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Capstone: Mock Loop1 / 4

1 min lesson

Timed practical build

Show why this lesson detail matters: "Design and partially build a usage-to-invoice pipeline (or a reconciliation / anomaly service) for a consumption-priced AI product."

Step 1 of 4

This is the round the role is really hiring for. Set a real timebox (90 minutes for practice, the day for the real thing), open Cursor and treat the prompt as deliberately under-specified. They are grading your judgment under ambiguity, not a finished artifact.

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Full explanation

Minutes 0-15: scope ruthlessly and state assumptions

Minutes 0-15: scope ruthlessly and state assumptionsEarn the right to build

  1. 1Write the assumptions down first. One metric (tokens), one plan shape (fixed rate per 1k tokens with a monthly minimum), one currency, monthly billing. State them as choices you would confirm with RevOps, not as facts.
  2. 2Pick the thin vertical slice. Raw usage event → idempotent landing → rated → aggregated to an invoice line, with one reconciliation check.
  3. 3Name the proof. Decide up front what 'done' demonstrates: re-running ingestion does not double-count and the usage total ties to the invoiced total.
  4. 4Say the meta-point. “I'm optimizing for proving the system design end-to-end over feature coverage, because a half-built sprawl tells you less than one slice that runs and ties out.”
WHAT TO BUILD FIRST

Interactive diagram. Tab through its regions; each focused region shows its detail in the panel below.

diagram: quadrant

In a timed build, sequence by signal-per-hour.

Watch out

Building breadth (a little of everything, none of it connected) reads as someone who cannot prioritize without a manager. The role is solo and greenfield, so they need to see you make a clean, defensible cut and own it.