# 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. ## ACONFIG — Release configuration without restarting every service A fictional internal reporting platform changes feature and timeout settings through environment edits. Partial rollouts leave API and worker processes interpreting different values. **Field:** Platform engineering. **Suggested stack:** TypeScript, PostgreSQL, HTTP. **Engineer value:** Practice configuration contracts, compatibility and failure recovery. **Company value:** Review controlled configuration delivery with inspectable blast radius. **Delivery agreement:** Ten scoped tickets across three phases. Build a synthetic local service or select a ticket after recreating its prerequisites; estimates exclude setup. ### Setup prerequisites - Create local API and worker configuration consumers. - Use fabricated settings without secrets. ### Make settings explicit Define typed settings and safe defaults. #### ACONFIG-101 — Inventory runtime settings with owners and restart requirements **Task · Medium priority · Foundational** noCV practice brief v5 · ACONFIG-101 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Make settings explicit. Depends on: No preceding ticket. Difficulty: Foundational. Estimated focused work: 90 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 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. Operators cannot tell whether changing a timeout requires a worker restart or takes effect on the next request. Acceptance criteria - List type, owner, default and adoption boundary for each setting. - Separate secrets from nonsecret runtime configuration. - Mark unknown behavior as unresolved before rollout. Implementation constraints - Use a small fictional inventory of eight settings. Verification - Trace one dynamic setting through its read boundary. - Identify a startup-only setting and prevent a dynamic edit. Deliverables - Configuration inventory and adoption contract Rollout and recovery: Review the inventory before exposing edits; keep unresolved settings read-only. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-102 — Reject invalid timeout combinations as one configuration unit **Bug · Medium priority · Intermediate** noCV practice brief v5 · ACONFIG-102 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Make settings explicit. Depends on: ACONFIG-101. Difficulty: Intermediate. Estimated focused work: 150 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 80% · Backend 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 retry timeout exceeds the entire request deadline, causing requests to continue working after callers have disconnected. Acceptance criteria - Validate relationships between attempt, retry and total deadlines. - Reject the complete candidate snapshot on any invalid relation. - Return field paths with safe values only. Implementation constraints - Use explicit duration units; reject implicit unit conversion. Verification - Accept a documented valid retry budget. - Reject a larger attempt timeout than total deadline without changing active settings. Deliverables - Snapshot validator and deadline fixtures Rollout and recovery: Add validation to drafts; preserve the active snapshot on any rejection. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-103 — Define an immutable configuration snapshot envelope **Task · Medium priority · Foundational** noCV practice brief v5 · ACONFIG-103 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Make settings explicit. Depends on: ACONFIG-101, ACONFIG-102. Difficulty: Foundational. Estimated focused work: 90 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 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 config endpoint returns a mutable object with no revision, so incident reports cannot establish which settings were read. Acceptance criteria - Include revision, canonical hash and schema version. - Published snapshot content cannot be edited in place. - Exclude secret material from serialization and logs. Implementation constraints - Use opaque IDs and UTC publication metadata. Verification - Read the same revision twice and compare hashes. - Attempt an in-place edit and reject it. Deliverables - Snapshot contract and immutability checks Rollout and recovery: Start versioned publication alongside legacy reads; retain published revisions for recovery. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. ### Distribute revisions Publish compatible snapshots and control adoption. #### ACONFIG-104 — Atomically adopt a validated configuration snapshot in each process **Story · High priority · Advanced** noCV practice brief v5 · ACONFIG-104 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Distribute revisions. Depends on: ACONFIG-103. Difficulty: Advanced. Estimated focused work: 210 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 60% · Backend 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 process updates settings one field at a time, briefly combining a new retry count with an old deadline. Acceptance criteria - Validate the full snapshot before replacing the active reference. - Each request captures one revision for its lifetime. - Failed adoption retains the complete previous snapshot. Implementation constraints - Avoid mutating shared configuration objects after publication. Verification - Switch snapshots during requests and observe one revision per request. - Reject one invalid field and retain every previous value. Deliverables - Atomic consumer adapter and concurrent-read probe Rollout and recovery: Canary a local worker consumer; pin its previous revision if adoption fails. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-105 — Publish configuration only against the revision reviewed by the operator **Story · Medium priority · Advanced** noCV practice brief v5 · ACONFIG-105 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Distribute revisions. Depends on: ACONFIG-103, ACONFIG-104. Difficulty: Advanced. Estimated focused work: 210 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 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. Two operators edit the same draft; the last publisher activates changes based on a stale review. Acceptance criteria - Require expected draft revision and reviewed hash. - Commit publication and active selection together. - Return a conflict with safe revision metadata on stale publication. Implementation constraints - Record actor and reason in an append-only audit record. Verification - Publish an unchanged reviewed snapshot. - Race two publishers and assert one accepted active transition. Deliverables - Optimistic publication command and race test Rollout and recovery: Enable publication for a synthetic operator role; disable writes if audit persistence fails. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-106 — Keep incompatible consumers on their last valid configuration **Task · Medium priority · Expert** noCV practice brief v5 · ACONFIG-106 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Distribute revisions. Depends on: ACONFIG-104, ACONFIG-105. Difficulty: Expert. Estimated focused work: 300 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 80% · API design 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 new configuration schema reaches an older worker that silently ignores a field needed to preserve retry limits. Acceptance criteria - Consumers declare accepted schema versions. - Incompatible snapshots are rejected with explicit adoption status. - Critical missing configuration fails closed under the documented startup policy. Implementation constraints - Do not coerce unknown versions into the current schema. Verification - Adopt compatible settings in old and new local consumers. - Send a new unsupported schema and preserve the old snapshot or fail startup as declared. Deliverables - Compatibility handshake and failure matrix Rollout and recovery: Deploy compatible readers before publishing new schema; repoint to the older supported revision if needed. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-107 — Stage a timeout revision for a named consumer cohort **Story · Medium priority · Intermediate** noCV practice brief v5 · ACONFIG-107 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Distribute revisions. Depends on: ACONFIG-105, ACONFIG-106. Difficulty: Intermediate. Estimated focused work: 180 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 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. The team wants to test a timeout change on background reports before affecting interactive requests. Acceptance criteria - Bind cohort selection to stable nonpersonal service identity. - Show intended and acknowledged revision per cohort. - Unselected consumers retain their current target revision. Implementation constraints - Use deterministic synthetic cohort membership. Verification - Adopt a revision in the report-worker cohort only. - Use an unknown cohort and reject publication without target changes. Deliverables - Cohort rollout command and targeting cases Rollout and recovery: Begin with one synthetic cohort; restore its previous target revision on errors. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. ### Handle stale consumers Observe adoption and recover rejected changes. #### ACONFIG-108 — Report configuration staleness separately from application health **Story · Medium priority · Foundational** noCV practice brief v5 · ACONFIG-108 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Handle stale consumers. Depends on: ACONFIG-106, ACONFIG-107. Difficulty: Foundational. Estimated focused work: 90 minutes; setup and prerequisite tickets are additional. Estimated field mix: Site reliability 60% · Platform 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 healthy process missed several configuration polls, but a green liveness check hides that it is running stale limits. Acceptance criteria - Expose active and target revision plus last successful poll time. - Distinguish stale, incompatible and unavailable states. - Avoid including configuration values in generic health payloads. Implementation constraints - Use a fake clock for staleness boundaries. Verification - Advance target while a consumer stays behind and report stale. - Lose the configuration endpoint and keep the declared last-known-good behavior visible. Deliverables - Adoption status projection Rollout and recovery: Add the status endpoint before alerts; disable noisy alerts without hiding adoption state. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-109 — Rollback configuration by selecting a prior immutable snapshot **Task · Medium priority · Intermediate** noCV practice brief v5 · ACONFIG-109 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Handle stale consumers. Depends on: ACONFIG-105, ACONFIG-108. Difficulty: Intermediate. Estimated focused work: 150 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 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. An operator attempts to repair a bad timeout by manually rewriting the active record, erasing the incident's configuration history. Acceptance criteria - Rollback appends a selection event with reason and actor. - Validate old snapshot compatibility before selection. - Retain the bad revision and its adoption record. Implementation constraints - Use the same guarded publication boundary as forward changes. Verification - Select a compatible prior revision and observe consumer adoption. - Attempt rollback to an incompatible schema and leave the target unchanged. Deliverables - Audited rollback command Rollout and recovery: Rehearse on synthetic consumers; pin a known compatible revision if adoption stalls. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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. #### ACONFIG-110 — Exercise configuration service loss during a rolling deployment **Task · Medium priority · Expert** noCV practice brief v5 · ACONFIG-110 · Release configuration without restarting every service Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included. Phase: Handle stale consumers. Depends on: ACONFIG-106, ACONFIG-109. Difficulty: Expert. Estimated focused work: 300 minutes; setup and prerequisite tickets are additional. Estimated field mix: Platform engineering 50% · Site reliability 30% · Quality 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. The configuration endpoint becomes unavailable while old and new workers are starting with different cached snapshots. Acceptance criteria - Describe startup and running-process behavior separately. - Prove critical settings cannot start from an unvalidated cache. - Record revision selection and recovery for both consumer versions. Implementation constraints - Use local fault injection; no production configuration changes. Verification - Disconnect the endpoint after valid adoption and retain the declared bounded behavior. - Start with a corrupt cache during outage and reject startup safely. Deliverables - Outage drill and compatibility trace Rollout and recovery: Run before rollout; halt the deployment if a consumer cannot demonstrate its selected revision. Project prerequisites: Create local API and worker configuration consumers. Use fabricated settings without secrets. Engineer value: Practice configuration contracts, compatibility and failure recovery. Company value: Review controlled configuration delivery with inspectable blast radius. 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.