTTP transcript beside your prediction for PagerDuty schedule ai-answer-primary. If the oracle is unmet (game day: primary misses ACK → secondary owns INC-OC-554 in 15m with access grant), stop and debug this page; do not compensate with prompt folktales. Re-run once after a clean process start to catch hidden global state that would invalidate INC-OC-554.

Performance sketch: measure local p95 for the fake-backed path so later regressions are obvious. Keep concurrency modest until failure-handling proves limits. Log a single structured event per success with request id, revision, and the evidence field behind ack_minutes and pages_per_week. Avoid hidden global caches in the happy path unless the lab is about caching — and even then key by tenant. If the path calls a model, pin model id in config and echo it in the response for auditability. Remember primary engineer receiving SEV2 after hours experiences wall-clock time, not your debugger’s single-step comfort.

Prefer explicit function names over a single god-object handleRequest. Thread a correlation id from ingress to the last log line. When streaming, define what partial failure means before coding. Snapshot one successful response body in fixtures after redaction. If the path writes to a queue, assert message attributes in the fake. Stop adding retries on this page; that is the next concern. In this chapter the product is humane escalation path for production AI answer platform, the human stakeholder is primary engineer receiving SEV2 after hours, and the incident id you design against is INC-OC-554. Re-state the oracle in your notes — game day: primary misses ACK → secondary owns INC-OC-554 in 15m with access grant — and keep the invariant visible: missed ACK in 15m escalates; SEV1 pages dual; handoff includes timeline + next action. Track ack_minutes and pages_per_week as the scoreboard. Surface under change control: PagerDuty schedule ai-answer-primary. If you only have forty minutes, finish the fixture for everyone paged for SEV3 noise → real SEV1 ignored before polishing UI. Promotion language stays ternary: promote, hold, or roll back based on evidence, not hope.