# noCV engineering task library Content version 5 Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs. Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence. ## BCOST — Object-storage cost controls A fictional analytics service stores exports and intermediate artifacts indefinitely. Finance sees a rising bill but engineers cannot explain which lifecycle policy is responsible. **Field:** Cloud infrastructure. **Suggested stack:** TypeScript, S3-compatible storage, CSV. **Engineer value:** Practice cost attribution, lifecycle modeling, and safe retention controls. **Company value:** Produce reviewable storage-cost options with recovery and data-retention consequences. **Delivery agreement:** Deliver an offline cost model and local policy rehearsal; delete no real cloud objects. ### Setup prerequisites - Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. ### Attribute storage Describe objects, ownership, and cost assumptions. #### BCOST-101 — Normalize object inventory units and ownership labels **Task · Medium priority · Foundational** noCV practice brief v5 · BCOST-101 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Attribute storage. Depends on: No preceding ticket. Difficulty: Foundational. Estimated focused work: 60 minutes; setup and prerequisite tickets are additional. Estimated field mix: Data engineering 60% · Cloud infrastructure 40%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Inventory exports mix byte counts, rounded sizes, and missing owners. Acceptance criteria - Use bytes as the canonical size unit. - Separate unknown owners from shared infrastructure. - Preserve inventory time and source identity. Implementation constraints - Use synthetic names without customer identifiers. Verification - Normalize mixed display units accurately. - Reject negative sizes and report missing ownership. Deliverables - Inventory parser. Rollout and recovery: Run read-only attribution before proposing lifecycle changes. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-102 — Model storage, requests, and transfer costs separately **Task · Medium priority · Intermediate** noCV practice brief v5 · BCOST-102 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Attribute storage. Depends on: BCOST-101. Difficulty: Intermediate. Estimated focused work: 120 minutes; setup and prerequisite tickets are additional. Estimated field mix: Cloud infrastructure 100%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A storage-only estimate ignores the cost of regenerating and downloading exports. Acceptance criteria - Version explicit fictional unit-price assumptions. - Calculate each cost component separately. - Show unknown request or transfer volume. Implementation constraints - Do not present modeled savings as observed billing results. Verification - Reconcile a hand-calculated synthetic example. - Refuse a total when a required unit conversion is ambiguous. Deliverables - Offline cost calculator. Rollout and recovery: Keep original assumptions with every report. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. ### Model lifecycle changes Evaluate retention and transfer controls safely. #### BCOST-103 — Classify objects by recovery and retention requirements **Task · High priority · Advanced** noCV practice brief v5 · BCOST-103 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Model lifecycle changes. Depends on: BCOST-101. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 50% · Cloud infrastructure 30% · Site reliability 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A broad expiry rule would remove the only copy of finalized reports. Acceptance criteria - Distinguish authoritative, reproducible, and temporary objects. - Attach minimum retention and recovery requirements. - Block lifecycle proposals for unclassified objects. Implementation constraints - Retention requirements are scenario inputs, not legal advice. Verification - Allow expiry of a declared temporary object. - Block deletion of an authoritative unclassified report. Deliverables - Object lifecycle classification. Rollout and recovery: Start with temporary classes only; preserve unknown objects. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-104 — Simulate lifecycle transitions before object deletion **Task · High priority · Intermediate** noCV practice brief v5 · BCOST-104 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Model lifecycle changes. Depends on: BCOST-103. Difficulty: Intermediate. Estimated focused work: 150 minutes; setup and prerequisite tickets are additional. Estimated field mix: Cloud infrastructure 40% · Storage systems 40% · Security 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Operators cannot see which objects a new rule would affect. Acceptance criteria - Produce a dry-run object set and byte total. - Bind the plan to inventory and policy digests. - Reject execution if the reviewed plan is stale. Implementation constraints - The exercise uses only a disposable local object store. Verification - Preview an eligible temporary set. - Change policy inputs and reject the stale plan. Deliverables - Lifecycle dry-run planner. Rollout and recovery: Require review of the exact plan; keep deletion disabled by default. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-105 — Account for retrieval delay in colder storage proposals **Task · High priority · Advanced** noCV practice brief v5 · BCOST-105 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Model lifecycle changes. Depends on: BCOST-102, BCOST-103. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Cloud infrastructure 50% · Storage systems 30% · Site reliability 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A cheaper storage tier may violate the reporting team's recovery expectations. Acceptance criteria - Model retrieval time and per-request charges explicitly. - Compare ordinary access and restore scenarios. - Exclude objects whose declared recovery target is incompatible. Implementation constraints - Use simulated tier behavior and labeled assumptions. Verification - Compare two fictional tier policies. - Reject a cheap option that misses the recovery requirement. Deliverables - Tier tradeoff report. Rollout and recovery: Pilot only reproducible artifacts with a tested restore path. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-106 — Bound export retention per tenant without crossing ownership **Task · High priority · Advanced** noCV practice brief v5 · BCOST-106 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Model lifecycle changes. Depends on: BCOST-104. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Security 50% · Storage systems 30% · Cloud infrastructure 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. One tenant's cleanup job selects similarly named exports belonging to another. Acceptance criteria - Scope inventory and policy evaluation by tenant identity. - Use opaque object references rather than name prefixes alone. - Audit planned and completed cleanup identities. Implementation constraints - Repository boundaries must enforce scope. Verification - Expire eligible exports for one tenant. - Attempt cross-tenant cleanup and verify denial. Deliverables - Scoped retention evaluator. Rollout and recovery: Trial on one synthetic tenant; stop on inventory discrepancies. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-107 — Reduce repeated downloads with integrity-aware caching **Task · Medium priority · Intermediate** noCV practice brief v5 · BCOST-107 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Model lifecycle changes. Depends on: BCOST-102. Difficulty: Intermediate. Estimated focused work: 150 minutes; setup and prerequisite tickets are additional. Estimated field mix: Performance engineering 40% · API design 30% · Security 30%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Unchanged exports are repeatedly transferred because clients cannot validate their cache. Acceptance criteria - Expose stable content validators for immutable exports. - Honor conditional reads correctly. - Invalidate cached authority when access is revoked. Implementation constraints - A content digest is not an access credential. Verification - Return unchanged status for an authorized matching validator. - Deny a revoked client despite its cached validator. Deliverables - Conditional-download contract. Rollout and recovery: Enable for immutable exports first; retain full-download fallback. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. ### Review savings proposals Compare options and expose uncertainty. #### BCOST-108 — Compare retention changes against rebuild workload and budget **Task · High priority · Expert** noCV practice brief v5 · BCOST-108 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Review savings proposals. Depends on: BCOST-105, BCOST-106, BCOST-107. Difficulty: Expert. Estimated focused work: 300 minutes; setup and prerequisite tickets are additional. Estimated field mix: Cloud infrastructure 50% · Performance engineering 30% · Storage systems 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Deleting intermediate files saves storage but may shift cost into repeated computation. Acceptance criteria - Model storage, rebuild, transfer, and operational effort together. - Run bounded local rebuild measurements with declared inputs. - Show uncertainty ranges and excluded costs. Implementation constraints - No claim of real bill reduction from synthetic data. Verification - Compare a retained and regenerated artifact policy. - Expose the case where regeneration costs more. Deliverables - Cost-control decision record. Rollout and recovery: Choose a reversible policy for reproducible data; preserve authoritative copies. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-109 — Add budget alerts that distinguish actual and forecast usage **Story · Medium priority · Intermediate** noCV practice brief v5 · BCOST-109 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Review savings proposals. Depends on: BCOST-108. Difficulty: Intermediate. Estimated focused work: 120 minutes; setup and prerequisite tickets are additional. Estimated field mix: Cloud infrastructure 60% · Site reliability 40%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. A forecast estimate appears in the same chart as already-incurred usage. Acceptance criteria - Label measured inventory cost and forecast separately. - Define alert thresholds and data freshness. - Avoid duplicate alerts for one reporting window. Implementation constraints - Alerts remain local outputs; send no external notifications. Verification - Trigger a synthetic budget threshold. - Show stale inventory as uncertain instead of a current total. Deliverables - Budget alert fixtures. Rollout and recovery: Run advisory reports before operational notification wiring. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence. #### BCOST-110 — Document restoration before approving local expiry rules **Chore · Low priority · Foundational** noCV practice brief v5 · BCOST-110 · Object-storage cost controls Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Review savings proposals. Depends on: BCOST-109. Difficulty: Foundational. Estimated focused work: 60 minutes; setup and prerequisite tickets are additional. Estimated field mix: Site reliability 50% · Cloud infrastructure 30% · Storage systems 20%. Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence. Cleanup reviewers need to understand which deleted artifacts can be recreated. Acceptance criteria - Identify rebuild inputs and commands. - State unrecoverable classes explicitly. - Include the latest dry-run plan identity. Implementation constraints - Do not promise recovery without retained inputs. Verification - Rebuild an expired synthetic intermediate artifact. - Reject expiry when required rebuild inputs are absent. Deliverables - Retention review checklist. Rollout and recovery: Attach to policy proposals and re-review after input changes. Project prerequisites: Create synthetic object inventories and a local object-store double; author fictional unit prices as explicit assumptions. Engineer value: Practice cost attribution, lifecycle modeling, and safe retention controls. Company value: Produce reviewable storage-cost options with recovery and data-retention consequences. AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior. Planning status does not create Outcome Evidence or Ownership Evidence.