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Capstone: Mock Loop1 / 2

1 min lesson

What the slice must cover

Walk through each part of "What the slice must cover", then explain what each one does.

Step 1 of 2

What the slice must coverHit these four even if you cut features

Non-negotiable surfaces
Data model
Immutable usage_events with a stable key; rated and aggregated layers; an invoice line
Idempotency / reconciliation
Re-run is a no-op; a check that usage total equals invoiced total within tolerance
Audit trail
Append-only events, recorded who/what/when, corrections as new entries not edits
Agent boundary
Where an agent could safely automate (flagging anomalies) vs. where it must not (posting journals unsupervised)

On the agent boundary, be specific to finance. An agent drafting a reconciliation summary or flagging a 30% usage spike for human review is safe. An agent posting a journal entry to the GL without a human approval and an immutable log is not, because it breaks segregation of duties and your audit story.

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Full explanation

Minutes 70-90: the closeout

Minutes 70-90: the closeoutHow you end is how they remember you

  1. 1What's built. Demo the proof live: run ingestion twice, show the count unchanged, show the tie-out passing.
  2. 2What's next. The deferred list, in priority order: tax, multi-currency, prepaid credits, dunning - and why each was safe to defer for this slice.
  3. 3Risks I deliberately deferred. Name them as risks, with the control you would add: 'no SOXSarbanes-Oxley Act. A US law that forces companies to keep auditable controls over any system that affects their financial reporting. Press Enter for the full definition. evidence yet; I'd add an approval gate and an immutable audit log before this touches a real GL.'
  4. 4The one trade-off you'd revisit. Pick the assumption you are least sure about and say what would change it.
Say it like this

“In 90 minutes I proved the spine: idempotent usage ingestion, rating, an invoice line and a reconciliation that ties out. I deliberately left tax, multi-currency and dunning as configured concerns and I'd add an approval gate plus an immutable audit log before this posts to a real GL. The assumption I'd pressure-test first with RevOps is the monthly-minimum treatment, because it changes whether the right-to-invoice expedient applies.”

QIn the build round, an AI assistant generates a clean-looking invoice-total function that stores currency amounts as floating-point dollars. What do you do and why does it matter for this role?