# Phase 1 Data Model: Inventory Coverage Truth (177)

## Existing Persisted Truth

### `OperationRun` as coverage basis
Represents the canonical execution record for inventory syncs and remains the source of per-type sync truth.

**Relevant existing fields**
- `workspace_id`
- `tenant_id`
- `type`
- `status`
- `outcome`
- `summary_counts`
- `failure_summary`
- `context`
- `started_at`
- `completed_at`

**Relevant existing inventory context shape**
- `context.inventory.coverage.policy_types`
- `context.inventory.coverage.foundation_types`
- each entry stores at minimum `status`
- optional fields already supported by `InventoryCoverage` normalization:
  - `item_count`
  - `error_code`

**Existing invariant**
- `InventoryCoverage::fromContext()` is the canonical parser for run coverage payload.

### `InventoryItem`
Represents last observed tenant inventory rows and remains the source of current observed-item counts.

**Relevant existing fields**
- `workspace_id`
- `tenant_id`
- `policy_type`
- `external_id`
- `display_name`
- `category`
- `platform`
- `meta_jsonb`
- `last_seen_at`
- `last_seen_operation_run_id`

**Existing invariant**
- Observed rows prove last observation only. They do not by themselves prove current tenant coverage completeness.

### `InventoryPolicyTypeMeta` + capability metadata
Represents product support and capability reference for supported and foundation types.

**Relevant existing fields and derived attributes**
- `type`
- `label`
- `category`
- `platform`
- `restore`
- `risk`
- foundation flag
- dependency support from `CoverageCapabilitiesResolver`

**Existing invariant**
- Capability metadata is product support truth, not tenant coverage truth.

## New Derived Runtime Contract

### `TenantCoverageTruth`
Derived runtime contract that answers the operator question: which supported types are currently covered for this tenant, which types need follow-up, and which run establishes that statement.

**Proposed fields**
- `tenant_id`
- `basis_run_id` nullable
- `basis_run_outcome` nullable
- `basis_completed_at` nullable
- `has_current_coverage_result` boolean
- `supported_type_count`
- `succeeded_type_count`
- `failed_type_count`
- `skipped_type_count`
- `unknown_type_count`
- `follow_up_type_count`
- `observed_item_total`
- `rows` list of `TenantCoverageTypeTruth`

**Derived invariants**
- Exactly one row exists for each supported policy type and foundation type currently in the product support catalog.
- `follow_up_type_count = failed + skipped + unknown`.
- `has_current_coverage_result` is true only when a completed inventory-sync basis run with parseable payload exists.
- The basis run is chosen independently from current item counts.

### `TenantCoverageTypeTruth`
Derived row contract for one supported type.

**Proposed fields**
- `type`
- `segment` (`policy` or `foundation`)
- `label`
- `category`
- `platform` nullable
- `coverage_state` (`succeeded`, `failed`, `skipped`, `unknown`)
- `follow_up_required` boolean
- `observed_item_count`
- `basis_error_code` nullable
- `restore_mode` nullable
- `risk_level` nullable
- `supports_dependencies` boolean

**Derived invariants**
- `follow_up_required` is true for `failed`, `skipped`, and `unknown`; false only for `succeeded`.
- `observed_item_count > 0` does not change `coverage_state`.
- `coverage_state = unknown` when the type is supported but absent from the basis run payload.
- `basis_error_code` is allowed only for non-succeeded payload-backed states.

## Derived State Family

### Coverage state family
This feature introduces one derived state family for tenant coverage rows:

- `Succeeded`
  - the basis run reported the type as successfully processed
- `Failed`
  - the basis run reported the type as attempted and failed
- `Skipped`
  - the basis run reported the type as intentionally skipped or not processed during that run
- `Unknown`
  - no current coverage result exists for the supported type in the basis run

**Behavioral consequence**
- `Failed`, `Skipped`, and `Unknown` all suppress calm claims and increment follow-up counts.
- `Unknown` is derived, not persisted.

## Relationships

- One `TenantCoverageTruth` resolves for one tenant at a time.
- One `TenantCoverageTruth` may reference zero or one basis `OperationRun`.
- One `TenantCoverageTruth` contains one row per supported product type from `InventoryPolicyTypeMeta::supported()` and `InventoryPolicyTypeMeta::foundations()`.
- Each `TenantCoverageTypeTruth` joins one supported type to zero or one payload-backed status from the basis run and zero or more `InventoryItem` rows from the current tenant observation set.

## Selection Rules

### Basis run selection
- candidate runs are `OperationRun` rows where:
  - `tenant_id` matches the selected tenant
  - `type = inventory_sync`
  - `status = completed`
- candidates are ordered by:
  - `completed_at DESC`
  - `id DESC`
- the selected basis run is the first candidate whose `context.inventory.coverage` payload can be parsed by `InventoryCoverage::fromContext()`
- if no candidate qualifies, the tenant has no current coverage basis run

### Unknown derivation
- if a supported type is absent from both `policy_types` and `foundation_types` in the selected basis payload, the type is `Unknown`
- absence from the basis payload is not converted into `Skipped`
- item presence from older runs does not upgrade `Unknown`

## Validation Rules

- No schema migration is required.
- No new persisted state is introduced.
- Coverage rows must remain tenant-scoped.
- Capability metadata must not alter the derived coverage state.
- Surfaces may cite the basis run only when they can do so without violating authorization.