diff --git a/.github/agents/copilot-instructions.md b/.github/agents/copilot-instructions.md
index 2b2c6c4..f3a70ab 100644
--- a/.github/agents/copilot-instructions.md
+++ b/.github/agents/copilot-instructions.md
@@ -39,6 +39,7 @@ ## Active Technologies
 - PostgreSQL (existing tables: `workspaces`, `workspace_memberships`, `users`, `audit_logs`) (107-workspace-chooser)
 - PHP 8.4 (Laravel 12) + Filament v5, Livewire v4, Laravel Framework v12 (109-review-pack-export)
 - PostgreSQL (jsonb columns for summary/options), local filesystem (`exports` disk) for ZIP artifacts (109-review-pack-export)
+- PHP 8.4 + Laravel 12, Filament v5, Livewire v4 (116-baseline-drift-engine)
 
 - PHP 8.4.15 (feat/005-bulk-operations)
 
@@ -58,8 +59,8 @@ ## Code Style
 PHP 8.4.15: Follow standard conventions
 
 ## Recent Changes
+- 116-baseline-drift-engine: Added PHP 8.4 + Laravel 12, Filament v5, Livewire v4
 - 110-ops-ux-enforcement: Added PHP 8.4.x + Laravel 12, Filament v5, Livewire v4
 - 109-review-pack-export: Added PHP 8.4 (Laravel 12) + Filament v5, Livewire v4, Laravel Framework v12
-- 109-review-pack-export: Added [if applicable, e.g., PostgreSQL, CoreData, files or N/A]
 <!-- MANUAL ADDITIONS START -->
 <!-- MANUAL ADDITIONS END -->
diff --git a/specs/116-baseline-drift-engine/checklists/requirements.md b/specs/116-baseline-drift-engine/checklists/requirements.md
new file mode 100644
index 0000000..adc3450
--- /dev/null
+++ b/specs/116-baseline-drift-engine/checklists/requirements.md
@@ -0,0 +1,35 @@
+# Specification Quality Checklist: Baseline Drift Engine (Final Architecture)
+
+**Purpose**: Validate specification completeness and quality before proceeding to planning
+**Created**: 2026-03-01
+**Feature**: [specs/116-baseline-drift-engine/spec.md](../spec.md)
+
+## Content Quality
+
+- [x] No implementation details (languages, frameworks, APIs)
+- [x] Focused on user value and business needs
+- [x] Written for non-technical stakeholders
+- [x] All mandatory sections completed
+
+## Requirement Completeness
+
+- [x] No [NEEDS CLARIFICATION] markers remain
+- [x] Requirements are testable and unambiguous
+- [x] Success criteria are measurable
+- [x] Success criteria are technology-agnostic (no implementation details)
+- [x] All acceptance scenarios are defined
+- [x] Edge cases are identified
+- [x] Scope is clearly bounded
+- [x] Dependencies and assumptions identified
+
+## Feature Readiness
+
+- [x] All functional requirements have clear acceptance criteria
+- [x] User scenarios cover primary flows
+- [x] Feature meets measurable outcomes defined in Success Criteria
+- [x] No implementation details leak into specification
+
+## Notes
+
+- Items marked incomplete require spec updates before `/speckit.clarify` or `/speckit.plan`
+- This spec uses internal domain terms like “Operation run”, “capability”, and “hash fidelity” intentionally; they are defined in-context and treated as product concepts rather than framework implementation.
diff --git a/specs/116-baseline-drift-engine/contracts/openapi.yaml b/specs/116-baseline-drift-engine/contracts/openapi.yaml
new file mode 100644
index 0000000..bf7716f
--- /dev/null
+++ b/specs/116-baseline-drift-engine/contracts/openapi.yaml
@@ -0,0 +1,157 @@
+openapi: 3.0.3
+info:
+  title: Spec 116 - Baseline Drift Engine
+  version: 0.1.0
+  description: |
+    Minimal contracts for Baseline capture/compare operations and finding summaries.
+    This repo is primarily Filament-driven; these endpoints represent conceptual contracts
+    or internal routes/services rather than guaranteed public APIs.
+
+servers:
+  - url: /
+
+paths:
+  /internal/baselines/{baselineProfileId}/snapshots:
+    post:
+      summary: Capture a baseline snapshot
+      parameters:
+        - in: path
+          name: baselineProfileId
+          required: true
+          schema:
+            type: integer
+      requestBody:
+        required: false
+      responses:
+        '202':
+          description: Snapshot capture queued
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/OperationQueued'
+
+  /internal/baselines/{baselineProfileId}/compare:
+    post:
+      summary: Compare baseline snapshot to tenant inventory
+      parameters:
+        - in: path
+          name: baselineProfileId
+          required: true
+          schema:
+            type: integer
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/BaselineCompareRequest'
+      responses:
+        '202':
+          description: Compare queued
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/OperationQueued'
+
+  /internal/tenants/{tenantId}/findings:
+    get:
+      summary: List findings for a tenant (filtered)
+      parameters:
+        - in: path
+          name: tenantId
+          required: true
+          schema:
+            type: integer
+        - in: query
+          name: scope_key
+          required: false
+          schema:
+            type: string
+        - in: query
+          name: status
+          required: false
+          schema:
+            type: string
+            enum: [open, resolved]
+      responses:
+        '200':
+          description: Findings list
+          content:
+            application/json:
+              schema:
+                type: object
+                properties:
+                  data:
+                    type: array
+                    items:
+                      $ref: '#/components/schemas/Finding'
+
+components:
+  schemas:
+    BaselineCompareRequest:
+      type: object
+      required: [tenant_id]
+      properties:
+        tenant_id:
+          type: integer
+        baseline_snapshot_id:
+          type: integer
+          nullable: true
+          description: Optional explicit snapshot selection. If omitted, latest successful snapshot is used.
+
+    OperationQueued:
+      type: object
+      required: [operation_run_id]
+      properties:
+        operation_run_id:
+          type: integer
+
+    Finding:
+      type: object
+      required: [id, tenant_id, fingerprint, scope_key, created_at]
+      properties:
+        id:
+          type: integer
+        tenant_id:
+          type: integer
+        fingerprint:
+          type: string
+          description: Stable identifier; for baseline drift equals recurrence_key.
+        recurrence_key:
+          type: string
+          nullable: true
+        scope_key:
+          type: string
+        change_type:
+          type: string
+          nullable: true
+        policy_type:
+          type: string
+          nullable: true
+        subject_external_id:
+          type: string
+          nullable: true
+        evidence:
+          type: object
+          additionalProperties: true
+        first_seen_at:
+          type: string
+          format: date-time
+          nullable: true
+        last_seen_at:
+          type: string
+          format: date-time
+          nullable: true
+        times_seen:
+          type: integer
+          nullable: true
+        resolved_at:
+          type: string
+          format: date-time
+          nullable: true
+        created_at:
+          type: string
+          format: date-time
+        updated_at:
+          type: string
+          format: date-time
diff --git a/specs/116-baseline-drift-engine/data-model.md b/specs/116-baseline-drift-engine/data-model.md
new file mode 100644
index 0000000..6ac2a92
--- /dev/null
+++ b/specs/116-baseline-drift-engine/data-model.md
@@ -0,0 +1,122 @@
+# Phase 1 — Data Model (Baseline Drift Engine)
+
+This document identifies the data/entities involved in Spec 116 and the minimal schema/config changes needed to implement it in this repository.
+
+## Existing Entities (Confirmed)
+
+### BaselineProfile
+Represents a baseline definition.
+
+- Fields (expected): `id`, `name`, `description`, `scope` (jsonb), `created_by`, timestamps
+- Relationships: has many snapshots; assigned to tenants via `BaselineTenantAssignment`
+
+### BaselineSnapshot
+Immutable capture of baseline state at a point in time.
+
+- Fields (expected): `id`, `baseline_profile_id`, `captured_at`, `status`, `operation_run_id`, timestamps
+- Relationships: has many items; belongs to baseline profile
+
+### BaselineSnapshotItem
+One item in a baseline snapshot.
+
+- Fields (expected):
+  - `id`, `baseline_snapshot_id`
+  - `policy_type`
+  - `external_id`
+  - `subject_json` (jsonb) or subject fields
+  - `baseline_hash` (string)
+  - `meta_jsonb` (jsonb)
+  - timestamps
+
+### Finding
+Generic drift finding storage.
+
+- Fields (confirmed by usage): `tenant_id`, `fingerprint` (unique with tenant), `recurrence_key` (nullable), `scope_key`, lifecycle fields (`first_seen_at`, `last_seen_at`, `times_seen`), evidence (jsonb)
+
+### OperationRun
+Tracks long-running operations.
+
+- Fields (by convention): `type`, `status/outcome`, `summary_counts` (numeric map), `context` (jsonb)
+
+## New / Adjusted Data Requirements
+
+### 1) Inventory sync coverage context
+
+**Goal:** Baseline compare must know which policy types were actually processed successfully by inventory sync.
+
+**Where:** `operation_runs.context` for the latest inventory sync run.
+
+**Shape (proposed):**
+
+```json
+{
+  "inventory": {
+    "coverage": {
+      "policy_types": {
+        "deviceConfigurations": {"status": "succeeded", "item_count": 123},
+        "compliancePolicies": {"status": "failed", "error": "..."}
+      },
+      "foundation_types": {
+        "securityBaselines": {"status": "succeeded", "item_count": 4}
+      }
+    }
+  }
+}
+```
+
+**Notes:**
+- Only `summary_counts` must remain numeric; detailed coverage lists live in `context`.
+- For Spec 116 v1, it’s sufficient to store `policy_types` coverage; adding `foundation_types` coverage at the same time keeps parity with scope rules.
+
+### 2) Baseline scope schema
+
+**Goal:** Support both policy and foundation scope with correct defaults.
+
+**Current:** `policy_types` only.
+
+**Target:**
+
+```json
+{
+  "policy_types": ["deviceConfigurations", "compliancePolicies"],
+  "foundation_types": ["securityBaselines"]
+}
+```
+
+**Default semantics:**
+- Empty `policy_types` means “all supported policy types excluding foundations”.
+- Empty `foundation_types` means “none”.
+
+### 3) Findings recurrence strategy
+
+**Goal:** Stable identity per snapshot and per subject.
+
+- `findings.recurrence_key`: populated for baseline compare findings.
+- `findings.fingerprint`: set to the same recurrence key (to satisfy existing uniqueness constraint).
+
+**Recurrence key inputs:**
+- `tenant_id`
+- `baseline_snapshot_id`
+- `policy_type`
+- `subject_external_id`
+- `change_type`
+
+**Grouping (scope_key):**
+- Keep `findings.scope_key = baseline_profile:{baselineProfileId}` for baseline compare findings.
+
+### 4) Inventory meta contract
+
+**Goal:** Explicitly define what is hashed for v1 comparisons.
+
+- Implemented as a dedicated builder class (no schema change required).
+- Used by baseline capture to compute `baseline_hash` and by compare to compute `current_hash`.
+
+## Potential Migrations (Likely)
+
+- If `baseline_profiles.scope` is not jsonb or does not include foundation types → migration to adjust structure (jsonb stays the same, but add support in code; DB change may be optional).
+- If coverage context needs persistence beyond operation run context → avoid adding tables unless proven necessary; context-based is sufficient for v1.
+
+## Index / Performance Notes
+
+- Findings queries commonly filter by `tenant_id` + `scope_key`; ensure there is an index on `(tenant_id, scope_key)`.
+- Baseline snapshot items must be efficiently loaded by `(baseline_snapshot_id, policy_type)`.
diff --git a/specs/116-baseline-drift-engine/plan.md b/specs/116-baseline-drift-engine/plan.md
new file mode 100644
index 0000000..9ff0ca4
--- /dev/null
+++ b/specs/116-baseline-drift-engine/plan.md
@@ -0,0 +1,242 @@
+# Implementation Plan: 116 — Baseline Drift Engine (Final Architecture)
+
+**Branch**: `116-baseline-drift-engine` | **Date**: 2026-03-01 | **Spec**: `specs/116-baseline-drift-engine/spec.md`
+**Input**: Feature specification from `specs/116-baseline-drift-engine/spec.md`
+
+## Summary
+
+Align the existing baseline capture/compare pipeline to Spec 116 by (1) defining an explicit meta-fidelity hash contract, (2) enforcing the “coverage guard” based on the latest inventory sync run, and (3) switching baseline-compare findings to snapshot-scoped stable identities (recurrence keys) while preserving existing baseline-profile grouping for UI/stats and auto-close semantics.
+
+## Technical Context
+
+**Language/Version**: PHP 8.4
+**Primary Dependencies**: Laravel 12, Filament v5, Livewire v4
+**Storage**: PostgreSQL (via Sail)
+**Testing**: Pest v4 (PHPUnit 12)
+**Target Platform**: Docker (Laravel Sail)
+**Project Type**: Web application (Laravel)
+**Performance Goals**: Compare jobs must remain bounded by scope size; avoid N+1 queries when loading snapshot + current inventory
+**Constraints**:
+- Ops-UX: OperationRun lifecycle + 3-surface feedback (toast queued-only, progress in widget/run detail, terminal DB notification exactly-once)
+- Summary counts numeric-only and keys restricted to `OperationSummaryKeys`
+- Tenant/workspace isolation + RBAC deny-as-not-found rules
+**Scale/Scope**: Tenant inventories may be large; baseline compare must be efficient on `(tenant_id, policy_type)` filtering
+
+## Constitution Check
+
+*GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.*
+
+- Inventory-first: PASS — compare uses Inventory as last observed state; baselines are immutable snapshots.
+- Read/write separation: PASS — this feature is read-only analysis; no Graph writes.
+- Graph contract path: PASS — inventory sync already uses `GraphClientInterface`; baseline compare itself is DB-only at render time.
+- Deterministic capabilities: PASS — baseline capability checks use existing registries/policies; no new ad-hoc strings.
+- Workspace + tenant isolation: PASS — baseline profiles are workspace-owned; runs/findings are tenant-owned; authorization remains deny-as-not-found for non-members.
+- Run observability (OperationRun): PASS — capture/compare already use OperationRun + queued jobs.
+- Ops-UX 3-surface feedback: PASS — existing pages use canonical queued toast presenter.
+- Ops-UX lifecycle: PASS — transitions must remain inside `OperationRunService`.
+- Ops-UX summary counts: PASS — only numeric summary counts using canonical keys.
+- Filament UI contract: PASS — only small scope-picker adjustments; no new pages beyond what exists.
+- Filament UX-001 layout: PASS — Baseline Profile Create/Edit will be updated to a Main/Aside layout as part of the scope-picker work.
+
+## Project Structure
+
+### Documentation (this feature)
+
+```text
+specs/116-baseline-drift-engine/
+├── plan.md
+├── research.md
+├── data-model.md
+├── quickstart.md
+├── contracts/
+│   └── openapi.yaml
+└── checklists/
+    └── requirements.md
+```
+
+### Source Code (repository root)
+
+```text
+app/
+├── Filament/
+│   ├── Pages/                # Baseline compare landing + run detail links (existing)
+│   ├── Resources/            # BaselineProfileResource (existing)
+│   └── Widgets/              # Baseline compare widgets (existing)
+├── Jobs/
+│   ├── CaptureBaselineSnapshotJob.php
+│   └── CompareBaselineToTenantJob.php
+├── Models/
+│   ├── BaselineProfile.php
+│   ├── BaselineSnapshot.php
+│   ├── BaselineSnapshotItem.php
+│   ├── Finding.php
+│   ├── InventoryItem.php
+│   └── OperationRun.php
+├── Services/
+│   ├── Baselines/
+│   │   ├── BaselineCaptureService.php
+│   │   ├── BaselineCompareService.php
+│   │   ├── BaselineAutoCloseService.php
+│   │   └── BaselineSnapshotIdentity.php
+│   ├── Drift/
+│   │   ├── DriftFindingGenerator.php
+│   │   └── DriftHasher.php
+│   ├── Inventory/
+│   │   └── InventorySyncService.php
+│   └── OperationRunService.php
+└── Support/
+    ├── Baselines/BaselineCompareStats.php
+    └── OpsUx/OperationSummaryKeys.php
+
+tests/
+└── Feature/
+    └── Baselines/
+        ├── BaselineCompareFindingsTest.php
+        ├── BaselineComparePreconditionsTest.php
+        ├── BaselineCompareStatsTest.php
+        └── BaselineOperabilityAutoCloseTest.php
+```
+
+**Structure Decision**: Web application (Laravel 12) — all work stays in existing `app/` services/jobs/models and `tests/Feature`.
+
+## Complexity Tracking
+
+No constitution violations are required for this feature.
+
+## Phase 0 — Outline & Research (DONE)
+
+Outputs:
+- `specs/116-baseline-drift-engine/research.md`
+
+Key reconciliations captured:
+- Baseline compare finding identity will move to recurrence-key based upsert (snapshot-scoped identity) aligned with the existing `DriftFindingGenerator` pattern.
+- Coverage guard requires persisting per-type coverage outcomes into the latest inventory sync run context.
+- Scope must include `policy_types` + `foundation_types` with correct empty-default semantics.
+
+## Phase 1 — Design & Contracts (DONE)
+
+Outputs:
+- `specs/116-baseline-drift-engine/data-model.md`
+- `specs/116-baseline-drift-engine/contracts/openapi.yaml`
+- `specs/116-baseline-drift-engine/quickstart.md`
+
+Design highlights:
+- Coverage lives in `operation_runs.context` for inventory sync runs (detailed lists), while `summary_counts` remain numeric-only.
+- Findings use `recurrence_key` and `fingerprint = recurrence_key` for idempotent upserts.
+- Findings remain grouped by `scope_key = baseline_profile:{id}` to preserve existing UI/stats and auto-close behavior.
+
+## Phase 1 — Agent Context Update (REQUIRED)
+
+Run:
+- `.specify/scripts/bash/update-agent-context.sh copilot`
+
+## Phase 2 — Implementation Plan
+
+### Step 1 — Baseline scope schema + UI picker
+
+Goal: implement FR-116v1-01 and FR-116v1-02.
+
+Changes:
+- Update baseline scope handling (`app/Support/Baselines/BaselineScope.php`) to support:
+  - `policy_types: []` meaning “all supported policy types excluding foundations”
+  - `foundation_types: []` meaning “none”
+- Update `BaselineProfile` form schema (Filament Resource) to show multi-selects for Policy Types and Foundations.
+
+Tests:
+- Update/add Pest tests around scope expansion defaults (prefer a focused unit-like test if an expansion helper exists).
+
+### Step 2 — Inventory Meta Contract (explicit hash input)
+
+Goal: implement FR-116v1-04, FR-116v1-05, FR-116v1-06.
+
+Changes:
+- Introduce a dedicated contract builder (e.g. `App\Services\Baselines\InventoryMetaContract`) that returns a normalized array for hashing.
+- Update baseline capture hashing (`BaselineSnapshotIdentity::hashItemContent()` or the capture service) to hash the contract output only.
+- Update baseline compare to compute `current_hash` using the same contract builder.
+
+Tests:
+- Add a small Pest test for contract normalization stability (ordering, missing fields, nullability).
+- Update baseline capture/compare tests if they currently assume hashing full `meta_jsonb`.
+
+### Step 3 — Inventory sync coverage recording
+
+Goal: provide coverage for FR-116v1-07.
+
+Changes:
+- Extend inventory sync pipeline (in `App\Services\Inventory\InventorySyncService` and/or the job that orchestrates sync) to write a coverage payload into the inventory sync `OperationRun.context`:
+  - Per policy type: status (`succeeded|failed|skipped`) and optional `item_count`.
+  - Foundations can be included in the same shape if they are part of selection.
+- Ensure this is written even when some types fail, so downstream compare can determine uncovered types.
+
+Tests:
+- Add/extend tests around inventory sync operation context writing (mocking Graph calls as needed; keep scope minimal).
+
+### Step 4 — Baseline compare coverage guard + outcome semantics
+
+Goal: implement FR-116v1-07 and align to Ops-UX.
+
+Changes:
+- In baseline compare job/service:
+  - Resolve the latest inventory sync run for the tenant.
+  - Compute `covered_policy_types` from sync run context.
+  - Compute `uncovered_policy_types = effective_scope.policy_types - covered_policy_types`.
+  - Skip emission of *all* finding types for uncovered policy types.
+  - Record coverage details into the compare run `context` for auditability.
+  - If uncovered types exist, set compare outcome to `partially_succeeded` via `OperationRunService` and set `summary_counts.errors_recorded = count(uncovered_policy_types)`.
+  - If effective scope expands to zero types, complete as `partially_succeeded` and set `summary_counts.errors_recorded = 1` so the warning remains visible under numeric-only summary counts.
+  - If there is no completed inventory sync run (or coverage proof is missing/unreadable), treat coverage as unproven for all effective-scope types (fail-safe): emit zero findings and complete as `partially_succeeded`.
+
+Tests:
+- Add a new Pest test in `tests/Feature/Baselines` asserting:
+  - uncovered types cause partial outcome
+  - uncovered types produce zero findings (even if snapshot/current data would otherwise create missing/unexpected/different)
+  - covered types still produce findings
+
+### Step 5 — Snapshot-scoped stable finding identity
+
+Goal: implement FR-116v1-09 and FR-116v1-10.
+
+Changes:
+- Replace hash-evidence-based `fingerprint` generation in baseline compare with a stable recurrence key:
+  - Inputs: `tenant_id`, `baseline_snapshot_id`, `policy_type`, `subject_external_id`, `change_type`
+- Persist:
+  - `findings.recurrence_key = <computed>`
+  - `findings.fingerprint = <same computed>`
+- Keep `scope_key = baseline_profile:{baselineProfileId}`.
+- Ensure retry idempotency: do not increment lifecycle counters more than once per run identity.
+
+Tests:
+- Update `tests/Feature/Baselines/BaselineCompareFindingsTest.php`:
+  - Ensure fingerprint no longer depends on baseline/current hash.
+  - Assert stable identity across re-runs with changed evidence hashes.
+- Add coverage for “recapture uses new snapshot id → new finding identity”.
+
+### Step 6 — Auto-close + stats compatibility
+
+Goal: preserve existing operability expectations and keep UI stable.
+
+Changes:
+- Ensure `BaselineAutoCloseService` still resolves stale findings after a fully successful compare, even though identities now include snapshot id.
+- Confirm `BaselineCompareStats` remains correct for grouping by `scope_key = baseline_profile:{id}`.
+
+Tests:
+- Update/keep `tests/Feature/Baselines/BaselineOperabilityAutoCloseTest.php` passing.
+- Update `tests/Feature/Baselines/BaselineCompareStatsTest.php` only if scope semantics change.
+
+### Step 7 — Ops UX + auditability
+
+Goal: implement FR-116v1-03 and FR-116v1-11.
+
+Changes:
+- Ensure both capture and compare runs write:
+  - `effective_scope.*` in run context
+  - coverage summary and uncovered lists when partial
+  - numeric summary counts using canonical keys only
+  - per-change-type finding counts in `operation_runs.context.findings.counts_by_change_type`
+
+Tests:
+- Add a regression test that asserts `summary_counts` contains only allowed keys and numeric values (where a helper exists).
+
+## Post-design Constitution Re-check
+
+Expected: PASS (no changes introduce new Graph endpoints or bypass services; OperationRun lifecycle + 3-surface feedback remain intact; RBAC deny-as-not-found semantics preserved).
diff --git a/specs/116-baseline-drift-engine/quickstart.md b/specs/116-baseline-drift-engine/quickstart.md
new file mode 100644
index 0000000..bfbe099
--- /dev/null
+++ b/specs/116-baseline-drift-engine/quickstart.md
@@ -0,0 +1,57 @@
+# Quickstart — Spec 116 Baseline Drift Engine
+
+This quickstart is for developers validating the behavior locally.
+
+## Prerequisites
+
+- Sail up: `vendor/bin/sail up -d`
+- Install deps (if needed): `vendor/bin/sail composer install`
+- Run migrations: `vendor/bin/sail artisan migrate`
+
+## Workflow
+
+### 1) Run an inventory sync (establish coverage)
+
+- Trigger inventory sync for a tenant using the existing UI/command for inventory sync.
+- Verify the latest inventory sync `operation_runs.context` contains a coverage payload:
+  - `inventory.coverage.policy_types.{type}.status = succeeded|failed`
+  - (optionally) `inventory.coverage.foundation_types.{type}.status = ...`
+
+Expected:
+- If some types fail or are not processed, the coverage payload reflects that.
+
+### 2) Capture a baseline snapshot
+
+- Use the Baseline Profile UI to capture a snapshot.
+
+Expected:
+- Snapshot items store `baseline_hash` computed from the Inventory Meta Contract.
+- Snapshot identity/dedupe follows existing snapshot identity rules, but content hashes come from the explicit contract.
+
+### 3) Compare baseline to tenant
+
+- Trigger “Compare now” from the Baseline Compare landing page.
+
+Expected:
+- Compare uses latest successful baseline snapshot by default (or explicit snapshot selection if provided).
+- Compare uses the latest inventory sync run coverage:
+  - For uncovered policy types, **no findings are emitted**.
+  - OperationRun outcome becomes “completed with warnings” (partial) when uncovered types exist.
+  - `summary_counts.errors_recorded = count(uncovered_types)`.
+  - Edge case: if effective scope expands to zero types, outcome is still partial (warnings) and `summary_counts.errors_recorded = 1`.
+- Findings identity:
+  - stable `recurrence_key` uses `baseline_snapshot_id` and does **not** include baseline/current hashes.
+  - `fingerprint == recurrence_key`.
+  - `scope_key` remains profile-scoped (`baseline_profile:{id}`).
+
+### 4) Validate UI counts
+
+- Verify baseline compare stats remain grouped by the profile scope (`scope_key = baseline_profile:{id}`), consistent with research.md Decision #2.
+- Validate that re-capturing (new snapshot) creates a new set of findings due to snapshot-scoped identity (recurrence key includes `baseline_snapshot_id`).
+
+## Minimal smoke test checklist
+
+- Compare with full coverage: produces correct findings; outcome success.
+- Compare with partial coverage: produces findings only for covered types; outcome partial; uncovered types listed in context.
+- Re-run compare with no changes: no new findings; `times_seen` increments.
+- Re-capture snapshot and compare: findings identity changes (snapshot-scoped).
diff --git a/specs/116-baseline-drift-engine/research.md b/specs/116-baseline-drift-engine/research.md
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+# Phase 0 — Research (Baseline Drift Engine)
+
+This document resolves the open design/implementation questions needed to produce a concrete implementation plan for Spec 116, grounded in the current codebase.
+
+## Repo Reality Check (What already exists)
+
+- Baseline domain tables exist: `baseline_profiles`, `baseline_snapshots`, `baseline_snapshot_items`, `baseline_tenant_assignments`.
+- Baseline ops exist:
+  - Capture: `App\Services\Baselines\BaselineCaptureService` → `App\Jobs\CaptureBaselineSnapshotJob`.
+  - Compare: `App\Services\Baselines\BaselineCompareService` → `App\Jobs\CompareBaselineToTenantJob`.
+- Findings lifecycle primitives exist (times_seen/first_seen/last_seen) and recurrence support exists (`findings.recurrence_key`).
+- An existing recurrence-based drift generator exists: `App\Services\Drift\DriftFindingGenerator` (uses `recurrence_key` and also sets `fingerprint = recurrence_key` to satisfy the unique constraint).
+- Inventory sync is OperationRun-based and stamps `inventory_items.last_seen_operation_run_id`.
+
+## Decisions
+
+### 1) Finding identity for baseline compare
+
+**Decision:** Baseline compare findings MUST use a stable recurrence key derived from:
+- `tenant_id`
+- `baseline_snapshot_id` (not baseline profile id)
+- `policy_type`
+- `subject_external_id`
+- `change_type`
+
+This recurrence key is stored in `findings.recurrence_key` and ALSO used as `findings.fingerprint` (to keep the existing unique constraint `unique(tenant_id, fingerprint)` effective).
+
+**Rationale:**
+- Matches Spec 116 (identity tied to `baseline_snapshot_id` and independent of evidence hashes).
+- Aligns with existing, proven pattern in `DriftFindingGenerator` (recurrence_key-based upsert; fingerprint reused).
+
+**Alternatives considered:**
+- Keep `DriftHasher::fingerprint(...)` with baseline/current hashes included → rejected because it changes identity when evidence changes (violates FR-116v1-09).
+- Add a new unique DB constraint on `(tenant_id, recurrence_key)` → possible later hardening; not required initially because fingerprint uniqueness already enforces dedupe when `fingerprint = recurrence_key`.
+
+### 2) Scope key for baseline compare findings
+
+**Decision:** Keep findings grouped by baseline profile using `scope_key = baseline_profile:{baselineProfileId}`.
+
+**Rationale:**
+- Spec 116 requires snapshot-scoped *identity* (via `baseline_snapshot_id` in the recurrence key), but does not require snapshot-scoped grouping.
+- The repository already has UI widgets/stats and auto-close behavior keyed to `baseline_profile:{id}`; keeping scope_key stable minimizes churn and preserves existing semantics.
+- Re-captures still create new finding identities because the recurrence key includes `baseline_snapshot_id`.
+
+**Alternatives considered:**
+- Snapshot-scoped `scope_key = baseline_snapshot:{id}` → rejected for v1 because it would require larger refactors to stats, widgets, and auto-close queries, without being mandated by the spec.
+
+### 3) Coverage guard (prevent false missing policies)
+
+**Decision:** Coverage MUST be derived from the latest completed `inventory_sync` OperationRun for the tenant:
+- Record per-policy-type processing outcomes into that run’s context (coverage payload).
+- Baseline compare MUST compute `uncovered_policy_types = effective_scope - covered_policy_types`.
+- Baseline compare MUST emit **no findings of any kind** for uncovered policy types.
+- The compare OperationRun outcome should be `partially_succeeded` when uncovered types exist ("completed with warnings" in Ops UX), and summary counts should include `errors_recorded = count(uncovered_policy_types)`.
+
+**Rationale:**
+- Spec FR-116v1-07 and SC-116-03.
+- Current compare logic uses `inventory_items.last_seen_operation_run_id` filter only; without an explicit coverage list, a missing type looks identical to a truly empty tenant.
+
+**Alternatives considered:**
+- Infer coverage purely from "were there any inventory items for this policy type in the last sync run" → rejected because a legitimately empty type would be indistinguishable from "not synced".
+
+### 4) Inventory meta contract hashing (v1 fidelity=meta)
+
+**Decision:** Introduce an explicit "Inventory Meta Contract" builder used by BOTH capture and compare in v1.
+
+- Inputs: `policy_type`, `external_id`, and a whitelist of stable signals from inventory/meta (etag, last modified, scope tags, assignment target count, version marker when available).
+- Output: a normalized associative array, hashed deterministically.
+
+**Rationale:**
+- Spec FR-116v1-04: hashing must be based on a stable contract, not arbitrary meta.
+- Current `BaselineSnapshotIdentity::hashItemContent()` hashes the entire `meta_jsonb` (including keys like `etag` which may be noisy and keys that may expand over time).
+
+**Alternatives considered:**
+- Keep current hashing of `meta_jsonb` → rejected because it is not an explicit contract and may drift as we add inventory metadata.
+
+### 5) Baseline scope + foundations
+
+**Decision:** Extend baseline scope JSON to include:
+- `policy_types: []` (empty means default "all supported policy types excluding foundations")
+- `foundation_types: []` (empty means default "none")
+
+Foundations list must be derived from the same canonical foundation list used by inventory sync selection logic.
+
+**Rationale:**
+- Spec FR-116v1-01.
+- Current `BaselineScope` only supports `policy_types` and treats empty as "all" (including foundations) which conflicts with the spec default.
+
+### 6) v2 architecture strategy (content fidelity)
+
+**Decision:** v2 is implemented as an extension of the same pipeline via a provider precedence chain:
+
+`PolicyVersion (if available) → Inventory content (if available) → Meta contract fallback (degraded)`
+
+The baseline compare engine stores dimension flags on the same finding (no additional finding identities).
+
+**Rationale:**
+- Spec FR-116v2-01 and FR-116v2-05.
+- There is already a content-normalization + hashing stack in `DriftFindingGenerator` (policy snapshot / assignments / scope tags) which can inform the content fidelity provider.
+
+## Notes / Risks
+
+- Existing baseline compare findings are currently keyed by `fingerprint` that includes baseline/current hashes and uses `scope_key = baseline_profile:{id}`. The v1 migration should plan for “old findings become stale” behavior; do not attempt silent in-place identity rewriting without an explicit migration/backfill plan.
+- Coverage persistence must remain numeric-only in `summary_counts` (per Ops-UX). Detailed coverage lists belong in `operation_runs.context`.
diff --git a/specs/116-baseline-drift-engine/spec.md b/specs/116-baseline-drift-engine/spec.md
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+# Feature Specification: Baseline Drift Engine (Final Architecture)
+
+**Feature Branch**: `116-baseline-drift-engine`  
+**Created**: 2026-03-01  
+**Status**: Draft  
+**Input**: User description: "Spec 116 — Baseline Drift Engine (Final Architecture)"
+
+## Spec Scope Fields *(mandatory)*
+
+- **Scope**: workspace (baseline definition + capture) + tenant (baseline compare monitoring)
+- **Primary Routes**:
+  - Workspace (admin): Baseline Profiles (create/edit scope, capture baseline)
+  - Tenant-context (admin): Baseline Compare runs (compare now, run detail) and Drift Findings landing
+- **Data Ownership**:
+  - Workspace-owned: Baseline profiles and baseline snapshots
+  - Tenant-scoped (within a workspace): Operation runs for baseline capture/compare; drift findings produced by compare
+- **RBAC**:
+  - Workspace (Baselines):
+    - `workspace_baselines.view`: view baseline profiles + snapshots
+    - `workspace_baselines.manage`: create/edit/archive baseline profiles, start capture runs
+  - Tenant (Compare):
+    - `tenant.sync`: start baseline compare runs
+    - `tenant_findings.view`: view drift findings
+  - Tenant access is required for tenant-context surfaces, in addition to workspace membership
+
+For canonical-view specs: not applicable (this is not a canonical-view feature).
+
+## Clarifications
+
+### Session 2026-03-01
+
+- Q: Should finding identity be stable across baseline re-captures, or tied to a specific baseline snapshot? → A: Tie finding identity to `baseline_snapshot_id` (stable within a snapshot; re-capture creates new finding identities).
+- Q: In v2, should drift dimensions be stored as flags on a single finding, or as separate findings per dimension? → A: Use one finding with dimension flags (no separate findings per dimension).
+- Q: When running a compare, which baseline snapshot should be used by default? → A: Default to latest successful baseline snapshot for the baseline profile; allow explicitly selecting a snapshot.
+- Q: When coverage is missing for a policy type, should compare emit any findings for that type? → A: Skip all finding emission for uncovered types (no `missing_policy`, no `unexpected_policy`, no `different_version`).
+
+## Outcomes
+
+- **O-1 One engine**: There is exactly one baseline drift compare engine; no parallel legacy compare/hash paths.
+- **O-2 Stable findings (recurrence)**: The same underlying drift maps to the same finding identity across retries and across runs, with lifecycle counters.
+- **O-3 Auditability & operator UX**: Each compare run records scope, coverage, and fidelity; partial coverage produces warnings (not misleading “missing policy” noise).
+- **O-4 No legacy logic after v2**: After the v2 extension, there are no “meta compare here / diff there” special cases; all drift flows through the same pipeline.
+
+## Definitions
+
+- **Policy subject**: A compare object uniquely identified by `(tenant_id, policy_type, external_id)`.
+- **Policy state**: A normalized representation of a policy subject, containing a deterministic hash, fidelity, and observation metadata.
+- **Fidelity**:
+  - **meta**: drift signal based on a stable “inventory meta contract” (signal-based fields)
+  - **content**: drift signal based on canonicalized policy content (semantic)
+- **Effective scope**: The expanded set of policy types processed by a run.
+- **Coverage**: Which policy types are confirmed to be present/updated in the current state at the time of compare.
+
+## Assumptions
+
+- Baseline drift is sold as “signal-based drift detection” in v1 (meta fidelity), and later upgraded to deep drift (content fidelity) without changing the compare engine semantics.
+- The system already has a tenant-scoped inventory sync mechanism capable of recording per-run coverage of which policy types were synced.
+- Foundations are treated as opt-in policy types; they are excluded unless explicitly selected.
+
+## User Scenarios & Testing *(mandatory)*
+
+### User Story 1 - Capture and compare a baseline with stable findings (Priority: P1)
+
+As a workspace admin, I want to define a baseline scope, capture a baseline snapshot, and compare a tenant against that baseline, so I can reliably detect and track drift over time.
+
+**Why this priority**: This is the core product slice that makes baseline drift sellable: consistent capture, consistent compare, and stable findings.
+
+**Independent Test**: Can be tested by creating a baseline profile with a defined scope, capturing a snapshot, running compare twice, and verifying stable finding identity and lifecycle counters.
+
+**Acceptance Scenarios**:
+
+1. **Given** a baseline profile with scope “all policy types (excluding foundations)”, **When** I capture a baseline snapshot, **Then** the snapshot contains only in-scope policy subjects and each snapshot item records its hash and fidelity.
+2. **Given** a captured baseline snapshot and a tenant current state, **When** I run compare twice with the same inputs, **Then** the same drift maps to the same finding identity and lifecycle counters increment at most once per run.
+
+---
+
+### User Story 2 - Coverage warnings prevent misleading missing-policy findings (Priority: P1)
+
+As an operator, I want the compare run to warn when current-state coverage is partial, so that missing policies are not falsely reported when the system simply lacks data.
+
+**Why this priority**: Trust depends on avoiding false negatives/positives; “missing policy” findings on partial sync is unacceptable noise.
+
+**Independent Test**: Can be tested by running compare with an effective scope where some policy types are intentionally marked as not synced, verifying warning outcome and suppression behavior.
+
+**Acceptance Scenarios**:
+
+1. **Given** a compare run where some policy types in effective scope were not synced, **When** compare is executed, **Then** the run completes with warnings and produces no findings at all for those missing-coverage types.
+2. **Given** a compare run where coverage is complete, **When** a baseline policy subject is missing in current state for a covered type, **Then** a missing-policy finding is produced.
+
+---
+
+### User Story 3 - Operators can understand scope, coverage, and fidelity in the UI (Priority: P2)
+
+As an operator, I want drift screens to clearly show what was compared (scope), how complete the data was (coverage), and how “deep” the drift signal is (fidelity), so I can interpret findings correctly.
+
+**Why this priority**: Drift findings are only actionable when the operator understands context and limitations.
+
+**Independent Test**: Can be tested by executing a compare run with and without coverage warnings, verifying that run detail and drift landing surfaces render scope counts, coverage badge, and fidelity indicators.
+
+**Acceptance Scenarios**:
+
+1. **Given** a compare run with full coverage, **When** I open run detail, **Then** I see the compared scope and a coverage status of OK.
+2. **Given** a compare run with partial coverage, **When** I open the drift landing and run detail, **Then** I see a warning banner and can see which types were missing coverage.
+
+### Edge Cases
+
+- Compare is retried after a transient failure: findings are not duplicated; lifecycle increments happen at most once per run identity.
+- Baseline capture is executed with empty scope lists (interpreted as default semantics): policy types means “all supported types excluding foundations”; foundations list means “none”.
+- Effective scope expands to zero types (e.g., no supported types): run completes with an explicit warning and produces no findings.
+- Policy subjects appear/disappear between inventory sync and compare: handled according to coverage rules; does not create missing-policy noise for uncovered types.
+- Two different policy subjects accidentally share an external identifier across types: identity is still unambiguous because `policy_type` is part of the subject key.
+
+## Requirements *(mandatory)*
+
+This feature introduces/extends long-running compare work and uses `OperationRun` for capture and compare runs.
+It must comply with:
+
+- **Run observability**: Every capture/compare run must have a visible run identity, scope context, coverage context, and outcome.
+- **Safety**: Compare must never claim missing policies for policy types where current-state coverage is not proven.
+- **Tenant isolation**: All stored states and findings are tenant-scoped; cross-tenant access must be deny-as-not-found.
+
+### Operational UX Contract (Ops-UX)
+
+- Capture and compare run lifecycle transitions are service-owned (not UI-owned).
+- Run summaries provide numeric-only counters using ONLY keys from `app/Support/OpsUx/OperationSummaryKeys.php`.
+  - Coverage warnings MUST be represented using an existing canonical numeric key (default: `errors_recorded`).
+- Warning semantics mapping (canonical):
+  - Any “completed with warnings” case MUST be represented as `OperationRun.outcome = partially_succeeded`.
+  - `summary_counts.errors_recorded` MUST be a numeric indicator of warning magnitude.
+    - Default: number of uncovered policy types in effective scope.
+    - Edge case (effective scope expands to zero types): `summary_counts.errors_recorded = 1` so the warning remains visible under the numeric-only summary_counts contract.
+- Scheduled/system-initiated runs (if any) must not generate user terminal DB notifications; audit is handled via monitoring surfaces.
+- Regression guard tests are added/updated to enforce correct run outcome semantics and summary counter rules.
+
+### Authorization Contract (RBAC-UX)
+
+- Workspace membership + capability gates:
+  - `workspace_baselines.view` is required to view baseline profiles and snapshots.
+  - `workspace_baselines.manage` is required to create/edit/archive baseline profiles and start capture runs.
+  - `tenant.sync` is required to start compare runs.
+  - `tenant_findings.view` is required to view drift findings.
+- 404 vs 403 semantics:
+  - Non-member or not entitled to workspace/tenant scope → 404 (deny-as-not-found)
+  - Member but missing capability → 403
+- Destructive-like actions (e.g., archiving a baseline profile) require an explicit confirmation step.
+- At least one positive and one negative authorization test exist for each mutation surface.
+
+### Functional Requirements
+
+#### v1 — Meta-fidelity baseline compare (sellable)
+
+- **FR-116v1-01 Baseline profile scope**: Baseline profiles MUST store a scope object with `policy_types` and `foundation_types` lists.
+  - Default semantics: `policy_types = []` means all supported policy types excluding foundations; `foundation_types = []` means no foundations.
+  - Foundations MUST only be included when explicitly selected.
+- **FR-116v1-02 UI scope picker**: The UI MUST provide multi-select controls for Policy Types and Foundations and communicate the default semantics (empty selection = default behavior).
+- **FR-116v1-03 Effective scope recorded on runs**: Capture and compare runs MUST record expanded effective scope in run context:
+  - `effective_scope.policy_types[]`, `effective_scope.foundation_types[]`, `effective_scope.all_types[]`, and a boolean `effective_scope.foundations_included`.
+- **FR-116v1-04 Inventory meta contract**: The system MUST define and persist a stable “inventory meta contract” (signal-based fields) for drift hashing.
+  - Minimum required signals: type identifier, version marker (when available), last modified time (when available), scope tags (when available), and assignment target count (when available).
+  - Drift hashing for v1 MUST be based only on this contract (not arbitrary meta fields).
+- **FR-116v1-05 Provide current-state policy states (meta fidelity)**: For all policy subjects in effective scope, the system MUST produce a normalized policy state for compare, including:
+  - subject key (policy type + external id), deterministic hash, fidelity=`meta`, source indicator, and observed timestamp.
+- **FR-116v1-06 Baseline capture stores states (not raw)**: Baseline capture MUST store per-subject snapshot items that include the subject identity and the captured hash + fidelity + source.
+  - Baseline snapshots MUST NOT contain out-of-scope items.
+- **FR-116v1-06a Compare snapshot selection**: Baseline compare MUST, by default, use the latest successful baseline snapshot of the selected baseline profile.
+  - The UI MAY allow selecting a specific snapshot explicitly for historical comparisons.
+- **FR-116v1-07 Coverage guard**: Compare MUST check current-state coverage recorded by the most recent inventory sync run.
+  - If effective scope contains policy types not present in coverage, the compare run MUST complete with warnings.
+  - For any uncovered policy type, the compare MUST NOT emit findings of any kind for that type (no `missing_policy`, no `unexpected_policy`, no `different_version`).
+  - Drift findings for types with proven coverage may still be produced.
+  - If there is no completed inventory sync run (or coverage proof is missing/unreadable), coverage MUST be treated as unproven for all types and the compare MUST produce zero findings (fail-safe) and complete with warnings.
+- **FR-116v1-08 Drift rules**: Compare MUST produce drift results per policy subject:
+  - Baseline-only → `missing_policy` (only when coverage is proven for the subject’s type)
+  - Current-only → `unexpected_policy`
+  - Both present and hashes differ → `different_version` (with fidelity=`meta`)
+- **FR-116v1-09 Stable finding identity**: Findings MUST have a stable identity key derived from: tenant, baseline snapshot, policy type, external id, and change type.
+  - Hashes are evidence fields and may update without changing identity.
+  - Finding identity MUST be tied to a specific baseline snapshot (re-capture creates a new baseline snapshot and therefore new finding identities).
+- **FR-116v1-10 Finding lifecycle + retry idempotency**: Findings MUST record first seen, last seen, and times seen.
+  - For a given run identity, lifecycle counters MUST not increment more than once.
+- **FR-116v1-11 Auditability**: Each capture and compare run MUST write an audit trail including effective scope counts, coverage warning summary (if any), and finding counts per change type.
+- Audit trail storage (canonical):
+  - Aggregations that do not fit `summary_counts` MUST be stored in `operation_runs.context` (not new summary keys).
+  - Compare MUST store per-change-type counts in run context under `findings.counts_by_change_type` (e.g., keys: `missing_policy`, `unexpected_policy`, `different_version`).
+- **FR-116v1-12 Drift UI context**: Compare run detail and drift landing MUST surface scope, coverage status, and fidelity (meta-based drift) and show a warning banner when coverage warnings were present.
+
+#### v2 — Content-fidelity extension (deep drift, same engine)
+
+**Deferred / out of scope for this delivery**: The v2 requirements below are intentionally not covered by `specs/116-baseline-drift-engine/tasks.md` and will be implemented in a follow-up spec/milestone.
+
+- **FR-116v2-01 Provider precedence**: Current state MUST be sourced with a precedence chain per policy type: “policy version (if available) → inventory content (if available) → meta fallback (explicitly marked degraded)”.
+- **FR-116v2-02 Content hash availability**: The inventory system MUST persist a content hash and capture timestamp for hydrated policy content.
+- **FR-116v2-03 Quota-aware hydration**: Content hydration MUST be throttling-safe and resumable, with explicit per-run caps and concurrency limits, and must record hydration coverage in run context.
+- **FR-116v2-04 Content normalization rules**: The system MUST define canonicalization rules per policy type, including volatile-field removal and (where needed) redaction hooks.
+- **FR-116v2-05 Drift dimensions (optional but final)**: The compare output MAY include dimension flags (content, assignments, scope tags) without changing finding identity.
+  - If dimension flags are present, they MUST be stored on the same finding record as evidence/flags; the system MUST NOT create separate findings per dimension.
+  - `change_type` semantics remain compatible with v1 (dimensions refine the “different_version” class rather than multiplying identities).
+- **FR-116v2-06 Capture/compare use the same pipeline**: Capture and compare MUST use the same policy state pipeline and hashing semantics; v2 must not introduce special-case compare paths.
+- **FR-116v2-07 Coverage/fidelity guard**: If content hydration is incomplete for some types, compare MAY still run but must clearly indicate degraded fidelity and must follow registry-defined behavior for those types.
+- **FR-116v2-08 No-legacy guarantee**: After v2 cutover, legacy compare/hash helpers are removed and CI guards prevent re-introduction.
+
+## UI Action Matrix *(mandatory when Filament is changed)*
+
+| Surface | Location | Header Actions | Inspect Affordance (List/Table) | Row Actions (max 2 visible) | Bulk Actions (grouped) | Empty-State CTA(s) | View Header Actions | Create/Edit Save+Cancel | Audit log? | Notes / Exemptions |
+|---|---|---|---|---|---|---|---|---|---|
+| Baseline Profiles | Workspace admin | Create Baseline Profile | View action / record inspection (per Action Surface Contract) | Edit, Archive (confirmed) | None | “Create Baseline Profile” | Capture Baseline (compare is tenant-context) | Save, Cancel | Yes | Archive requires confirmation; capture starts OperationRuns and is audited |
+| Baseline Capture Run Detail | Workspace admin | None | Linked from runs list | None | None | None | None | N/A | Yes | Shows effective scope + fidelity + counts + warnings |
+| Baseline Compare Run Detail | Tenant-context admin | Run Compare (if shown), Re-run Compare (if allowed) | Linked from runs list | None | None | None | None | N/A | Yes | Shows coverage badge and warning banner; uncovered types emit no findings |
+| Drift Findings Landing | Tenant-context admin | None | Table filter by change type | View (optional), Acknowledge/Resolve (if workflow exists) | None | None | None | N/A | Yes | Surfaces fidelity + coverage context; no destructive actions required for v1 |
+
+### Key Entities *(include if feature involves data)*
+
+- **Baseline profile**: Defines scope (policy types + opt-in foundations) and is the parent for baseline snapshots.
+- **Baseline snapshot item**: Stores per-policy-subject baseline state evidence (hash, fidelity, source, observed timestamp).
+- **Compare run**: A recorded operation that compares a tenant current state to a baseline snapshot, including effective scope and coverage warnings.
+- **Finding**: A stable, recurring drift finding with lifecycle fields (first seen, last seen, times seen) and evidence (baseline/current hashes, fidelity).
+
+## Success Criteria *(mandatory)*
+
+### Measurable Outcomes
+
+- **SC-116-01 One engine**: All baseline compare and capture runs use exactly one drift pipeline; no alternative compare paths exist in production code.
+- **SC-116-02 Stable recurrence**: For a fixed baseline snapshot + tenant + policy subject + change type, repeated compares (including retries) produce at most one finding identity, and lifecycle counters increment at most once per run.
+- **SC-116-03 Coverage safety**: When coverage is partial for any effective-scope type, the compare run is visibly marked as “completed with warnings” and produces zero findings for those uncovered types.
+- **SC-116-04 Operator clarity**: On the compare run detail screen, operators can see effective scope counts, coverage status, and fidelity within one page load, with a clear warning banner when applicable.
+- **SC-116-05 Performance guard (v1)**: Compare runs complete without per-item external hydration calls; runtime scales with number of in-scope subjects via chunking.
diff --git a/specs/116-baseline-drift-engine/tasks.md b/specs/116-baseline-drift-engine/tasks.md
new file mode 100644
index 0000000..729b991
--- /dev/null
+++ b/specs/116-baseline-drift-engine/tasks.md
@@ -0,0 +1,233 @@
+---
+
+description: "Executable task breakdown for Spec 116 implementation"
+
+---
+
+# Tasks: 116 — Baseline Drift Engine (Final Architecture)
+
+**Input**: Design documents in `specs/116-baseline-drift-engine/` (`plan.md`, `spec.md`, `research.md`, `data-model.md`, `quickstart.md`, `specs/116-baseline-drift-engine/contracts/openapi.yaml`)
+
+**Tests**: REQUIRED (Pest) for all runtime behavior changes.
+
+---
+
+## Phase 1: Setup (Shared Infrastructure)
+
+**Purpose**: Ensure local dev + feature artifacts are ready.
+
+- [ ] T001 Re-run Speckit prerequisites check via `.specify/scripts/bash/check-prerequisites.sh` (references `specs/116-baseline-drift-engine/plan.md`)
+- [ ] T002 Ensure Sail + migrations are up for local validation (references `docker-compose.yml` and `database/migrations/`)
+- [ ] T003 [P] Re-validate Spec 116 UI Action Matrix remains accurate after planned UI tweaks in `specs/116-baseline-drift-engine/spec.md`
+- [ ] T004 [P] Confirm supported policy types + foundations config sources match UI selectors (`config/tenantpilot.php` and `app/Support/Inventory/InventoryPolicyTypeMeta.php`)
+
+---
+
+## Phase 2: Foundational (Blocking Prerequisites)
+
+**Purpose**: Shared primitives that all user stories depend on (scope semantics, data defaults, and UI inputs).
+
+**Independent Test**: Baseline Profile can be created with the new scope shape, and scope defaults expand deterministically.
+
+- [ ] T005 Update baseline scope schema + default semantics (policy_types excludes foundations by default; foundation_types defaults to none) in `app/Support/Baselines/BaselineScope.php`
+- [ ] T006 [P] Update BaselineProfile default scope shape to include `foundation_types` in `database/factories/BaselineProfileFactory.php`
+- [ ] T007 [P] Ensure BaselineProfile scope casting/normalization supports `foundation_types` safely in `app/Models/BaselineProfile.php`
+- [ ] T008 [P] Create focused tests for scope expansion defaults (empty policy_types => supported excluding foundations; empty foundation_types => none) in `tests/Unit/Baselines/BaselineScopeTest.php`
+- [ ] T009 Update BaselineProfile Create/Edit form layout to satisfy UX-001 (Main/Aside 3-column layout; no naked inputs) while preserving existing fields in `app/Filament/Resources/BaselineProfileResource.php`
+- [ ] T010 Update BaselineProfile scope picker UI to include Foundations multi-select + corrected helper text semantics in `app/Filament/Resources/BaselineProfileResource.php`
+- [ ] T011 Update BaselineProfile infolist to display selected foundations (and default “None”) in `app/Filament/Resources/BaselineProfileResource.php`
+- [ ] T012 Run focused verification for foundational scope/UI changes with `vendor/bin/sail artisan test --compact tests/Unit/Baselines/BaselineScopeTest.php` (references `tests/Unit/Baselines/BaselineScopeTest.php`)
+
+**Checkpoint**: Scope semantics + scope UI are correct and test-covered.
+
+---
+
+## Phase 3: User Story 1 — Capture and compare a baseline with stable findings (Priority: P1) 🎯
+
+**Goal**: Define the v1 meta-fidelity hash contract, use it for capture/compare, and make baseline-compare findings snapshot-scoped stable identities.
+
+**Independent Test**: Capture a snapshot, run compare twice with the same inputs, and verify finding identity stability + lifecycle idempotency.
+
+### Tests for User Story 1 (write first)
+
+- [ ] T013 [P] [US1] Update capture tests for effective_scope recording + contract-based hashing in `tests/Feature/Baselines/BaselineCaptureTest.php`
+- [ ] T014 [P] [US1] Update compare findings tests to assert recurrence-key-based identity (no hashes in fingerprint) + lifecycle idempotency per run + `run.context.findings.counts_by_change_type` is present and accurate in `tests/Feature/Baselines/BaselineCompareFindingsTest.php`
+- [ ] T015 [P] [US1] Add/adjust preconditions tests for default baseline snapshot selection (latest successful snapshot) in `tests/Feature/Baselines/BaselineComparePreconditionsTest.php`
+- [ ] T016 [P] [US1] Add test that re-capturing (new snapshot id) produces new finding identities (snapshot-scoped) in `tests/Feature/Baselines/BaselineCompareFindingsTest.php`
+- [ ] T017 [P] [US1] Add negative auth test ensuring compare start surface is gated by capability (`tenant.sync` / `Capabilities::TENANT_SYNC`) in `tests/Feature/Filament/BaselineCompareLandingStartSurfaceTest.php`
+
+### Implementation for User Story 1
+
+- [ ] T018 [US1] Create + implement Inventory Meta Contract builder (normalized whitelist inputs; deterministic ordering) in `app/Services/Baselines/InventoryMetaContract.php`
+- [ ] T019 [US1] Update snapshot hashing to hash ONLY the meta contract output (not entire meta_jsonb) in `app/Services/Baselines/BaselineSnapshotIdentity.php`
+- [ ] T020 [US1] Update baseline capture job to compute/store baseline_hash via InventoryMetaContract + record fidelity/meta observation evidence in `app/Jobs/CaptureBaselineSnapshotJob.php`
+- [ ] T021 [US1] Ensure capture OperationRun context records `effective_scope.*` (policy_types, foundation_types, all_types, foundations_included) in `app/Services/Baselines/BaselineCaptureService.php`
+- [ ] T022 [US1] Update baseline compare job to compute current_hash via InventoryMetaContract consistently with capture in `app/Jobs/CompareBaselineToTenantJob.php`
+- [ ] T023 [US1] Switch baseline-compare finding identity to recurrence key derived from (tenant, baseline_snapshot_id, policy_type, external_id, change_type) and set `fingerprint == recurrence_key` in `app/Jobs/CompareBaselineToTenantJob.php`
+- [ ] T024 [US1] Enforce per-run idempotency by using `findings.current_operation_run_id` (and/or evidence) so `times_seen` increments at most once per run identity in `app/Jobs/CompareBaselineToTenantJob.php`
+- [ ] T025 [US1] Ensure compare run context includes `baseline_profile_id`, `baseline_snapshot_id`, and `findings.counts_by_change_type` for stats/widgets/auditability in `app/Services/Baselines/BaselineCompareService.php`
+
+**Checkpoint**: US1 tests pass: `vendor/bin/sail artisan test --compact tests/Feature/Baselines/BaselineCaptureTest.php tests/Feature/Baselines/BaselineCompareFindingsTest.php tests/Feature/Baselines/BaselineComparePreconditionsTest.php`.
+
+---
+
+## Phase 4: User Story 2 — Coverage warnings prevent misleading missing-policy findings (Priority: P1)
+
+**Goal**: Persist per-type coverage from inventory sync and enforce the coverage guard in baseline compare (uncovered types emit zero findings; compare outcome is partial with warnings).
+
+**Independent Test**: Run compare with missing coverage for some in-scope types; verify partial outcome + zero findings for uncovered types.
+
+### Tests for User Story 2 (write first)
+
+- [ ] T026 [P] [US2] Extend inventory sync tests to assert per-type coverage payload is written to OperationRun context in `tests/Feature/Inventory/InventorySyncStartSurfaceTest.php`
+- [ ] T027 [P] [US2] Create coverage-guard regression test: (a) uncovered types => no findings of any kind; (b) no completed inventory sync run / missing coverage payload => fail-safe zero findings; (c) effective scope expands to zero types => warnings + zero findings; outcome partially_succeeded; covered types still emit findings in `tests/Feature/Baselines/BaselineCompareCoverageGuardTest.php`
+
+### Implementation for User Story 2
+
+- [ ] T028 [US2] Persist inventory sync coverage payload into latest inventory sync run context (`inventory.coverage.policy_types` + `inventory.coverage.foundation_types`) in `app/Services/Inventory/InventorySyncService.php`
+- [ ] T029 [P] [US2] Create a small coverage parser/helper to normalize context payload for downstream consumers in `app/Support/Inventory/InventoryCoverage.php`
+- [ ] T030 [US2] Update baseline compare to read latest inventory sync run coverage, compute uncovered types, skip emission for uncovered types, and write coverage details into compare run context in `app/Jobs/CompareBaselineToTenantJob.php`
+- [ ] T031 [US2] Treat missing coverage proof (no completed inventory sync run, or unreadable/missing coverage payload) as uncovered-for-all-types (fail-safe): emit zero findings and mark outcome partially_succeeded (via OperationRunService), setting numeric summary_counts (including errors_recorded) using canonical keys only in `app/Jobs/CompareBaselineToTenantJob.php`
+
+**Note (canonical warning magnitude)**: For (c) “effective scope expands to zero types”, the compare MUST still surface a warning and therefore MUST set `summary_counts.errors_recorded = 1` (even though uncovered-types count is 0), to keep the warning visible under the numeric-only summary_counts contract.
+
+**Checkpoint**: US2 tests pass: `vendor/bin/sail artisan test --compact tests/Feature/Inventory/InventorySyncStartSurfaceTest.php tests/Feature/Baselines/BaselineCompareCoverageGuardTest.php`.
+
+---
+
+## Phase 5: User Story 3 — Operators can understand scope, coverage, and fidelity in the UI (Priority: P2)
+
+**Goal**: Surface effective scope, coverage status, and fidelity (meta) in Baseline Compare landing + drift findings surfaces.
+
+**Independent Test**: Execute a compare with and without coverage warnings; verify UI surfaces show badge/banner + scope/coverage/fidelity context.
+
+### Tests for User Story 3 (write first)
+
+- [ ] T032 [P] [US3] Update Baseline Compare landing tests to cover warning/coverage state rendering inputs (stats DTO fields) in `tests/Feature/Filament/BaselineCompareLandingStartSurfaceTest.php`
+- [ ] T033 [P] [US3] Update drift landing comparison-info tests to include coverage/fidelity context when source is baseline compare in `tests/Feature/Drift/DriftLandingShowsComparisonInfoTest.php`
+
+### Implementation for User Story 3
+
+- [ ] T034 [US3] Extend BaselineCompareStats DTO to include coverage status + uncovered types summary + fidelity indicator sourced from latest compare run context in `app/Support/Baselines/BaselineCompareStats.php`
+- [ ] T035 [US3] Wire new stats fields into the BaselineCompareLanding Livewire page state in `app/Filament/Pages/BaselineCompareLanding.php`
+- [ ] T036 [US3] Render coverage badge + warning banner + fidelity label on the landing view in `resources/views/filament/pages/baseline-compare-landing.blade.php`
+- [ ] T037 [US3] Add a findings-list banner when latest baseline compare run had uncovered types (linking to the run) in `app/Filament/Resources/FindingResource/Pages/ListFindings.php`
+- [ ] T038 [US3] Ensure run detail already shows context; if needed, add baseline compare “Coverage” summary entry for readability in `app/Filament/Resources/OperationRunResource.php`
+
+**Checkpoint**: US3 tests pass: `vendor/bin/sail artisan test --compact tests/Feature/Filament/BaselineCompareLandingStartSurfaceTest.php tests/Feature/Drift/DriftLandingShowsComparisonInfoTest.php`.
+
+---
+
+## Phase 6: Polish & Cross-Cutting Concerns
+
+**Purpose**: Preserve operability semantics (auto-close, stats), Ops-UX compliance, and fast regression feedback.
+
+- [ ] T039 Confirm baseline compare stats remain profile-grouped via `scope_key = baseline_profile:{id}` after identity change in `app/Support/Baselines/BaselineCompareStats.php`
+- [ ] T040 Ensure baseline auto-close behavior still works with snapshot-scoped identities (no stale open findings after successful compare) in `app/Services/Baselines/BaselineAutoCloseService.php`
+- [ ] T041 [P] Update/verify auto-close regression test remains valid after identity change in `tests/Feature/Baselines/BaselineOperabilityAutoCloseTest.php`
+- [ ] T042 [P] Add/extend guard test asserting OperationRun summary_counts are numeric-only and keys are limited to `OperationSummaryKeys::all()` for baseline capture/compare runs in `tests/Feature/Baselines/BaselineCompareFindingsTest.php`
+- [ ] T043 Run baseline-focused test pack for Spec 116: `vendor/bin/sail artisan test --compact tests/Feature/Baselines/` (references `tests/Feature/Baselines/`)
+- [ ] T044 Run Pint formatter on changed files: `vendor/bin/sail bin pint --dirty --format agent` (references `app/` and `tests/`)
+- [ ] T045 Validate developer quickstart still matches real behavior (update if needed) in `specs/116-baseline-drift-engine/quickstart.md`
+- [ ] T046 [P] Create Baseline Profile archive action tests (confirmation required + RBAC 403/404 semantics + success path) in `tests/Feature/Baselines/BaselineProfileArchiveActionTest.php`
+- [ ] T047 [P] Ensure archive action is declared in Action Surface slots and remains “More” row action only (max 2 visible row actions) in `tests/Feature/Guards/ActionSurfaceContractTest.php`
+
+---
+
+## Dependencies & Execution Order
+
+### User Story Dependency Graph
+
+```mermaid
+graph TD
+	P1[Phase 1: Setup] --> P2[Phase 2: Foundational]
+	P2 --> US1[US1: Stable capture/compare + findings]
+	US1 --> US2[US2: Coverage guard]
+	US2 --> US3[US3: UI context]
+	US2 --> P6[Phase 6: Polish]
+	US3 --> P6
+```
+
+### Phase Dependencies
+
+- **Setup (Phase 1)** → blocks nothing, but should be done first.
+- **Foundational (Phase 2)** → BLOCKS all user stories.
+- **US1 / US2 / US3** → can start after Foundational; in practice US1 then US2 reduces merge conflicts in `app/Jobs/CompareBaselineToTenantJob.php`.
+- **Polish (Phase 6)** → after US1/US2 at minimum.
+
+### User Story Dependencies
+
+- **US1 (P1)**: Depends on Phase 2.
+- **US2 (P1)**: Depends on Phase 2; touches compare + inventory sync. Strongly recommended after US1 to keep compare changes coherent.
+- **US3 (P2)**: Depends on US2 (needs coverage context) and Phase 2.
+
+---
+
+## Parallel Example: User Story 1
+
+```bash
+# Tests can be updated in parallel:
+Task: "Update capture tests" (tests/Feature/Baselines/BaselineCaptureTest.php)
+Task: "Update compare findings tests" (tests/Feature/Baselines/BaselineCompareFindingsTest.php)
+Task: "Update compare preconditions tests" (tests/Feature/Baselines/BaselineComparePreconditionsTest.php)
+
+# Implementation can be split with care (different files):
+Task: "Implement InventoryMetaContract" (app/Services/Baselines/InventoryMetaContract.php)
+Task: "Update BaselineProfileResource scope UI" (app/Filament/Resources/BaselineProfileResource.php)
+
+```
+
+---
+
+## Parallel Example: User Story 2
+
+```bash
+# Tests can be updated in parallel:
+Task: "Assert inventory sync coverage is written" (tests/Feature/Inventory/InventorySyncStartSurfaceTest.php)
+Task: "Add coverage-guard regression test" (tests/Feature/Baselines/BaselineCompareCoverageGuardTest.php)
+
+# Implementation can be split (different files):
+Task: "Write coverage payload to sync run context" (app/Services/Inventory/InventorySyncService.php)
+Task: "Implement coverage parser helper" (app/Support/Inventory/InventoryCoverage.php)
+```
+
+---
+
+## Parallel Example: User Story 3
+
+```bash
+# Tests can be updated in parallel:
+Task: "Update landing test for coverage/fidelity state" (tests/Feature/Filament/BaselineCompareLandingStartSurfaceTest.php)
+Task: "Update drift landing comparison-info test" (tests/Feature/Drift/DriftLandingShowsComparisonInfoTest.php)
+
+# Implementation can be split (different files):
+Task: "Extend stats DTO + wiring" (app/Support/Baselines/BaselineCompareStats.php)
+Task: "Render landing banner/badges" (resources/views/filament/pages/baseline-compare-landing.blade.php)
+Task: "Add findings list banner" (app/Filament/Resources/FindingResource/Pages/ListFindings.php)
+```
+
+---
+
+## Implementation Strategy
+
+### Suggested MVP Scope
+
+- **MVP**: US1 (stable capture/compare + stable findings).
+- **Trust-critical follow-up**: US2 (coverage guard) is also P1 in the spec and should typically ship immediately after MVP.
+
+### Incremental Delivery
+
+1. Phase 1 + Phase 2
+2. US1 → validate stable identities + contract hashing
+3. US2 → validate coverage guard + partial outcome semantics
+4. US3 → validate operator clarity (badges/banners)
+5. Phase 6 → ensure operability + guards + formatting
+
+---
+
+## Notes
+
+- [P] tasks = parallelizable (different files, minimal dependency)
+- All tasks include explicit file targets for fast handoff
+- Destructive actions already require confirmation (Filament actions use `->requiresConfirmation()`); keep that invariant when editing UI surfaces
+- Spec 116 includes a v2 section for future work; v2 requirements are explicitly deferred and are not covered by this tasks list