Implement one traceable happy path

Code the narrow path that serves solo builder operating pka.example for 50 beta users: accept → authorize/normalize → call dependency → validate → record. Keep stages named so a trace can show which boundary passed. Success must emit evidence useful to readyz_ok, kill_switch_seconds, secret_age_days ≤ 30, not only a 200 with prose. Predict the observable for https://pka.example/v1/ask before running: ship v1.2.0: smoke+readyz pass; kill switch drill < 60s; on-call roster non-empty.

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 Personal Knowledge Assistant API with flags, probes, secrets, on-call owner — resist adding unrelated features mid-path.

For Capstone ops lab, paste the CLI/HTTP transcript beside your prediction for https://pka.example/v1/ask. If the oracle is unmet (ship v1.2.0: smoke+readyz pass; kill switch drill < 60s; on-call roster non-empty), 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 CAP-OPS-PKA-12.

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 readyz_ok, kill_switch_seconds, secret_age_days ≤ 30. 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 solo builder operating pka.example for 50 beta users 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 Personal Knowledge Assistant API with flags, probes, secrets, on-call owner, the human stakeholder is solo builder operating pka.example for 50 beta users, and the incident id you design against is CAP-OPS-PKA-12. Re-state the oracle in your notes — ship v1.2.0: smoke+readyz pass; kill switch drill < 60s; on-call roster non-empty — and keep the invariant visible: versioned release with readyz, flag kill switch, rotated secret, named on-call. Track readyz_ok, kill_switch_seconds, secret_age_days ≤ 30 as the scoreboard. Surface under change control: https://pka.example/v1/ask. If you only have forty minutes, finish the fixture for app runs on laptop only — no probes, no owner, secret in .env committed before polishing UI. Promotion language stays ternary: promote, hold, or roll back based on evidence, not hope.