Build the first working grounded café FAQ application

Code the narrow path that serves café ops lead answering hours/wifi/pets questions from a kiosk: accept → authorize/normalize → call dependency → validate → record. Keep stages named so a trace can show which boundary passed. Success must emit evidence useful to gold_pass and demo_seconds, not only a 200 with prose. Predict the observable for CLI faq_ask before running: gold 5/5 cited + 3/3 abstain; demo under 120s from clean checkout.

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 grounded café FAQ app with validation, five-note retrieval, citations, tests, demo — resist adding unrelated features mid-path.

For Capstone: ship a tiny AI app, paste the CLI/HTTP transcript beside your prediction for CLI faq_ask. If the oracle is unmet (gold 5/5 cited + 3/3 abstain; demo under 120s from clean checkout), 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-CAFE-DEMO-01.

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 gold_pass and demo_seconds. 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 café ops lead answering hours/wifi/pets questions from a kiosk 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 grounded café FAQ app with validation, five-note retrieval, citations, tests, demo, the human stakeholder is café ops lead answering hours/wifi/pets questions from a kiosk, and the incident id you design against is CAP-CAFE-DEMO-01. Re-state the oracle in your notes — gold 5/5 cited + 3/3 abstain; demo under 120s from clean checkout — and keep the invariant visible: unsupported questions abstain; every answer cites a note id; two-minute clean-room demo. Track gold_pass and demo_seconds as the scoreboard. Surface under change control: CLI faq_ask. If you only have forty minutes, finish the fixture for demo relies on personal .env and unreproducible notebook state before polishing UI. Promotion language stays ternary: promote, hold, or roll back based on evidence, not hope.