# 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. ## CBACK — Verifiable archive backup and restore Fictional archive Alder backs up synthetic document metadata and generated blobs into a dedicated local directory. No real organizational data or cloud accounts are required. **Field:** Storage systems. **Suggested stack:** TypeScript, SQLite, Filesystem adapter, Vitest. **Engineer value:** Practice consistent snapshots and recoverable restoration. **Company value:** Inspect whether backup success can be substantiated by a usable restore. **Delivery agreement:** Record local restore evidence; production disaster-recovery qualification remains separate. ### Setup prerequisites - Create synthetic metadata and generated blob fixtures. - Provide isolated source backup and restore directories. ### Describe backup content Define scope and integrity. #### CBACK-101 — Define archive backup manifests with explicit format versions **Task · Medium priority · Foundational** noCV practice brief v5 · CBACK-101 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Describe backup content. Depends on: No preceding ticket. Difficulty: Foundational. Estimated focused work: 75 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 80% · Data engineering 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. Backup folders contain unnamed files with no declared schema. Add a bounded manifest describing required objects. Acceptance criteria - Manifest declares version - Entries have size and digest - Duplicate logical paths fail validation Implementation constraints - Treat manifest text as untrusted input. Verification - Parse valid fixture - Reject duplicate and future-version entries Deliverables - Manifest schema and parser Rollout and recovery: Keep unknown backup versions read-only. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-102 — Exclude temporary archive uploads from backup inventories **Bug · Medium priority · Foundational** noCV practice brief v5 · CBACK-102 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Describe backup content. Depends on: CBACK-101. Difficulty: Foundational. Estimated focused work: 75 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 60% · Database engineering 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 backup includes partial uploads and later calls them missing documents. Inventory only committed archive references. Acceptance criteria - Committed blobs are listed - Temporary uploads are excluded - Excluded counts are reported separately Implementation constraints - Inventory must derive from authoritative metadata state. Verification - Inventory committed fixture - Add incomplete upload Deliverables - Backup inventory projection Rollout and recovery: Pause backup capture if committed scope is uncertain. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-103 — Verify archive backup bytes against manifest digests **Task · High priority · Intermediate** noCV practice brief v5 · CBACK-103 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Describe backup content. Depends on: CBACK-101, CBACK-102. Difficulty: Intermediate. Estimated focused work: 120 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 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. Copy completion alone marks backup success. Stream verification of every required object before success. Acceptance criteria - Digest and size both match - Missing object fails verification - Failure identifies logical object safely Implementation constraints - Do not buffer entire backups in memory. Verification - Verify generated fixture - Flip one copied byte Deliverables - Streaming verifier and corruption cases Rollout and recovery: Mark affected backups unusable until reverified. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. ### Capture coherently Handle interruption and version boundaries. #### CBACK-104 — Capture archive metadata and blob references at one snapshot boundary **Bug · High priority · Expert** noCV practice brief v5 · CBACK-104 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Capture coherently. Depends on: CBACK-102, CBACK-103. Difficulty: Expert. Estimated focused work: 240 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 50% · Database engineering 30% · Distributed 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. A document changes while backup runs and the manifest references an uncopied blob. Define one consistent capture boundary. Acceptance criteria - Manifest reflects one metadata snapshot - Required blobs remain pinned during capture - Concurrent new versions belong to later backups Implementation constraints - Specify adapter transaction and pin lifetime. Verification - Update after snapshot - Delete reference during capture Deliverables - Snapshot protocol and race cases Rollout and recovery: Pause pruning until capture pins are reliable. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-105 — Resume archive backup copying without accepting stale partial files **Story · Medium priority · Advanced** noCV practice brief v5 · CBACK-105 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Capture coherently. Depends on: CBACK-103, CBACK-104. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 70% · Site reliability 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. Restarted backup trusts an existing filename although the earlier copy was interrupted. Revalidate reusable files. Acceptance criteria - Matching verified files may be reused - Partial files are recopied - Resume retains original snapshot identity Implementation constraints - Reuse decisions require digest agreement. Verification - Resume with valid copied file - Resume with truncated file Deliverables - Copy-resume coordinator and cases Rollout and recovery: Start a new isolated backup if snapshot identity is lost. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-106 — Finalize archive backups with an explicit complete marker **Task · High priority · Intermediate** noCV practice brief v5 · CBACK-106 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Capture coherently. Depends on: CBACK-103, CBACK-105. Difficulty: Intermediate. Estimated focused work: 120 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 80% · 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. Operators select directories still being copied. Publish a durable completion marker only after required verification. Acceptance criteria - Incomplete directories are not selectable - Marker binds manifest digest - Failure cannot leave valid-looking completion Implementation constraints - Marker creation follows verification acknowledgement. Verification - Finish valid backup - Crash before marker creation Deliverables - Finalization protocol and tests Rollout and recovery: Withdraw completion marker if later validation fails. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-107 — Refuse archive restore paths outside the selected target directory **Bug · High priority · Advanced** noCV practice brief v5 · CBACK-107 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Capture coherently. Depends on: CBACK-101, CBACK-106. Difficulty: Advanced. Estimated focused work: 150 minutes; setup and prerequisite tickets are additional. Estimated field mix: Security 60% · Storage systems 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 crafted backup path can escape the restore root. Validate resolved destinations before creating files. Acceptance criteria - Traversal and absolute paths fail - Symlink escape is rejected by adapter policy - Valid files remain inside target Implementation constraints - Use a dedicated empty fixture directory. Verification - Restore valid nested object - Attempt parent traversal or symlink escape Deliverables - Restore-path boundary and cases Rollout and recovery: Abort restore before writes if containment cannot be established. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. ### Restore into isolation Validate before switching authority. #### CBACK-108 — Restore archive backups into an isolated staging generation **Story · High priority · Advanced** noCV practice brief v5 · CBACK-108 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Restore into isolation. Depends on: CBACK-106, CBACK-107. Difficulty: Advanced. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 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. Direct restoration overwrites the active archive before integrity checks finish. Build and validate a separate generation. Acceptance criteria - Active data remains untouched - Staging contains all required records - Failed validation leaves active generation selected Implementation constraints - No recursive operations on unspecified user directories. Verification - Restore valid fixture - Fail halfway through copying Deliverables - Staged restore and isolation checks Rollout and recovery: Discard only the verified staging directory on failure. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-109 — Switch restored archive authority with a rollback pointer **Task · High priority · Expert** noCV practice brief v5 · CBACK-109 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Restore into isolation. Depends on: CBACK-108. Difficulty: Expert. Estimated focused work: 240 minutes; setup and prerequisite tickets are additional. Estimated field mix: Storage systems 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 successful staging restore still needs a safe handoff. Activate one generation while retaining the previous pointer. Acceptance criteria - Switch selects one validated generation - Interrupted activation recovers deterministically - Rollback selects prior intact generation Implementation constraints - Document concurrent-reader behavior at the switch. Verification - Activate restored fixture - Crash during pointer update Deliverables - Activation record and recovery tests Rollout and recovery: Restore previous validated pointer if post-switch checks fail. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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. #### CBACK-110 — Prove one archive restore through observable consistency checks **Chore · Medium priority · Intermediate** noCV practice brief v5 · CBACK-110 · Verifiable archive backup and restore Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Restore into isolation. Depends on: CBACK-109. Difficulty: Intermediate. Estimated focused work: 150 minutes; setup and prerequisite tickets are additional. Estimated field mix: Quality engineering 40% · Storage systems 30% · Site reliability 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. A backup report says Success without reading restored documents. Add a repeatable restore exercise and recorded checks. Acceptance criteria - Restored references resolve - Document counts match manifest scope - Excluded temporary data stays excluded Implementation constraints - Report local fixture results and unresolved assumptions. Verification - Read every small fixture object - Remove one restored blob and detect failure Deliverables - Restore exercise and result record Rollout and recovery: Reclassify the backup as unverified if checks fail. Project prerequisites: Create synthetic metadata and generated blob fixtures. Provide isolated source backup and restore directories. Engineer value: Practice consistent snapshots and recoverable restoration. Company value: Inspect whether backup success can be substantiated by a usable restore. 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.