# V1 Public API Baseline

Status: Captured during Block 11.1.

Starting commit: `775c2ed406f03a73a9b0ca621dea5b4482468616`

Public import:

```dart
import 'package:adhd_scheduler_core/scheduler_core.dart';
```

The public library entry point is `lib/scheduler_core.dart`. It exports the
following source files:

- `src/models.dart`
- `src/application_commands.dart`
- `src/application_layer.dart`
- `src/application_management.dart`
- `src/application_recovery.dart`
- `src/backlog.dart`
- `src/child_tasks.dart`
- `src/document_mapping.dart`
- `src/free_slots.dart`
- `src/locked_time.dart`
- `src/occupancy_policy.dart`
- `src/persistence_contract.dart`
- `src/project_statistics.dart`
- `src/quick_capture.dart`
- `src/reminder_policy.dart`
- `src/repositories.dart`
- `src/scheduling_engine.dart`
- `src/task_actions.dart`
- `src/task_lifecycle.dart`
- `src/task_statistics.dart`
- `src/time_contracts.dart`
- `src/today_state.dart`
- `src/timeline_state.dart`

This baseline is used by later chunks to distinguish intentional breaking
changes from accidental API drift.

## Public enums

| File | Enums |
|---|---|
| `src/application_commands.dart` | `ApplicationCommandCode` |
| `src/application_management.dart` | `ApplicationManagementCommandCode`, `OwnerSettingsWarningCode` |
| `src/application_recovery.dart` | `AppOpenRecoveryOutcome` |
| `src/application_layer.dart` | `ApplicationFailureCode` |
| `src/document_mapping.dart` | `DocumentMappingFailureCode` |
| `src/models.dart` | `DomainValidationCode`, `TaskType`, `TaskStatus`, `PriorityLevel`, `RewardLevel`, `DifficultyLevel`, `ReminderProfile`, `BacklogTag` |
| `src/backlog.dart` | `BacklogFilter`, `BacklogSortKey`, `BacklogStalenessMarker` |
| `src/free_slots.dart` | `RequiredCommitmentScheduleStatus` |
| `src/locked_time.dart` | `LockedWeekday`, `LockedBlockOverrideType` |
| `src/occupancy_policy.dart` | `OccupancyCategory`, `OccupancySource` |
| `src/project_statistics.dart` | `ProjectCompletionTimeBucket`, `ProjectSuggestionType`, `ProjectSuggestionConfidence` |
| `src/quick_capture.dart` | `QuickCaptureStatus` |
| `src/reminder_policy.dart` | `ReminderDirectiveAction`, `ReminderDirectiveReason`, `EffectiveReminderProfileSource` |
| `src/scheduling_engine.dart` | `SchedulingNoticeType`, `SchedulingOperationCode`, `SchedulingOutcomeCode`, `SchedulingIssueCode`, `SchedulingMovementCode`, `SchedulingConflictCode` |
| `src/task_actions.dart` | `FlexibleTaskQuickAction`, `RequiredTaskAction`, `PushDestination` |
| `src/task_lifecycle.dart` | `TaskTransitionCode`, `TaskActivityCode`, `TaskTransitionOutcomeCode` |
| `src/time_contracts.dart` | `LocalTimeResolution`, `NonexistentLocalTimePolicy`, `RepeatedLocalTimePolicy` |
| `src/today_state.dart` | `TodayTimelineItemSource` |
| `src/timeline_state.dart` | `TimelineItemCategory`, `TimelineBackgroundToken`, `TimelineRewardIconToken`, `TimelineDifficultyIconToken`, `TimelineQuickAction` |

## Public classes and top-level functions

| File | Public API |
|---|---|
| `src/application_commands.dart` | `ApplicationChildTaskDraft`, `ApplicationCommandReadHint`, `ApplicationCommandResult`, `V1ApplicationCommandUseCases` |
| `src/application_layer.dart` | `OwnerTimeZoneContext`, `ApplicationOperationContext`, `ApplicationFailure`, `ApplicationResult`, `ApplicationFailureException`, `ApplicationPersistenceException`, `ApplicationOperationRecord`, `NoticeAcknowledgementRecord`, `OwnerSettings`, `TaskActivityRepository`, `ProjectStatisticsRepository`, `OwnerSettingsRepository`, `NoticeAcknowledgementRepository`, `ApplicationOperationRepository`, `ApplicationUnitOfWorkRepositories`, `ApplicationUnitOfWork`, `ApplicationSchedulingLoader`, `InMemoryApplicationUnitOfWork` |
| `src/application_management.dart` | `GetBacklogRequest`, `BacklogItemReadModel`, `BacklogQueryResult`, `GetProjectDefaultsRequest`, `ProjectDefaultsQueryResult`, `ProjectProfileDraft`, `ProjectProfileUpdate`, `LockedBlockDraft`, `LockedBlockUpdate`, `OwnerSettingsUpdateResult`, `OwnerSettingsUpdate`, `NoticeAcknowledgementResult`, `V1ApplicationManagementUseCases` |
| `src/application_recovery.dart` | `RunAppOpenRecoveryRequest`, `AppOpenRecoveryResult`, `V1AppOpenRecoveryUseCases` |
| `src/models.dart` | `DomainValidationException`, `Task`, `ProjectProfile`, `TimeInterval` |
| `src/backlog.dart` | `BacklogStalenessSettings`, `BacklogView` |
| `src/child_tasks.dart` | `ChildTaskEntry`, `ChildTaskBreakUpRequest`, `ChildTaskBreakUpResult`, `ChildTaskBreakUpService`, `ChildTaskView`, `ChildTaskCompletionResult`, `ChildTaskCompletionService`, `ChildTaskSummary` |
| `src/document_mapping.dart` | `DocumentMappingException`, `DocumentMetadata`, `PersistenceEnumMapping`, `TaskDocumentMapping`, `TaskStatisticsDocumentMapping`, `ProjectDocumentMapping`, `ProjectStatisticsDocumentMapping`, `LockedBlockRecurrenceDocumentMapping`, `LockedBlockDocumentMapping`, `LockedBlockOverrideDocumentMapping`, `TaskActivityDocumentMapping`, `OwnerSettingsDocumentMapping`, `BacklogStalenessDocumentMapping`, `NoticeAcknowledgementDocumentMapping`, `ApplicationOperationDocumentMapping`, `SchedulingSnapshotDocumentMapping`, `SchedulingWindowDocumentMapping`, `TimeIntervalDocumentMapping`, `SchedulingNoticeDocumentMapping`, `SchedulingChangeDocumentMapping`, `SchedulingOverlapDocumentMapping`, `TaskDocumentExtension`, `TaskStatisticsDocumentExtension`, `ProjectStatisticsDocumentExtension` |
| `src/free_slots.dart` | `ProtectedFreeSlotConflict`, `RequiredCommitmentScheduleResult`, `FreeSlotService` |
| `src/locked_time.dart` | `ClockTime`, `LockedBlockRecurrence`, `LockedBlock`, `LockedBlockOccurrence`, `LockedBlockOverride`, `LockedScheduleExpansion`, `expandLockedBlocksForDay`, `lockedSchedulingIntervalsForDay`, `trackCompletedDuringLockedHours`, `completedDuringLockedHoursMinutes` |
| `src/occupancy_policy.dart` | `OccupancyEntry`, `OccupancyPolicy` |
| `src/persistence_contract.dart` | `v1SchemaVersion`, `PersistenceDateTimeConvention`, `PersistenceCivilDateConvention`, `PersistenceWallTimeConvention`, `PersistenceEnumName`, V1 document field-name classes |
| `src/project_statistics.dart` | `ProjectStatistics`, `ProjectStatisticsApplicationResult`, `ProjectStatisticsAggregationService`, `ProjectSuggestionPolicy`, `ProjectSuggestion`, `ProjectSuggestionSet`, `ProjectDefaultResolution`, `ProjectSuggestionService` |
| `src/quick_capture.dart` | `QuickCaptureRequest`, `QuickCaptureResult`, `QuickCaptureService` |
| `src/reminder_policy.dart` | `EffectiveReminderProfile`, `ReminderDirective`, `ReminderPolicyService` |
| `src/repositories.dart` | `SchedulingStateSnapshot`, `InMemoryTaskRepository`, `InMemoryProjectRepository`, `InMemoryLockedBlockRepository`, `InMemorySchedulingSnapshotRepository` |
| `src/scheduling_engine.dart` | `SchedulingWindow`, `SchedulingInput`, `SchedulingChange`, `SchedulingOverlap`, `SchedulingNotice`, `SchedulingResult`, `SchedulingEngine` |
| `src/task_actions.dart` | `FlexibleTaskActionResult`, `PushDestinationResult`, `RequiredTaskActionResult`, `SurpriseTaskLogRequest`, `SurpriseTaskLogResult`, `FlexibleTaskActionService`, `RequiredTaskActionService`, `SurpriseTaskLogService` |
| `src/task_lifecycle.dart` | `TaskActivity`, `TaskActivityApplicationResult`, `TaskActivityAccountingService`, `TaskTransitionResult`, `TaskTransitionService` |
| `src/task_statistics.dart` | `TaskStatistics` |
| `src/time_contracts.dart` | `Clock`, `SystemClock`, `FixedClock`, `IdGenerator`, `SequentialIdGenerator`, `CivilDate`, `WallTime`, `TimeZoneResolutionOptions`, `ResolvedLocalDateTime`, `TimeZoneResolver`, `FixedOffsetTimeZoneResolver` |
| `src/today_state.dart` | `GetTodayStateRequest`, `TodayTimelineItem`, `TodayCompactState`, `TodayPendingNotice`, `TodayState`, `GetTodayStateQuery` |
| `src/timeline_state.dart` | `TimelineItem`, `CompactTimelineState`, `TimelineItemMapper` |

## Current model baseline

`TaskType` values:

- `flexible`
- `inflexible`
- `critical`
- `locked`
- `surprise`
- `freeSlot`

`TaskStatus` values:

- `planned`
- `active`
- `completed`
- `missed`
- `cancelled`
- `noLongerRelevant`
- `backlog`

Current notable model fields:

- `Task`: `id`, `title`, `projectId`, `type`, `status`, `priority`,
  `reward`, `difficulty`, `durationMinutes`, `scheduledStart`, `scheduledEnd`,
  `actualStart`, `actualEnd`, `completedAt`, `parentTaskId`, `backlogTags`,
  `reminderOverride`, `createdAt`, `updatedAt`, `stats`
- `ProjectProfile`: `id`, `name`, `colorKey`, default priority/reward/
  difficulty/reminder profile/duration fields, `archivedAt`
- `ProjectStatistics`: completion count, duration sample counts,
  completion-time buckets, pushes-before-completion totals, reward/difficulty
  distributions, and reminder-profile observations
- `TimeInterval`: `start`, `end`, optional `label`
- `TaskStatistics`: skip/push/backlog/missed/cancelled/late/locked-hour,
  completed-after-shield, and push-before-completion counters. Parent/child
  completion patterns are carried as activity metadata.

Known baseline gaps to preserve as explicit later work:

- `TaskStatus` does not include `pushed` or `skipped`; Chunk 11.2 resolves the
  status/event distinction.
- `Task` does not yet have an explicit backlog-entered timestamp field.
- Instant ranges still use `DateTime`; locked recurrence dates, wall-clock
  rules, clocks, IDs, and timezone resolution are explicit Chunk 11.4
  contracts.

## Intentional API Changes After Baseline

Chunk 11.3 intentionally changed the public API:

- Added `DomainValidationCode` and `DomainValidationException`.
- Added `Task.actualStart`, `Task.actualEnd`, and `Task.reminderOverride`.
- Added explicit `copyWith` clear flags for nullable task fields.
- Added `ProjectProfile.copyWith(clearDefaultDuration: true)`.
- Changed several public value constructors from `const` to runtime-validating
  constructors.
- Public collection fields now expose unmodifiable snapshots instead of caller
  mutable collections.

Chunk 11.4 intentionally changed the public API:

- Added clock, ID, civil-date, wall-time, timezone resolver, DST policy, and
  fixed-offset resolver contracts in `src/time_contracts.dart`.
- Exported `src/time_contracts.dart` from `scheduler_core.dart`.
- Added `nonexistentLocalTime` and `ambiguousLocalTime` validation codes.
- Changed `ClockTime` to a backwards-compatible alias of `WallTime`.
- Changed locked block dates and override dates from `DateTime` to `CivilDate`.
- Changed locked-time expansion helpers and override interval conversion to
  require explicit `timeZoneId` and `TimeZoneResolver`.
- Added injected `Clock` boundaries to scheduling/action/child completion
  services and optional `IdGenerator` convenience wrappers for quick capture and
  surprise logging.
- Added civil-date and wall-time persistence conventions that store strings
  without timezone conversion.

Chunk 12.1 intentionally changed the public API:

- Added `src/occupancy_policy.dart` and exported it from `scheduler_core.dart`.
- Added `OccupancyCategory`, `OccupancySource`, `OccupancyEntry`, and
  `OccupancyPolicy`.
- Added policy-derived `SchedulingInput.occupancyEntries`,
  `SchedulingInput.movablePlannedFlexibleTasks`, and
  `SchedulingInput.conflictReportingOccupancies`.
- Changed `SchedulingInput.blockedIntervals` to derive from the central
  occupancy policy rather than from duplicated task-type filters.

Chunk 12.2 intentionally changed the public API:

- Added `src/free_slots.dart` and exported it from `scheduler_core.dart`.
- Added `RequiredCommitmentScheduleStatus`, `ProtectedFreeSlotConflict`,
  `RequiredCommitmentScheduleResult`, and `FreeSlotService`.
- Added validated Free Slot create/update helpers and a typed explicit required
  commitment scheduling result for protected-rest conflicts.

Chunk 12.3 intentionally changed the public API:

- Added optional `revealHiddenLockedDetails` parameters to
  `SurpriseTaskLogService.log` and `SurpriseTaskLogService.logNew`.
- Defined `SurpriseTaskLogRequest.id` as the idempotency key for retrying the
  same surprise log operation.
- Surprise tasks with known time now populate `actualStart` and `actualEnd` in
  addition to the existing scheduled interval compatibility fields.

Chunk 12.4 intentionally changed the public API:

- Added stable scheduler code enums: `SchedulingOperationCode`,
  `SchedulingOutcomeCode`, `SchedulingIssueCode`, `SchedulingMovementCode`, and
  `SchedulingConflictCode`.
- Added `SchedulingResult.operationCode` and `SchedulingResult.outcomeCode`.
- Added `SchedulingNotice.issueCode`, `SchedulingNotice.movementCode`,
  `SchedulingNotice.conflictCode`, and immutable `SchedulingNotice.parameters`.
- Changed `SchedulingNotice` from a `const` constructor to a runtime constructor
  so notice parameters can be defensively copied.
- Added a `SchedulingResult` assertion that each notice uses at most one issue,
  movement, or conflict code.

Chunk 13.1 intentionally changed the public API:

- Added `src/task_lifecycle.dart` and exported it from `scheduler_core.dart`.
- Added `TaskTransitionCode`, `TaskActivityCode`, `TaskTransitionOutcomeCode`,
  `TaskActivity`, `TaskTransitionResult`, and `TaskTransitionService`.
- Added `Task.completedAt` and `Task.copyWith(clearCompletion: true)`.
- Added `TaskActivityDocumentFields` and `TaskDocumentFields.completedAt`.
- Added activity and transition outcome fields to flexible, push-destination, and
  required task action results.
- Routed flexible/required direct action services through the canonical
  transition service while preserving existing scheduling helper compatibility.

Chunk 13.2 intentionally changed the public API:

- Added `TaskActivityApplicationResult` and `TaskActivityAccountingService`.
- Added `TaskStatistics.completedAfterShieldCount`,
  `TaskStatistics.completedAfterPushCount`, and
  `TaskStatistics.totalPushesBeforeCompletion`.
- Added `TaskStatistics.recordPushesBeforeCompletion`.
- Added matching `TaskStatisticsDocumentFields` constants and document mapping.
- Added `appliedActivityIds` and `lockedIntervals` parameters to
  `TaskTransitionService.apply`.
- Added actual/locked interval parameters to flexible and required action
  completion paths.
- Added `SurpriseTaskLogResult.activities` and routed surprise completion
  through the same accounting boundary.

Chunk 13.3 intentionally changed the public API:

- Added `ChildTaskBreakUpRequest`, `ChildTaskBreakUpResult`, and
  `ChildTaskBreakUpService`.
- Added `activities` and `transitionOutcomeCodes` to
  `ChildTaskCompletionResult`.
- Added `transitionService` injection to `ChildTaskCompletionService`.
- Added `operationId`, existing-activity, and applied-activity parameters to
  child and parent completion methods.
- Added `ChildTaskCompletionService.completeParentFromChild`.
- Routed parent/child completion through canonical lifecycle transitions and
  parent/child completion metadata.

Chunk 13.4 intentionally changed the public API:

- Added `src/project_statistics.dart` and exported it from `scheduler_core.dart`.
- Added project-statistics enums, aggregate model, exactly-once aggregation
  result/service, suggestion policy/result types, and configured-default
  resolution.
- Added `ProjectStatisticsDocumentFields`,
  `ProjectStatisticsDocumentMapping`, and `ProjectStatisticsDocumentExtension`.
- Added project-statistics field sets to the persistence field registry.
- Expanded completion activity metadata with duration, reward, difficulty, and
  reminder-profile observations for project aggregation.

Chunk 13.5 intentionally changed the public API:

- Added `src/reminder_policy.dart` and exported it from `scheduler_core.dart`.
- Added reminder directive action/reason enums and effective-profile source
  enum.
- Added `EffectiveReminderProfile`, `ReminderDirective`, and
  `ReminderPolicyService`.
- Added deterministic effective-profile resolution using task override, project
  configured default, then fallback.
- Added typed reminder directives for normal delivery, suppression, deferral,
  and required-task acknowledgement, including protected Free Slot suppression.

Chunk 14.1 intentionally changed the public API:

- Added `src/application_layer.dart` and exported it from
  `scheduler_core.dart`.
- Added application operation context, owner time-zone context, typed
  result/failure contracts, and expected application/persistence exceptions.
- Added activity, project-statistics, owner-settings, operation-record, and
  unit-of-work repository contracts for application orchestration.
- Added `OwnerSettings`, `ApplicationOperationRecord`,
  `ApplicationSchedulingLoader`, and `InMemoryApplicationUnitOfWork`.
- Added in-memory staged transaction behavior with exactly-once operation
  records and rollback on typed failures or persistence failures.

Chunk 14.2 intentionally changed the public API:

- Added `src/today_state.dart` and exported it from `scheduler_core.dart`.
- Added `GetTodayStateQuery`, `GetTodayStateRequest`, `TodayState`,
  `TodayTimelineItem`, `TodayCompactState`, and `TodayPendingNotice`.
- Added `TodayTimelineItemSource` for stable task-vs-overlay source metadata.
- Added `ApplicationUnitOfWork.read` so application queries can access
  repositories without creating operation records.
- Added an optional `occurrenceDate` parameter to
  `TimelineItemMapper.fromLockedOccurrence` so Today read models can produce
  date-stable locked overlay IDs.
- Updated compact next-flexible selection so the current flexible item is not
  also returned as `nextFlexibleItem`.

Chunk 14.3 intentionally changed the public API:

- Added `src/application_commands.dart` and exported it from
  `scheduler_core.dart`.
- Added `ApplicationCommandCode`, `ApplicationChildTaskDraft`,
  `ApplicationCommandReadHint`, `ApplicationCommandResult`, and
  `V1ApplicationCommandUseCases`.
- Added atomic V1 commands for quick capture, backlog scheduling, flexible
  push/backlog/completion, required task actions, surprise logging, protected
  Free Slot create/update/remove, child break-up, and parent/child completion.
- Command results return changed tasks, persisted activities, project aggregate
  updates, scheduler notices/changes/overlaps, child ids, and read refresh
  hints.
- Application command failures use stable `ApplicationFailureCode` values for
  not found, stale revision, no slot, validation, persistence, and duplicate
  operation outcomes.

Chunk 14.4 intentionally changed the public API:

- Added `src/application_management.dart` and exported it from
  `scheduler_core.dart`.
- Added management query/command contracts for backlog, project defaults,
  project create/update/archive, locked-block create/update/archive, one-day
  locked overrides, owner settings updates, and notice acknowledgement.
- Added `ProjectProfile.archivedAt` and `LockedBlock.archivedAt` soft-archive
  fields.
- Added `NoticeAcknowledgementRecord` and
  `NoticeAcknowledgementRepository`.
- Added stable notice IDs to `TodayPendingNotice` and Today-state filtering for
  acknowledged notices.

Chunk 14.5 intentionally changed the public API:

- Added `src/application_recovery.dart` and exported it from
  `scheduler_core.dart`.
- Added `AppOpenRecoveryOutcome`, `RunAppOpenRecoveryRequest`,
  `AppOpenRecoveryResult`, and `V1AppOpenRecoveryUseCases`.
- Added `InMemoryApplicationUnitOfWork.currentSchedulingSnapshots` for
  application/recovery contract tests.

Chunk 15.2 intentionally changed the public API:

- Replaced legacy enum `.name` document encoding in `document_mapping.dart` with
  explicit stable V1 code tables through `PersistenceEnumMapping`.
- Added `DocumentMappingFailureCode`, `DocumentMappingException`, and
  `DocumentMetadata`.
- Expanded document codecs to every V1 persisted entity: project profiles,
  project statistics, locked blocks/overrides, activities, owner settings,
  notice acknowledgements, operation records, scheduling snapshots, notices,
  changes, overlaps, windows, intervals, civil dates, and wall times.
- Changed top-level document `toDocument` helpers/extensions to require owner
  scope and V1 metadata where the domain model does not carry it directly.
- Expanded `persistence_contract.dart` with `v1SchemaVersion`, common document
  fields, and V1 field sets for every persisted repository entity.

Chunk 15.3 intentionally changed the public API:

- Added `src/document_migration.dart` and exported it from `scheduler_core.dart`.
- Added `V1DocumentMigrationService` for pure Dart V0-to-V1 migration of task,
  project, locked block, and locked override documents.
- Added typed migration surface area:
  `DocumentMigrationEntity`, `DocumentMigrationStatus`,
  `DocumentMigrationFailureCode`, `DocumentMigrationNoteCode`,
  `DocumentMigrationProvenance`, `DocumentMigrationNote`,
  `DocumentMigrationReport`, and `DocumentMigrationResult`.
- Migration results expose `document`, `isSuccess`, and `shouldWrite` so
  persistence adapters can dry-run migrations and refuse to overwrite unreadable
  source documents.
- Legacy backlog tasks now carry explicit provenance when `backlogEnteredAt` is
  approximated from `createdAt`.

Chunk 15.4 intentionally changed the public API:

- Added adapter-neutral repository conflict/paging/record contracts:
  `RepositoryFailureCode`, `RepositoryFailure`, `RepositoryMutationResult`,
  `RepositoryRecord`, `RepositoryPageRequest`, `RepositoryPage`, and
  `BacklogCandidateQuery`.
- Expanded `TaskRepository` with owner, project, parent, backlog-candidate,
  local-day/window, record/revision, insert, and compare-and-set save methods.
- Expanded `ProjectRepository` and `LockedBlockRepository` with owner-scoped
  paged queries, revision records, compare-and-set saves, duplicate insert
  failures, archive methods, and date-scoped locked override lookup.
- Expanded application-layer repository interfaces for task activity owner
  queries/appends, project statistics/settings revision saves, notice
  acknowledgement insert/paging, and idempotent operation lookup/insert.
- In-memory unit-of-work repositories now track owner/revision metadata in the
  staged transaction state.

Chunk 15.5 intentionally changed the public API:

- Added V1 collection/index contract types and constants:
  `PersistenceCollections`, `PersistenceIndexDirection`,
  `PersistenceIndexField`, `PersistenceIndexSpec`, `RepositoryQueryNames`, and
  `PersistenceIndexCatalog`.
- Added bounded payload/retention guard surface:
  `PersistencePayloadLimits`, `PersistenceGuardResult`, and
  `PersistencePayloadGuard`.
- Added repository integrity failure codes for invalid revisions and owner
  mismatches.
- Added `V1_BLOCK_16_REPOSITORY_ADAPTER_CHECKLIST.md` for MongoDB adapter
  implementation prerequisites.

## Repository contracts

The current repository surface is pure Dart and in-memory only:

- Task repository behavior is represented by `InMemoryTaskRepository`.
- Project repository behavior is represented by `InMemoryProjectRepository`.
- Locked block repository behavior is represented by
  `InMemoryLockedBlockRepository`.
- Snapshot repository behavior is represented by
  `InMemorySchedulingSnapshotRepository`.
- Application transaction behavior is represented by
  `InMemoryApplicationUnitOfWork`.
- Application read-query behavior uses `ApplicationUnitOfWork.read`, which
  stages repository access without committing operation records.

Future MongoDB adapter work must remain behind repository interfaces and must
not import MongoDB APIs into the scheduling core.
