---
status: demonstration
audience: public-demonstration
fixture: kibble-and-co (fictional)
---

# 8. Scope Boundary & Engagement Model

This section is normative for the bid. It defines what is being purchased, what is
explicitly deferred, which product policies are already decided, and how requirement
changes are governed once the engagement starts. A bid that silently redraws any
boundary in this section is treated as out of scope for the fixed bid on that item.

## 8.1 Engagement premise

1. **Kibble & Co. owns the requirements.** The requirements summarized in this
   package (28 epics, 218 stories with per-story acceptance criteria) are the
   contractual statement of scope. The vendor's role during bid preparation is to
   **validate and tighten** — challenge feasibility, flag ambiguity, propose
   sharpening — not to re-derive requirements from first principles.
2. **There is no billed discovery phase.** Questions raised during bid preparation
   are answered from this package, the requirements export, and bounded Q&A sessions
   with Kibble & Co.'s product and technical owners (see 8.7). Vendor effort to
   understand the problem space before contract signature is bid diligence and is
   carried by the vendor.
3. **The bid is fixed-scope against the MVP phase** (see 8.2), with later phases
   priced as separately exercisable options (see 8.3).
4. **Commercial terms are handled separately** by Kibble & Co.'s procurement team.
   Outcome-based incentive structures (delivery bonus / holdback mechanics) are
   under consideration; this package deliberately contains no commercial figures.

## 8.2 In scope — initial engagement (MVP phase)

The initial engagement delivers every story tagged **MVP** in the work-breakdown
register ([07-work-breakdown.md](07-work-breakdown.md)) — approximately 104 of the
218 stories, spanning all ten capability domains — built natively on Kibble & Co.'s
existing BigCommerce storefront. In addition to the story scope itself, the
engagement includes:

- **Solution architecture** for the native build, including a written position on
  every platform-integration decision point enumerated in
  [05-platform-integration-contract.md](05-platform-integration-contract.md) §5.2.
- **Test strategy and evidence** meeting the acceptance bar in
  [06-non-functional-requirements.md](06-non-functional-requirements.md) §6.9 —
  each NFR category carries a named verification method and delivered evidence.
- **Demonstration against the user journeys** in
  [03-user-journeys.md](03-user-journeys.md): each journey runs end-to-end in a
  pre-production environment as part of acceptance.
- **Documentation**: store-admin help content for Kibble & Co.'s operations team,
  developer-facing docs (API reference for the Platform-domain surfaces), and
  runbook-level operational docs.
- **Knowledge transfer** sufficient for Kibble & Co.'s engineering team to own the
  capability after handover (see 8.6/8.7; the KT plan is a scored bid deliverable
  per [09-estimation-scaffold.md](09-estimation-scaffold.md)).

## 8.3 Deferred scope — priced options, not silent inclusions

Stories tagged **P1**, **P2**, and **P3** in the register are out of the initial
fixed-scope build. Bids must price them as options at the domain level so Kibble &
Co. can exercise them without renegotiating from zero. Headline deferred items (the
register is authoritative):

| Deferred item | Phase tag | Note for estimators |
|---|---|---|
| Migration tooling from incumbent subscription apps | P1/P2 | Highest-value fast-follow; option should be priced with its own timeline |
| Additional processor adapters beyond the initial rail set | P2 | Gateway matrix in 05 §5.4 defines the landscape |
| Multi-storefront / channel-scoped plans | P2 | |
| Customer-group–scoped plans; prepaid / fixed-term subscriptions | P2 | |
| SMS notifications; marketing-platform integrations | P2 | |
| Cancel-flow experimentation (A/B) and intervention analytics | P2 | |
| B2B account support (company accounts, approvals, PO-based billing) | P3 | Distinct persona surface; see Epic 24 |
| Build-a-box / bundle subscriptions | P3 | |
| Usage-based billing primitive | P3 | Scoped separately by Kibble & Co.; do not price here |
| White-label subscriber portal (custom domain, full theming) | P3 | |

Anything not present in the written requirements is out of scope entirely and enters
only through change control (8.5).

## 8.4 Decided product policies — not open for re-litigation

The following behaviors look like open design questions but are **already decided**
— most in story acceptance criteria, the remainder as recorded product-policy
decisions Kibble & Co. made before bid issuance (noted per item). Bids should treat
them as fixed inputs; proposals to revisit them belong in change control, with an
impact statement.

1. **Price drift at renewal** — default: current catalog price wins at renewal;
   merchant-configurable lock-at-creation alternative (a Catalog-domain story in the work breakdown).
2. **Inventory conflict at renewal** — merchant-configurable policy: allow
   (continue/backorder), skip the cycle, substitute a configured alternate
   variant, or pause the subscription (Orders-domain stories in the work breakdown, including a proactive pre-renewal scan and a merchant resolution flow).
3. **Tax recalculation** — always recalculated at renewal from the current address;
   an address change mid-subscription triggers recalculation at the next cycle.
4. **Multi-currency** — plan prices are denominated in Kibble & Co.'s store default
   currency; presentment-currency conversion happens at display time only.
   (A recorded product-policy decision rather than a story AC — the vendor's
   solution design states how it is honored.)
5. **Data deletion** — platform customer deletion cascades: subscription PII is
   hard-deleted; only anonymized revenue records are retained. Charge records
   required for financial/legal retention survive with subscription state closed.
6. **Platform API budget discipline** — renewal processing must respect platform
   rate limits by design (scheduling jitter / queued spreading), not by retry-storm.
7. **Raw card data** — the system never touches it. All recurring charges ride the
   stored-instruments vault rail (05 §5.3). This is a hard architectural constraint,
   not a preference.

## 8.5 Requirements change control

- **Single product owner.** Kibble & Co. names one accountable requirements owner;
  all scope communication routes through them. The vendor names one accountable
  delivery owner as the counterpart.
- **Changes are written, story-addressed, and priced.** Any change — including
  vendor-discovered gaps, ambiguities, or "we found more than expected" — is logged
  as a written change proposal against specific US-IDs, with schedule and cost
  impact stated, and is not worked until approved. Discovery of a gap is never, by
  itself, authorization to expand scope.
- **Ambiguity resolution is free; scope expansion is not.** Where a story's AC is
  ambiguous, the product owner's written clarification binds both parties at no
  cost change. Where a clarification genuinely adds behavior, it is a change
  proposal like any other.
- **The reference implementation settles behavior disputes** in the first instance
  ([10-reference-prototype.md](10-reference-prototype.md)): where written AC and
  observed prototype behavior diverge, the written AC governs, and the divergence
  is flagged to Kibble & Co.'s product owner for disposition.

## 8.6 What the vendor owns

- Native solution architecture on the BigCommerce platform, including the 05 §5.2
  decision points, subject to Kibble & Co.'s architectural approval.
- Delivery plan, staffing, and internal tracking (seeded from the requirements
  export; story identity — US-IDs — must be preserved in the vendor's tracker so
  acceptance maps 1:1).
- Engineering quality: production-grade code, test coverage per 06, operational
  readiness (observability, runbooks, failure-mode documentation).
- Knowledge transfer execution per the KT plan committed at bid time.

## 8.7 What Kibble & Co. owns

- Requirements, prioritization, and acceptance sign-off at every phase gate.
- Platform access: sandbox store, API credentials, pre-production environments, and
  internal escalation paths to Kibble & Co.'s own IT and product teams.
- Bounded SME availability: scheduled architecture/product Q&A cadence (expected
  weekly during solution design, tapering during build) — not embedded full-time
  staff, and not an open-ended interview program.
- Timely turnaround on clarifications and change-proposal dispositions, so vendor
  idle time is not a cost lever against Kibble & Co.

## 8.8 Acceptance & definition of done

A story is done when its acceptance criteria pass in a pre-production environment
against a real BigCommerce store, with evidence retained. The engagement is done
when:

1. Every MVP-phase story passes its ACs.
2. Every NFR category carries delivered evidence per 06 §6.9.
3. Every journey in 03 demonstrates end-to-end, including the renewal and
   decline/dunning system journeys against real (sandbox) payment rails.
4. The system demonstrably instruments the operational health measures the product
   defines for launch readiness — charge success rate, dunning recovery rate,
   reconciliation drift (target <1% inconsistent state across system ↔ platform ↔
   processor), and subscriber self-service resolution — such that Kibble & Co. can
   operate against them from day one. (Commercial launch outcomes themselves are
   Kibble & Co.'s accountability, not the vendor's.)
5. Knowledge transfer is delivered and accepted by the receiving Kibble & Co.
   engineering team.

---

Kibble & Co. is a fictional demo merchant. This package is an independent
demonstration by Nino Chavez of a scoping method — not a BigCommerce product, and
not a real procurement.
