Phase 7 follow-up #246 — Phase7Composer + Program.cs wire-in

Activates the Phase 7 engines in production. Loads Script + VirtualTag +
ScriptedAlarm rows from the bootstrapped generation, wires the engines through
the Phase7EngineComposer kernel (#243), starts the DriverSubscriptionBridge feed
(#244), and late-binds the resulting IReadable sources to OpcUaApplicationHost
before OPC UA server start.

## Phase7Composer (Server.Phase7)

Singleton orchestrator. PrepareAsync loads the three Phase 7 row sets in one
DB scope, builds CachedTagUpstreamSource, calls Phase7EngineComposer.Compose,
constructs DriverSubscriptionBridge with one DriverFeed per registered
ISubscribable driver (path-to-fullRef map built from EquipmentNamespaceContent
via MapPathsToFullRefs), starts the bridge.

DisposeAsync tears down in the right order: bridge first (no more events fired
into the cache), then engines (cascades + timers stop), then any disposable sink.

MapPathsToFullRefs: deterministic path convention is
  /{areaName}/{lineName}/{equipmentName}/{tagName}
matching exactly what EquipmentNodeWalker emits into the OPC UA browse tree, so
script literals against the operator-visible UNS tree work without translation.
Tags missing EquipmentId or pointing at unknown Equipment are skipped silently
(Galaxy SystemPlatform-style tags + dangling references handled).

## OpcUaApplicationHost.SetPhase7Sources

New late-bind setter. Throws InvalidOperationException if called after
StartAsync because OtOpcUaServer + DriverNodeManagers capture the field values
at construction; mutation post-start would silently fail.

## OpcUaServerService

After bootstrap loads the current generation, calls phase7Composer.PrepareAsync
+ applicationHost.SetPhase7Sources before applicationHost.StartAsync. StopAsync
disposes Phase7Composer first so the bridge stops feeding the cache before the
OPC UA server tears down its node managers (avoids in-flight cascades surfacing
as noisy shutdown warnings).

## Program.cs

Registers IAlarmHistorianSink as NullAlarmHistorianSink.Instance (task #247
swaps in the real Galaxy.Host-writer-backed SqliteStoreAndForwardSink), Serilog
root logger, and Phase7Composer singleton.

## Tests — 5 new Phase7ComposerMappingTests = 34 Phase 7 tests total

Maps tag → walker UNS path, skips null EquipmentId, skips unknown Equipment
reference, multiple tags under same equipment map distinctly, empty content
yields empty map. Pure functions; no DI/DB needed.

The real PrepareAsync DB query path can't be exercised without SQL Server in
the test environment — it's exercised by the live E2E smoke (task #240) which
unblocks once #247 lands.

## Phase 7 production wiring chain status
- ✅ #243 composition kernel
- ✅ #245 scripted-alarm IReadable adapter
- ✅ #244 driver bridge
- ✅ #246 this — Program.cs wire-in
- 🟡 #247 — Galaxy.Host SqliteStoreAndForwardSink writer adapter (replaces NullSink)
- 🟡 #240 — live E2E smoke (unblocks once #247 lands)

ZB.MOM.WW.OtOpcUa.slnx

@@ -6,6 +6,7 @@
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.csproj"/>
+        <Project Path="src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Server/ZB.MOM.WW.OtOpcUa.Server.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj"/>
         <Project Path="src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.csproj"/>
@@ -32,8 +33,10 @@
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.Scripting.Tests/ZB.MOM.WW.OtOpcUa.Core.Scripting.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.Tests/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.Tests/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Server.Tests/ZB.MOM.WW.OtOpcUa.Server.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Admin.Tests/ZB.MOM.WW.OtOpcUa.Admin.Tests.csproj"/>
+        <Project Path="tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host.Tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Host.Tests.csproj"/>
         <Project Path="tests/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.TestSupport/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.TestSupport.csproj"/>

docs/v2/implementation/exit-gate-phase-7.md

@@ -0,0 +1,79 @@
+# Phase 7 Exit Gate — Scripting, Virtual Tags, Scripted Alarms, Historian Sink
+
+> **Status**: Open. Closed when every compliance check passes + every deferred item either ships or is filed as a post-v2-release follow-up.
+>
+> **Compliance script**: `scripts/compliance/phase-7-compliance.ps1`
+> **Plan doc**: `docs/v2/implementation/phase-7-scripting-and-alarming.md`
+
+## What shipped
+
+| Stream | PR | Summary |
+|--------|-----|---------|
+| A | #177–#179 | `Core.Scripting` — Roslyn sandbox + `DependencyExtractor` + `ForbiddenTypeAnalyzer` + per-script Serilog sink + 63 tests |
+| B | #180 | `Core.VirtualTags` — dep graph (iterative Tarjan) + engine + timer scheduler + `VirtualTagSource` + 36 tests |
+| C | #181 | `Core.ScriptedAlarms` — Part 9 state machine + predicate engine + message template + `ScriptedAlarmSource` + 47 tests |
+| D | #182 | `Core.AlarmHistorian` — SQLite store-and-forward + backoff ladder + dead-letter retention + Galaxy.Host IPC contracts + 14 tests |
+| E | #183 | Config DB schema — `Script` / `VirtualTag` / `ScriptedAlarm` / `ScriptedAlarmState` entities + migration + 12 tests |
+| F | #185 | Admin UI — `ScriptService` / `VirtualTagService` / `ScriptedAlarmService` / `ScriptTestHarnessService` / `HistorianDiagnosticsService` + Monaco editor + `/alarms/historian` page + 13 tests |
+| G | #184 | Walker emits Virtual + ScriptedAlarm variables with `NodeSourceKind` discriminator + 5 tests |
+| G follow-up | #186 | `DriverNodeManager` dispatch routes by `NodeSourceKind` + writes rejected for non-Driver sources + 7 tests |
+
+**Phase 7 totals**: ~197 new tests across 7 projects. Plan decisions #1–#22 all realised in code.
+
+## Compliance Checks (run at exit gate)
+
+Covered by `scripts/compliance/phase-7-compliance.ps1`:
+
+- [x] Roslyn sandbox anchored on `ScriptContext` assembly with `ForbiddenTypeAnalyzer` defense-in-depth (plan #6)
+- [x] `DependencyExtractor` rejects non-literal tag paths with source spans (plan #7)
+- [x] Per-script rolling Serilog sink + companion-forwarding Error+ to main log (plan #12)
+- [x] VirtualTag dep graph uses iterative SCC — no stack overflow on 10 000-deep chains
+- [x] `VirtualTagSource` implements `IReadable` + `ISubscribable` per ADR-002
+- [x] Part 9 state machine covers every transition (Apply/Ack/Confirm/Shelve/Unshelve/Enable/Disable/Comment/ShelvingCheck)
+- [x] `AlarmPredicateContext` rejects `SetVirtualTag` at runtime (predicates must be pure)
+- [x] `MessageTemplate` substitutes `{TagPath}` tokens at event emission (plan #13); missing/bad → `{?}`
+- [x] SQLite sink backoff ladder 1s → 2s → 5s → 15s → 60s cap (plan #16)
+- [x] Default 1M-row capacity + 30-day dead-letter retention (plan #21)
+- [x] Per-event outcomes Ack/RetryPlease/PermanentFail on the wire
+- [x] Galaxy.Host IPC contracts (`HistorianAlarmEventRequest` / `Response` / `ConnectivityStatusNotification`)
+- [x] Config DB check constraints: trigger-required, timer-min, severity-range, alarm-type-enum, JSON comments
+- [x] `ScriptedAlarmState` keyed on `ScriptedAlarmId` (not generation-scoped) per plan #14
+- [x] Admin services: SourceHash preserves compile-cache hit on rename; Update recomputes on source change
+- [x] `ScriptTestHarnessService` enforces declared-inputs-only contract (plan #22)
+- [x] Monaco editor via CDN + textarea fallback (plan #18)
+- [x] `/alarms/historian` page with Retry-dead-lettered operator action
+- [x] Walker emits `NodeSourceKind.Virtual` + `NodeSourceKind.ScriptedAlarm` variables
+- [x] `DriverNodeManager` dispatch routes Reads by source; Writes to non-Driver rejected with `BadUserAccessDenied` (plan #6)
+
+## Deferred to Post-Gate Follow-ups
+
+Kept out of the capstone so the gate can close cleanly while the less-critical wiring lands in targeted PRs:
+
+- [ ] **SealedBootstrap composition root** (task #239) — instantiate `VirtualTagEngine` + `ScriptedAlarmEngine` + `SqliteStoreAndForwardSink` in `Program.cs`; pass `VirtualTagSource` + `ScriptedAlarmSource` as the new `IReadable` parameters on `DriverNodeManager`. Without this, the engines are dormant in production even though every piece is tested.
+- [ ] **Live OPC UA end-to-end smoke** (task #240) — Client.CLI browse + read a virtual tag computed by Roslyn; Client.CLI acknowledge a scripted alarm via the Part 9 method node; historian-disabled deployment returns `BadNotFound` for virtual nodes rather than silent failure.
+- [ ] **sp_ComputeGenerationDiff extension** (task #241) — emit Script / VirtualTag / ScriptedAlarm sections alongside the existing Namespace/DriverInstance/Equipment/Tag/NodeAcl rows so the Admin DiffViewer shows Phase 7 changes between generations.
+
+## Completion Checklist
+
+- [x] Stream A shipped + merged
+- [x] Stream B shipped + merged
+- [x] Stream C shipped + merged
+- [x] Stream D shipped + merged
+- [x] Stream E shipped + merged
+- [x] Stream F shipped + merged
+- [x] Stream G shipped + merged
+- [x] Stream G follow-up (dispatch) shipped + merged
+- [x] `phase-7-compliance.ps1` present and passes
+- [x] Full solution `dotnet test` passes (no new failures beyond pre-existing tolerated CLI flake)
+- [x] Exit-gate doc checked in
+- [ ] `SealedBootstrap` composition follow-up filed + tracked
+- [ ] Live end-to-end smoke follow-up filed + tracked
+- [ ] `sp_ComputeGenerationDiff` extension follow-up filed + tracked
+
+## How to run
+
+```powershell
+pwsh ./scripts/compliance/phase-7-compliance.ps1
+```
+
+Exit code 0 = all pass; non-zero = failures listed in the preceding `[FAIL]` lines.

scripts/compliance/phase-7-compliance.ps1

@@ -0,0 +1,151 @@
+<#
+.SYNOPSIS
+    Phase 7 exit-gate compliance check. Each check either passes or records a failure;
+    non-zero exit = fail.
+
+.DESCRIPTION
+    Validates Phase 7 (scripting runtime + virtual tags + scripted alarms + historian
+    alarm sink + Admin UI + address-space integration) per
+    `docs/v2/implementation/phase-7-scripting-and-alarming.md`.
+
+.NOTES
+    Usage:  pwsh ./scripts/compliance/phase-7-compliance.ps1
+    Exit:   0 = all checks passed; non-zero = one or more FAILs
+#>
+[CmdletBinding()]
+param()
+
+$ErrorActionPreference = 'Stop'
+$script:failures = 0
+$repoRoot = (Resolve-Path (Join-Path $PSScriptRoot '..\..')).Path
+
+function Assert-Pass { param([string]$C) Write-Host "  [PASS] $C" -ForegroundColor Green }
+function Assert-Fail { param([string]$C, [string]$R) Write-Host "  [FAIL] $C - $R" -ForegroundColor Red; $script:failures++ }
+function Assert-Deferred { param([string]$C, [string]$P) Write-Host "  [DEFERRED] $C  (follow-up: $P)" -ForegroundColor Yellow }
+
+function Assert-FileExists {
+    param([string]$C, [string]$P)
+    if (Test-Path (Join-Path $repoRoot $P)) { Assert-Pass "$C  ($P)" }
+    else { Assert-Fail $C "missing file: $P" }
+}
+
+function Assert-TextFound {
+    param([string]$C, [string]$Pat, [string[]]$Paths)
+    foreach ($p in $Paths) {
+        $full = Join-Path $repoRoot $p
+        if (-not (Test-Path $full)) { continue }
+        if (Select-String -Path $full -Pattern $Pat -Quiet) {
+            Assert-Pass "$C  (matched in $p)"
+            return
+        }
+    }
+    Assert-Fail $C "pattern '$Pat' not found in any of: $($Paths -join ', ')"
+}
+
+Write-Host ""
+Write-Host "=== Phase 7 compliance - scripting + virtual tags + scripted alarms + historian ===" -ForegroundColor Cyan
+Write-Host ""
+
+Write-Host "Stream A - Core.Scripting (Roslyn + sandbox + AST inference + logger)"
+Assert-FileExists "Core.Scripting project" "src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"
+Assert-TextFound "ScriptSandbox allow-list anchored on ScriptContext assembly" "contextType\.Assembly" @("src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptSandbox.cs")
+Assert-TextFound "ForbiddenTypeAnalyzer defense-in-depth (plan decision #6)" "class ForbiddenTypeAnalyzer" @("src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ForbiddenTypeAnalyzer.cs")
+Assert-TextFound "DependencyExtractor rejects non-literal paths (plan decision #7)" "class DependencyExtractor" @("src/ZB.MOM.WW.OtOpcUa.Core.Scripting/DependencyExtractor.cs")
+Assert-TextFound "Per-script log companion sink forwards Error+ to main log (plan decision #12)" "class ScriptLogCompanionSink" @("src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptLogCompanionSink.cs")
+Assert-TextFound "ScriptContext static Deadband helper" "static bool Deadband" @("src/ZB.MOM.WW.OtOpcUa.Core.Scripting/ScriptContext.cs")
+
+Write-Host ""
+Write-Host "Stream B - Core.VirtualTags (dependency graph + change/timer + source)"
+Assert-FileExists "Core.VirtualTags project" "src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/ZB.MOM.WW.OtOpcUa.Core.VirtualTags.csproj"
+Assert-TextFound "DependencyGraph iterative Tarjan SCC (no stack overflow on 10k chains)" "class DependencyGraph" @("src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/DependencyGraph.cs")
+Assert-TextFound "VirtualTagEngine SemaphoreSlim async-safe cascade" "SemaphoreSlim" @("src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagEngine.cs")
+Assert-TextFound "VirtualTagSource IReadable + ISubscribable per ADR-002" "class VirtualTagSource" @("src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/VirtualTagSource.cs")
+Assert-TextFound "TimerTriggerScheduler groups by interval" "class TimerTriggerScheduler" @("src/ZB.MOM.WW.OtOpcUa.Core.VirtualTags/TimerTriggerScheduler.cs")
+
+Write-Host ""
+Write-Host "Stream C - Core.ScriptedAlarms (Part 9 state machine + predicate engine + IAlarmSource)"
+Assert-FileExists "Core.ScriptedAlarms project" "src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.csproj"
+Assert-TextFound "Part9StateMachine pure functions" "class Part9StateMachine" @("src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/Part9StateMachine.cs")
+Assert-TextFound "Alarm condition state with GxP audit Comments list" "Comments" @("src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/AlarmConditionState.cs")
+Assert-TextFound "MessageTemplate {TagPath} substitution (plan decision #13)" "class MessageTemplate" @("src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/MessageTemplate.cs")
+Assert-TextFound "AlarmPredicateContext rejects SetVirtualTag (predicates must be pure)" "class AlarmPredicateContext" @("src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/AlarmPredicateContext.cs")
+Assert-TextFound "ScriptedAlarmSource implements IAlarmSource" "class ScriptedAlarmSource" @("src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/ScriptedAlarmSource.cs")
+Assert-TextFound "IAlarmStateStore abstraction + in-memory default" "class InMemoryAlarmStateStore" @("src/ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms/IAlarmStateStore.cs")
+
+Write-Host ""
+Write-Host "Stream D - Core.AlarmHistorian (SQLite store-and-forward + Galaxy.Host IPC contracts)"
+Assert-FileExists "Core.AlarmHistorian project" "src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"
+Assert-TextFound "SqliteStoreAndForwardSink backoff ladder (1s..60s cap)" "BackoffLadder" @("src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/SqliteStoreAndForwardSink.cs")
+Assert-TextFound "Default 1M row capacity + 30-day dead-letter retention (plan decision #21)" "DefaultDeadLetterRetention" @("src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/SqliteStoreAndForwardSink.cs")
+Assert-TextFound "Per-event outcomes (Ack/RetryPlease/PermanentFail)" "HistorianWriteOutcome" @("src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/IAlarmHistorianSink.cs")
+Assert-TextFound "Galaxy.Host IPC contract HistorianAlarmEventRequest" "class HistorianAlarmEventRequest" @("src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/Contracts/HistorianAlarms.cs")
+Assert-TextFound "Historian connectivity status notification" "HistorianConnectivityStatusNotification" @("src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/Contracts/HistorianAlarms.cs")
+
+Write-Host ""
+Write-Host "Stream E - Config DB schema"
+Assert-FileExists "Script entity" "src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/Script.cs"
+Assert-FileExists "VirtualTag entity" "src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/VirtualTag.cs"
+Assert-FileExists "ScriptedAlarm entity" "src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/ScriptedAlarm.cs"
+Assert-FileExists "ScriptedAlarmState entity (logical-id keyed per plan decision #14)" "src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/ScriptedAlarmState.cs"
+Assert-TextFound "VirtualTag trigger check constraint (change OR timer)" "CK_VirtualTag_Trigger_AtLeastOne" @("src/ZB.MOM.WW.OtOpcUa.Configuration/OtOpcUaConfigDbContext.cs")
+Assert-TextFound "ScriptedAlarm severity range check" "CK_ScriptedAlarm_Severity_Range" @("src/ZB.MOM.WW.OtOpcUa.Configuration/OtOpcUaConfigDbContext.cs")
+Assert-TextFound "ScriptedAlarm type enum check" "CK_ScriptedAlarm_AlarmType" @("src/ZB.MOM.WW.OtOpcUa.Configuration/OtOpcUaConfigDbContext.cs")
+Assert-TextFound "ScriptedAlarmState.CommentsJson is ISJSON (GxP audit)" "CK_ScriptedAlarmState_CommentsJson_IsJson" @("src/ZB.MOM.WW.OtOpcUa.Configuration/OtOpcUaConfigDbContext.cs")
+Assert-FileExists "Phase 7 migration present" "src/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/20260420231641_AddPhase7ScriptingTables.cs"
+
+Write-Host ""
+Write-Host "Stream F - Admin UI (services + Monaco editor + test harness + historian diagnostics)"
+Assert-FileExists "ScriptService" "src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptService.cs"
+Assert-FileExists "VirtualTagService" "src/ZB.MOM.WW.OtOpcUa.Admin/Services/VirtualTagService.cs"
+Assert-FileExists "ScriptedAlarmService" "src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptedAlarmService.cs"
+Assert-FileExists "ScriptTestHarnessService" "src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptTestHarnessService.cs"
+Assert-FileExists "HistorianDiagnosticsService" "src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs"
+Assert-FileExists "ScriptEditor Razor component" "src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptEditor.razor"
+Assert-FileExists "ScriptsTab Razor component" "src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptsTab.razor"
+Assert-FileExists "AlarmsHistorian diagnostics page" "src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/AlarmsHistorian.razor"
+Assert-FileExists "Monaco loader (CDN progressive enhancement)" "src/ZB.MOM.WW.OtOpcUa.Admin/wwwroot/js/monaco-loader.js"
+Assert-TextFound "Scripts tab wired into DraftEditor" "ScriptsTab " @("src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DraftEditor.razor")
+Assert-TextFound "Harness enforces declared-inputs-only contract (plan decision #22)" "UnknownInputs" @("src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptTestHarnessService.cs")
+
+Write-Host ""
+Write-Host "Stream G - Address-space integration"
+Assert-TextFound "NodeSourceKind discriminator in DriverAttributeInfo" "enum NodeSourceKind" @("src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverAttributeInfo.cs")
+Assert-TextFound "Walker emits VirtualTag variables with Source=Virtual" "AddVirtualTagVariable" @("src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/EquipmentNodeWalker.cs")
+Assert-TextFound "Walker emits ScriptedAlarm variables with Source=ScriptedAlarm + IsAlarm" "AddScriptedAlarmVariable" @("src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/EquipmentNodeWalker.cs")
+Assert-TextFound "EquipmentNamespaceContent carries VirtualTags + ScriptedAlarms" "VirtualTags" @("src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/EquipmentNodeWalker.cs")
+Assert-TextFound "DriverNodeManager selects IReadable by source kind" "SelectReadable" @("src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/DriverNodeManager.cs")
+Assert-TextFound "Virtual/ScriptedAlarm writes rejected (plan decision #6)" "IsWriteAllowedBySource" @("src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/DriverNodeManager.cs")
+
+Write-Host ""
+Write-Host "Deferred surfaces"
+Assert-Deferred "SealedBootstrap composition root wiring (VirtualTagEngine + ScriptedAlarmEngine + SqliteStoreAndForwardSink)" "task #239"
+Assert-Deferred "Live OPC UA end-to-end test (virtual-tag Read + scripted-alarm Ack via method node)" "task #240"
+Assert-Deferred "sp_ComputeGenerationDiff extension for Script/VirtualTag/ScriptedAlarm sections" "task #241"
+
+Write-Host ""
+Write-Host "Cross-cutting"
+Write-Host "  Running full solution test suite..." -ForegroundColor DarkGray
+$prevPref = $ErrorActionPreference
+$ErrorActionPreference = 'Continue'
+$testOutput = & dotnet test (Join-Path $repoRoot 'ZB.MOM.WW.OtOpcUa.slnx') --nologo 2>&1
+$ErrorActionPreference = $prevPref
+$passLine = $testOutput | Select-String 'Passed:\s+(\d+)' -AllMatches
+$failLine = $testOutput | Select-String 'Failed:\s+(\d+)' -AllMatches
+$passCount = 0; foreach ($m in $passLine.Matches) { $passCount += [int]$m.Groups[1].Value }
+$failCount = 0; foreach ($m in $failLine.Matches) { $failCount += [int]$m.Groups[1].Value }
+
+# Phase 6.4 exit-gate baseline was 1137; Phase 7 adds ~197 across 7 streams.
+$baseline = 1300
+if ($passCount -ge $baseline) { Assert-Pass "No test-count regression ($passCount >= $baseline pre-Phase-7-exit baseline)" }
+else { Assert-Fail "Test-count regression" "passed $passCount < baseline $baseline" }
+
+if ($failCount -le 1) { Assert-Pass "No new failing tests (pre-existing CLI flake tolerated)" }
+else { Assert-Fail "New failing tests" "$failCount failures > 1 tolerated" }
+
+Write-Host ""
+if ($script:failures -eq 0) {
+    Write-Host "Phase 7 compliance: PASS" -ForegroundColor Green
+    exit 0
+}
+Write-Host "Phase 7 compliance: $script:failures FAIL(s)" -ForegroundColor Red
+exit 1

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/AlarmsHistorian.razor

@@ -0,0 +1,79 @@
+@page "/alarms/historian"
+@using ZB.MOM.WW.OtOpcUa.Admin.Services
+@using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian
+@inject HistorianDiagnosticsService Diag
+
+<h1>Alarm historian</h1>
+<p class="text-muted">Local store-and-forward queue that ships alarm events to Aveva Historian via Galaxy.Host.</p>
+
+<div class="card mb-3">
+    <div class="card-body">
+        <div class="row">
+            <div class="col-md-3">
+                <small class="text-muted">Drain state</small>
+                <h4><span class="badge @BadgeFor(_status.DrainState)">@_status.DrainState</span></h4>
+            </div>
+            <div class="col-md-3">
+                <small class="text-muted">Queue depth</small>
+                <h4>@_status.QueueDepth.ToString("N0")</h4>
+            </div>
+            <div class="col-md-3">
+                <small class="text-muted">Dead-letter depth</small>
+                <h4 class="@(_status.DeadLetterDepth > 0 ? "text-warning" : "")">@_status.DeadLetterDepth.ToString("N0")</h4>
+            </div>
+            <div class="col-md-3">
+                <small class="text-muted">Last success</small>
+                <h4>@(_status.LastSuccessUtc?.ToString("u") ?? "—")</h4>
+            </div>
+        </div>
+
+        @if (!string.IsNullOrEmpty(_status.LastError))
+        {
+            <div class="alert alert-warning mt-3 mb-0">
+                <strong>Last error:</strong> @_status.LastError
+            </div>
+        }
+    </div>
+</div>
+
+<div class="d-flex gap-2">
+    <button class="btn btn-outline-secondary" @onclick="RefreshAsync">Refresh</button>
+    <button class="btn btn-warning" disabled="@(_status.DeadLetterDepth == 0)" @onclick="RetryDeadLetteredAsync">
+        Retry dead-lettered (@_status.DeadLetterDepth)
+    </button>
+</div>
+
+@if (_retryResult is not null)
+{
+    <div class="alert alert-success mt-3">Requeued @_retryResult row(s) for retry.</div>
+}
+
+@code {
+    private HistorianSinkStatus _status = new(0, 0, null, null, null, HistorianDrainState.Disabled);
+    private int? _retryResult;
+
+    protected override void OnInitialized() => _status = Diag.GetStatus();
+
+    private Task RefreshAsync()
+    {
+        _status = Diag.GetStatus();
+        _retryResult = null;
+        return Task.CompletedTask;
+    }
+
+    private Task RetryDeadLetteredAsync()
+    {
+        _retryResult = Diag.TryRetryDeadLettered();
+        _status = Diag.GetStatus();
+        return Task.CompletedTask;
+    }
+
+    private static string BadgeFor(HistorianDrainState s) => s switch
+    {
+        HistorianDrainState.Idle => "bg-success",
+        HistorianDrainState.Draining => "bg-info",
+        HistorianDrainState.BackingOff => "bg-warning text-dark",
+        HistorianDrainState.Disabled => "bg-secondary",
+        _ => "bg-secondary",
+    };
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DraftEditor.razor

@@ -23,6 +23,7 @@
     <li class="nav-item"><button class="nav-link @Active("namespaces")" @onclick='() => _tab = "namespaces"'>Namespaces</button></li>
     <li class="nav-item"><button class="nav-link @Active("drivers")" @onclick='() => _tab = "drivers"'>Drivers</button></li>
     <li class="nav-item"><button class="nav-link @Active("acls")" @onclick='() => _tab = "acls"'>ACLs</button></li>
+    <li class="nav-item"><button class="nav-link @Active("scripts")" @onclick='() => _tab = "scripts"'>Scripts</button></li>
 </ul>
 
 <div class="row">
@@ -32,6 +33,7 @@
         else if (_tab == "namespaces") { <NamespacesTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
         else if (_tab == "drivers") { <DriversTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
         else if (_tab == "acls") { <AclsTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
+        else if (_tab == "scripts") { <ScriptsTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
     </div>
     <div class="col-md-4">
         <div class="card sticky-top">

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptEditor.razor

@@ -0,0 +1,41 @@
+@using Microsoft.AspNetCore.Components.Web
+@inject IJSRuntime JS
+
+@*
+    Monaco-backed C# code editor (Phase 7 Stream F). Progressive enhancement:
+    textarea renders immediately, Monaco mounts via JS interop after first render.
+    Monaco script tags are loaded once from the parent layout (wwwroot/js/monaco-loader.js
+    pulls the CDN bundle).
+
+    Stream F keeps the interop surface small — bind `Source` two-way, and the parent
+    tab re-renders on change for the dependency preview. The test-harness button
+    lives in the parent so one editor can drive multiple script types.
+*@
+
+<div class="script-editor">
+    <textarea class="form-control font-monospace" rows="14" spellcheck="false"
+              @bind="Source" @bind:event="oninput" id="@_editorId">@Source</textarea>
+</div>
+
+@code {
+    [Parameter] public string Source { get; set; } = string.Empty;
+    [Parameter] public EventCallback<string> SourceChanged { get; set; }
+
+    private readonly string _editorId = $"script-editor-{Guid.NewGuid():N}";
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (firstRender)
+        {
+            try
+            {
+                await JS.InvokeVoidAsync("otOpcUaScriptEditor.attach", _editorId);
+            }
+            catch (JSException)
+            {
+                // Monaco bundle not yet loaded on this page — textarea fallback is
+                // still functional.
+            }
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptsTab.razor

@@ -0,0 +1,224 @@
+@using ZB.MOM.WW.OtOpcUa.Admin.Services
+@using ZB.MOM.WW.OtOpcUa.Configuration.Entities
+@using ZB.MOM.WW.OtOpcUa.Core.Abstractions
+@using ZB.MOM.WW.OtOpcUa.Core.Scripting
+@inject ScriptService ScriptSvc
+@inject ScriptTestHarnessService Harness
+
+<div class="d-flex justify-content-between align-items-center mb-3">
+    <div>
+        <h4 class="mb-0">Scripts</h4>
+        <small class="text-muted">C# (Roslyn). Used by virtual tags + scripted alarms.</small>
+    </div>
+    <button class="btn btn-primary" @onclick="StartNew">+ New script</button>
+</div>
+
+<script src="/js/monaco-loader.js"></script>
+
+@if (_loading) { <p class="text-muted">Loading…</p> }
+else if (_scripts.Count == 0 && _editing is null)
+{
+    <div class="alert alert-info">No scripts yet in this draft.</div>
+}
+else
+{
+    <div class="row">
+        <div class="col-md-4">
+            <div class="list-group">
+                @foreach (var s in _scripts)
+                {
+                    <button class="list-group-item list-group-item-action @(_editing?.ScriptId == s.ScriptId ? "active" : "")"
+                            @onclick="() => Open(s)">
+                        <strong>@s.Name</strong>
+                        <div class="small text-muted font-monospace">@s.ScriptId</div>
+                    </button>
+                }
+            </div>
+        </div>
+        <div class="col-md-8">
+            @if (_editing is not null)
+            {
+                <div class="card">
+                    <div class="card-header d-flex justify-content-between align-items-center">
+                        <strong>@(_isNew ? "New script" : _editing.Name)</strong>
+                        <div>
+                            @if (!_isNew)
+                            {
+                                <button class="btn btn-sm btn-outline-danger me-2" @onclick="DeleteAsync">Delete</button>
+                            }
+                            <button class="btn btn-sm btn-primary" disabled="@_busy" @onclick="SaveAsync">Save</button>
+                        </div>
+                    </div>
+                    <div class="card-body">
+                        <div class="mb-2">
+                            <label class="form-label">Name</label>
+                            <input class="form-control" @bind="_editing.Name"/>
+                        </div>
+                        <label class="form-label">Source</label>
+                        <ScriptEditor @bind-Source="_editing.SourceCode"/>
+
+                        <div class="mt-3">
+                            <button class="btn btn-sm btn-outline-secondary" @onclick="PreviewDependencies">Analyze dependencies</button>
+                            <button class="btn btn-sm btn-outline-info ms-2" @onclick="RunHarnessAsync" disabled="@_harnessBusy">Run test harness</button>
+                        </div>
+
+                        @if (_dependencies is not null)
+                        {
+                            <div class="mt-3">
+                                <strong>Inferred reads</strong>
+                                @if (_dependencies.Reads.Count == 0) { <span class="text-muted ms-2">none</span> }
+                                else
+                                {
+                                    <ul class="mb-1">
+                                        @foreach (var r in _dependencies.Reads) { <li><code>@r</code></li> }
+                                    </ul>
+                                }
+                                <strong>Inferred writes</strong>
+                                @if (_dependencies.Writes.Count == 0) { <span class="text-muted ms-2">none</span> }
+                                else
+                                {
+                                    <ul class="mb-1">
+                                        @foreach (var w in _dependencies.Writes) { <li><code>@w</code></li> }
+                                    </ul>
+                                }
+                                @if (_dependencies.Rejections.Count > 0)
+                                {
+                                    <div class="alert alert-danger mt-2">
+                                        <strong>Non-literal paths rejected:</strong>
+                                        <ul class="mb-0">
+                                            @foreach (var r in _dependencies.Rejections) { <li>@r.Message</li> }
+                                        </ul>
+                                    </div>
+                                }
+                            </div>
+                        }
+
+                        @if (_testResult is not null)
+                        {
+                            <div class="mt-3 border-top pt-3">
+                                <strong>Harness result:</strong> <span class="badge bg-secondary">@_testResult.Outcome</span>
+                                @if (_testResult.Outcome == ScriptTestOutcome.Success)
+                                {
+                                    <div>Output: <code>@(_testResult.Output?.ToString() ?? "null")</code></div>
+                                    @if (_testResult.Writes.Count > 0)
+                                    {
+                                        <div class="mt-1"><strong>Writes:</strong>
+                                            <ul class="mb-0">
+                                                @foreach (var kv in _testResult.Writes) { <li><code>@kv.Key</code> = <code>@(kv.Value?.ToString() ?? "null")</code></li> }
+                                            </ul>
+                                        </div>
+                                    }
+                                }
+                                @if (_testResult.Errors.Count > 0)
+                                {
+                                    <div class="alert alert-warning mt-2 mb-0">
+                                        @foreach (var e in _testResult.Errors) { <div>@e</div> }
+                                    </div>
+                                }
+                                @if (_testResult.LogEvents.Count > 0)
+                                {
+                                    <div class="mt-2"><strong>Script log output:</strong>
+                                        <ul class="small mb-0">
+                                            @foreach (var e in _testResult.LogEvents) { <li>[@e.Level] @e.RenderMessage()</li> }
+                                        </ul>
+                                    </div>
+                                }
+                            </div>
+                        }
+                    </div>
+                </div>
+            }
+        </div>
+    </div>
+}
+
+@code {
+    [Parameter] public long GenerationId { get; set; }
+    [Parameter] public string ClusterId { get; set; } = string.Empty;
+
+    private bool _loading = true;
+    private bool _busy;
+    private bool _harnessBusy;
+    private bool _isNew;
+    private List<Script> _scripts = [];
+    private Script? _editing;
+    private DependencyExtractionResult? _dependencies;
+    private ScriptTestResult? _testResult;
+
+    protected override async Task OnParametersSetAsync()
+    {
+        _loading = true;
+        _scripts = await ScriptSvc.ListAsync(GenerationId, CancellationToken.None);
+        _loading = false;
+    }
+
+    private void Open(Script s)
+    {
+        _editing = new Script
+        {
+            ScriptRowId = s.ScriptRowId, GenerationId = s.GenerationId,
+            ScriptId = s.ScriptId, Name = s.Name, SourceCode = s.SourceCode,
+            SourceHash = s.SourceHash, Language = s.Language,
+        };
+        _isNew = false;
+        _dependencies = null;
+        _testResult = null;
+    }
+
+    private void StartNew()
+    {
+        _editing = new Script
+        {
+            GenerationId = GenerationId, ScriptId = "",
+            Name = "new-script", SourceCode = "return 0;", SourceHash = "",
+        };
+        _isNew = true;
+        _dependencies = null;
+        _testResult = null;
+    }
+
+    private async Task SaveAsync()
+    {
+        if (_editing is null) return;
+        _busy = true;
+        try
+        {
+            if (_isNew)
+                await ScriptSvc.AddAsync(GenerationId, _editing.Name, _editing.SourceCode, CancellationToken.None);
+            else
+                await ScriptSvc.UpdateAsync(GenerationId, _editing.ScriptId, _editing.Name, _editing.SourceCode, CancellationToken.None);
+            _scripts = await ScriptSvc.ListAsync(GenerationId, CancellationToken.None);
+            _isNew = false;
+        }
+        finally { _busy = false; }
+    }
+
+    private async Task DeleteAsync()
+    {
+        if (_editing is null || _isNew) return;
+        await ScriptSvc.DeleteAsync(GenerationId, _editing.ScriptId, CancellationToken.None);
+        _editing = null;
+        _scripts = await ScriptSvc.ListAsync(GenerationId, CancellationToken.None);
+    }
+
+    private void PreviewDependencies()
+    {
+        if (_editing is null) return;
+        _dependencies = DependencyExtractor.Extract(_editing.SourceCode);
+    }
+
+    private async Task RunHarnessAsync()
+    {
+        if (_editing is null) return;
+        _harnessBusy = true;
+        try
+        {
+            _dependencies ??= DependencyExtractor.Extract(_editing.SourceCode);
+            var inputs = new Dictionary<string, DataValueSnapshot>();
+            foreach (var read in _dependencies.Reads)
+                inputs[read] = new DataValueSnapshot(0.0, 0u, DateTime.UtcNow, DateTime.UtcNow);
+            _testResult = await Harness.RunVirtualTagAsync(_editing.SourceCode, inputs, CancellationToken.None);
+        }
+        finally { _harnessBusy = false; }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Program.cs

@@ -57,6 +57,18 @@ builder.Services.AddScoped<EquipmentImportBatchService>();
 builder.Services.AddScoped<ZB.MOM.WW.OtOpcUa.Configuration.Services.ILdapGroupRoleMappingService,
     ZB.MOM.WW.OtOpcUa.Configuration.Services.LdapGroupRoleMappingService>();
 
+// Phase 7 Stream F — scripting + virtual tag + scripted alarm draft services, test
+// harness, and historian diagnostics. The historian sink is the Null variant here —
+// the real SqliteStoreAndForwardSink lives in the server process. Admin reads status
+// from whichever sink is provided at composition time.
+builder.Services.AddScoped<ScriptService>();
+builder.Services.AddScoped<VirtualTagService>();
+builder.Services.AddScoped<ScriptedAlarmService>();
+builder.Services.AddScoped<ScriptTestHarnessService>();
+builder.Services.AddScoped<HistorianDiagnosticsService>();
+builder.Services.AddSingleton<ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.IAlarmHistorianSink>(
+    ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.NullAlarmHistorianSink.Instance);
+
 // Cert-trust management — reads the OPC UA server's PKI store root so rejected client certs
 // can be promoted to trusted via the Admin UI. Singleton: no per-request state, just
 // filesystem operations.

src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs

@@ -0,0 +1,32 @@
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Surfaces the local-node historian queue health on the Admin UI's
+///     <c>/alarms/historian</c> diagnostics page (Phase 7 plan decisions #16/#21).
+///     Exposes queue depth / drain state / last-error, and lets the operator retry
+///     dead-lettered rows without restarting the node.
+/// </summary>
+/// <remarks>
+///     The sink injected here is the server-process <see cref="IAlarmHistorianSink"/>.
+///     When <see cref="NullAlarmHistorianSink"/> is bound (historian disabled for this
+///     deployment), <see cref="TryRetryDeadLettered"/> silently returns 0 and
+///     <see cref="GetStatus"/> reports <see cref="HistorianDrainState.Disabled"/>.
+/// </remarks>
+public sealed class HistorianDiagnosticsService(IAlarmHistorianSink sink)
+{
+    public HistorianSinkStatus GetStatus() => sink.GetStatus();
+
+    /// <summary>
+    ///     Operator action from the UI's "Retry dead-lettered" button. Returns the number
+    ///     of rows revived so the UI can flash a confirmation. When the live sink doesn't
+    ///     implement retry (test doubles, Null sink), returns 0.
+    /// </summary>
+    public int TryRetryDeadLettered()
+    {
+        if (sink is SqliteStoreAndForwardSink concrete)
+            return concrete.RetryDeadLettered();
+        return 0;
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptService.cs

@@ -0,0 +1,66 @@
+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Draft-generation CRUD for <see cref="Script"/> rows — the C# source code referenced
+///     by Phase 7 virtual tags and scripted alarms. <see cref="Script.SourceHash"/> is
+///     recomputed on every save so Core.Scripting's compile cache sees a fresh key when
+///     source changes and reuses the compile when it doesn't.
+/// </summary>
+public sealed class ScriptService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<Script>> ListAsync(long generationId, CancellationToken ct) =>
+        db.Scripts.AsNoTracking()
+            .Where(s => s.GenerationId == generationId)
+            .OrderBy(s => s.Name)
+            .ToListAsync(ct);
+
+    public Task<Script?> GetAsync(long generationId, string scriptId, CancellationToken ct) =>
+        db.Scripts.AsNoTracking()
+            .FirstOrDefaultAsync(s => s.GenerationId == generationId && s.ScriptId == scriptId, ct);
+
+    public async Task<Script> AddAsync(long generationId, string name, string sourceCode, CancellationToken ct)
+    {
+        var s = new Script
+        {
+            GenerationId = generationId,
+            ScriptId = $"scr-{Guid.NewGuid():N}"[..20],
+            Name = name,
+            SourceCode = sourceCode,
+            SourceHash = ComputeHash(sourceCode),
+        };
+        db.Scripts.Add(s);
+        await db.SaveChangesAsync(ct);
+        return s;
+    }
+
+    public async Task<Script> UpdateAsync(long generationId, string scriptId, string name, string sourceCode, CancellationToken ct)
+    {
+        var s = await db.Scripts.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.ScriptId == scriptId, ct)
+            ?? throw new InvalidOperationException($"Script '{scriptId}' not found in generation {generationId}");
+        s.Name = name;
+        s.SourceCode = sourceCode;
+        s.SourceHash = ComputeHash(sourceCode);
+        await db.SaveChangesAsync(ct);
+        return s;
+    }
+
+    public async Task DeleteAsync(long generationId, string scriptId, CancellationToken ct)
+    {
+        var s = await db.Scripts.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.ScriptId == scriptId, ct);
+        if (s is null) return;
+        db.Scripts.Remove(s);
+        await db.SaveChangesAsync(ct);
+    }
+
+    internal static string ComputeHash(string source)
+    {
+        var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(source ?? string.Empty));
+        return Convert.ToHexString(bytes);
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptTestHarnessService.cs

@@ -0,0 +1,121 @@
+using Serilog;  // resolves Serilog.ILogger explicitly in signatures
+using Serilog.Core;
+using Serilog.Events;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.Scripting;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Dry-run harness for the Phase 7 scripting UI. Takes a script + a synthetic input
+///     map + evaluates once, returns the output (or rejection / exception) plus any
+///     logger emissions the script produced. Per Phase 7 plan decision #22: only inputs
+///     the <see cref="DependencyExtractor"/> identified can be supplied, so a dependency
+///     the harness can't prove statically surfaces as a harness error, not a runtime
+///     surprise later.
+/// </summary>
+public sealed class ScriptTestHarnessService
+{
+    /// <summary>
+    ///     Evaluate <paramref name="source"/> as a virtual-tag script (return value is the
+    ///     tag's new value). <paramref name="inputs"/> supplies synthetic
+    ///     <see cref="DataValueSnapshot"/>s for every path the extractor found.
+    /// </summary>
+    public async Task<ScriptTestResult> RunVirtualTagAsync(
+        string source, IDictionary<string, DataValueSnapshot> inputs, CancellationToken ct)
+    {
+        var deps = DependencyExtractor.Extract(source);
+        if (!deps.IsValid)
+            return ScriptTestResult.DependencyRejections(deps.Rejections);
+
+        var missing = deps.Reads.Where(r => !inputs.ContainsKey(r)).ToArray();
+        if (missing.Length > 0)
+            return ScriptTestResult.MissingInputs(missing);
+
+        var extra = inputs.Keys.Where(k => !deps.Reads.Contains(k)).ToArray();
+        if (extra.Length > 0)
+            return ScriptTestResult.UnknownInputs(extra);
+
+        ScriptEvaluator<HarnessVirtualTagContext, object?> evaluator;
+        try
+        {
+            evaluator = ScriptEvaluator<HarnessVirtualTagContext, object?>.Compile(source);
+        }
+        catch (Exception compileEx)
+        {
+            return ScriptTestResult.Threw(compileEx.Message, []);
+        }
+        var capturing = new CapturingSink();
+        var logger = new LoggerConfiguration().MinimumLevel.Verbose().WriteTo.Sink(capturing).CreateLogger();
+        var ctx = new HarnessVirtualTagContext(inputs, logger);
+
+        try
+        {
+            var result = await evaluator.RunAsync(ctx, ct);
+            return ScriptTestResult.Ok(result, ctx.Writes, capturing.Events);
+        }
+        catch (Exception ex)
+        {
+            return ScriptTestResult.Threw(ex.Message, capturing.Events);
+        }
+    }
+
+    // Public so Roslyn's script compilation can reference the context type through the
+    // ScriptGlobals<T> surface. The harness instantiates this directly; operators never see it.
+    public sealed class HarnessVirtualTagContext(
+        IDictionary<string, DataValueSnapshot> inputs, Serilog.ILogger logger) : ScriptContext
+    {
+        public Dictionary<string, object?> Writes { get; } = [];
+        public override DataValueSnapshot GetTag(string path) =>
+            inputs.TryGetValue(path, out var v)
+                ? v
+                : new DataValueSnapshot(null, Ua.StatusCodes.BadNotFound, null, DateTime.UtcNow);
+        public override void SetVirtualTag(string path, object? value) => Writes[path] = value;
+        public override DateTime Now => DateTime.UtcNow;
+        public override Serilog.ILogger Logger => logger;
+    }
+
+    private sealed class CapturingSink : ILogEventSink
+    {
+        public List<LogEvent> Events { get; } = [];
+        public void Emit(LogEvent e) => Events.Add(e);
+    }
+}
+
+/// <summary>Harness outcome: outputs, write-set, logger events, or a rejection/throw reason.</summary>
+public sealed record ScriptTestResult(
+    ScriptTestOutcome Outcome,
+    object? Output,
+    IReadOnlyDictionary<string, object?> Writes,
+    IReadOnlyList<LogEvent> LogEvents,
+    IReadOnlyList<string> Errors)
+{
+    public static ScriptTestResult Ok(object? output, IReadOnlyDictionary<string, object?> writes, IReadOnlyList<LogEvent> logs) =>
+        new(ScriptTestOutcome.Success, output, writes, logs, []);
+    public static ScriptTestResult Threw(string reason, IReadOnlyList<LogEvent> logs) =>
+        new(ScriptTestOutcome.Threw, null, new Dictionary<string, object?>(), logs, [reason]);
+    public static ScriptTestResult DependencyRejections(IReadOnlyList<DependencyRejection> rejs) =>
+        new(ScriptTestOutcome.DependencyRejected, null, new Dictionary<string, object?>(), [],
+            rejs.Select(r => r.Message).ToArray());
+    public static ScriptTestResult MissingInputs(string[] paths) =>
+        new(ScriptTestOutcome.MissingInputs, null, new Dictionary<string, object?>(), [],
+            paths.Select(p => $"Missing synthetic input: {p}").ToArray());
+    public static ScriptTestResult UnknownInputs(string[] paths) =>
+        new(ScriptTestOutcome.UnknownInputs, null, new Dictionary<string, object?>(), [],
+            paths.Select(p => $"Input '{p}' is not referenced by the script — remove it").ToArray());
+}
+
+public enum ScriptTestOutcome
+{
+    Success,
+    Threw,
+    DependencyRejected,
+    MissingInputs,
+    UnknownInputs,
+}
+
+file static class Ua
+{
+    // Mirrors OPC UA StatusCodes.BadNotFound without pulling the OPC stack into Admin.
+    public static class StatusCodes { public const uint BadNotFound = 0x803E0000; }
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptedAlarmService.cs

@@ -0,0 +1,55 @@
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>Draft-generation CRUD for <see cref="ScriptedAlarm"/> rows.</summary>
+public sealed class ScriptedAlarmService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<ScriptedAlarm>> ListAsync(long generationId, CancellationToken ct) =>
+        db.ScriptedAlarms.AsNoTracking()
+            .Where(a => a.GenerationId == generationId)
+            .OrderBy(a => a.EquipmentId).ThenBy(a => a.Name)
+            .ToListAsync(ct);
+
+    public async Task<ScriptedAlarm> AddAsync(
+        long generationId, string equipmentId, string name, string alarmType,
+        int severity, string messageTemplate, string predicateScriptId,
+        bool historizeToAveva, bool retain, CancellationToken ct)
+    {
+        var a = new ScriptedAlarm
+        {
+            GenerationId = generationId,
+            ScriptedAlarmId = $"sal-{Guid.NewGuid():N}"[..20],
+            EquipmentId = equipmentId,
+            Name = name,
+            AlarmType = alarmType,
+            Severity = severity,
+            MessageTemplate = messageTemplate,
+            PredicateScriptId = predicateScriptId,
+            HistorizeToAveva = historizeToAveva,
+            Retain = retain,
+        };
+        db.ScriptedAlarms.Add(a);
+        await db.SaveChangesAsync(ct);
+        return a;
+    }
+
+    public async Task DeleteAsync(long generationId, string scriptedAlarmId, CancellationToken ct)
+    {
+        var a = await db.ScriptedAlarms.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.ScriptedAlarmId == scriptedAlarmId, ct);
+        if (a is null) return;
+        db.ScriptedAlarms.Remove(a);
+        await db.SaveChangesAsync(ct);
+    }
+
+    /// <summary>
+    ///     Returns the persistent state row (ack/confirm/shelve) for this alarm identity —
+    ///     alarm state is NOT generation-scoped per Phase 7 plan decision #14, so the
+    ///     lookup is by <see cref="ScriptedAlarm.ScriptedAlarmId"/> only.
+    /// </summary>
+    public Task<ScriptedAlarmState?> GetStateAsync(string scriptedAlarmId, CancellationToken ct) =>
+        db.ScriptedAlarmStates.AsNoTracking()
+            .FirstOrDefaultAsync(s => s.ScriptedAlarmId == scriptedAlarmId, ct);
+}

src/ZB.MOM.WW.OtOpcUa.Admin/Services/VirtualTagService.cs

@@ -0,0 +1,53 @@
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>Draft-generation CRUD for <see cref="VirtualTag"/> rows.</summary>
+public sealed class VirtualTagService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<VirtualTag>> ListAsync(long generationId, CancellationToken ct) =>
+        db.VirtualTags.AsNoTracking()
+            .Where(v => v.GenerationId == generationId)
+            .OrderBy(v => v.EquipmentId).ThenBy(v => v.Name)
+            .ToListAsync(ct);
+
+    public async Task<VirtualTag> AddAsync(
+        long generationId, string equipmentId, string name, string dataType, string scriptId,
+        bool changeTriggered, int? timerIntervalMs, bool historize, CancellationToken ct)
+    {
+        var v = new VirtualTag
+        {
+            GenerationId = generationId,
+            VirtualTagId = $"vt-{Guid.NewGuid():N}"[..20],
+            EquipmentId = equipmentId,
+            Name = name,
+            DataType = dataType,
+            ScriptId = scriptId,
+            ChangeTriggered = changeTriggered,
+            TimerIntervalMs = timerIntervalMs,
+            Historize = historize,
+        };
+        db.VirtualTags.Add(v);
+        await db.SaveChangesAsync(ct);
+        return v;
+    }
+
+    public async Task DeleteAsync(long generationId, string virtualTagId, CancellationToken ct)
+    {
+        var v = await db.VirtualTags.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.VirtualTagId == virtualTagId, ct);
+        if (v is null) return;
+        db.VirtualTags.Remove(v);
+        await db.SaveChangesAsync(ct);
+    }
+
+    public async Task<VirtualTag> UpdateEnabledAsync(long generationId, string virtualTagId, bool enabled, CancellationToken ct)
+    {
+        var v = await db.VirtualTags.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.VirtualTagId == virtualTagId, ct)
+            ?? throw new InvalidOperationException($"VirtualTag '{virtualTagId}' not found in generation {generationId}");
+        v.Enabled = enabled;
+        await db.SaveChangesAsync(ct);
+        return v;
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj

@@ -23,6 +23,8 @@
     <ItemGroup>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Configuration\ZB.MOM.WW.OtOpcUa.Configuration.csproj"/>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Scripting\ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
     </ItemGroup>
 
     <ItemGroup>

src/ZB.MOM.WW.OtOpcUa.Admin/wwwroot/js/monaco-loader.js

@@ -0,0 +1,59 @@
+// Phase 7 Stream F — Monaco editor loader for ScriptEditor.razor.
+// Progressive enhancement: the textarea is authoritative until Monaco attaches;
+// after attach, Monaco syncs back into the textarea on every change so Blazor's
+// @bind still sees the latest value.
+
+(function () {
+    if (window.otOpcUaScriptEditor) return;
+
+    const MONACO_CDN = 'https://cdn.jsdelivr.net/npm/monaco-editor@0.52.2/min/vs';
+    let loaderPromise = null;
+
+    function ensureLoader() {
+        if (loaderPromise) return loaderPromise;
+        loaderPromise = new Promise((resolve, reject) => {
+            const script = document.createElement('script');
+            script.src = `${MONACO_CDN}/loader.js`;
+            script.onload = () => {
+                window.require.config({ paths: { vs: MONACO_CDN } });
+                window.require(['vs/editor/editor.main'], () => resolve(window.monaco));
+            };
+            script.onerror = () => reject(new Error('Monaco CDN unreachable'));
+            document.head.appendChild(script);
+        });
+        return loaderPromise;
+    }
+
+    window.otOpcUaScriptEditor = {
+        attach: async function (textareaId) {
+            const ta = document.getElementById(textareaId);
+            if (!ta) return;
+            const monaco = await ensureLoader();
+
+            // Mount Monaco over the textarea. The textarea stays in the DOM as the
+            // source of truth for Blazor's @bind — Monaco mirrors into it on every
+            // keystroke so server-side state stays in sync.
+            const host = document.createElement('div');
+            host.style.height = '340px';
+            host.style.border = '1px solid #ced4da';
+            host.style.borderRadius = '0.25rem';
+            ta.style.display = 'none';
+            ta.parentNode.insertBefore(host, ta);
+
+            const editor = monaco.editor.create(host, {
+                value: ta.value,
+                language: 'csharp',
+                theme: 'vs',
+                automaticLayout: true,
+                fontSize: 13,
+                minimap: { enabled: false },
+                scrollBeyondLastLine: false,
+            });
+
+            editor.onDidChangeModelContent(() => {
+                ta.value = editor.getValue();
+                ta.dispatchEvent(new Event('input', { bubbles: true }));
+            });
+        },
+    };
+})();

src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/Script.cs

@@ -0,0 +1,38 @@
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+/// <summary>
+///     Per Phase 7 plan decision #8 — user-authored C# script source, referenced by
+///     <see cref="VirtualTag"/> and <see cref="ScriptedAlarm"/>. One row per script,
+///     per generation. <c>SourceHash</c> is the compile-cache key.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Scripts are generation-scoped: a draft's edit creates a new row in the draft
+///         generation, the old row stays frozen in the published generation. Shape mirrors
+///         the other generation-scoped entities (Equipment, Tag, etc.) — <c>ScriptId</c> is
+///         the stable logical id that carries across generations; <c>ScriptRowId</c> is the
+///         row identity.
+///     </para>
+/// </remarks>
+public sealed class Script
+{
+    public Guid ScriptRowId { get; set; }
+    public long GenerationId { get; set; }
+
+    /// <summary>Stable logical id. Carries across generations.</summary>
+    public required string ScriptId { get; set; }
+
+    /// <summary>Operator-friendly name for log filtering + Admin UI list view.</summary>
+    public required string Name { get; set; }
+
+    /// <summary>Raw C# source. Size bounded by the DB column (nvarchar(max)).</summary>
+    public required string SourceCode { get; set; }
+
+    /// <summary>SHA-256 of <see cref="SourceCode"/> — compile-cache key for Phase 7 Stream A's <c>CompiledScriptCache</c>.</summary>
+    public required string SourceHash { get; set; }
+
+    /// <summary>Language — always "CSharp" today; placeholder for future engines (Python/Lua).</summary>
+    public string Language { get; set; } = "CSharp";
+
+    public ConfigGeneration? Generation { get; set; }
+}

src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/ScriptedAlarm.cs

@@ -0,0 +1,59 @@
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+/// <summary>
+///     Per Phase 7 plan decisions #5, #13, #15 — a scripted OPC UA Part 9 alarm whose
+///     condition is the predicate <see cref="Script"/> referenced by
+///     <see cref="PredicateScriptId"/>. Materialized by <c>Core.ScriptedAlarms</c> as a
+///     concrete <c>AlarmConditionType</c> subtype per <see cref="AlarmType"/>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Message tokens (<c>{TagPath}</c>) resolved at emission time per plan decision #13.
+///         <see cref="HistorizeToAveva"/> (plan decision #15) gates whether transitions
+///         route through the Core.AlarmHistorian SQLite queue + Galaxy.Host to the Aveva
+///         Historian alarm schema.
+///     </para>
+/// </remarks>
+public sealed class ScriptedAlarm
+{
+    public Guid ScriptedAlarmRowId { get; set; }
+    public long GenerationId { get; set; }
+
+    /// <summary>Stable logical id — drives <c>AlarmConditionType.ConditionName</c>.</summary>
+    public required string ScriptedAlarmId { get; set; }
+
+    /// <summary>Logical FK to <see cref="Equipment.EquipmentId"/> — owner of this alarm.</summary>
+    public required string EquipmentId { get; set; }
+
+    /// <summary>Operator-facing alarm name.</summary>
+    public required string Name { get; set; }
+
+    /// <summary>Concrete Part 9 type — "AlarmCondition" / "LimitAlarm" / "OffNormalAlarm" / "DiscreteAlarm".</summary>
+    public required string AlarmType { get; set; }
+
+    /// <summary>Numeric severity 1..1000 per OPC UA Part 9 (usual bands: 1-250 Low, 251-500 Medium, 501-750 High, 751-1000 Critical).</summary>
+    public int Severity { get; set; } = 500;
+
+    /// <summary>Template with <c>{TagPath}</c> tokens resolved at emission time.</summary>
+    public required string MessageTemplate { get; set; }
+
+    /// <summary>Logical FK to <see cref="Script.ScriptId"/> — predicate script returning <c>bool</c>.</summary>
+    public required string PredicateScriptId { get; set; }
+
+    /// <summary>
+    ///     Plan decision #15 — when true, transitions route through the SQLite store-and-forward
+    ///     queue to the Aveva Historian. Defaults on for scripted alarms because they are the
+    ///     primary motivation for the historian sink; operator can disable per alarm.
+    /// </summary>
+    public bool HistorizeToAveva { get; set; } = true;
+
+    /// <summary>
+    ///     OPC UA Part 9 <c>Retain</c> flag — whether the alarm keeps active-state between
+    ///     sessions. Most plant alarms are retained; one-shot event-style alarms are not.
+    /// </summary>
+    public bool Retain { get; set; } = true;
+
+    public bool Enabled { get; set; } = true;
+
+    public ConfigGeneration? Generation { get; set; }
+}

src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/ScriptedAlarmState.cs

@@ -0,0 +1,62 @@
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+/// <summary>
+///     Per Phase 7 plan decision #14 — persistent runtime state for each scripted alarm.
+///     Survives process restart so operators don't re-ack and ack history survives for
+///     GxP / 21 CFR Part 11 compliance. Keyed on <c>ScriptedAlarmId</c> logically (not
+///     per-generation) because ack state follows the alarm's stable identity across
+///     generations — a Modified alarm keeps its ack history.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <c>ActiveState</c> is deliberately NOT persisted — it rederives from the current
+///         predicate evaluation on startup. Only operator-supplied state (<see cref="AckedState"/>,
+///         <see cref="ConfirmedState"/>, <see cref="ShelvingState"/>) + audit trail persist.
+///     </para>
+///     <para>
+///         <see cref="CommentsJson"/> is an append-only JSON array of <c>{user, utc, text}</c>
+///         tuples — one per operator comment. Core.ScriptedAlarms' <c>AlarmConditionState.Comments</c>
+///         serializes directly into this column.
+///     </para>
+/// </remarks>
+public sealed class ScriptedAlarmState
+{
+    /// <summary>Logical FK — matches <see cref="ScriptedAlarm.ScriptedAlarmId"/>. One row per alarm identity.</summary>
+    public required string ScriptedAlarmId { get; set; }
+
+    /// <summary>Enabled/Disabled. Persists across restart per plan decision #14.</summary>
+    public required string EnabledState { get; set; } = "Enabled";
+
+    /// <summary>Unacknowledged / Acknowledged.</summary>
+    public required string AckedState { get; set; } = "Unacknowledged";
+
+    /// <summary>Unconfirmed / Confirmed.</summary>
+    public required string ConfirmedState { get; set; } = "Unconfirmed";
+
+    /// <summary>Unshelved / OneShotShelved / TimedShelved.</summary>
+    public required string ShelvingState { get; set; } = "Unshelved";
+
+    /// <summary>When a TimedShelve expires — null if not shelved or OneShotShelved.</summary>
+    public DateTime? ShelvingExpiresUtc { get; set; }
+
+    /// <summary>User who last acknowledged. Null if never acked.</summary>
+    public string? LastAckUser { get; set; }
+
+    /// <summary>Operator-supplied ack comment. Null if no comment or never acked.</summary>
+    public string? LastAckComment { get; set; }
+
+    public DateTime? LastAckUtc { get; set; }
+
+    /// <summary>User who last confirmed.</summary>
+    public string? LastConfirmUser { get; set; }
+
+    public string? LastConfirmComment { get; set; }
+
+    public DateTime? LastConfirmUtc { get; set; }
+
+    /// <summary>JSON array of operator comments, append-only (GxP audit).</summary>
+    public string CommentsJson { get; set; } = "[]";
+
+    /// <summary>Row write timestamp — tracks last state change.</summary>
+    public DateTime UpdatedAtUtc { get; set; }
+}

src/ZB.MOM.WW.OtOpcUa.Configuration/Entities/VirtualTag.cs

@@ -0,0 +1,53 @@
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+/// <summary>
+///     Per Phase 7 plan decision #2 — a virtual (calculated) tag that lives in the
+///     Equipment tree alongside driver tags. Value is produced by the
+///     <see cref="Script"/> referenced by <see cref="ScriptId"/>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <see cref="EquipmentId"/> is mandatory — virtual tags are always scoped to an
+///         Equipment node per plan decision #2 (unified Equipment tree, not a separate
+///         /Virtual namespace). <see cref="DataType"/> matches the shape used by
+///         <c>Tag.DataType</c>.
+///     </para>
+///     <para>
+///         <see cref="ChangeTriggered"/> and <see cref="TimerIntervalMs"/> together realize
+///         plan decision #3 (change + timer). At least one must produce evaluations; the
+///         Core.VirtualTags engine rejects an all-disabled tag at load time.
+///     </para>
+/// </remarks>
+public sealed class VirtualTag
+{
+    public Guid VirtualTagRowId { get; set; }
+    public long GenerationId { get; set; }
+
+    /// <summary>Stable logical id.</summary>
+    public required string VirtualTagId { get; set; }
+
+    /// <summary>Logical FK to <see cref="Equipment.EquipmentId"/> — owner of this virtual tag.</summary>
+    public required string EquipmentId { get; set; }
+
+    /// <summary>Browse name — unique within owning Equipment.</summary>
+    public required string Name { get; set; }
+
+    /// <summary>DataType string — same vocabulary as <see cref="Tag.DataType"/>.</summary>
+    public required string DataType { get; set; }
+
+    /// <summary>Logical FK to <see cref="Script.ScriptId"/> — the script that computes this tag's value.</summary>
+    public required string ScriptId { get; set; }
+
+    /// <summary>Re-evaluate when any referenced input tag changes. Default on.</summary>
+    public bool ChangeTriggered { get; set; } = true;
+
+    /// <summary>Timer re-evaluation cadence in milliseconds. <c>null</c> = no timer.</summary>
+    public int? TimerIntervalMs { get; set; }
+
+    /// <summary>Per plan decision #10 — checkbox to route this tag's values through <c>IHistoryWriter</c>.</summary>
+    public bool Historize { get; set; }
+
+    public bool Enabled { get; set; } = true;
+
+    public ConfigGeneration? Generation { get; set; }
+}

src/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/20260420231641_AddPhase7ScriptingTables.cs

@@ -0,0 +1,186 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddPhase7ScriptingTables : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "Script",
+                columns: table => new
+                {
+                    ScriptRowId = table.Column<Guid>(type: "uniqueidentifier", nullable: false, defaultValueSql: "NEWSEQUENTIALID()"),
+                    GenerationId = table.Column<long>(type: "bigint", nullable: false),
+                    ScriptId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: true),
+                    Name = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: false),
+                    SourceCode = table.Column<string>(type: "nvarchar(max)", nullable: false),
+                    SourceHash = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    Language = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Script", x => x.ScriptRowId);
+                    table.ForeignKey(
+                        name: "FK_Script_ConfigGeneration_GenerationId",
+                        column: x => x.GenerationId,
+                        principalTable: "ConfigGeneration",
+                        principalColumn: "GenerationId",
+                        onDelete: ReferentialAction.Restrict);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "ScriptedAlarm",
+                columns: table => new
+                {
+                    ScriptedAlarmRowId = table.Column<Guid>(type: "uniqueidentifier", nullable: false, defaultValueSql: "NEWSEQUENTIALID()"),
+                    GenerationId = table.Column<long>(type: "bigint", nullable: false),
+                    ScriptedAlarmId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: true),
+                    EquipmentId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    Name = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: false),
+                    AlarmType = table.Column<string>(type: "nvarchar(32)", maxLength: 32, nullable: false),
+                    Severity = table.Column<int>(type: "int", nullable: false),
+                    MessageTemplate = table.Column<string>(type: "nvarchar(1024)", maxLength: 1024, nullable: false),
+                    PredicateScriptId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    HistorizeToAveva = table.Column<bool>(type: "bit", nullable: false),
+                    Retain = table.Column<bool>(type: "bit", nullable: false),
+                    Enabled = table.Column<bool>(type: "bit", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ScriptedAlarm", x => x.ScriptedAlarmRowId);
+                    table.CheckConstraint("CK_ScriptedAlarm_AlarmType", "AlarmType IN ('AlarmCondition','LimitAlarm','OffNormalAlarm','DiscreteAlarm')");
+                    table.CheckConstraint("CK_ScriptedAlarm_Severity_Range", "Severity BETWEEN 1 AND 1000");
+                    table.ForeignKey(
+                        name: "FK_ScriptedAlarm_ConfigGeneration_GenerationId",
+                        column: x => x.GenerationId,
+                        principalTable: "ConfigGeneration",
+                        principalColumn: "GenerationId",
+                        onDelete: ReferentialAction.Restrict);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "ScriptedAlarmState",
+                columns: table => new
+                {
+                    ScriptedAlarmId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    EnabledState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    AckedState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    ConfirmedState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    ShelvingState = table.Column<string>(type: "nvarchar(16)", maxLength: 16, nullable: false),
+                    ShelvingExpiresUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: true),
+                    LastAckUser = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: true),
+                    LastAckComment = table.Column<string>(type: "nvarchar(1024)", maxLength: 1024, nullable: true),
+                    LastAckUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: true),
+                    LastConfirmUser = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: true),
+                    LastConfirmComment = table.Column<string>(type: "nvarchar(1024)", maxLength: 1024, nullable: true),
+                    LastConfirmUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: true),
+                    CommentsJson = table.Column<string>(type: "nvarchar(max)", nullable: false),
+                    UpdatedAtUtc = table.Column<DateTime>(type: "datetime2(3)", nullable: false, defaultValueSql: "SYSUTCDATETIME()")
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ScriptedAlarmState", x => x.ScriptedAlarmId);
+                    table.CheckConstraint("CK_ScriptedAlarmState_CommentsJson_IsJson", "ISJSON(CommentsJson) = 1");
+                });
+
+            migrationBuilder.CreateTable(
+                name: "VirtualTag",
+                columns: table => new
+                {
+                    VirtualTagRowId = table.Column<Guid>(type: "uniqueidentifier", nullable: false, defaultValueSql: "NEWSEQUENTIALID()"),
+                    GenerationId = table.Column<long>(type: "bigint", nullable: false),
+                    VirtualTagId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: true),
+                    EquipmentId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    Name = table.Column<string>(type: "nvarchar(128)", maxLength: 128, nullable: false),
+                    DataType = table.Column<string>(type: "nvarchar(32)", maxLength: 32, nullable: false),
+                    ScriptId = table.Column<string>(type: "nvarchar(64)", maxLength: 64, nullable: false),
+                    ChangeTriggered = table.Column<bool>(type: "bit", nullable: false),
+                    TimerIntervalMs = table.Column<int>(type: "int", nullable: true),
+                    Historize = table.Column<bool>(type: "bit", nullable: false),
+                    Enabled = table.Column<bool>(type: "bit", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_VirtualTag", x => x.VirtualTagRowId);
+                    table.CheckConstraint("CK_VirtualTag_TimerInterval_Min", "TimerIntervalMs IS NULL OR TimerIntervalMs >= 50");
+                    table.CheckConstraint("CK_VirtualTag_Trigger_AtLeastOne", "ChangeTriggered = 1 OR TimerIntervalMs IS NOT NULL");
+                    table.ForeignKey(
+                        name: "FK_VirtualTag_ConfigGeneration_GenerationId",
+                        column: x => x.GenerationId,
+                        principalTable: "ConfigGeneration",
+                        principalColumn: "GenerationId",
+                        onDelete: ReferentialAction.Restrict);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Script_Generation_SourceHash",
+                table: "Script",
+                columns: new[] { "GenerationId", "SourceHash" });
+
+            migrationBuilder.CreateIndex(
+                name: "UX_Script_Generation_LogicalId",
+                table: "Script",
+                columns: new[] { "GenerationId", "ScriptId" },
+                unique: true,
+                filter: "[ScriptId] IS NOT NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ScriptedAlarm_Generation_Script",
+                table: "ScriptedAlarm",
+                columns: new[] { "GenerationId", "PredicateScriptId" });
+
+            migrationBuilder.CreateIndex(
+                name: "UX_ScriptedAlarm_Generation_EquipmentPath",
+                table: "ScriptedAlarm",
+                columns: new[] { "GenerationId", "EquipmentId", "Name" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "UX_ScriptedAlarm_Generation_LogicalId",
+                table: "ScriptedAlarm",
+                columns: new[] { "GenerationId", "ScriptedAlarmId" },
+                unique: true,
+                filter: "[ScriptedAlarmId] IS NOT NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_VirtualTag_Generation_Script",
+                table: "VirtualTag",
+                columns: new[] { "GenerationId", "ScriptId" });
+
+            migrationBuilder.CreateIndex(
+                name: "UX_VirtualTag_Generation_EquipmentPath",
+                table: "VirtualTag",
+                columns: new[] { "GenerationId", "EquipmentId", "Name" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "UX_VirtualTag_Generation_LogicalId",
+                table: "VirtualTag",
+                columns: new[] { "GenerationId", "VirtualTagId" },
+                unique: true,
+                filter: "[VirtualTagId] IS NOT NULL");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "Script");
+
+            migrationBuilder.DropTable(
+                name: "ScriptedAlarm");
+
+            migrationBuilder.DropTable(
+                name: "ScriptedAlarmState");
+
+            migrationBuilder.DropTable(
+                name: "VirtualTag");
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/20260420232000_ExtendComputeGenerationDiffWithPhase7.cs

@@ -0,0 +1,232 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
+{
+    /// <summary>
+    ///     Phase 7 follow-up (task #241) — extends <c>dbo.sp_ComputeGenerationDiff</c> to emit
+    ///     Script / VirtualTag / ScriptedAlarm rows alongside the existing Namespace /
+    ///     DriverInstance / Equipment / Tag / NodeAcl output. Admin DiffViewer now shows
+    ///     Phase 7 changes between generations.
+    /// </summary>
+    /// <remarks>
+    ///     Logical ids: ScriptId, VirtualTagId, ScriptedAlarmId — stable across generations
+    ///     so a Script whose source changes surfaces as Modified (CHECKSUM picks up the
+    ///     SourceHash delta) while a renamed script surfaces as Modified on Name alone.
+    ///     ScriptedAlarmState is deliberately excluded — it's not generation-scoped, so
+    ///     diffing it between generations is meaningless.
+    /// </remarks>
+    /// <inheritdoc />
+    public partial class ExtendComputeGenerationDiffWithPhase7 : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql(Procs.ComputeGenerationDiffV3);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql(Procs.ComputeGenerationDiffV2);
+        }
+
+        private static class Procs
+        {
+            /// <summary>V3 — adds Script / VirtualTag / ScriptedAlarm sections.</summary>
+            public const string ComputeGenerationDiffV3 = @"
+CREATE OR ALTER PROCEDURE dbo.sp_ComputeGenerationDiff
+    @FromGenerationId bigint,
+    @ToGenerationId   bigint
+AS
+BEGIN
+    SET NOCOUNT ON;
+
+    CREATE TABLE #diff (TableName nvarchar(32), LogicalId nvarchar(128), ChangeKind nvarchar(16));
+
+    WITH f AS (SELECT NamespaceId AS LogicalId, CHECKSUM(NamespaceUri, Kind, Enabled, Notes) AS Sig FROM dbo.Namespace WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT NamespaceId AS LogicalId, CHECKSUM(NamespaceUri, Kind, Enabled, Notes) AS Sig FROM dbo.Namespace WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Namespace', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (SELECT DriverInstanceId AS LogicalId, CHECKSUM(ClusterId, NamespaceId, Name, DriverType, Enabled, CONVERT(varchar(max), DriverConfig)) AS Sig FROM dbo.DriverInstance WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT DriverInstanceId AS LogicalId, CHECKSUM(ClusterId, NamespaceId, Name, DriverType, Enabled, CONVERT(varchar(max), DriverConfig)) AS Sig FROM dbo.DriverInstance WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'DriverInstance', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (SELECT EquipmentId AS LogicalId, CHECKSUM(EquipmentUuid, DriverInstanceId, UnsLineId, Name, MachineCode, ZTag, SAPID, EquipmentClassRef, Manufacturer, Model, SerialNumber) AS Sig FROM dbo.Equipment WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT EquipmentId AS LogicalId, CHECKSUM(EquipmentUuid, DriverInstanceId, UnsLineId, Name, MachineCode, ZTag, SAPID, EquipmentClassRef, Manufacturer, Model, SerialNumber) AS Sig FROM dbo.Equipment WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Equipment', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (SELECT TagId AS LogicalId, CHECKSUM(DriverInstanceId, DeviceId, EquipmentId, PollGroupId, FolderPath, Name, DataType, AccessLevel, WriteIdempotent, CONVERT(varchar(max), TagConfig)) AS Sig FROM dbo.Tag WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT TagId AS LogicalId, CHECKSUM(DriverInstanceId, DeviceId, EquipmentId, PollGroupId, FolderPath, Name, DataType, AccessLevel, WriteIdempotent, CONVERT(varchar(max), TagConfig)) AS Sig FROM dbo.Tag WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Tag', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (
+            SELECT  CONVERT(nvarchar(128), LdapGroup + '|' + CONVERT(nvarchar(16), ScopeKind) + '|' + ISNULL(ScopeId, '(cluster)')) AS LogicalId,
+                    CHECKSUM(ClusterId, PermissionFlags, Notes) AS Sig
+            FROM    dbo.NodeAcl WHERE GenerationId = @FromGenerationId),
+         t AS (
+            SELECT  CONVERT(nvarchar(128), LdapGroup + '|' + CONVERT(nvarchar(16), ScopeKind) + '|' + ISNULL(ScopeId, '(cluster)')) AS LogicalId,
+                    CHECKSUM(ClusterId, PermissionFlags, Notes) AS Sig
+            FROM    dbo.NodeAcl WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'NodeAcl', COALESCE(f.LogicalId, t.LogicalId),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    -- Phase 7 — Script section. CHECKSUM picks up source changes via SourceHash + rename
+    -- via Name; Language future-proofs for non-C# engines. Same Name + same Source =
+    -- Unchanged (identical hash).
+    WITH f AS (SELECT ScriptId AS LogicalId, CHECKSUM(Name, SourceHash, Language) AS Sig FROM dbo.Script WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT ScriptId AS LogicalId, CHECKSUM(Name, SourceHash, Language) AS Sig FROM dbo.Script WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Script', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    -- Phase 7 — VirtualTag section.
+    WITH f AS (SELECT VirtualTagId AS LogicalId, CHECKSUM(EquipmentId, Name, DataType, ScriptId, ChangeTriggered, TimerIntervalMs, Historize, Enabled) AS Sig FROM dbo.VirtualTag WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT VirtualTagId AS LogicalId, CHECKSUM(EquipmentId, Name, DataType, ScriptId, ChangeTriggered, TimerIntervalMs, Historize, Enabled) AS Sig FROM dbo.VirtualTag WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'VirtualTag', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    -- Phase 7 — ScriptedAlarm section. ScriptedAlarmState (operator ack trail) is
+    -- logical-id keyed outside the generation scope + intentionally excluded here —
+    -- diffing ack state between generations is semantically meaningless.
+    WITH f AS (SELECT ScriptedAlarmId AS LogicalId, CHECKSUM(EquipmentId, Name, AlarmType, Severity, MessageTemplate, PredicateScriptId, HistorizeToAveva, Retain, Enabled) AS Sig FROM dbo.ScriptedAlarm WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT ScriptedAlarmId AS LogicalId, CHECKSUM(EquipmentId, Name, AlarmType, Severity, MessageTemplate, PredicateScriptId, HistorizeToAveva, Retain, Enabled) AS Sig FROM dbo.ScriptedAlarm WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'ScriptedAlarm', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    SELECT TableName, LogicalId, ChangeKind FROM #diff;
+    DROP TABLE #diff;
+END
+";
+
+            /// <summary>V2 — restores the pre-Phase-7 proc on Down().</summary>
+            public const string ComputeGenerationDiffV2 = @"
+CREATE OR ALTER PROCEDURE dbo.sp_ComputeGenerationDiff
+    @FromGenerationId bigint,
+    @ToGenerationId   bigint
+AS
+BEGIN
+    SET NOCOUNT ON;
+
+    CREATE TABLE #diff (TableName nvarchar(32), LogicalId nvarchar(128), ChangeKind nvarchar(16));
+
+    WITH f AS (SELECT NamespaceId AS LogicalId, CHECKSUM(NamespaceUri, Kind, Enabled, Notes) AS Sig FROM dbo.Namespace WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT NamespaceId AS LogicalId, CHECKSUM(NamespaceUri, Kind, Enabled, Notes) AS Sig FROM dbo.Namespace WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Namespace', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (SELECT DriverInstanceId AS LogicalId, CHECKSUM(ClusterId, NamespaceId, Name, DriverType, Enabled, CONVERT(varchar(max), DriverConfig)) AS Sig FROM dbo.DriverInstance WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT DriverInstanceId AS LogicalId, CHECKSUM(ClusterId, NamespaceId, Name, DriverType, Enabled, CONVERT(varchar(max), DriverConfig)) AS Sig FROM dbo.DriverInstance WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'DriverInstance', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (SELECT EquipmentId AS LogicalId, CHECKSUM(EquipmentUuid, DriverInstanceId, UnsLineId, Name, MachineCode, ZTag, SAPID, EquipmentClassRef, Manufacturer, Model, SerialNumber) AS Sig FROM dbo.Equipment WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT EquipmentId AS LogicalId, CHECKSUM(EquipmentUuid, DriverInstanceId, UnsLineId, Name, MachineCode, ZTag, SAPID, EquipmentClassRef, Manufacturer, Model, SerialNumber) AS Sig FROM dbo.Equipment WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Equipment', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (SELECT TagId AS LogicalId, CHECKSUM(DriverInstanceId, DeviceId, EquipmentId, PollGroupId, FolderPath, Name, DataType, AccessLevel, WriteIdempotent, CONVERT(varchar(max), TagConfig)) AS Sig FROM dbo.Tag WHERE GenerationId = @FromGenerationId),
+         t AS (SELECT TagId AS LogicalId, CHECKSUM(DriverInstanceId, DeviceId, EquipmentId, PollGroupId, FolderPath, Name, DataType, AccessLevel, WriteIdempotent, CONVERT(varchar(max), TagConfig)) AS Sig FROM dbo.Tag WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'Tag', CONVERT(nvarchar(128), COALESCE(f.LogicalId, t.LogicalId)),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    WITH f AS (
+            SELECT  CONVERT(nvarchar(128), LdapGroup + '|' + CONVERT(nvarchar(16), ScopeKind) + '|' + ISNULL(ScopeId, '(cluster)')) AS LogicalId,
+                    CHECKSUM(ClusterId, PermissionFlags, Notes) AS Sig
+            FROM    dbo.NodeAcl WHERE GenerationId = @FromGenerationId),
+         t AS (
+            SELECT  CONVERT(nvarchar(128), LdapGroup + '|' + CONVERT(nvarchar(16), ScopeKind) + '|' + ISNULL(ScopeId, '(cluster)')) AS LogicalId,
+                    CHECKSUM(ClusterId, PermissionFlags, Notes) AS Sig
+            FROM    dbo.NodeAcl WHERE GenerationId = @ToGenerationId)
+    INSERT #diff
+    SELECT 'NodeAcl', COALESCE(f.LogicalId, t.LogicalId),
+           CASE WHEN f.LogicalId IS NULL THEN 'Added'
+                WHEN t.LogicalId IS NULL THEN 'Removed'
+                WHEN f.Sig <> t.Sig       THEN 'Modified'
+                ELSE 'Unchanged' END
+    FROM   f FULL OUTER JOIN t ON f.LogicalId = t.LogicalId
+    WHERE  f.LogicalId IS NULL OR t.LogicalId IS NULL OR f.Sig <> t.Sig;
+
+    SELECT TableName, LogicalId, ChangeKind FROM #diff;
+    DROP TABLE #diff;
+END
+";
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Configuration/Migrations/OtOpcUaConfigDbContextModelSnapshot.cs

@@ -1027,6 +1027,193 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
                         });
                 });
 
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.Script", b =>
+                {
+                    b.Property<Guid>("ScriptRowId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier")
+                        .HasDefaultValueSql("NEWSEQUENTIALID()");
+
+                    b.Property<long>("GenerationId")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Language")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("nvarchar(16)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<string>("ScriptId")
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<string>("SourceCode")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("SourceHash")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.HasKey("ScriptRowId");
+
+                    b.HasIndex("GenerationId", "ScriptId")
+                        .IsUnique()
+                        .HasDatabaseName("UX_Script_Generation_LogicalId")
+                        .HasFilter("[ScriptId] IS NOT NULL");
+
+                    b.HasIndex("GenerationId", "SourceHash")
+                        .HasDatabaseName("IX_Script_Generation_SourceHash");
+
+                    b.ToTable("Script", (string)null);
+                });
+
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ScriptedAlarm", b =>
+                {
+                    b.Property<Guid>("ScriptedAlarmRowId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier")
+                        .HasDefaultValueSql("NEWSEQUENTIALID()");
+
+                    b.Property<string>("AlarmType")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("nvarchar(32)");
+
+                    b.Property<bool>("Enabled")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("EquipmentId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<long>("GenerationId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("HistorizeToAveva")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("MessageTemplate")
+                        .IsRequired()
+                        .HasMaxLength(1024)
+                        .HasColumnType("nvarchar(1024)");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<string>("PredicateScriptId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<bool>("Retain")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("ScriptedAlarmId")
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<int>("Severity")
+                        .HasColumnType("int");
+
+                    b.HasKey("ScriptedAlarmRowId");
+
+                    b.HasIndex("GenerationId", "PredicateScriptId")
+                        .HasDatabaseName("IX_ScriptedAlarm_Generation_Script");
+
+                    b.HasIndex("GenerationId", "ScriptedAlarmId")
+                        .IsUnique()
+                        .HasDatabaseName("UX_ScriptedAlarm_Generation_LogicalId")
+                        .HasFilter("[ScriptedAlarmId] IS NOT NULL");
+
+                    b.HasIndex("GenerationId", "EquipmentId", "Name")
+                        .IsUnique()
+                        .HasDatabaseName("UX_ScriptedAlarm_Generation_EquipmentPath");
+
+                    b.ToTable("ScriptedAlarm", null, t =>
+                        {
+                            t.HasCheckConstraint("CK_ScriptedAlarm_AlarmType", "AlarmType IN ('AlarmCondition','LimitAlarm','OffNormalAlarm','DiscreteAlarm')");
+
+                            t.HasCheckConstraint("CK_ScriptedAlarm_Severity_Range", "Severity BETWEEN 1 AND 1000");
+                        });
+                });
+
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ScriptedAlarmState", b =>
+                {
+                    b.Property<string>("ScriptedAlarmId")
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<string>("AckedState")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("nvarchar(16)");
+
+                    b.Property<string>("CommentsJson")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<string>("ConfirmedState")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("nvarchar(16)");
+
+                    b.Property<string>("EnabledState")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("nvarchar(16)");
+
+                    b.Property<string>("LastAckComment")
+                        .HasMaxLength(1024)
+                        .HasColumnType("nvarchar(1024)");
+
+                    b.Property<string>("LastAckUser")
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<DateTime?>("LastAckUtc")
+                        .HasColumnType("datetime2(3)");
+
+                    b.Property<string>("LastConfirmComment")
+                        .HasMaxLength(1024)
+                        .HasColumnType("nvarchar(1024)");
+
+                    b.Property<string>("LastConfirmUser")
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<DateTime?>("LastConfirmUtc")
+                        .HasColumnType("datetime2(3)");
+
+                    b.Property<DateTime?>("ShelvingExpiresUtc")
+                        .HasColumnType("datetime2(3)");
+
+                    b.Property<string>("ShelvingState")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("nvarchar(16)");
+
+                    b.Property<DateTime>("UpdatedAtUtc")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("datetime2(3)")
+                        .HasDefaultValueSql("SYSUTCDATETIME()");
+
+                    b.HasKey("ScriptedAlarmId");
+
+                    b.ToTable("ScriptedAlarmState", null, t =>
+                        {
+                            t.HasCheckConstraint("CK_ScriptedAlarmState_CommentsJson_IsJson", "ISJSON(CommentsJson) = 1");
+                        });
+                });
+
             modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ServerCluster", b =>
                 {
                     b.Property<string>("ClusterId")
@@ -1274,6 +1461,74 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
                     b.ToTable("UnsLine", (string)null);
                 });
 
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.VirtualTag", b =>
+                {
+                    b.Property<Guid>("VirtualTagRowId")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier")
+                        .HasDefaultValueSql("NEWSEQUENTIALID()");
+
+                    b.Property<bool>("ChangeTriggered")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("DataType")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("nvarchar(32)");
+
+                    b.Property<bool>("Enabled")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("EquipmentId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<long>("GenerationId")
+                        .HasColumnType("bigint");
+
+                    b.Property<bool>("Historize")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<string>("ScriptId")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.Property<int?>("TimerIntervalMs")
+                        .HasColumnType("int");
+
+                    b.Property<string>("VirtualTagId")
+                        .HasMaxLength(64)
+                        .HasColumnType("nvarchar(64)");
+
+                    b.HasKey("VirtualTagRowId");
+
+                    b.HasIndex("GenerationId", "ScriptId")
+                        .HasDatabaseName("IX_VirtualTag_Generation_Script");
+
+                    b.HasIndex("GenerationId", "VirtualTagId")
+                        .IsUnique()
+                        .HasDatabaseName("UX_VirtualTag_Generation_LogicalId")
+                        .HasFilter("[VirtualTagId] IS NOT NULL");
+
+                    b.HasIndex("GenerationId", "EquipmentId", "Name")
+                        .IsUnique()
+                        .HasDatabaseName("UX_VirtualTag_Generation_EquipmentPath");
+
+                    b.ToTable("VirtualTag", null, t =>
+                        {
+                            t.HasCheckConstraint("CK_VirtualTag_TimerInterval_Min", "TimerIntervalMs IS NULL OR TimerIntervalMs >= 50");
+
+                            t.HasCheckConstraint("CK_VirtualTag_Trigger_AtLeastOne", "ChangeTriggered = 1 OR TimerIntervalMs IS NOT NULL");
+                        });
+                });
+
             modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ClusterNode", b =>
                 {
                     b.HasOne("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ServerCluster", "Cluster")
@@ -1435,6 +1690,28 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
                     b.Navigation("Generation");
                 });
 
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.Script", b =>
+                {
+                    b.HasOne("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ConfigGeneration", "Generation")
+                        .WithMany()
+                        .HasForeignKey("GenerationId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("Generation");
+                });
+
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ScriptedAlarm", b =>
+                {
+                    b.HasOne("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ConfigGeneration", "Generation")
+                        .WithMany()
+                        .HasForeignKey("GenerationId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("Generation");
+                });
+
             modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.Tag", b =>
                 {
                     b.HasOne("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ConfigGeneration", "Generation")
@@ -1476,6 +1753,17 @@ namespace ZB.MOM.WW.OtOpcUa.Configuration.Migrations
                     b.Navigation("Generation");
                 });
 
+            modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.VirtualTag", b =>
+                {
+                    b.HasOne("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ConfigGeneration", "Generation")
+                        .WithMany()
+                        .HasForeignKey("GenerationId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.Navigation("Generation");
+                });
+
             modelBuilder.Entity("ZB.MOM.WW.OtOpcUa.Configuration.Entities.ClusterNode", b =>
                 {
                     b.Navigation("Credentials");

src/ZB.MOM.WW.OtOpcUa.Configuration/OtOpcUaConfigDbContext.cs

@@ -32,6 +32,10 @@ public sealed class OtOpcUaConfigDbContext(DbContextOptions<OtOpcUaConfigDbConte
     public DbSet<LdapGroupRoleMapping> LdapGroupRoleMappings => Set<LdapGroupRoleMapping>();
     public DbSet<EquipmentImportBatch> EquipmentImportBatches => Set<EquipmentImportBatch>();
     public DbSet<EquipmentImportRow> EquipmentImportRows => Set<EquipmentImportRow>();
+    public DbSet<Script> Scripts => Set<Script>();
+    public DbSet<VirtualTag> VirtualTags => Set<VirtualTag>();
+    public DbSet<ScriptedAlarm> ScriptedAlarms => Set<ScriptedAlarm>();
+    public DbSet<ScriptedAlarmState> ScriptedAlarmStates => Set<ScriptedAlarmState>();
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
@@ -56,6 +60,10 @@ public sealed class OtOpcUaConfigDbContext(DbContextOptions<OtOpcUaConfigDbConte
         ConfigureDriverInstanceResilienceStatus(modelBuilder);
         ConfigureLdapGroupRoleMapping(modelBuilder);
         ConfigureEquipmentImportBatch(modelBuilder);
+        ConfigureScript(modelBuilder);
+        ConfigureVirtualTag(modelBuilder);
+        ConfigureScriptedAlarm(modelBuilder);
+        ConfigureScriptedAlarmState(modelBuilder);
     }
 
     private static void ConfigureServerCluster(ModelBuilder modelBuilder)
@@ -619,4 +627,106 @@ public sealed class OtOpcUaConfigDbContext(DbContextOptions<OtOpcUaConfigDbConte
             e.HasIndex(x => x.BatchId).HasDatabaseName("IX_EquipmentImportRow_Batch");
         });
     }
+
+    private static void ConfigureScript(ModelBuilder modelBuilder)
+    {
+        modelBuilder.Entity<Script>(e =>
+        {
+            e.ToTable("Script");
+            e.HasKey(x => x.ScriptRowId);
+            e.Property(x => x.ScriptRowId).HasDefaultValueSql("NEWSEQUENTIALID()");
+            e.Property(x => x.ScriptId).HasMaxLength(64);
+            e.Property(x => x.Name).HasMaxLength(128);
+            e.Property(x => x.SourceCode).HasColumnType("nvarchar(max)");
+            e.Property(x => x.SourceHash).HasMaxLength(64);
+            e.Property(x => x.Language).HasMaxLength(16);
+
+            e.HasOne(x => x.Generation).WithMany().HasForeignKey(x => x.GenerationId).OnDelete(DeleteBehavior.Restrict);
+
+            e.HasIndex(x => new { x.GenerationId, x.ScriptId }).IsUnique().HasDatabaseName("UX_Script_Generation_LogicalId");
+            e.HasIndex(x => new { x.GenerationId, x.SourceHash }).HasDatabaseName("IX_Script_Generation_SourceHash");
+        });
+    }
+
+    private static void ConfigureVirtualTag(ModelBuilder modelBuilder)
+    {
+        modelBuilder.Entity<VirtualTag>(e =>
+        {
+            e.ToTable("VirtualTag", t =>
+            {
+                t.HasCheckConstraint("CK_VirtualTag_Trigger_AtLeastOne",
+                    "ChangeTriggered = 1 OR TimerIntervalMs IS NOT NULL");
+                t.HasCheckConstraint("CK_VirtualTag_TimerInterval_Min",
+                    "TimerIntervalMs IS NULL OR TimerIntervalMs >= 50");
+            });
+            e.HasKey(x => x.VirtualTagRowId);
+            e.Property(x => x.VirtualTagRowId).HasDefaultValueSql("NEWSEQUENTIALID()");
+            e.Property(x => x.VirtualTagId).HasMaxLength(64);
+            e.Property(x => x.EquipmentId).HasMaxLength(64);
+            e.Property(x => x.Name).HasMaxLength(128);
+            e.Property(x => x.DataType).HasMaxLength(32);
+            e.Property(x => x.ScriptId).HasMaxLength(64);
+
+            e.HasOne(x => x.Generation).WithMany().HasForeignKey(x => x.GenerationId).OnDelete(DeleteBehavior.Restrict);
+
+            e.HasIndex(x => new { x.GenerationId, x.VirtualTagId }).IsUnique().HasDatabaseName("UX_VirtualTag_Generation_LogicalId");
+            e.HasIndex(x => new { x.GenerationId, x.EquipmentId, x.Name }).IsUnique().HasDatabaseName("UX_VirtualTag_Generation_EquipmentPath");
+            e.HasIndex(x => new { x.GenerationId, x.ScriptId }).HasDatabaseName("IX_VirtualTag_Generation_Script");
+        });
+    }
+
+    private static void ConfigureScriptedAlarm(ModelBuilder modelBuilder)
+    {
+        modelBuilder.Entity<ScriptedAlarm>(e =>
+        {
+            e.ToTable("ScriptedAlarm", t =>
+            {
+                t.HasCheckConstraint("CK_ScriptedAlarm_Severity_Range", "Severity BETWEEN 1 AND 1000");
+                t.HasCheckConstraint("CK_ScriptedAlarm_AlarmType",
+                    "AlarmType IN ('AlarmCondition','LimitAlarm','OffNormalAlarm','DiscreteAlarm')");
+            });
+            e.HasKey(x => x.ScriptedAlarmRowId);
+            e.Property(x => x.ScriptedAlarmRowId).HasDefaultValueSql("NEWSEQUENTIALID()");
+            e.Property(x => x.ScriptedAlarmId).HasMaxLength(64);
+            e.Property(x => x.EquipmentId).HasMaxLength(64);
+            e.Property(x => x.Name).HasMaxLength(128);
+            e.Property(x => x.AlarmType).HasMaxLength(32);
+            e.Property(x => x.MessageTemplate).HasMaxLength(1024);
+            e.Property(x => x.PredicateScriptId).HasMaxLength(64);
+
+            e.HasOne(x => x.Generation).WithMany().HasForeignKey(x => x.GenerationId).OnDelete(DeleteBehavior.Restrict);
+
+            e.HasIndex(x => new { x.GenerationId, x.ScriptedAlarmId }).IsUnique().HasDatabaseName("UX_ScriptedAlarm_Generation_LogicalId");
+            e.HasIndex(x => new { x.GenerationId, x.EquipmentId, x.Name }).IsUnique().HasDatabaseName("UX_ScriptedAlarm_Generation_EquipmentPath");
+            e.HasIndex(x => new { x.GenerationId, x.PredicateScriptId }).HasDatabaseName("IX_ScriptedAlarm_Generation_Script");
+        });
+    }
+
+    private static void ConfigureScriptedAlarmState(ModelBuilder modelBuilder)
+    {
+        modelBuilder.Entity<ScriptedAlarmState>(e =>
+        {
+            // Logical-id keyed (not generation-scoped) because ack state follows the alarm's
+            // stable identity across generations — Modified alarms keep their ack audit trail.
+            e.ToTable("ScriptedAlarmState", t =>
+            {
+                t.HasCheckConstraint("CK_ScriptedAlarmState_CommentsJson_IsJson", "ISJSON(CommentsJson) = 1");
+            });
+            e.HasKey(x => x.ScriptedAlarmId);
+            e.Property(x => x.ScriptedAlarmId).HasMaxLength(64);
+            e.Property(x => x.EnabledState).HasMaxLength(16);
+            e.Property(x => x.AckedState).HasMaxLength(16);
+            e.Property(x => x.ConfirmedState).HasMaxLength(16);
+            e.Property(x => x.ShelvingState).HasMaxLength(16);
+            e.Property(x => x.ShelvingExpiresUtc).HasColumnType("datetime2(3)");
+            e.Property(x => x.LastAckUser).HasMaxLength(128);
+            e.Property(x => x.LastAckComment).HasMaxLength(1024);
+            e.Property(x => x.LastAckUtc).HasColumnType("datetime2(3)");
+            e.Property(x => x.LastConfirmUser).HasMaxLength(128);
+            e.Property(x => x.LastConfirmComment).HasMaxLength(1024);
+            e.Property(x => x.LastConfirmUtc).HasColumnType("datetime2(3)");
+            e.Property(x => x.CommentsJson).HasColumnType("nvarchar(max)");
+            e.Property(x => x.UpdatedAtUtc).HasColumnType("datetime2(3)").HasDefaultValueSql("SYSUTCDATETIME()");
+        });
+    }
 }

src/ZB.MOM.WW.OtOpcUa.Core.Abstractions/DriverAttributeInfo.cs

@@ -33,6 +33,18 @@ namespace ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 ///     (holding registers with level-set values, set-point writes to analog tags) — the
 ///     capability invoker respects this flag when deciding whether to apply Polly retry.
 /// </param>
+/// <param name="Source">
+///     Per ADR-002 — discriminates which runtime subsystem owns this node's dispatch.
+///     Defaults to <see cref="NodeSourceKind.Driver"/> so existing callers are unchanged.
+/// </param>
+/// <param name="VirtualTagId">
+///     Set when <paramref name="Source"/> is <see cref="NodeSourceKind.Virtual"/> — stable
+///     logical id the VirtualTagEngine addresses by. Null otherwise.
+/// </param>
+/// <param name="ScriptedAlarmId">
+///     Set when <paramref name="Source"/> is <see cref="NodeSourceKind.ScriptedAlarm"/> —
+///     stable logical id the ScriptedAlarmEngine addresses by. Null otherwise.
+/// </param>
 public sealed record DriverAttributeInfo(
     string FullName,
     DriverDataType DriverDataType,
@@ -41,4 +53,21 @@ public sealed record DriverAttributeInfo(
     SecurityClassification SecurityClass,
     bool IsHistorized,
     bool IsAlarm = false,
-    bool WriteIdempotent = false);
+    bool WriteIdempotent = false,
+    NodeSourceKind Source = NodeSourceKind.Driver,
+    string? VirtualTagId = null,
+    string? ScriptedAlarmId = null);
+
+/// <summary>
+///     Per ADR-002 — discriminates which runtime subsystem owns this node's Read/Write/
+///     Subscribe dispatch. <c>Driver</c> = a real IDriver capability surface;
+///     <c>Virtual</c> = a Phase 7 <see cref="DriverAttributeInfo"/>.VirtualTagId'd tag
+///     computed by the VirtualTagEngine; <c>ScriptedAlarm</c> = a scripted Part 9 alarm
+///     materialized by the ScriptedAlarmEngine.
+/// </summary>
+public enum NodeSourceKind
+{
+    Driver = 0,
+    Virtual = 1,
+    ScriptedAlarm = 2,
+}

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/AlarmHistorianEvent.cs

@@ -0,0 +1,36 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+/// <summary>
+///     The event shape the historian sink consumes — source-agnostic across scripted
+///     alarms + Galaxy-native + AB CIP ALMD + any future IAlarmSource per Phase 7 plan
+///     decision #15 (sink scope = all alarm sources, not just scripted). A per-alarm
+///     <c>HistorizeToAveva</c> toggle on the producer side gates which events flow.
+/// </summary>
+/// <param name="AlarmId">Stable condition identity.</param>
+/// <param name="EquipmentPath">UNS path of the Equipment node the alarm hangs under. Doubles as the "SourceNode" in Historian's alarm schema.</param>
+/// <param name="AlarmName">Human-readable alarm name.</param>
+/// <param name="AlarmTypeName">Concrete Part 9 subtype — "LimitAlarm" / "DiscreteAlarm" / "OffNormalAlarm" / "AlarmCondition". Used as the Historian "AlarmType" column.</param>
+/// <param name="Severity">Mapped to Historian's numeric priority on the sink side.</param>
+/// <param name="EventKind">
+///     Which state transition this event represents — "Activated" / "Cleared" /
+///     "Acknowledged" / "Confirmed" / "Shelved" / "Unshelved" / "Disabled" / "Enabled" /
+///     "CommentAdded". Free-form string because different alarm sources use different
+///     vocabularies; the Galaxy.Host handler maps to the historian's enum on the wire.
+/// </param>
+/// <param name="Message">Fully-rendered message text — template tokens already resolved upstream.</param>
+/// <param name="User">Operator who triggered the transition. "system" for engine-driven events (shelving expiry, predicate change).</param>
+/// <param name="Comment">Operator-supplied free-form text, if any.</param>
+/// <param name="TimestampUtc">When the transition occurred.</param>
+public sealed record AlarmHistorianEvent(
+    string AlarmId,
+    string EquipmentPath,
+    string AlarmName,
+    string AlarmTypeName,
+    AlarmSeverity Severity,
+    string EventKind,
+    string Message,
+    string User,
+    string? Comment,
+    DateTime TimestampUtc);

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/IAlarmHistorianSink.cs

@@ -0,0 +1,82 @@
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+/// <summary>
+///     The historian sink contract — where qualifying alarm events land. Phase 7 plan
+///     decision #17: ingestion routes through Galaxy.Host's pipe so we reuse the
+///     already-loaded <c>aahClientManaged</c> DLLs without loading 32-bit native code
+///     in the main .NET 10 server. Tests use an in-memory fake; production uses
+///     <see cref="SqliteStoreAndForwardSink"/>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <see cref="EnqueueAsync"/> is fire-and-forget from the engine's perspective —
+///         the sink MUST NOT block the emitting thread. Production implementations
+///         (<see cref="SqliteStoreAndForwardSink"/>) persist to a local SQLite queue
+///         first, then drain asynchronously to the actual historian. Per Phase 7 plan
+///         decision #16, failed downstream writes replay with exponential backoff;
+///         operator actions are never blocked waiting on the historian.
+///     </para>
+///     <para>
+///         <see cref="GetStatus"/> exposes queue depth + drain rate + last error
+///         for the Admin UI <c>/alarms/historian</c> diagnostics page (Stream F).
+///     </para>
+/// </remarks>
+public interface IAlarmHistorianSink
+{
+    /// <summary>Durably enqueue the event. Returns as soon as the queue row is committed.</summary>
+    Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken);
+
+    /// <summary>Snapshot of current queue depth + drain health.</summary>
+    HistorianSinkStatus GetStatus();
+}
+
+/// <summary>No-op default for tests or deployments that don't historize alarms.</summary>
+public sealed class NullAlarmHistorianSink : IAlarmHistorianSink
+{
+    public static readonly NullAlarmHistorianSink Instance = new();
+    public Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken) => Task.CompletedTask;
+    public HistorianSinkStatus GetStatus() => new(
+        QueueDepth: 0,
+        DeadLetterDepth: 0,
+        LastDrainUtc: null,
+        LastSuccessUtc: null,
+        LastError: null,
+        DrainState: HistorianDrainState.Disabled);
+}
+
+/// <summary>Diagnostic snapshot surfaced to the Admin UI + /healthz endpoints.</summary>
+public sealed record HistorianSinkStatus(
+    long QueueDepth,
+    long DeadLetterDepth,
+    DateTime? LastDrainUtc,
+    DateTime? LastSuccessUtc,
+    string? LastError,
+    HistorianDrainState DrainState);
+
+/// <summary>Where the drain worker is in its state machine.</summary>
+public enum HistorianDrainState
+{
+    Disabled,
+    Idle,
+    Draining,
+    BackingOff,
+}
+
+/// <summary>Signaled by the Galaxy.Host-side handler when it fails a batch — drain worker uses this to decide retry cadence.</summary>
+public enum HistorianWriteOutcome
+{
+    /// <summary>Successfully persisted to the historian. Remove from queue.</summary>
+    Ack,
+    /// <summary>Transient failure (historian disconnected, timeout, busy). Leave queued; retry after backoff.</summary>
+    RetryPlease,
+    /// <summary>Permanent failure (malformed event, unrecoverable SDK error). Move to dead-letter table.</summary>
+    PermanentFail,
+}
+
+/// <summary>What the drain worker delegates writes to — Stream G wires this to the Galaxy.Host IPC client.</summary>
+public interface IAlarmHistorianWriter
+{
+    /// <summary>Push a batch of events to the historian. Returns one outcome per event, same order.</summary>
+    Task<IReadOnlyList<HistorianWriteOutcome>> WriteBatchAsync(
+        IReadOnlyList<AlarmHistorianEvent> batch, CancellationToken cancellationToken);
+}

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/SqliteStoreAndForwardSink.cs

@@ -0,0 +1,397 @@
+using System.Text.Json;
+using Microsoft.Data.Sqlite;
+using Serilog;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+/// <summary>
+///     Phase 7 plan decisions #16–#17 implementation: durable SQLite queue on the node
+///     absorbs every qualifying alarm event, a drain worker batches rows to Galaxy.Host
+///     via <see cref="IAlarmHistorianWriter"/> on an exponential-backoff cadence, and
+///     operator acks never block on the historian being reachable.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Queue schema:
+///         <code>
+///         CREATE TABLE Queue (
+///             RowId INTEGER PRIMARY KEY AUTOINCREMENT,
+///             AlarmId TEXT NOT NULL,
+///             EnqueuedUtc TEXT NOT NULL,
+///             PayloadJson TEXT NOT NULL,
+///             AttemptCount INTEGER NOT NULL DEFAULT 0,
+///             LastAttemptUtc TEXT NULL,
+///             LastError TEXT NULL,
+///             DeadLettered INTEGER NOT NULL DEFAULT 0
+///         );
+///         </code>
+///         Dead-lettered rows stay in place for the configured retention window (default
+///         30 days per Phase 7 plan decision #21) so operators can inspect + manually
+///         retry before the sweeper purges them. Regular queue capacity is bounded —
+///         overflow evicts the oldest non-dead-lettered rows with a WARN log.
+///     </para>
+///     <para>
+///         Drain runs on a shared <see cref="System.Threading.Timer"/>. Exponential
+///         backoff on <see cref="HistorianWriteOutcome.RetryPlease"/>: 1s → 2s → 5s →
+///         15s → 60s cap. <see cref="HistorianWriteOutcome.PermanentFail"/> rows flip
+///         the <c>DeadLettered</c> flag on the individual row; neighbors in the batch
+///         still retry on their own cadence.
+///     </para>
+/// </remarks>
+public sealed class SqliteStoreAndForwardSink : IAlarmHistorianSink, IDisposable
+{
+    /// <summary>Default queue capacity — oldest non-dead-lettered rows evicted past this.</summary>
+    public const long DefaultCapacity = 1_000_000;
+    public static readonly TimeSpan DefaultDeadLetterRetention = TimeSpan.FromDays(30);
+
+    private static readonly TimeSpan[] BackoffLadder =
+    [
+        TimeSpan.FromSeconds(1),
+        TimeSpan.FromSeconds(2),
+        TimeSpan.FromSeconds(5),
+        TimeSpan.FromSeconds(15),
+        TimeSpan.FromSeconds(60),
+    ];
+
+    private readonly string _connectionString;
+    private readonly IAlarmHistorianWriter _writer;
+    private readonly ILogger _logger;
+    private readonly int _batchSize;
+    private readonly long _capacity;
+    private readonly TimeSpan _deadLetterRetention;
+    private readonly Func<DateTime> _clock;
+
+    private readonly SemaphoreSlim _drainGate = new(1, 1);
+    private Timer? _drainTimer;
+    private int _backoffIndex;
+    private DateTime? _lastDrainUtc;
+    private DateTime? _lastSuccessUtc;
+    private string? _lastError;
+    private HistorianDrainState _drainState = HistorianDrainState.Idle;
+    private bool _disposed;
+
+    public SqliteStoreAndForwardSink(
+        string databasePath,
+        IAlarmHistorianWriter writer,
+        ILogger logger,
+        int batchSize = 100,
+        long capacity = DefaultCapacity,
+        TimeSpan? deadLetterRetention = null,
+        Func<DateTime>? clock = null)
+    {
+        if (string.IsNullOrWhiteSpace(databasePath))
+            throw new ArgumentException("Database path required.", nameof(databasePath));
+        _writer = writer ?? throw new ArgumentNullException(nameof(writer));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+        _batchSize = batchSize > 0 ? batchSize : throw new ArgumentOutOfRangeException(nameof(batchSize));
+        _capacity = capacity > 0 ? capacity : throw new ArgumentOutOfRangeException(nameof(capacity));
+        _deadLetterRetention = deadLetterRetention ?? DefaultDeadLetterRetention;
+        _clock = clock ?? (() => DateTime.UtcNow);
+        _connectionString = $"Data Source={databasePath}";
+
+        InitializeSchema();
+    }
+
+    /// <summary>
+    ///     Start the background drain worker. Not started automatically so tests can
+    ///     drive <see cref="DrainOnceAsync"/> deterministically.
+    /// </summary>
+    public void StartDrainLoop(TimeSpan tickInterval)
+    {
+        if (_disposed) throw new ObjectDisposedException(nameof(SqliteStoreAndForwardSink));
+        _drainTimer?.Dispose();
+        _drainTimer = new Timer(_ => _ = DrainOnceAsync(CancellationToken.None),
+            null, tickInterval, tickInterval);
+    }
+
+    public Task EnqueueAsync(AlarmHistorianEvent evt, CancellationToken cancellationToken)
+    {
+        if (evt is null) throw new ArgumentNullException(nameof(evt));
+        if (_disposed) throw new ObjectDisposedException(nameof(SqliteStoreAndForwardSink));
+
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+
+        EnforceCapacity(conn);
+
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            INSERT INTO Queue (AlarmId, EnqueuedUtc, PayloadJson, AttemptCount)
+            VALUES ($alarmId, $enqueued, $payload, 0);
+            """;
+        cmd.Parameters.AddWithValue("$alarmId", evt.AlarmId);
+        cmd.Parameters.AddWithValue("$enqueued", _clock().ToString("O"));
+        cmd.Parameters.AddWithValue("$payload", JsonSerializer.Serialize(evt));
+        cmd.ExecuteNonQuery();
+        return Task.CompletedTask;
+    }
+
+    /// <summary>
+    ///     Read up to <see cref="_batchSize"/> queued rows, forward through the writer,
+    ///     remove Ack'd rows, dead-letter PermanentFail rows, and extend the backoff
+    ///     on RetryPlease. Safe to call from multiple threads; the semaphore enforces
+    ///     serial execution.
+    /// </summary>
+    public async Task DrainOnceAsync(CancellationToken ct)
+    {
+        if (_disposed) return;
+        if (!await _drainGate.WaitAsync(0, ct).ConfigureAwait(false)) return;
+        try
+        {
+            _drainState = HistorianDrainState.Draining;
+            _lastDrainUtc = _clock();
+
+            PurgeAgedDeadLetters();
+            var (rowIds, events) = ReadBatch();
+            if (rowIds.Count == 0)
+            {
+                _drainState = HistorianDrainState.Idle;
+                return;
+            }
+
+            IReadOnlyList<HistorianWriteOutcome> outcomes;
+            try
+            {
+                outcomes = await _writer.WriteBatchAsync(events, ct).ConfigureAwait(false);
+                _lastError = null;
+            }
+            catch (OperationCanceledException)
+            {
+                throw;
+            }
+            catch (Exception ex)
+            {
+                // Writer-side exception — treat entire batch as RetryPlease.
+                _lastError = ex.Message;
+                _logger.Warning(ex, "Historian writer threw on batch of {Count}; deferring retry", events.Count);
+                BumpBackoff();
+                _drainState = HistorianDrainState.BackingOff;
+                return;
+            }
+
+            if (outcomes.Count != events.Count)
+                throw new InvalidOperationException(
+                    $"Writer returned {outcomes.Count} outcomes for {events.Count} events — expected 1:1");
+
+            using var conn = new SqliteConnection(_connectionString);
+            conn.Open();
+            using var tx = conn.BeginTransaction();
+            for (var i = 0; i < outcomes.Count; i++)
+            {
+                var outcome = outcomes[i];
+                var rowId = rowIds[i];
+                switch (outcome)
+                {
+                    case HistorianWriteOutcome.Ack:
+                        DeleteRow(conn, tx, rowId);
+                        break;
+                    case HistorianWriteOutcome.PermanentFail:
+                        DeadLetterRow(conn, tx, rowId, $"permanent fail at {_clock():O}");
+                        break;
+                    case HistorianWriteOutcome.RetryPlease:
+                        BumpAttempt(conn, tx, rowId, "retry-please");
+                        break;
+                }
+            }
+            tx.Commit();
+
+            var acks = outcomes.Count(o => o == HistorianWriteOutcome.Ack);
+            if (acks > 0) _lastSuccessUtc = _clock();
+
+            if (outcomes.Any(o => o == HistorianWriteOutcome.RetryPlease))
+            {
+                BumpBackoff();
+                _drainState = HistorianDrainState.BackingOff;
+            }
+            else
+            {
+                ResetBackoff();
+                _drainState = HistorianDrainState.Idle;
+            }
+        }
+        finally
+        {
+            _drainGate.Release();
+        }
+    }
+
+    public HistorianSinkStatus GetStatus()
+    {
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+
+        long queued;
+        long deadlettered;
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = "SELECT COUNT(*) FROM Queue WHERE DeadLettered = 0";
+            queued = (long)(cmd.ExecuteScalar() ?? 0L);
+        }
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = "SELECT COUNT(*) FROM Queue WHERE DeadLettered = 1";
+            deadlettered = (long)(cmd.ExecuteScalar() ?? 0L);
+        }
+
+        return new HistorianSinkStatus(
+            QueueDepth: queued,
+            DeadLetterDepth: deadlettered,
+            LastDrainUtc: _lastDrainUtc,
+            LastSuccessUtc: _lastSuccessUtc,
+            LastError: _lastError,
+            DrainState: _drainState);
+    }
+
+    /// <summary>Operator action from Admin UI — retry every dead-lettered row. Non-cascading: they rejoin the regular queue + get a fresh backoff.</summary>
+    public int RetryDeadLettered()
+    {
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE Queue SET DeadLettered = 0, AttemptCount = 0, LastError = NULL WHERE DeadLettered = 1";
+        return cmd.ExecuteNonQuery();
+    }
+
+    private (List<long> rowIds, List<AlarmHistorianEvent> events) ReadBatch()
+    {
+        var rowIds = new List<long>();
+        var events = new List<AlarmHistorianEvent>();
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            SELECT RowId, PayloadJson FROM Queue
+            WHERE DeadLettered = 0
+            ORDER BY RowId ASC
+            LIMIT $limit
+            """;
+        cmd.Parameters.AddWithValue("$limit", _batchSize);
+        using var reader = cmd.ExecuteReader();
+        while (reader.Read())
+        {
+            rowIds.Add(reader.GetInt64(0));
+            var payload = reader.GetString(1);
+            var evt = JsonSerializer.Deserialize<AlarmHistorianEvent>(payload);
+            if (evt is not null) events.Add(evt);
+        }
+        return (rowIds, events);
+    }
+
+    private static void DeleteRow(SqliteConnection conn, SqliteTransaction tx, long rowId)
+    {
+        using var cmd = conn.CreateCommand();
+        cmd.Transaction = tx;
+        cmd.CommandText = "DELETE FROM Queue WHERE RowId = $id";
+        cmd.Parameters.AddWithValue("$id", rowId);
+        cmd.ExecuteNonQuery();
+    }
+
+    private void DeadLetterRow(SqliteConnection conn, SqliteTransaction tx, long rowId, string reason)
+    {
+        using var cmd = conn.CreateCommand();
+        cmd.Transaction = tx;
+        cmd.CommandText = """
+            UPDATE Queue SET DeadLettered = 1, LastAttemptUtc = $now, LastError = $err, AttemptCount = AttemptCount + 1
+            WHERE RowId = $id
+            """;
+        cmd.Parameters.AddWithValue("$now", _clock().ToString("O"));
+        cmd.Parameters.AddWithValue("$err", reason);
+        cmd.Parameters.AddWithValue("$id", rowId);
+        cmd.ExecuteNonQuery();
+    }
+
+    private void BumpAttempt(SqliteConnection conn, SqliteTransaction tx, long rowId, string reason)
+    {
+        using var cmd = conn.CreateCommand();
+        cmd.Transaction = tx;
+        cmd.CommandText = """
+            UPDATE Queue SET LastAttemptUtc = $now, LastError = $err, AttemptCount = AttemptCount + 1
+            WHERE RowId = $id
+            """;
+        cmd.Parameters.AddWithValue("$now", _clock().ToString("O"));
+        cmd.Parameters.AddWithValue("$err", reason);
+        cmd.Parameters.AddWithValue("$id", rowId);
+        cmd.ExecuteNonQuery();
+    }
+
+    private void EnforceCapacity(SqliteConnection conn)
+    {
+        // Count non-dead-lettered rows only — dead-lettered rows retain for
+        // post-mortem per the configured retention window.
+        long count;
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = "SELECT COUNT(*) FROM Queue WHERE DeadLettered = 0";
+            count = (long)(cmd.ExecuteScalar() ?? 0L);
+        }
+        if (count < _capacity) return;
+
+        var toEvict = count - _capacity + 1;
+        using (var cmd = conn.CreateCommand())
+        {
+            cmd.CommandText = """
+                DELETE FROM Queue
+                WHERE RowId IN (
+                    SELECT RowId FROM Queue
+                    WHERE DeadLettered = 0
+                    ORDER BY RowId ASC
+                    LIMIT $n
+                )
+                """;
+            cmd.Parameters.AddWithValue("$n", toEvict);
+            cmd.ExecuteNonQuery();
+        }
+        _logger.Warning(
+            "Historian queue at capacity {Cap} — evicted {Count} oldest row(s) to make room",
+            _capacity, toEvict);
+    }
+
+    private void PurgeAgedDeadLetters()
+    {
+        var cutoff = (_clock() - _deadLetterRetention).ToString("O");
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            DELETE FROM Queue
+            WHERE DeadLettered = 1 AND LastAttemptUtc IS NOT NULL AND LastAttemptUtc < $cutoff
+            """;
+        cmd.Parameters.AddWithValue("$cutoff", cutoff);
+        var purged = cmd.ExecuteNonQuery();
+        if (purged > 0)
+            _logger.Information("Purged {Count} dead-lettered row(s) past retention window", purged);
+    }
+
+    private void InitializeSchema()
+    {
+        using var conn = new SqliteConnection(_connectionString);
+        conn.Open();
+        using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            CREATE TABLE IF NOT EXISTS Queue (
+                RowId INTEGER PRIMARY KEY AUTOINCREMENT,
+                AlarmId TEXT NOT NULL,
+                EnqueuedUtc TEXT NOT NULL,
+                PayloadJson TEXT NOT NULL,
+                AttemptCount INTEGER NOT NULL DEFAULT 0,
+                LastAttemptUtc TEXT NULL,
+                LastError TEXT NULL,
+                DeadLettered INTEGER NOT NULL DEFAULT 0
+            );
+            CREATE INDEX IF NOT EXISTS IX_Queue_Drain ON Queue (DeadLettered, RowId);
+            """;
+        cmd.ExecuteNonQuery();
+    }
+
+    private void BumpBackoff() => _backoffIndex = Math.Min(_backoffIndex + 1, BackoffLadder.Length - 1);
+    private void ResetBackoff() => _backoffIndex = 0;
+    public TimeSpan CurrentBackoff => BackoffLadder[_backoffIndex];
+
+    public void Dispose()
+    {
+        if (_disposed) return;
+        _disposed = true;
+        _drainTimer?.Dispose();
+        _drainGate.Dispose();
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <LangVersion>latest</LangVersion>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+        <GenerateDocumentationFile>true</GenerateDocumentationFile>
+        <NoWarn>$(NoWarn);CS1591</NoWarn>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.Data.Sqlite" Version="9.0.0"/>
+        <PackageReference Include="Serilog" Version="4.2.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <InternalsVisibleTo Include="ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-37gx-xxp4-5rgx"/>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-w3x6-4m5h-cxqf"/>
+    </ItemGroup>
+
+</Project>

src/ZB.MOM.WW.OtOpcUa.Core/OpcUa/EquipmentNodeWalker.cs

@@ -87,6 +87,16 @@ public static class EquipmentNodeWalker
             .GroupBy(t => t.EquipmentId!, StringComparer.OrdinalIgnoreCase)
             .ToDictionary(g => g.Key, g => g.OrderBy(t => t.Name, StringComparer.Ordinal).ToList(), StringComparer.OrdinalIgnoreCase);
 
+        var virtualTagsByEquipment = (content.VirtualTags ?? [])
+            .Where(v => v.Enabled)
+            .GroupBy(v => v.EquipmentId, StringComparer.OrdinalIgnoreCase)
+            .ToDictionary(g => g.Key, g => g.OrderBy(v => v.Name, StringComparer.Ordinal).ToList(), StringComparer.OrdinalIgnoreCase);
+
+        var scriptedAlarmsByEquipment = (content.ScriptedAlarms ?? [])
+            .Where(a => a.Enabled)
+            .GroupBy(a => a.EquipmentId, StringComparer.OrdinalIgnoreCase)
+            .ToDictionary(g => g.Key, g => g.OrderBy(a => a.Name, StringComparer.Ordinal).ToList(), StringComparer.OrdinalIgnoreCase);
+
         foreach (var area in content.Areas.OrderBy(a => a.Name, StringComparer.Ordinal))
         {
             var areaBuilder = namespaceBuilder.Folder(area.Name, area.Name);
@@ -103,9 +113,17 @@ public static class EquipmentNodeWalker
                     AddIdentifierProperties(equipmentBuilder, equipment);
                     IdentificationFolderBuilder.Build(equipmentBuilder, equipment);
 
-                    if (!tagsByEquipment.TryGetValue(equipment.EquipmentId, out var equipmentTags)) continue;
-                    foreach (var tag in equipmentTags)
-                        AddTagVariable(equipmentBuilder, tag);
+                    if (tagsByEquipment.TryGetValue(equipment.EquipmentId, out var equipmentTags))
+                        foreach (var tag in equipmentTags)
+                            AddTagVariable(equipmentBuilder, tag);
+
+                    if (virtualTagsByEquipment.TryGetValue(equipment.EquipmentId, out var vTags))
+                        foreach (var vtag in vTags)
+                            AddVirtualTagVariable(equipmentBuilder, vtag);
+
+                    if (scriptedAlarmsByEquipment.TryGetValue(equipment.EquipmentId, out var alarms))
+                        foreach (var alarm in alarms)
+                            AddScriptedAlarmVariable(equipmentBuilder, alarm);
                 }
             }
         }
@@ -157,6 +175,55 @@ public static class EquipmentNodeWalker
     /// </summary>
     private static DriverDataType ParseDriverDataType(string raw) =>
         Enum.TryParse<DriverDataType>(raw, ignoreCase: true, out var parsed) ? parsed : DriverDataType.String;
+
+    /// <summary>
+    ///     Emit a <see cref="VirtualTag"/> row as a <see cref="NodeSourceKind.Virtual"/>
+    ///     variable node. <c>FullName</c> doubles as the UNS path Phase 7's VirtualTagEngine
+    ///     addresses its engine-side entries by. The <c>VirtualTagId</c> discriminator lets
+    ///     the DriverNodeManager dispatch Reads/Subscribes to the engine rather than any
+    ///     driver.
+    /// </summary>
+    private static void AddVirtualTagVariable(IAddressSpaceBuilder equipmentBuilder, VirtualTag vtag)
+    {
+        var attr = new DriverAttributeInfo(
+            FullName: vtag.VirtualTagId,
+            DriverDataType: ParseDriverDataType(vtag.DataType),
+            IsArray: false,
+            ArrayDim: null,
+            SecurityClass: SecurityClassification.FreeAccess,
+            IsHistorized: vtag.Historize,
+            IsAlarm: false,
+            WriteIdempotent: false,
+            Source: NodeSourceKind.Virtual,
+            VirtualTagId: vtag.VirtualTagId,
+            ScriptedAlarmId: null);
+        equipmentBuilder.Variable(vtag.Name, vtag.Name, attr);
+    }
+
+    /// <summary>
+    ///     Emit a <see cref="ScriptedAlarm"/> row as a <see cref="NodeSourceKind.ScriptedAlarm"/>
+    ///     variable node. The OPC UA Part 9 alarm-condition materialization happens at the
+    ///     node-manager level (which wires the concrete <c>AlarmConditionState</c> subclass
+    ///     per <see cref="ScriptedAlarm.AlarmType"/>); this walker provides the browse-level
+    ///     anchor + the <see cref="DriverAttributeInfo.IsAlarm"/> flag that triggers that
+    ///     materialization path.
+    /// </summary>
+    private static void AddScriptedAlarmVariable(IAddressSpaceBuilder equipmentBuilder, ScriptedAlarm alarm)
+    {
+        var attr = new DriverAttributeInfo(
+            FullName: alarm.ScriptedAlarmId,
+            DriverDataType: DriverDataType.Boolean,
+            IsArray: false,
+            ArrayDim: null,
+            SecurityClass: SecurityClassification.FreeAccess,
+            IsHistorized: false,
+            IsAlarm: true,
+            WriteIdempotent: false,
+            Source: NodeSourceKind.ScriptedAlarm,
+            VirtualTagId: null,
+            ScriptedAlarmId: alarm.ScriptedAlarmId);
+        equipmentBuilder.Variable(alarm.Name, alarm.Name, attr);
+    }
 }
 
 /// <summary>
@@ -170,4 +237,6 @@ public sealed record EquipmentNamespaceContent(
     IReadOnlyList<UnsArea> Areas,
     IReadOnlyList<UnsLine> Lines,
     IReadOnlyList<Equipment> Equipment,
-    IReadOnlyList<Tag> Tags);
+    IReadOnlyList<Tag> Tags,
+    IReadOnlyList<VirtualTag>? VirtualTags = null,
+    IReadOnlyList<ScriptedAlarm>? ScriptedAlarms = null);

src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/Contracts/Framing.cs

@@ -60,6 +60,14 @@ public enum MessageKind : byte
     HostConnectivityStatus     = 0x70,
     RuntimeStatusChange        = 0x71,
 
+    // Phase 7 Stream D — historian alarm sink. Main server → Galaxy.Host batched
+    // writes into the Aveva Historian alarm schema via the already-loaded
+    // aahClientManaged DLLs. HistorianConnectivityStatus fires proactively from the
+    // Host when the SDK session transitions so diagnostics flip promptly.
+    HistorianAlarmEventRequest        = 0x80,
+    HistorianAlarmEventResponse       = 0x81,
+    HistorianConnectivityStatus       = 0x82,
+
     RecycleHostRequest         = 0xF0,
     RecycleStatusResponse      = 0xF1,
 

src/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared/Contracts/HistorianAlarms.cs

@@ -0,0 +1,92 @@
+using System;
+using MessagePack;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Shared.Contracts;
+
+/// <summary>
+///     Phase 7 Stream D — IPC contracts for routing Part 9 alarm transitions from the
+///     main .NET 10 server into Galaxy.Host's already-loaded <c>aahClientManaged</c>
+///     DLLs. Reuses the Tier-C isolation + licensing pathway rather than loading 32-bit
+///     native historian code into the main server.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Batched on the wire to amortize IPC overhead — the main server's SqliteStoreAndForwardSink
+///         ships up to 100 events per request per Phase 7 plan Stream D.5.
+///     </para>
+///     <para>
+///         Per-event outcomes (Ack / RetryPlease / PermanentFail) let the drain worker
+///         dead-letter malformed events without blocking neighbors in the batch.
+///         <see cref="HistorianConnectivityStatusNotification"/> fires proactively from
+///         the Host when the SDK session drops so the /hosts + /alarms/historian Admin
+///         diagnostics pages flip to red promptly instead of waiting for the next
+///         drain cycle.
+///     </para>
+/// </remarks>
+[MessagePackObject]
+public sealed class HistorianAlarmEventRequest
+{
+    [Key(0)] public HistorianAlarmEventDto[] Events { get; set; } = Array.Empty<HistorianAlarmEventDto>();
+}
+
+[MessagePackObject]
+public sealed class HistorianAlarmEventResponse
+{
+    /// <summary>Per-event outcome, same order as the request.</summary>
+    [Key(0)] public HistorianAlarmEventOutcomeDto[] Outcomes { get; set; } = Array.Empty<HistorianAlarmEventOutcomeDto>();
+}
+
+/// <summary>Outcome enum — bytes on the wire so it stays compact.</summary>
+public enum HistorianAlarmEventOutcomeDto : byte
+{
+    /// <summary>Successfully persisted to the historian — remove from queue.</summary>
+    Ack = 0,
+    /// <summary>Transient failure (historian disconnected, timeout, busy) — retry after backoff.</summary>
+    RetryPlease = 1,
+    /// <summary>Permanent failure (malformed, unrecoverable SDK error) — move to dead-letter.</summary>
+    PermanentFail = 2,
+}
+
+/// <summary>One alarm-transition payload. Fields mirror <c>Core.AlarmHistorian.AlarmHistorianEvent</c>.</summary>
+[MessagePackObject]
+public sealed class HistorianAlarmEventDto
+{
+    [Key(0)] public string AlarmId { get; set; } = string.Empty;
+    [Key(1)] public string EquipmentPath { get; set; } = string.Empty;
+    [Key(2)] public string AlarmName { get; set; } = string.Empty;
+
+    /// <summary>Concrete Part 9 subtype name — "LimitAlarm" / "OffNormalAlarm" / "AlarmCondition" / "DiscreteAlarm".</summary>
+    [Key(3)] public string AlarmTypeName { get; set; } = string.Empty;
+
+    /// <summary>Numeric severity the Host maps to the historian's priority scale.</summary>
+    [Key(4)] public int Severity { get; set; }
+
+    /// <summary>Which transition this event represents — "Activated" / "Cleared" / "Acknowledged" / etc.</summary>
+    [Key(5)] public string EventKind { get; set; } = string.Empty;
+
+    /// <summary>Pre-rendered message — template tokens resolved upstream.</summary>
+    [Key(6)] public string Message { get; set; } = string.Empty;
+
+    /// <summary>Operator who triggered the transition. "system" for engine-driven events.</summary>
+    [Key(7)] public string User { get; set; } = "system";
+
+    /// <summary>Operator-supplied free-form comment, if any.</summary>
+    [Key(8)] public string? Comment { get; set; }
+
+    /// <summary>Source timestamp (UTC Unix milliseconds).</summary>
+    [Key(9)] public long TimestampUtcUnixMs { get; set; }
+}
+
+/// <summary>
+///     Proactive notification — Galaxy.Host pushes this when the historian SDK session
+///     transitions (connected / disconnected / degraded). The main server reflects this
+///     into the historian sink status so Admin UI surfaces the problem without the
+///     operator having to scrutinize drain cadence.
+/// </summary>
+[MessagePackObject]
+public sealed class HistorianConnectivityStatusNotification
+{
+    [Key(0)] public string Status { get; set; } = "unknown"; // connected | disconnected | degraded
+    [Key(1)] public string? Detail { get; set; }
+    [Key(2)] public long ObservedAtUtcUnixMs { get; set; }
+}

src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/DriverNodeManager.cs

@@ -68,9 +68,18 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
     private readonly AuthorizationGate? _authzGate;
     private readonly NodeScopeResolver? _scopeResolver;
 
+    // Phase 7 Stream G follow-up — per-variable NodeSourceKind so OnReadValue can dispatch
+    // to the VirtualTagEngine / ScriptedAlarmEngine instead of the driver's IReadable per
+    // ADR-002. Absent entries default to Driver so drivers registered before Phase 7
+    // keep working unchanged.
+    private readonly Dictionary<string, NodeSourceKind> _sourceByFullRef = new(StringComparer.OrdinalIgnoreCase);
+    private readonly IReadable? _virtualReadable;
+    private readonly IReadable? _scriptedAlarmReadable;
+
     public DriverNodeManager(IServerInternal server, ApplicationConfiguration configuration,
         IDriver driver, CapabilityInvoker invoker, ILogger<DriverNodeManager> logger,
-        AuthorizationGate? authzGate = null, NodeScopeResolver? scopeResolver = null)
+        AuthorizationGate? authzGate = null, NodeScopeResolver? scopeResolver = null,
+        IReadable? virtualReadable = null, IReadable? scriptedAlarmReadable = null)
         : base(server, configuration, namespaceUris: $"urn:OtOpcUa:{driver.DriverInstanceId}")
     {
         _driver = driver;
@@ -80,6 +89,8 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
         _invoker = invoker;
         _authzGate = authzGate;
         _scopeResolver = scopeResolver;
+        _virtualReadable = virtualReadable;
+        _scriptedAlarmReadable = scriptedAlarmReadable;
         _logger = logger;
     }
 
@@ -185,6 +196,7 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
             _variablesByFullRef[attributeInfo.FullName] = v;
             _securityByFullRef[attributeInfo.FullName] = attributeInfo.SecurityClass;
             _writeIdempotentByFullRef[attributeInfo.FullName] = attributeInfo.WriteIdempotent;
+            _sourceByFullRef[attributeInfo.FullName] = attributeInfo.Source;
 
             v.OnReadValue = OnReadValue;
             v.OnWriteValue = OnWriteValue;
@@ -216,16 +228,18 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
     private ServiceResult OnReadValue(ISystemContext context, NodeState node, NumericRange indexRange,
         QualifiedName dataEncoding, ref object? value, ref StatusCode statusCode, ref DateTime timestamp)
     {
-        if (_readable is null)
+        var fullRef = node.NodeId.Identifier as string ?? "";
+        var source = _sourceByFullRef.TryGetValue(fullRef, out var s) ? s : NodeSourceKind.Driver;
+        var readable = SelectReadable(source, _readable, _virtualReadable, _scriptedAlarmReadable);
+
+        if (readable is null)
         {
-            statusCode = StatusCodes.BadNotReadable;
+            statusCode = source == NodeSourceKind.Driver ? StatusCodes.BadNotReadable : StatusCodes.BadNotFound;
             return ServiceResult.Good;
         }
 
         try
         {
-            var fullRef = node.NodeId.Identifier as string ?? "";
-
             // Phase 6.2 Stream C — authorization gate. Runs ahead of the invoker so a denied
             // read never hits the driver. Returns true in lax mode when identity lacks LDAP
             // groups; strict mode denies those cases. See AuthorizationGate remarks.
@@ -242,7 +256,7 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
             var result = _invoker.ExecuteAsync(
                 DriverCapability.Read,
                 ResolveHostFor(fullRef),
-                async ct => (IReadOnlyList<DataValueSnapshot>)await _readable.ReadAsync([fullRef], ct).ConfigureAwait(false),
+                async ct => (IReadOnlyList<DataValueSnapshot>)await readable.ReadAsync([fullRef], ct).ConfigureAwait(false),
                 CancellationToken.None).AsTask().GetAwaiter().GetResult();
             if (result.Count == 0)
             {
@@ -262,6 +276,32 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
         return ServiceResult.Good;
     }
 
+    /// <summary>
+    ///     Picks the <see cref="IReadable"/> the dispatch layer routes through based on the
+    ///     node's Phase 7 source kind (ADR-002). Extracted as a pure function for unit test
+    ///     coverage — the full dispatch requires the OPC UA server stack, but this kernel is
+    ///     deterministic and small.
+    /// </summary>
+    internal static IReadable? SelectReadable(
+        NodeSourceKind source,
+        IReadable? driverReadable,
+        IReadable? virtualReadable,
+        IReadable? scriptedAlarmReadable) => source switch
+    {
+        NodeSourceKind.Virtual => virtualReadable,
+        NodeSourceKind.ScriptedAlarm => scriptedAlarmReadable,
+        _ => driverReadable,
+    };
+
+    /// <summary>
+    ///     Plan decision #6 gate — returns true only when the write is allowed. Virtual tags
+    ///     and scripted alarms reject OPC UA writes because the write path for virtual tags
+    ///     is <c>ctx.SetVirtualTag</c> from within a script, and the write path for alarm
+    ///     state is the Part 9 method nodes (Acknowledge / Confirm / Shelve).
+    /// </summary>
+    internal static bool IsWriteAllowedBySource(NodeSourceKind source) =>
+        source == NodeSourceKind.Driver;
+
     private static NodeId MapDataType(DriverDataType t) => t switch
     {
         DriverDataType.Boolean => DataTypeIds.Boolean,
@@ -414,10 +454,19 @@ public sealed class DriverNodeManager : CustomNodeManager2, IAddressSpaceBuilder
     private ServiceResult OnWriteValue(ISystemContext context, NodeState node, NumericRange indexRange,
         QualifiedName dataEncoding, ref object? value, ref StatusCode statusCode, ref DateTime timestamp)
     {
-        if (_writable is null) return StatusCodes.BadNotWritable;
         var fullRef = node.NodeId.Identifier as string;
         if (string.IsNullOrEmpty(fullRef)) return StatusCodes.BadNodeIdUnknown;
 
+        // Per Phase 7 plan decision #6 — virtual tags + scripted alarms reject direct
+        // OPC UA writes with BadUserAccessDenied. Scripts can write to virtual tags
+        // via ctx.SetVirtualTag; operators cannot. Operator alarm actions go through
+        // the Part 9 method nodes (Acknowledge / Confirm / Shelve), not through the
+        // variable-value write path.
+        if (_sourceByFullRef.TryGetValue(fullRef!, out var source) && !IsWriteAllowedBySource(source))
+            return new ServiceResult(StatusCodes.BadUserAccessDenied);
+
+        if (_writable is null) return StatusCodes.BadNotWritable;
+
         // PR 26: server-layer write authorization. Look up the attribute's classification
         // (populated during Variable() in Discover) and check the session's roles against the
         // policy table. Drivers don't participate in this decision — IWritable.WriteAsync

src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/OpcUaApplicationHost.cs

@@ -30,6 +30,16 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
     private readonly Func<string, ZB.MOM.WW.OtOpcUa.Core.Abstractions.DriverTier>? _tierLookup;
     private readonly Func<string, string?>? _resilienceConfigLookup;
     private readonly Func<string, ZB.MOM.WW.OtOpcUa.Core.OpcUa.EquipmentNamespaceContent?>? _equipmentContentLookup;
+
+    // Phase 7 Stream G follow-up (task #239). When composed with the VirtualTagEngine +
+    // ScriptedAlarmEngine sources these route node reads to the engines instead of the
+    // driver. Null = Phase 7 engines not enabled for this deployment (identical to pre-
+    // Phase-7 behaviour). Late-bindable via SetPhase7Sources because the engines need
+    // the bootstrapped generation id before they can compose, which is only known after
+    // the host has been DI-constructed (task #246).
+    private ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? _virtualReadable;
+    private ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? _scriptedAlarmReadable;
+
     private readonly ILoggerFactory _loggerFactory;
     private readonly ILogger<OpcUaApplicationHost> _logger;
     private ApplicationInstance? _application;
@@ -45,7 +55,9 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
         StaleConfigFlag? staleConfigFlag = null,
         Func<string, ZB.MOM.WW.OtOpcUa.Core.Abstractions.DriverTier>? tierLookup = null,
         Func<string, string?>? resilienceConfigLookup = null,
-        Func<string, ZB.MOM.WW.OtOpcUa.Core.OpcUa.EquipmentNamespaceContent?>? equipmentContentLookup = null)
+        Func<string, ZB.MOM.WW.OtOpcUa.Core.OpcUa.EquipmentNamespaceContent?>? equipmentContentLookup = null,
+        ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? virtualReadable = null,
+        ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? scriptedAlarmReadable = null)
     {
         _options = options;
         _driverHost = driverHost;
@@ -57,12 +69,32 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
         _tierLookup = tierLookup;
         _resilienceConfigLookup = resilienceConfigLookup;
         _equipmentContentLookup = equipmentContentLookup;
+        _virtualReadable = virtualReadable;
+        _scriptedAlarmReadable = scriptedAlarmReadable;
         _loggerFactory = loggerFactory;
         _logger = logger;
     }
 
     public OtOpcUaServer? Server => _server;
 
+    /// <summary>
+    ///     Late-bind the Phase 7 engine-backed <c>IReadable</c> sources. Must be
+    ///     called BEFORE <see cref="StartAsync"/> — once the OPC UA server starts, the
+    ///     <see cref="OtOpcUaServer"/> ctor captures the field values + per-node
+    ///     <see cref="DriverNodeManager"/>s are constructed. Calling this after start has
+    ///     no effect on already-materialized node managers.
+    /// </summary>
+    public void SetPhase7Sources(
+        ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? virtualReadable,
+        ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? scriptedAlarmReadable)
+    {
+        if (_server is not null)
+            throw new InvalidOperationException(
+                "Phase 7 sources must be set before OpcUaApplicationHost.StartAsync; the OtOpcUaServer + DriverNodeManagers have already captured the previous values.");
+        _virtualReadable = virtualReadable;
+        _scriptedAlarmReadable = scriptedAlarmReadable;
+    }
+
     /// <summary>
     ///     Builds the <see cref="ApplicationConfiguration"/>, validates/creates the application
     ///     certificate, constructs + starts the <see cref="OtOpcUaServer"/>, then drives
@@ -85,7 +117,8 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
 
         _server = new OtOpcUaServer(_driverHost, _authenticator, _pipelineBuilder, _loggerFactory,
             authzGate: _authzGate, scopeResolver: _scopeResolver,
-            tierLookup: _tierLookup, resilienceConfigLookup: _resilienceConfigLookup);
+            tierLookup: _tierLookup, resilienceConfigLookup: _resilienceConfigLookup,
+            virtualReadable: _virtualReadable, scriptedAlarmReadable: _scriptedAlarmReadable);
         await _application.Start(_server).ConfigureAwait(false);
 
         _logger.LogInformation("OPC UA server started — endpoint={Endpoint} driverCount={Count}",

src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/OtOpcUaServer.cs

@@ -25,6 +25,15 @@ public sealed class OtOpcUaServer : StandardServer
     private readonly NodeScopeResolver? _scopeResolver;
     private readonly Func<string, DriverTier>? _tierLookup;
     private readonly Func<string, string?>? _resilienceConfigLookup;
+
+    // Phase 7 Stream G follow-up wiring (task #239). Shared across every DriverNodeManager
+    // instantiated by this server so virtual-tag reads and scripted-alarm reads from any
+    // driver's address-space subtree route to the same engine. When null (no Phase 7
+    // engines composed for this deployment) DriverNodeManager falls back to driver-only
+    // dispatch — identical to pre-Phase-7 behaviour.
+    private readonly IReadable? _virtualReadable;
+    private readonly IReadable? _scriptedAlarmReadable;
+
     private readonly ILoggerFactory _loggerFactory;
     private readonly List<DriverNodeManager> _driverNodeManagers = new();
 
@@ -36,7 +45,9 @@ public sealed class OtOpcUaServer : StandardServer
         AuthorizationGate? authzGate = null,
         NodeScopeResolver? scopeResolver = null,
         Func<string, DriverTier>? tierLookup = null,
-        Func<string, string?>? resilienceConfigLookup = null)
+        Func<string, string?>? resilienceConfigLookup = null,
+        IReadable? virtualReadable = null,
+        IReadable? scriptedAlarmReadable = null)
     {
         _driverHost = driverHost;
         _authenticator = authenticator;
@@ -45,6 +56,8 @@ public sealed class OtOpcUaServer : StandardServer
         _scopeResolver = scopeResolver;
         _tierLookup = tierLookup;
         _resilienceConfigLookup = resilienceConfigLookup;
+        _virtualReadable = virtualReadable;
+        _scriptedAlarmReadable = scriptedAlarmReadable;
         _loggerFactory = loggerFactory;
     }
 
@@ -77,7 +90,8 @@ public sealed class OtOpcUaServer : StandardServer
 
             var invoker = new CapabilityInvoker(_pipelineBuilder, driver.DriverInstanceId, () => options, driver.DriverType);
             var manager = new DriverNodeManager(server, configuration, driver, invoker, logger,
-                authzGate: _authzGate, scopeResolver: _scopeResolver);
+                authzGate: _authzGate, scopeResolver: _scopeResolver,
+                virtualReadable: _virtualReadable, scriptedAlarmReadable: _scriptedAlarmReadable);
             _driverNodeManagers.Add(manager);
         }
 

src/ZB.MOM.WW.OtOpcUa.Server/OpcUaServerService.cs

@@ -3,6 +3,7 @@ using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
 using ZB.MOM.WW.OtOpcUa.Server.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
 
 namespace ZB.MOM.WW.OtOpcUa.Server;
 
@@ -17,6 +18,7 @@ public sealed class OpcUaServerService(
     DriverHost driverHost,
     OpcUaApplicationHost applicationHost,
     DriverEquipmentContentRegistry equipmentContentRegistry,
+    Phase7Composer phase7Composer,
     IServiceScopeFactory scopeFactory,
     ILogger<OpcUaServerService> logger) : BackgroundService
 {
@@ -34,12 +36,19 @@ public sealed class OpcUaServerService(
         // Skipped when no generation is Published yet — the fleet boots into a UNS-less
         // address space until the first publish, then the registry fills on next restart.
         if (result.GenerationId is { } gen)
+        {
             await PopulateEquipmentContentAsync(gen, stoppingToken);
 
-        // PR 17: stand up the OPC UA server + drive discovery per registered driver. Driver
-        // registration itself (RegisterAsync on DriverHost) happens during an earlier DI
-        // extension once the central config DB query + per-driver factory land; for now the
-        // server comes up with whatever drivers are in DriverHost at start time.
+            // Phase 7 follow-up #246 — load Script + VirtualTag + ScriptedAlarm rows,
+            // compose VirtualTagEngine + ScriptedAlarmEngine, start the driver-bridge
+            // feed. SetPhase7Sources MUST run before applicationHost.StartAsync because
+            // OtOpcUaServer + DriverNodeManager construction captures the field values
+            // — late binding after server start is rejected with InvalidOperationException.
+            // No-op when the generation has no virtual tags or scripted alarms.
+            var phase7 = await phase7Composer.PrepareAsync(gen, stoppingToken);
+            applicationHost.SetPhase7Sources(phase7.VirtualReadable, phase7.ScriptedAlarmReadable);
+        }
+
         await applicationHost.StartAsync(stoppingToken);
 
         logger.LogInformation("OtOpcUa.Server running. Hosted drivers: {Count}", driverHost.RegisteredDriverIds.Count);
@@ -57,6 +66,11 @@ public sealed class OpcUaServerService(
     public override async Task StopAsync(CancellationToken cancellationToken)
     {
         await base.StopAsync(cancellationToken);
+        // Dispose Phase 7 first so the bridge stops feeding the cache + the engines
+        // stop firing alarm/historian events before the OPC UA server tears down its
+        // node managers. Otherwise an in-flight cascade could try to push through a
+        // disposed source and surface as a noisy shutdown warning.
+        await phase7Composer.DisposeAsync();
         await applicationHost.DisposeAsync();
         await driverHost.DisposeAsync();
     }

src/ZB.MOM.WW.OtOpcUa.Server/Phase7/CachedTagUpstreamSource.cs

@@ -0,0 +1,84 @@
+using System.Collections.Concurrent;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+/// <summary>
+///     Production <c>ITagUpstreamSource</c> for the Phase 7 engines (implements both the
+///     Core.VirtualTags and Core.ScriptedAlarms variants — identical shape, distinct
+///     namespaces). Per the interface docstring, reads are synchronous — user scripts
+///     call <c>ctx.GetTag</c> inline — so we serve from a last-known-value cache that
+///     the driver-bridge populates asynchronously via <see cref="Push"/>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <see cref="Push"/> is called by the driver-bridge (wiring added by task #244)
+///         every time a driver's <c>ISubscribable.OnDataChange</c> fires. Subscribers
+///         registered via <see cref="SubscribeTag"/> are notified synchronously on the
+///         calling thread — the VirtualTagEngine + ScriptedAlarmEngine handle their own
+///         async hand-off via <c>SemaphoreSlim</c>.
+///     </para>
+///     <para>
+///         Reads of a path that has never been <see cref="Push"/>-ed return
+///         <see cref="UpstreamNotConfigured"/>-quality — which scripts see as
+///         <c>ctx.GetTag("...").StatusCode == BadNodeIdUnknown</c> and can branch on.
+///     </para>
+/// </remarks>
+public sealed class CachedTagUpstreamSource
+    : Core.VirtualTags.ITagUpstreamSource,
+      Core.ScriptedAlarms.ITagUpstreamSource
+{
+    private readonly ConcurrentDictionary<string, DataValueSnapshot> _values = new(StringComparer.Ordinal);
+    private readonly ConcurrentDictionary<string, List<Action<string, DataValueSnapshot>>> _observers
+        = new(StringComparer.Ordinal);
+
+    public DataValueSnapshot ReadTag(string path)
+    {
+        if (string.IsNullOrEmpty(path)) throw new ArgumentException("path required", nameof(path));
+        return _values.TryGetValue(path, out var snap)
+            ? snap
+            : new DataValueSnapshot(null, UpstreamNotConfigured, null, DateTime.UtcNow);
+    }
+
+    public IDisposable SubscribeTag(string path, Action<string, DataValueSnapshot> observer)
+    {
+        if (string.IsNullOrEmpty(path)) throw new ArgumentException("path required", nameof(path));
+        ArgumentNullException.ThrowIfNull(observer);
+
+        var list = _observers.GetOrAdd(path, _ => []);
+        lock (list) list.Add(observer);
+        return new Unsub(this, path, observer);
+    }
+
+    /// <summary>
+    ///     Driver-bridge write path — called when a driver delivers a value change for
+    ///     <paramref name="path"/>. Updates the cache + fans out to every observer.
+    ///     Safe for concurrent callers; observers fire on the caller's thread.
+    /// </summary>
+    public void Push(string path, DataValueSnapshot snapshot)
+    {
+        if (string.IsNullOrEmpty(path)) throw new ArgumentException("path required", nameof(path));
+        ArgumentNullException.ThrowIfNull(snapshot);
+
+        _values[path] = snapshot;
+        if (!_observers.TryGetValue(path, out var list)) return;
+        Action<string, DataValueSnapshot>[] snapshotList;
+        lock (list) snapshotList = list.ToArray();
+        foreach (var observer in snapshotList) observer(path, snapshot);
+    }
+
+    /// <summary>Mirror of OPC UA <c>StatusCodes.BadNodeIdUnknown</c> without pulling the OPC stack dependency.</summary>
+    public const uint UpstreamNotConfigured = 0x80340000;
+
+    private sealed class Unsub(CachedTagUpstreamSource owner, string path, Action<string, DataValueSnapshot> observer) : IDisposable
+    {
+        private bool _disposed;
+        public void Dispose()
+        {
+            if (_disposed) return;
+            _disposed = true;
+            if (owner._observers.TryGetValue(path, out var list))
+                lock (list) list.Remove(observer);
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Server/Phase7/DriverSubscriptionBridge.cs

@@ -0,0 +1,146 @@
+using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+/// <summary>
+///     Phase 7 follow-up (task #244). Subscribes to live driver <see cref="ISubscribable"/>
+///     surfaces for every input path the Phase 7 engines care about + pushes incoming
+///     <see cref="DataChangeEventArgs.Snapshot"/>s into <see cref="CachedTagUpstreamSource"/>
+///     so <c>ctx.GetTag</c> reads see the freshest driver value.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Each <see cref="DriverFeed"/> declares a driver + the path-to-fullRef map for the
+///         attributes that driver provides. The bridge groups by driver so each <see cref="ISubscribable"/>
+///         gets one <c>SubscribeAsync</c> call with a batched fullRef list — drivers that
+///         poll under the hood (Modbus, AB CIP, S7) consolidate the polls; drivers with
+///         native subscriptions (Galaxy, OPC UA Client, TwinCAT) get a single watch list.
+///     </para>
+///     <para>
+///         Because driver fullRefs are opaque + driver-specific (Galaxy
+///         <c>"DelmiaReceiver_001.Temp"</c>, Modbus <c>"40001"</c>, AB CIP
+///         <c>"Temperature[0]"</c>), the bridge keeps a per-feed reverse map from fullRef
+///         back to UNS path. <c>OnDataChange</c> fires keyed by fullRef; the bridge
+///         translates to the script-side path before calling <see cref="CachedTagUpstreamSource.Push"/>.
+///     </para>
+///     <para>
+///         Lifecycle: construct → <see cref="StartAsync"/> with the feeds → keep alive
+///         alongside the engines → <see cref="DisposeAsync"/> unsubscribes from every
+///         driver + unhooks the OnDataChange handlers. Driver subscriptions don't leak
+///         even on abnormal shutdown because the disposal awaits each
+///         <c>UnsubscribeAsync</c>.
+///     </para>
+/// </remarks>
+public sealed class DriverSubscriptionBridge : IAsyncDisposable
+{
+    private readonly CachedTagUpstreamSource _sink;
+    private readonly ILogger<DriverSubscriptionBridge> _logger;
+    private readonly List<ActiveSubscription> _active = [];
+    private bool _started;
+    private bool _disposed;
+
+    public DriverSubscriptionBridge(
+        CachedTagUpstreamSource sink,
+        ILogger<DriverSubscriptionBridge> logger)
+    {
+        _sink = sink ?? throw new ArgumentNullException(nameof(sink));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+    }
+
+    /// <summary>
+    ///     Subscribe each feed's driver to its declared fullRefs + wire push-to-cache.
+    ///     Idempotent guard rejects double-start. Throws on the first subscribe failure
+    ///     so misconfiguration surfaces fast — partial-subscribe state doesn't linger.
+    /// </summary>
+    public async Task StartAsync(IEnumerable<DriverFeed> feeds, CancellationToken ct)
+    {
+        ArgumentNullException.ThrowIfNull(feeds);
+        if (_disposed) throw new ObjectDisposedException(nameof(DriverSubscriptionBridge));
+        if (_started) throw new InvalidOperationException("DriverSubscriptionBridge already started");
+        _started = true;
+
+        foreach (var feed in feeds)
+        {
+            if (feed.PathToFullRef.Count == 0) continue;
+
+            // Reverse map for OnDataChange dispatch — driver fires keyed by FullReference,
+            // we push keyed by the script-side path.
+            var fullRefToPath = feed.PathToFullRef
+                .ToDictionary(kv => kv.Value, kv => kv.Key, StringComparer.Ordinal);
+            var fullRefs = feed.PathToFullRef.Values.Distinct(StringComparer.Ordinal).ToList();
+
+            EventHandler<DataChangeEventArgs> handler = (_, e) =>
+            {
+                if (fullRefToPath.TryGetValue(e.FullReference, out var unsPath))
+                    _sink.Push(unsPath, e.Snapshot);
+            };
+            feed.Driver.OnDataChange += handler;
+
+            try
+            {
+                // OTOPCUA0001 suppression — the analyzer flags ISubscribable calls outside
+                // CapabilityInvoker. This bridge IS the lifecycle-coordinator for Phase 7
+                // subscriptions: it runs once at engine compose, doesn't hot-path per
+                // script evaluation (the engines read from the cache instead), and surfaces
+                // any subscribe failure by aborting bridge start. Wrapping in the per-call
+                // resilience pipeline would add nothing — there's no caller to retry on
+                // behalf of, and the breaker/bulkhead semantics belong to actual driver Read
+                // dispatch, which still goes through CapabilityInvoker via DriverNodeManager.
+#pragma warning disable OTOPCUA0001
+                var handle = await feed.Driver.SubscribeAsync(fullRefs, feed.PublishingInterval, ct).ConfigureAwait(false);
+#pragma warning restore OTOPCUA0001
+                _active.Add(new ActiveSubscription(feed.Driver, handle, handler));
+                _logger.LogInformation(
+                    "Phase 7 bridge subscribed {Count} attribute(s) from driver {Driver} (handle {Handle})",
+                    fullRefs.Count, feed.Driver.GetType().Name, handle.DiagnosticId);
+            }
+            catch
+            {
+                feed.Driver.OnDataChange -= handler;
+                throw;
+            }
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_disposed) return;
+        _disposed = true;
+        foreach (var sub in _active)
+        {
+            sub.Driver.OnDataChange -= sub.Handler;
+            try
+            {
+#pragma warning disable OTOPCUA0001 // bridge lifecycle — see StartAsync suppression rationale
+                await sub.Driver.UnsubscribeAsync(sub.Handle, CancellationToken.None).ConfigureAwait(false);
+#pragma warning restore OTOPCUA0001
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex,
+                    "Driver {Driver} UnsubscribeAsync threw on bridge dispose (handle {Handle})",
+                    sub.Driver.GetType().Name, sub.Handle.DiagnosticId);
+            }
+        }
+        _active.Clear();
+    }
+
+    private sealed record ActiveSubscription(
+        ISubscribable Driver,
+        ISubscriptionHandle Handle,
+        EventHandler<DataChangeEventArgs> Handler);
+}
+
+/// <summary>
+///     One driver's contribution to the Phase 7 bridge — the driver's <see cref="ISubscribable"/>
+///     surface plus the path-to-fullRef map the bridge uses to translate driver-side
+///     <see cref="DataChangeEventArgs.FullReference"/> back to script-side paths.
+/// </summary>
+/// <param name="Driver">The driver's subscribable surface (every shipped driver implements <see cref="ISubscribable"/>).</param>
+/// <param name="PathToFullRef">UNS path the script uses → driver-opaque fullRef. Empty map = nothing to subscribe (skipped).</param>
+/// <param name="PublishingInterval">Forwarded to the driver's <see cref="ISubscribable.SubscribeAsync"/>.</param>
+public sealed record DriverFeed(
+    ISubscribable Driver,
+    IReadOnlyDictionary<string, string> PathToFullRef,
+    TimeSpan PublishingInterval);

src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7Composer.cs

@@ -0,0 +1,183 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+using ZB.MOM.WW.OtOpcUa.Core.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
+using ZB.MOM.WW.OtOpcUa.Server.OpcUa;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+/// <summary>
+///     Phase 7 follow-up (task #246) — orchestrates the runtime composition of virtual
+///     tags + scripted alarms + the historian sink + the driver-bridge that feeds the
+///     engines. Called by <see cref="OpcUaServerService"/> after the bootstrap generation
+///     loads + before <see cref="OpcUaApplicationHost.StartAsync"/>.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <see cref="PrepareAsync"/> reads Script / VirtualTag / ScriptedAlarm rows from
+///         the central config DB at the bootstrapped generation, instantiates a
+///         <see cref="CachedTagUpstreamSource"/>, runs <see cref="Phase7EngineComposer.Compose"/>,
+///         starts a <see cref="DriverSubscriptionBridge"/> per registered driver feeding
+///         <see cref="EquipmentNamespaceContent"/>'s tag rows into the cache, and returns
+///         the engine-backed <see cref="Core.Abstractions.IReadable"/> sources for
+///         <see cref="OpcUaApplicationHost.SetPhase7Sources"/>.
+///     </para>
+///     <para>
+///         <see cref="DisposeAsync"/> tears down the bridge first (so no more events
+///         arrive at the cache), then the engines (so cascades + timer ticks stop), then
+///         the SQLite sink (which flushes any in-flight drain). Lifetime is owned by the
+///         host; <see cref="OpcUaServerService.StopAsync"/> calls dispose during graceful
+///         shutdown.
+///     </para>
+/// </remarks>
+public sealed class Phase7Composer : IAsyncDisposable
+{
+    private readonly IServiceScopeFactory _scopeFactory;
+    private readonly DriverHost _driverHost;
+    private readonly DriverEquipmentContentRegistry _equipmentRegistry;
+    private readonly IAlarmHistorianSink _historianSink;
+    private readonly ILoggerFactory _loggerFactory;
+    private readonly Serilog.ILogger _scriptLogger;
+    private readonly ILogger<Phase7Composer> _logger;
+
+    private DriverSubscriptionBridge? _bridge;
+    private Phase7ComposedSources _sources = Phase7ComposedSources.Empty;
+    private bool _disposed;
+
+    public Phase7Composer(
+        IServiceScopeFactory scopeFactory,
+        DriverHost driverHost,
+        DriverEquipmentContentRegistry equipmentRegistry,
+        IAlarmHistorianSink historianSink,
+        ILoggerFactory loggerFactory,
+        Serilog.ILogger scriptLogger,
+        ILogger<Phase7Composer> logger)
+    {
+        _scopeFactory = scopeFactory ?? throw new ArgumentNullException(nameof(scopeFactory));
+        _driverHost = driverHost ?? throw new ArgumentNullException(nameof(driverHost));
+        _equipmentRegistry = equipmentRegistry ?? throw new ArgumentNullException(nameof(equipmentRegistry));
+        _historianSink = historianSink ?? throw new ArgumentNullException(nameof(historianSink));
+        _loggerFactory = loggerFactory ?? throw new ArgumentNullException(nameof(loggerFactory));
+        _scriptLogger = scriptLogger ?? throw new ArgumentNullException(nameof(scriptLogger));
+        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+    }
+
+    public Phase7ComposedSources Sources => _sources;
+
+    public async Task<Phase7ComposedSources> PrepareAsync(long generationId, CancellationToken ct)
+    {
+        if (_disposed) throw new ObjectDisposedException(nameof(Phase7Composer));
+
+        // Load the three Phase 7 row sets in one DB scope.
+        List<Script> scripts;
+        List<VirtualTag> virtualTags;
+        List<ScriptedAlarm> scriptedAlarms;
+        using (var scope = _scopeFactory.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<OtOpcUaConfigDbContext>();
+            scripts = await db.Scripts.AsNoTracking()
+                .Where(s => s.GenerationId == generationId).ToListAsync(ct).ConfigureAwait(false);
+            virtualTags = await db.VirtualTags.AsNoTracking()
+                .Where(v => v.GenerationId == generationId && v.Enabled).ToListAsync(ct).ConfigureAwait(false);
+            scriptedAlarms = await db.ScriptedAlarms.AsNoTracking()
+                .Where(a => a.GenerationId == generationId && a.Enabled).ToListAsync(ct).ConfigureAwait(false);
+        }
+
+        if (virtualTags.Count == 0 && scriptedAlarms.Count == 0)
+        {
+            _logger.LogInformation("Phase 7: no virtual tags or scripted alarms in generation {Gen}; engines dormant", generationId);
+            return Phase7ComposedSources.Empty;
+        }
+
+        var upstream = new CachedTagUpstreamSource();
+
+        _sources = Phase7EngineComposer.Compose(
+            scripts: scripts,
+            virtualTags: virtualTags,
+            scriptedAlarms: scriptedAlarms,
+            upstream: upstream,
+            alarmStateStore: new InMemoryAlarmStateStore(),
+            historianSink: _historianSink,
+            rootScriptLogger: _scriptLogger,
+            loggerFactory: _loggerFactory);
+
+        _logger.LogInformation(
+            "Phase 7: composed engines from generation {Gen} — {Vt} virtual tag(s), {Al} scripted alarm(s), {Sc} script(s)",
+            generationId, virtualTags.Count, scriptedAlarms.Count, scripts.Count);
+
+        // Build driver feeds from each registered driver's EquipmentNamespaceContent + start
+        // the bridge. Drivers without populated content (Galaxy SystemPlatform-kind, drivers
+        // whose Equipment rows haven't been published yet) contribute an empty feed which
+        // the bridge silently skips.
+        _bridge = new DriverSubscriptionBridge(upstream, _loggerFactory.CreateLogger<DriverSubscriptionBridge>());
+        var feeds = BuildDriverFeeds(_driverHost, _equipmentRegistry);
+        await _bridge.StartAsync(feeds, ct).ConfigureAwait(false);
+
+        return _sources;
+    }
+
+    /// <summary>
+    ///     For each registered driver that exposes <see cref="Core.Abstractions.ISubscribable"/>,
+    ///     build a UNS-path → driver-fullRef map from its EquipmentNamespaceContent.
+    ///     Path convention: <c>/{areaName}/{lineName}/{equipmentName}/{tagName}</c> matching
+    ///     what the EquipmentNodeWalker emits into the OPC UA browse tree, so script literals
+    ///     written against the operator-visible tree work without translation.
+    /// </summary>
+    internal static IReadOnlyList<DriverFeed> BuildDriverFeeds(
+        DriverHost driverHost, DriverEquipmentContentRegistry equipmentRegistry)
+    {
+        var feeds = new List<DriverFeed>();
+        foreach (var driverId in driverHost.RegisteredDriverIds)
+        {
+            var driver = driverHost.GetDriver(driverId);
+            if (driver is not Core.Abstractions.ISubscribable subscribable) continue;
+
+            var content = equipmentRegistry.Get(driverId);
+            if (content is null) continue;
+
+            var pathToFullRef = MapPathsToFullRefs(content);
+            if (pathToFullRef.Count == 0) continue;
+
+            feeds.Add(new DriverFeed(subscribable, pathToFullRef, TimeSpan.FromSeconds(1)));
+        }
+        return feeds;
+    }
+
+    internal static IReadOnlyDictionary<string, string> MapPathsToFullRefs(EquipmentNamespaceContent content)
+    {
+        var result = new Dictionary<string, string>(StringComparer.Ordinal);
+        var areaById = content.Areas.ToDictionary(a => a.UnsAreaId, StringComparer.OrdinalIgnoreCase);
+        var lineById = content.Lines.ToDictionary(l => l.UnsLineId, StringComparer.OrdinalIgnoreCase);
+        var equipmentById = content.Equipment.ToDictionary(e => e.EquipmentId, StringComparer.OrdinalIgnoreCase);
+
+        foreach (var tag in content.Tags)
+        {
+            if (string.IsNullOrEmpty(tag.EquipmentId)) continue;
+            if (!equipmentById.TryGetValue(tag.EquipmentId!, out var eq)) continue;
+            if (!lineById.TryGetValue(eq.UnsLineId, out var line)) continue;
+            if (!areaById.TryGetValue(line.UnsAreaId, out var area)) continue;
+
+            var path = $"/{area.Name}/{line.Name}/{eq.Name}/{tag.Name}";
+            result[path] = tag.TagConfig;  // duplicate-path collisions naturally win-last; UI publish-validation rules out duplicate names
+        }
+        return result;
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_disposed) return;
+        _disposed = true;
+        if (_bridge is not null) await _bridge.DisposeAsync().ConfigureAwait(false);
+        foreach (var d in _sources.Disposables)
+        {
+            try { d.Dispose(); }
+            catch (Exception ex) { _logger.LogWarning(ex, "Phase 7 disposable threw during shutdown"); }
+        }
+        if (_historianSink is IDisposable disposableSink) disposableSink.Dispose();
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Server/Phase7/Phase7EngineComposer.cs

@@ -0,0 +1,208 @@
+using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+using ZB.MOM.WW.OtOpcUa.Core.Scripting;
+using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
+using ZB.MOM.WW.OtOpcUa.Core.VirtualTags;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+/// <summary>
+///     Phase 7 follow-up (task #243) — maps the generation's <see cref="Script"/> /
+///     <see cref="VirtualTag"/> / <see cref="ScriptedAlarm"/> rows into the runtime
+///     definitions <see cref="VirtualTagEngine"/> + <see cref="ScriptedAlarmEngine"/>
+///     expect, builds the engine instances, and returns the <see cref="IReadable"/>
+///     sources plus an <see cref="IAlarmSource"/> for the <c>DriverNodeManager</c>
+///     wiring added by task #239.
+/// </summary>
+/// <remarks>
+///     <para>
+///         Empty Phase 7 config (no virtual tags + no scripted alarms) is a valid state:
+///         <see cref="Compose"/> returns a <see cref="Phase7ComposedSources"/> with null
+///         sources so Program.cs can pass them through to <c>OpcUaApplicationHost</c>
+///         unchanged — deployments without scripts behave exactly as they did before
+///         Phase 7.
+///     </para>
+///     <para>
+///         The caller owns the returned <see cref="Phase7ComposedSources.Disposables"/>
+///         and must dispose them on shutdown. Engine cascades + timer ticks run off
+///         background threads until then.
+///     </para>
+/// </remarks>
+public static class Phase7EngineComposer
+{
+    public static Phase7ComposedSources Compose(
+        IReadOnlyList<Script> scripts,
+        IReadOnlyList<VirtualTag> virtualTags,
+        IReadOnlyList<ScriptedAlarm> scriptedAlarms,
+        CachedTagUpstreamSource upstream,
+        IAlarmStateStore alarmStateStore,
+        IAlarmHistorianSink historianSink,
+        Serilog.ILogger rootScriptLogger,
+        ILoggerFactory loggerFactory)
+    {
+        ArgumentNullException.ThrowIfNull(scripts);
+        ArgumentNullException.ThrowIfNull(virtualTags);
+        ArgumentNullException.ThrowIfNull(scriptedAlarms);
+        ArgumentNullException.ThrowIfNull(upstream);
+        ArgumentNullException.ThrowIfNull(alarmStateStore);
+        ArgumentNullException.ThrowIfNull(historianSink);
+        ArgumentNullException.ThrowIfNull(rootScriptLogger);
+        ArgumentNullException.ThrowIfNull(loggerFactory);
+
+        if (virtualTags.Count == 0 && scriptedAlarms.Count == 0)
+            return Phase7ComposedSources.Empty;
+
+        var scriptById = scripts
+            .Where(s => s.Enabled())
+            .ToDictionary(s => s.ScriptId, StringComparer.Ordinal);
+
+        var scriptLoggerFactory = new ScriptLoggerFactory(rootScriptLogger);
+        var disposables = new List<IDisposable>();
+
+        // Engines take Serilog.ILogger — each engine gets its own so rolling-file emissions
+        // stay keyed to the right source in the scripts-*.log.
+        VirtualTagSource? vtSource = null;
+        if (virtualTags.Count > 0)
+        {
+            var vtDefs = ProjectVirtualTags(virtualTags, scriptById).ToList();
+            var vtEngine = new VirtualTagEngine(upstream, scriptLoggerFactory, rootScriptLogger);
+            vtEngine.Load(vtDefs);
+            vtSource = new VirtualTagSource(vtEngine);
+            disposables.Add(vtEngine);
+        }
+
+        IReadable? alarmReadable = null;
+        if (scriptedAlarms.Count > 0)
+        {
+            var alarmDefs = ProjectScriptedAlarms(scriptedAlarms, scriptById).ToList();
+            var alarmEngine = new ScriptedAlarmEngine(upstream, alarmStateStore, scriptLoggerFactory, rootScriptLogger);
+            // Wire alarm emissions to the historian sink (Stream D). Fire-and-forget because
+            // the sink's EnqueueAsync is already non-blocking from the producer's view.
+            var engineLogger = loggerFactory.CreateLogger("Phase7HistorianRouter");
+            alarmEngine.OnEvent += (_, e) => _ = RouteToHistorianAsync(e, historianSink, engineLogger);
+            alarmEngine.LoadAsync(alarmDefs, CancellationToken.None).GetAwaiter().GetResult();
+            var alarmSource = new ScriptedAlarmSource(alarmEngine);
+            // Task #245 — expose each alarm's current Active state as IReadable so OPC UA
+            // variable reads on Source=ScriptedAlarm nodes return the live predicate truth
+            // instead of BadNotFound. ScriptedAlarmSource stays registered as IAlarmSource
+            // for the event stream; the IReadable is a separate adapter over the same engine.
+            alarmReadable = new ScriptedAlarmReadable(alarmEngine);
+            disposables.Add(alarmEngine);
+            disposables.Add(alarmSource);
+        }
+
+        return new Phase7ComposedSources(vtSource, alarmReadable, disposables);
+    }
+
+    internal static IEnumerable<VirtualTagDefinition> ProjectVirtualTags(
+        IReadOnlyList<VirtualTag> rows, IReadOnlyDictionary<string, Script> scriptById)
+    {
+        foreach (var row in rows)
+        {
+            if (!row.Enabled) continue;
+            if (!scriptById.TryGetValue(row.ScriptId, out var script))
+                throw new InvalidOperationException(
+                    $"VirtualTag '{row.VirtualTagId}' references unknown / disabled Script '{row.ScriptId}' in this generation");
+
+            yield return new VirtualTagDefinition(
+                Path: row.VirtualTagId,
+                DataType: ParseDataType(row.DataType),
+                ScriptSource: script.SourceCode,
+                ChangeTriggered: row.ChangeTriggered,
+                TimerInterval: row.TimerIntervalMs.HasValue
+                    ? TimeSpan.FromMilliseconds(row.TimerIntervalMs.Value)
+                    : null,
+                Historize: row.Historize);
+        }
+    }
+
+    internal static IEnumerable<ScriptedAlarmDefinition> ProjectScriptedAlarms(
+        IReadOnlyList<ScriptedAlarm> rows, IReadOnlyDictionary<string, Script> scriptById)
+    {
+        foreach (var row in rows)
+        {
+            if (!row.Enabled) continue;
+            if (!scriptById.TryGetValue(row.PredicateScriptId, out var script))
+                throw new InvalidOperationException(
+                    $"ScriptedAlarm '{row.ScriptedAlarmId}' references unknown / disabled predicate Script '{row.PredicateScriptId}'");
+
+            yield return new ScriptedAlarmDefinition(
+                AlarmId: row.ScriptedAlarmId,
+                EquipmentPath: row.EquipmentId,
+                AlarmName: row.Name,
+                Kind: ParseAlarmKind(row.AlarmType),
+                Severity: MapSeverity(row.Severity),
+                MessageTemplate: row.MessageTemplate,
+                PredicateScriptSource: script.SourceCode,
+                HistorizeToAveva: row.HistorizeToAveva,
+                Retain: row.Retain);
+        }
+    }
+
+    private static DriverDataType ParseDataType(string raw) =>
+        Enum.TryParse<DriverDataType>(raw, ignoreCase: true, out var parsed) ? parsed : DriverDataType.String;
+
+    private static AlarmKind ParseAlarmKind(string raw) => raw switch
+    {
+        "AlarmCondition" => AlarmKind.AlarmCondition,
+        "LimitAlarm" => AlarmKind.LimitAlarm,
+        "DiscreteAlarm" => AlarmKind.DiscreteAlarm,
+        "OffNormalAlarm" => AlarmKind.OffNormalAlarm,
+        _ => throw new InvalidOperationException($"Unknown AlarmType '{raw}' — DB check constraint should have caught this"),
+    };
+
+    // OPC UA Part 9 severity bands (1..1000) → AlarmSeverity enum. Matches the same
+    // banding the AB CIP ALMA projection + OpcUaClient MapSeverity use.
+    private static AlarmSeverity MapSeverity(int s) => s switch
+    {
+        <= 250 => AlarmSeverity.Low,
+        <= 500 => AlarmSeverity.Medium,
+        <= 750 => AlarmSeverity.High,
+        _ => AlarmSeverity.Critical,
+    };
+
+    private static async Task RouteToHistorianAsync(
+        ScriptedAlarmEvent e, IAlarmHistorianSink sink, Microsoft.Extensions.Logging.ILogger log)
+    {
+        try
+        {
+            var historianEvent = new AlarmHistorianEvent(
+                AlarmId: e.AlarmId,
+                EquipmentPath: e.EquipmentPath,
+                AlarmName: e.AlarmName,
+                AlarmTypeName: e.Kind.ToString(),
+                Severity: e.Severity,
+                EventKind: e.Emission.ToString(),
+                Message: e.Message,
+                User: e.Condition.LastAckUser ?? "system",
+                Comment: e.Condition.LastAckComment,
+                TimestampUtc: e.TimestampUtc);
+            await sink.EnqueueAsync(historianEvent, CancellationToken.None).ConfigureAwait(false);
+        }
+        catch (Exception ex)
+        {
+            log.LogWarning(ex, "Historian enqueue failed for alarm {AlarmId}/{Emission}", e.AlarmId, e.Emission);
+        }
+    }
+}
+
+/// <summary>What <see cref="Phase7EngineComposer.Compose"/> returns.</summary>
+/// <param name="VirtualReadable">Non-null when virtual tags were composed; pass to <c>OpcUaApplicationHost.virtualReadable</c>.</param>
+/// <param name="ScriptedAlarmReadable">Non-null when scripted alarms were composed; pass to <c>OpcUaApplicationHost.scriptedAlarmReadable</c>.</param>
+/// <param name="Disposables">Engine + source instances the caller owns. Dispose on shutdown.</param>
+public sealed record Phase7ComposedSources(
+    IReadable? VirtualReadable,
+    IReadable? ScriptedAlarmReadable,
+    IReadOnlyList<IDisposable> Disposables)
+{
+    public static readonly Phase7ComposedSources Empty =
+        new(null, null, Array.Empty<IDisposable>());
+}
+
+internal static class ScriptEnabledExtensions
+{
+    // Script has no explicit Enabled column; every row in the generation is a live script.
+    public static bool Enabled(this Script _) => true;
+}

src/ZB.MOM.WW.OtOpcUa.Server/Phase7/ScriptedAlarmReadable.cs

@@ -0,0 +1,58 @@
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+/// <summary>
+///     <see cref="IReadable"/> adapter exposing each scripted alarm's current
+///     <see cref="AlarmActiveState"/> as an OPC UA boolean. Phase 7 follow-up (task #245).
+/// </summary>
+/// <remarks>
+///     <para>
+///         Paired with the <see cref="NodeSourceKind.ScriptedAlarm"/> dispatch in
+///         <c>DriverNodeManager.OnReadValue</c>. Full-reference lookup is the
+///         <c>ScriptedAlarmId</c> the walker wrote into <c>DriverAttributeInfo.FullName</c>
+///         when emitting the alarm variable node.
+///     </para>
+///     <para>
+///         Unknown alarm ids return <c>BadNodeIdUnknown</c> so misconfiguration surfaces
+///         instead of silently reading <c>false</c>. Alarms whose predicate has never
+///         been evaluated (brand new, before the engine's first cascade tick) report
+///         <see cref="AlarmActiveState.Inactive"/> via <see cref="AlarmConditionState.Fresh"/>,
+///         which matches the Part 9 initial-state semantics.
+///     </para>
+/// </remarks>
+public sealed class ScriptedAlarmReadable : IReadable
+{
+    /// <summary>OPC UA <c>StatusCodes.BadNodeIdUnknown</c> — kept local so we don't pull the OPC stack.</summary>
+    private const uint BadNodeIdUnknown = 0x80340000;
+
+    private readonly ScriptedAlarmEngine _engine;
+
+    public ScriptedAlarmReadable(ScriptedAlarmEngine engine)
+    {
+        _engine = engine ?? throw new ArgumentNullException(nameof(engine));
+    }
+
+    public Task<IReadOnlyList<DataValueSnapshot>> ReadAsync(
+        IReadOnlyList<string> fullReferences, CancellationToken cancellationToken)
+    {
+        ArgumentNullException.ThrowIfNull(fullReferences);
+
+        var now = DateTime.UtcNow;
+        var results = new DataValueSnapshot[fullReferences.Count];
+        for (var i = 0; i < fullReferences.Count; i++)
+        {
+            var alarmId = fullReferences[i];
+            var state = _engine.GetState(alarmId);
+            if (state is null)
+            {
+                results[i] = new DataValueSnapshot(null, BadNodeIdUnknown, null, now);
+                continue;
+            }
+            var active = state.Active == AlarmActiveState.Active;
+            results[i] = new DataValueSnapshot(active, 0u, now, now);
+        }
+        return Task.FromResult<IReadOnlyList<DataValueSnapshot>>(results);
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Server/Program.cs

@@ -8,8 +8,10 @@ using Serilog.Formatting.Compact;
 using ZB.MOM.WW.OtOpcUa.Configuration;
 using ZB.MOM.WW.OtOpcUa.Configuration.LocalCache;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
 using ZB.MOM.WW.OtOpcUa.Server;
 using ZB.MOM.WW.OtOpcUa.Server.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
 using ZB.MOM.WW.OtOpcUa.Server.Security;
 
 var builder = Host.CreateApplicationBuilder(args);
@@ -113,5 +115,13 @@ builder.Services.AddDbContext<OtOpcUaConfigDbContext>(opt =>
     opt.UseSqlServer(options.ConfigDbConnectionString));
 builder.Services.AddHostedService<HostStatusPublisher>();
 
+// Phase 7 follow-up #246 — historian sink + engine composer. NullAlarmHistorianSink
+// is the default until the Galaxy.Host SqliteStoreAndForwardSink writer adapter
+// lands (task #248). The composer reads Script/VirtualTag/ScriptedAlarm rows on
+// generation bootstrap, builds the engines, and starts the driver-bridge feed.
+builder.Services.AddSingleton<IAlarmHistorianSink>(NullAlarmHistorianSink.Instance);
+builder.Services.AddSingleton(Log.Logger);  // Serilog root for ScriptLoggerFactory
+builder.Services.AddSingleton<Phase7Composer>();
+
 var host = builder.Build();
 await host.RunAsync();

src/ZB.MOM.WW.OtOpcUa.Server/ZB.MOM.WW.OtOpcUa.Server.csproj

@@ -30,6 +30,10 @@
 
     <ItemGroup>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Scripting\ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.VirtualTags\ZB.MOM.WW.OtOpcUa.Core.VirtualTags.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms\ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Analyzers\ZB.MOM.WW.OtOpcUa.Analyzers.csproj"
                           OutputItemType="Analyzer" ReferenceOutputAssembly="false"/>
     </ItemGroup>

tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/AdminWebAppFactory.cs

@@ -0,0 +1,130 @@
+using System.Net;
+using System.Net.Sockets;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.E2ETests;
+
+/// <summary>
+///     Stands up the Admin Blazor Server host on a free TCP port with the live SQL Server
+///     context swapped for an EF Core InMemory DbContext + the LDAP cookie auth swapped for
+///     <see cref="TestAuthHandler"/>. Playwright connects to <see cref="BaseUrl"/>.
+///     InMemory is sufficient because UnsService's drag-drop path exercises EF operations,
+///     not raw SQL.
+/// </summary>
+/// <remarks>
+///     We deliberately build a <see cref="WebApplication"/> directly rather than going through
+///     <c>WebApplicationFactory&lt;Program&gt;</c> — the factory's TestServer transport doesn't
+///     coexist cleanly with Kestrel-on-a-real-port, and Playwright needs a real loopback HTTP
+///     endpoint to hit. This mirrors the Program.cs entry-points for everything else.
+/// </remarks>
+public sealed class AdminWebAppFactory : IAsyncDisposable
+{
+    private WebApplication? _app;
+
+    public string BaseUrl { get; private set; } = "";
+    public long SeededGenerationId { get; private set; }
+    public string SeededClusterId { get; } = "e2e-cluster";
+
+    public async Task StartAsync()
+    {
+        var port = GetFreeTcpPort();
+        BaseUrl = $"http://127.0.0.1:{port}";
+
+        var builder = WebApplication.CreateBuilder(Array.Empty<string>());
+        builder.WebHost.UseUrls(BaseUrl);
+
+        // --- Mirror the Admin composition in Program.cs, but with the InMemory DB + test
+        // auth swaps instead of SQL Server + LDAP cookie auth.
+        builder.Services.AddRazorComponents().AddInteractiveServerComponents();
+        builder.Services.AddHttpContextAccessor();
+        builder.Services.AddSignalR();
+        builder.Services.AddAntiforgery();
+
+        builder.Services.AddAuthentication(TestAuthHandler.SchemeName)
+            .AddScheme<AuthenticationSchemeOptions, TestAuthHandler>(TestAuthHandler.SchemeName, _ => { });
+        builder.Services.AddAuthorizationBuilder()
+            .AddPolicy("CanEdit", p => p.RequireRole(Admin.Services.AdminRoles.ConfigEditor, Admin.Services.AdminRoles.FleetAdmin))
+            .AddPolicy("CanPublish", p => p.RequireRole(Admin.Services.AdminRoles.FleetAdmin));
+        builder.Services.AddCascadingAuthenticationState();
+
+        builder.Services.AddDbContext<OtOpcUaConfigDbContext>(opt =>
+            opt.UseInMemoryDatabase($"e2e-{Guid.NewGuid():N}"));
+
+        builder.Services.AddScoped<Admin.Services.ClusterService>();
+        builder.Services.AddScoped<Admin.Services.GenerationService>();
+        builder.Services.AddScoped<Admin.Services.UnsService>();
+        builder.Services.AddScoped<Admin.Services.EquipmentService>();
+        builder.Services.AddScoped<Admin.Services.NamespaceService>();
+        builder.Services.AddScoped<Admin.Services.DriverInstanceService>();
+        builder.Services.AddScoped<Admin.Services.DraftValidationService>();
+
+        _app = builder.Build();
+        _app.UseStaticFiles();
+        _app.UseRouting();
+        _app.UseAuthentication();
+        _app.UseAuthorization();
+        _app.UseAntiforgery();
+        _app.MapRazorComponents<Admin.Components.App>().AddInteractiveServerRenderMode();
+
+        // Seed the draft BEFORE starting the host so Playwright sees a ready page on first nav.
+        using (var scope = _app.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<OtOpcUaConfigDbContext>();
+            SeededGenerationId = Seed(db, SeededClusterId);
+        }
+
+        await _app.StartAsync();
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (_app is not null)
+        {
+            await _app.StopAsync();
+            await _app.DisposeAsync();
+        }
+    }
+
+    private static long Seed(OtOpcUaConfigDbContext db, string clusterId)
+    {
+        var cluster = new ServerCluster
+        {
+            ClusterId = clusterId, Name = "e2e", Enterprise = "zb", Site = "lab",
+            RedundancyMode = RedundancyMode.None, NodeCount = 1, CreatedBy = "e2e",
+        };
+        var gen = new ConfigGeneration
+        {
+            ClusterId = clusterId, Status = GenerationStatus.Draft, CreatedBy = "e2e",
+        };
+
+        db.ServerClusters.Add(cluster);
+        db.ConfigGenerations.Add(gen);
+        db.SaveChanges();
+
+        db.UnsAreas.AddRange(
+            new UnsArea { UnsAreaId = "area-a", ClusterId = clusterId, Name = "warsaw", GenerationId = gen.GenerationId },
+            new UnsArea { UnsAreaId = "area-b", ClusterId = clusterId, Name = "berlin", GenerationId = gen.GenerationId });
+        db.UnsLines.Add(new UnsLine
+        {
+            UnsLineId = "line-a1", UnsAreaId = "area-a", Name = "oven-line", GenerationId = gen.GenerationId,
+        });
+        db.SaveChanges();
+        return gen.GenerationId;
+    }
+
+    private static int GetFreeTcpPort()
+    {
+        var listener = new TcpListener(IPAddress.Loopback, 0);
+        listener.Start();
+        var port = ((IPEndPoint)listener.LocalEndpoint).Port;
+        listener.Stop();
+        return port;
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/PlaywrightFixture.cs

@@ -0,0 +1,44 @@
+using Microsoft.Playwright;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.E2ETests;
+
+/// <summary>
+///     One Playwright runtime + Chromium browser for the whole E2E suite. Tests
+///     open a fresh <see cref="IBrowserContext"/> per fixture so cookies + localStorage
+///     stay isolated. Browser install is a one-time step:
+///     <c>pwsh tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/bin/Debug/net10.0/playwright.ps1 install chromium</c>.
+///     When the browser binary isn't present the suite reports a <see cref="PlaywrightBrowserMissingException"/>
+///     so CI can distinguish missing-browser from real test failure.
+/// </summary>
+public sealed class PlaywrightFixture : IAsyncLifetime
+{
+    public IPlaywright Playwright { get; private set; } = null!;
+    public IBrowser Browser { get; private set; } = null!;
+
+    public async ValueTask InitializeAsync()
+    {
+        Playwright = await Microsoft.Playwright.Playwright.CreateAsync();
+        try
+        {
+            Browser = await Playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions { Headless = true });
+        }
+        catch (PlaywrightException ex) when (ex.Message.Contains("Executable doesn't exist"))
+        {
+            throw new PlaywrightBrowserMissingException(ex.Message);
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (Browser is not null) await Browser.CloseAsync();
+        Playwright?.Dispose();
+    }
+}
+
+/// <summary>
+///     Thrown by <see cref="PlaywrightFixture"/> when Chromium isn't installed. Tests
+///     catching this mark themselves as "skipped" rather than "failed", so CI without
+///     the install step stays green.
+/// </summary>
+public sealed class PlaywrightBrowserMissingException(string message) : Exception(message);

tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/TestAuthHandler.cs

@@ -0,0 +1,34 @@
+using System.Security.Claims;
+using System.Text.Encodings.Web;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.E2ETests;
+
+/// <summary>
+///     Stamps every request with a FleetAdmin principal so E2E tests can hit
+///     authenticated Razor pages without the LDAP login flow. Registered as the
+///     default authentication scheme by <see cref="AdminWebAppFactory"/>.
+/// </summary>
+public sealed class TestAuthHandler(
+    IOptionsMonitor<AuthenticationSchemeOptions> options,
+    ILoggerFactory logger,
+    UrlEncoder encoder)
+    : AuthenticationHandler<AuthenticationSchemeOptions>(options, logger, encoder)
+{
+    public const string SchemeName = "Test";
+
+    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
+    {
+        var claims = new[]
+        {
+            new Claim(ClaimTypes.Name, "e2e-test-user"),
+            new Claim(ClaimTypes.Role, AdminRoles.FleetAdmin),
+        };
+        var identity = new ClaimsIdentity(claims, SchemeName);
+        var ticket = new AuthenticationTicket(new ClaimsPrincipal(identity), SchemeName);
+        return Task.FromResult(AuthenticateResult.Success(ticket));
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/UnsTabDragDropE2ETests.cs

@@ -0,0 +1,74 @@
+using Microsoft.Playwright;
+using Shouldly;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.E2ETests;
+
+/// <summary>
+///     Phase 6.4 UnsTab drag-drop E2E smoke (task #199). This PR lands the Playwright +
+///     WebApplicationFactory-equivalent scaffolding so future E2E coverage builds on it
+///     rather than setting it up from scratch.
+/// </summary>
+/// <remarks>
+///     <para>
+///         <b>Prerequisite.</b> Chromium must be installed locally:
+///         <c>pwsh tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/bin/Debug/net10.0/playwright.ps1 install chromium</c>.
+///         When the binary is missing the tests <see cref="Assert.Skip"/> rather than fail hard,
+///         so CI pipelines that don't run the install step still report green.
+///     </para>
+///     <para>
+///         <b>Current scope.</b> The host-reachability smoke below proves the infra works:
+///         Kestrel-on-a-free-port, InMemory DbContext swap, <see cref="TestAuthHandler"/>
+///         bypass, and Playwright-to-real-browser are all exercised. The actual drag-drop
+///         interactive assertion is filed as a follow-up (task #242) because
+///         Blazor Server interactive render through a test-owned pipeline needs a dedicated
+///         diagnosis pass — the scaffolding lands here first so that follow-up can focus on
+///         the Blazor-specific wiring instead of rebuilding the harness.
+///     </para>
+/// </remarks>
+[Trait("Category", "E2E")]
+public sealed class UnsTabDragDropE2ETests
+{
+    [Fact]
+    public async Task Admin_host_serves_HTTP_via_Playwright_scaffolding()
+    {
+        await using var app = new AdminWebAppFactory();
+        await app.StartAsync();
+
+        PlaywrightFixture fixture;
+        try
+        {
+            fixture = new PlaywrightFixture();
+            await fixture.InitializeAsync();
+        }
+        catch (PlaywrightBrowserMissingException)
+        {
+            Assert.Skip("Chromium not installed. Run playwright.ps1 install chromium.");
+            return;
+        }
+
+        try
+        {
+            var ctx = await fixture.Browser.NewContextAsync();
+            var page = await ctx.NewPageAsync();
+
+            // Navigate to the root. We only assert the host is live + returns HTML — not
+            // that the Blazor Server interactive render has booted. Booting the interactive
+            // circuit in a test-owned pipeline is task #242.
+            var response = await page.GotoAsync(app.BaseUrl);
+
+            response.ShouldNotBeNull();
+            response!.Status.ShouldBeLessThan(500,
+                $"Admin host returned HTTP {response.Status} at root — scaffolding broken");
+
+            // Static HTML shell should at least include the <body> and some content. This
+            // rules out 404s + verifies the MapRazorComponents route pipeline is wired.
+            var body = await page.Locator("body").InnerHTMLAsync();
+            body.Length.ShouldBeGreaterThan(0, "empty body = routing pipeline didn't hit Razor");
+        }
+        finally
+        {
+            await fixture.DisposeAsync();
+        }
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests/ZB.MOM.WW.OtOpcUa.Admin.E2ETests.csproj

@@ -0,0 +1,34 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Admin.E2ETests</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="xunit.v3" Version="1.1.0"/>
+        <PackageReference Include="Shouldly" Version="4.3.0"/>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0"/>
+        <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2">
+            <PrivateAssets>all</PrivateAssets>
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+        </PackageReference>
+        <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="10.0.0"/>
+        <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.0"/>
+        <PackageReference Include="Microsoft.Playwright" Version="1.51.0"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\ZB.MOM.WW.OtOpcUa.Admin\ZB.MOM.WW.OtOpcUa.Admin.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-37gx-xxp4-5rgx"/>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-w3x6-4m5h-cxqf"/>
+    </ItemGroup>
+
+</Project>

tests/ZB.MOM.WW.OtOpcUa.Admin.Tests/Phase7ServicesTests.cs

@@ -0,0 +1,196 @@
+using Microsoft.EntityFrameworkCore;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Admin.Services;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Tests;
+
+/// <summary>
+///     Admin-side services shipped in Phase 7 Stream F — draft CRUD for scripts + virtual
+///     tags + scripted alarms, the pre-publish test harness, and the historian
+///     diagnostics façade.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class Phase7ServicesTests
+{
+    private static OtOpcUaConfigDbContext NewDb([System.Runtime.CompilerServices.CallerMemberName] string test = "")
+    {
+        var options = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
+            .UseInMemoryDatabase($"phase7-{test}-{Guid.NewGuid():N}")
+            .Options;
+        return new OtOpcUaConfigDbContext(options);
+    }
+
+    [Fact]
+    public async Task ScriptService_AddAsync_generates_logical_id_and_hash()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+
+        var s = await svc.AddAsync(5, "line-rate", "return ctx.GetTag(\"a\").Value;", default);
+
+        s.ScriptId.ShouldStartWith("scr-");
+        s.GenerationId.ShouldBe(5);
+        s.SourceHash.Length.ShouldBe(64);
+        (await svc.ListAsync(5, default)).Count.ShouldBe(1);
+    }
+
+    [Fact]
+    public async Task ScriptService_UpdateAsync_recomputes_hash_on_source_change()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+        var s = await svc.AddAsync(5, "s", "return 1;", default);
+        var hashBefore = s.SourceHash;
+
+        var updated = await svc.UpdateAsync(5, s.ScriptId, "s", "return 2;", default);
+        updated.SourceHash.ShouldNotBe(hashBefore);
+    }
+
+    [Fact]
+    public async Task ScriptService_UpdateAsync_same_source_same_hash()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+        var s = await svc.AddAsync(5, "s", "return 1;", default);
+        var updated = await svc.UpdateAsync(5, s.ScriptId, "renamed", "return 1;", default);
+
+        updated.SourceHash.ShouldBe(s.SourceHash, "source unchanged → hash unchanged → compile cache hit preserved");
+    }
+
+    [Fact]
+    public async Task ScriptService_DeleteAsync_is_idempotent()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+
+        await Should.NotThrowAsync(() => svc.DeleteAsync(5, "nonexistent", default));
+    }
+
+    [Fact]
+    public async Task VirtualTagService_round_trips_trigger_flags()
+    {
+        using var db = NewDb();
+        var svc = new VirtualTagService(db);
+
+        var v = await svc.AddAsync(7, "eq-1", "LineRate", "Float32", "scr-1",
+            changeTriggered: true, timerIntervalMs: 1000, historize: true, default);
+
+        v.ChangeTriggered.ShouldBeTrue();
+        v.TimerIntervalMs.ShouldBe(1000);
+        v.Historize.ShouldBeTrue();
+        v.Enabled.ShouldBeTrue();
+        (await svc.ListAsync(7, default)).Single().VirtualTagId.ShouldBe(v.VirtualTagId);
+    }
+
+    [Fact]
+    public async Task VirtualTagService_update_enabled_toggles_flag()
+    {
+        using var db = NewDb();
+        var svc = new VirtualTagService(db);
+        var v = await svc.AddAsync(7, "eq-1", "N", "Int32", "scr-1", true, null, false, default);
+
+        var disabled = await svc.UpdateEnabledAsync(7, v.VirtualTagId, false, default);
+        disabled.Enabled.ShouldBeFalse();
+    }
+
+    [Fact]
+    public async Task ScriptedAlarmService_defaults_HistorizeToAveva_true_per_plan_decision_15()
+    {
+        using var db = NewDb();
+        var svc = new ScriptedAlarmService(db);
+
+        var a = await svc.AddAsync(9, "eq-1", "HighTemp", "LimitAlarm", severity: 800,
+            messageTemplate: "{Temp} too high", predicateScriptId: "scr-9",
+            historizeToAveva: true, retain: true, default);
+
+        a.HistorizeToAveva.ShouldBeTrue();
+        a.Severity.ShouldBe(800);
+        a.ScriptedAlarmId.ShouldStartWith("sal-");
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_runs_successful_script_and_captures_writes()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """
+            ctx.SetVirtualTag("Out", 42);
+            return ctx.GetTag("In").Value;
+            """;
+        var inputs = new Dictionary<string, DataValueSnapshot>
+        {
+            ["In"] = new(123, 0u, DateTime.UtcNow, DateTime.UtcNow),
+        };
+
+        var result = await harness.RunVirtualTagAsync(source, inputs, default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.Success);
+        result.Output.ShouldBe(123);
+        result.Writes["Out"].ShouldBe(42);
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_rejects_missing_synthetic_input()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """return ctx.GetTag("A").Value;""";
+
+        var result = await harness.RunVirtualTagAsync(source, new Dictionary<string, DataValueSnapshot>(), default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.MissingInputs);
+        result.Errors[0].ShouldContain("A");
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_rejects_extra_synthetic_input_not_referenced_by_script()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """return 1;""";  // no GetTag calls
+        var inputs = new Dictionary<string, DataValueSnapshot>
+        {
+            ["Unexpected"] = new(0, 0u, DateTime.UtcNow, DateTime.UtcNow),
+        };
+
+        var result = await harness.RunVirtualTagAsync(source, inputs, default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.UnknownInputs);
+        result.Errors[0].ShouldContain("Unexpected");
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_rejects_non_literal_path()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """
+            var p = "A";
+            return ctx.GetTag(p).Value;
+            """;
+
+        var result = await harness.RunVirtualTagAsync(source, new Dictionary<string, DataValueSnapshot>(), default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.DependencyRejected);
+        result.Errors.ShouldNotBeEmpty();
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_surfaces_compile_error_as_Threw()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = "this is not valid C#;";
+
+        var result = await harness.RunVirtualTagAsync(source, new Dictionary<string, DataValueSnapshot>(), default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.Threw);
+    }
+
+    [Fact]
+    public void HistorianDiagnosticsService_reports_Disabled_for_null_sink()
+    {
+        var diag = new HistorianDiagnosticsService(NullAlarmHistorianSink.Instance);
+        diag.GetStatus().DrainState.ShouldBe(HistorianDrainState.Disabled);
+        diag.TryRetryDeadLettered().ShouldBe(0);
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Configuration.Tests/Phase7ScriptingEntitiesTests.cs

@@ -0,0 +1,184 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.Extensions.DependencyInjection;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Configuration.Tests;
+
+/// <summary>
+///     Verifies the Phase 7 Stream E entities (<see cref="Script"/>, <see cref="VirtualTag"/>,
+///     <see cref="ScriptedAlarm"/>, <see cref="ScriptedAlarmState"/>) register correctly in
+///     the EF model, map to the expected tables/columns/indexes, and carry the check constraints
+///     the plan decisions call for. Introspection only — no SQL Server required.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class Phase7ScriptingEntitiesTests
+{
+    private static OtOpcUaConfigDbContext BuildCtx()
+    {
+        var options = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
+            .UseSqlServer("Server=(local);Database=dummy;Integrated Security=true") // not connected
+            .Options;
+        return new OtOpcUaConfigDbContext(options);
+    }
+
+    private static Microsoft.EntityFrameworkCore.Metadata.IModel DesignModel(OtOpcUaConfigDbContext ctx)
+        => ctx.GetService<IDesignTimeModel>().Model;
+
+    [Fact]
+    public void Script_entity_registered_with_expected_table_and_columns()
+    {
+        using var ctx = BuildCtx();
+        var entity = ctx.Model.FindEntityType(typeof(Script)).ShouldNotBeNull();
+
+        entity.GetTableName().ShouldBe("Script");
+        entity.FindProperty(nameof(Script.ScriptRowId)).ShouldNotBeNull();
+        entity.FindProperty(nameof(Script.ScriptId)).ShouldNotBeNull()
+            .GetMaxLength().ShouldBe(64);
+        entity.FindProperty(nameof(Script.SourceCode)).ShouldNotBeNull()
+            .GetColumnType().ShouldBe("nvarchar(max)");
+        entity.FindProperty(nameof(Script.SourceHash)).ShouldNotBeNull()
+            .GetMaxLength().ShouldBe(64);
+        entity.FindProperty(nameof(Script.Language)).ShouldNotBeNull()
+            .GetMaxLength().ShouldBe(16);
+    }
+
+    [Fact]
+    public void Script_has_unique_logical_id_per_generation()
+    {
+        using var ctx = BuildCtx();
+        var entity = ctx.Model.FindEntityType(typeof(Script)).ShouldNotBeNull();
+        entity.GetIndexes().ShouldContain(
+            i => i.IsUnique && i.GetDatabaseName() == "UX_Script_Generation_LogicalId");
+        entity.GetIndexes().ShouldContain(
+            i => i.GetDatabaseName() == "IX_Script_Generation_SourceHash");
+    }
+
+    [Fact]
+    public void VirtualTag_entity_registered_with_trigger_check_constraint()
+    {
+        using var ctx = BuildCtx();
+        var entity = DesignModel(ctx).FindEntityType(typeof(VirtualTag)).ShouldNotBeNull();
+        entity.GetTableName().ShouldBe("VirtualTag");
+
+        var checks = entity.GetCheckConstraints().Select(c => c.Name).ToArray();
+        checks.ShouldContain("CK_VirtualTag_Trigger_AtLeastOne");
+        checks.ShouldContain("CK_VirtualTag_TimerInterval_Min");
+    }
+
+    [Fact]
+    public void VirtualTag_enforces_unique_name_per_Equipment()
+    {
+        using var ctx = BuildCtx();
+        var entity = ctx.Model.FindEntityType(typeof(VirtualTag)).ShouldNotBeNull();
+        entity.GetIndexes().ShouldContain(
+            i => i.IsUnique && i.GetDatabaseName() == "UX_VirtualTag_Generation_EquipmentPath");
+    }
+
+    [Fact]
+    public void VirtualTag_has_ChangeTriggered_and_Historize_flags()
+    {
+        using var ctx = BuildCtx();
+        var entity = ctx.Model.FindEntityType(typeof(VirtualTag)).ShouldNotBeNull();
+        entity.FindProperty(nameof(VirtualTag.ChangeTriggered)).ShouldNotBeNull()
+            .ClrType.ShouldBe(typeof(bool));
+        entity.FindProperty(nameof(VirtualTag.Historize)).ShouldNotBeNull()
+            .ClrType.ShouldBe(typeof(bool));
+        entity.FindProperty(nameof(VirtualTag.TimerIntervalMs)).ShouldNotBeNull()
+            .ClrType.ShouldBe(typeof(int?));
+    }
+
+    [Fact]
+    public void ScriptedAlarm_entity_registered_with_severity_and_type_checks()
+    {
+        using var ctx = BuildCtx();
+        var entity = DesignModel(ctx).FindEntityType(typeof(ScriptedAlarm)).ShouldNotBeNull();
+        entity.GetTableName().ShouldBe("ScriptedAlarm");
+
+        var checks = entity.GetCheckConstraints().Select(c => c.Name).ToArray();
+        checks.ShouldContain("CK_ScriptedAlarm_Severity_Range");
+        checks.ShouldContain("CK_ScriptedAlarm_AlarmType");
+    }
+
+    [Fact]
+    public void ScriptedAlarm_has_HistorizeToAveva_default_true_per_plan_decision_15()
+    {
+        // Defaults live on the CLR default assignment — verify the initializer.
+        var alarm = new ScriptedAlarm
+        {
+            ScriptedAlarmId = "a1",
+            EquipmentId = "eq1",
+            Name = "n",
+            AlarmType = "LimitAlarm",
+            MessageTemplate = "m",
+            PredicateScriptId = "s1",
+        };
+        alarm.HistorizeToAveva.ShouldBeTrue();
+        alarm.Retain.ShouldBeTrue();
+        alarm.Severity.ShouldBe(500);
+        alarm.Enabled.ShouldBeTrue();
+    }
+
+    [Fact]
+    public void ScriptedAlarmState_keyed_on_ScriptedAlarmId_not_generation_scoped()
+    {
+        using var ctx = BuildCtx();
+        var entity = ctx.Model.FindEntityType(typeof(ScriptedAlarmState)).ShouldNotBeNull();
+        entity.GetTableName().ShouldBe("ScriptedAlarmState");
+
+        var pk = entity.FindPrimaryKey().ShouldNotBeNull();
+        pk.Properties.Count.ShouldBe(1);
+        pk.Properties[0].Name.ShouldBe(nameof(ScriptedAlarmState.ScriptedAlarmId));
+
+        // State is NOT generation-scoped — GenerationId column should not exist per plan decision #14.
+        entity.FindProperty("GenerationId").ShouldBeNull(
+            "ack state follows alarm identity across generations");
+    }
+
+    [Fact]
+    public void ScriptedAlarmState_default_state_values_match_Part9_initial_states()
+    {
+        var state = new ScriptedAlarmState
+        {
+            ScriptedAlarmId = "a1",
+            EnabledState = "Enabled",
+            AckedState = "Unacknowledged",
+            ConfirmedState = "Unconfirmed",
+            ShelvingState = "Unshelved",
+        };
+        state.CommentsJson.ShouldBe("[]");
+        state.LastAckUser.ShouldBeNull();
+        state.LastAckUtc.ShouldBeNull();
+    }
+
+    [Fact]
+    public void ScriptedAlarmState_has_JSON_check_constraint_on_CommentsJson()
+    {
+        using var ctx = BuildCtx();
+        var entity = DesignModel(ctx).FindEntityType(typeof(ScriptedAlarmState)).ShouldNotBeNull();
+        var checks = entity.GetCheckConstraints().Select(c => c.Name).ToArray();
+        checks.ShouldContain("CK_ScriptedAlarmState_CommentsJson_IsJson");
+    }
+
+    [Fact]
+    public void All_new_entities_exposed_via_DbSet()
+    {
+        using var ctx = BuildCtx();
+        ctx.Scripts.ShouldNotBeNull();
+        ctx.VirtualTags.ShouldNotBeNull();
+        ctx.ScriptedAlarms.ShouldNotBeNull();
+        ctx.ScriptedAlarmStates.ShouldNotBeNull();
+    }
+
+    [Fact]
+    public void AddPhase7ScriptingTables_migration_exists_in_assembly()
+    {
+        // The migration type carries the design-time snapshot + Up/Down methods EF uses to
+        // apply the schema. Missing = schema won't roll forward in deployments.
+        var t = typeof(Migrations.AddPhase7ScriptingTables);
+        t.ShouldNotBeNull();
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests/SqliteStoreAndForwardSinkTests.cs

@@ -0,0 +1,286 @@
+using Serilog;
+using Serilog.Core;
+using Serilog.Events;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests;
+
+/// <summary>
+///     Verifies the durable SQLite store-and-forward queue behind the historian sink:
+///     round-trip Ack, backoff ladder on RetryPlease, dead-lettering on PermanentFail,
+///     capacity eviction, and retention-based dead-letter purge.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class SqliteStoreAndForwardSinkTests : IDisposable
+{
+    private readonly string _dbPath;
+    private readonly ILogger _log;
+
+    public SqliteStoreAndForwardSinkTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"otopcua-historian-{Guid.NewGuid():N}.sqlite");
+        _log = new LoggerConfiguration().MinimumLevel.Verbose().CreateLogger();
+    }
+
+    public void Dispose()
+    {
+        try { if (File.Exists(_dbPath)) File.Delete(_dbPath); } catch { }
+    }
+
+    private sealed class FakeWriter : IAlarmHistorianWriter
+    {
+        public Queue<HistorianWriteOutcome> NextOutcomePerEvent { get; } = new();
+        public HistorianWriteOutcome DefaultOutcome { get; set; } = HistorianWriteOutcome.Ack;
+        public List<IReadOnlyList<AlarmHistorianEvent>> Batches { get; } = [];
+        public Exception? ThrowOnce { get; set; }
+
+        public Task<IReadOnlyList<HistorianWriteOutcome>> WriteBatchAsync(
+            IReadOnlyList<AlarmHistorianEvent> batch, CancellationToken ct)
+        {
+            if (ThrowOnce is not null)
+            {
+                var e = ThrowOnce;
+                ThrowOnce = null;
+                throw e;
+            }
+            Batches.Add(batch);
+            var outcomes = new List<HistorianWriteOutcome>();
+            for (var i = 0; i < batch.Count; i++)
+                outcomes.Add(NextOutcomePerEvent.Count > 0 ? NextOutcomePerEvent.Dequeue() : DefaultOutcome);
+            return Task.FromResult<IReadOnlyList<HistorianWriteOutcome>>(outcomes);
+        }
+    }
+
+    private static AlarmHistorianEvent Event(string alarmId, DateTime? ts = null) => new(
+        AlarmId: alarmId,
+        EquipmentPath: "/Site/Line1/Cell",
+        AlarmName: "HighTemp",
+        AlarmTypeName: "LimitAlarm",
+        Severity: AlarmSeverity.High,
+        EventKind: "Activated",
+        Message: "temp exceeded",
+        User: "system",
+        Comment: null,
+        TimestampUtc: ts ?? DateTime.UtcNow);
+
+    [Fact]
+    public async Task EnqueueThenDrain_Ack_removes_row()
+    {
+        var writer = new FakeWriter();
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        sink.GetStatus().QueueDepth.ShouldBe(1);
+
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        writer.Batches.Count.ShouldBe(1);
+        writer.Batches[0].Count.ShouldBe(1);
+        writer.Batches[0][0].AlarmId.ShouldBe("A1");
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(0);
+        status.DeadLetterDepth.ShouldBe(0);
+        status.LastSuccessUtc.ShouldNotBeNull();
+    }
+
+    [Fact]
+    public async Task Drain_with_empty_queue_is_noop()
+    {
+        var writer = new FakeWriter();
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        writer.Batches.ShouldBeEmpty();
+        sink.GetStatus().DrainState.ShouldBe(HistorianDrainState.Idle);
+    }
+
+    [Fact]
+    public async Task RetryPlease_bumps_backoff_and_keeps_row()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.RetryPlease);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        var before = sink.CurrentBackoff;
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.CurrentBackoff.ShouldBeGreaterThan(before);
+        sink.GetStatus().QueueDepth.ShouldBe(1, "row stays in queue for retry");
+        sink.GetStatus().DrainState.ShouldBe(HistorianDrainState.BackingOff);
+    }
+
+    [Fact]
+    public async Task Ack_after_Retry_resets_backoff()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.RetryPlease);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.CurrentBackoff.ShouldBeGreaterThan(TimeSpan.FromSeconds(1) - TimeSpan.FromMilliseconds(1));
+
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.Ack);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.CurrentBackoff.ShouldBe(TimeSpan.FromSeconds(1));
+        sink.GetStatus().QueueDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task PermanentFail_dead_letters_one_row_only()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.PermanentFail);
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.Ack);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("bad"), CancellationToken.None);
+        await sink.EnqueueAsync(Event("good"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(0, "good row acked");
+        status.DeadLetterDepth.ShouldBe(1, "bad row dead-lettered");
+    }
+
+    [Fact]
+    public async Task Writer_exception_treated_as_retry_for_whole_batch()
+    {
+        var writer = new FakeWriter { ThrowOnce = new InvalidOperationException("pipe broken") };
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(1);
+        status.LastError.ShouldBe("pipe broken");
+        status.DrainState.ShouldBe(HistorianDrainState.BackingOff);
+
+        // Next drain after the writer recovers should Ack.
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.GetStatus().QueueDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task Capacity_eviction_drops_oldest_nondeadlettered_row()
+    {
+        var writer = new FakeWriter();
+        using var sink = new SqliteStoreAndForwardSink(
+            _dbPath, writer, _log, batchSize: 100, capacity: 3);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+        await sink.EnqueueAsync(Event("A2"), CancellationToken.None);
+        await sink.EnqueueAsync(Event("A3"), CancellationToken.None);
+        // A4 enqueue must evict the oldest (A1).
+        await sink.EnqueueAsync(Event("A4"), CancellationToken.None);
+
+        sink.GetStatus().QueueDepth.ShouldBe(3);
+
+        await sink.DrainOnceAsync(CancellationToken.None);
+        var drained = writer.Batches[0].Select(e => e.AlarmId).ToArray();
+        drained.ShouldNotContain("A1");
+        drained.ShouldContain("A2");
+        drained.ShouldContain("A3");
+        drained.ShouldContain("A4");
+    }
+
+    [Fact]
+    public async Task Deadlettered_rows_are_purged_past_retention()
+    {
+        var now = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+        DateTime clock = now;
+
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.PermanentFail);
+        using var sink = new SqliteStoreAndForwardSink(
+            _dbPath, writer, _log, deadLetterRetention: TimeSpan.FromDays(30),
+            clock: () => clock);
+
+        await sink.EnqueueAsync(Event("bad"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.GetStatus().DeadLetterDepth.ShouldBe(1);
+
+        // Advance past retention + tick drain (which runs PurgeAgedDeadLetters).
+        clock = now.AddDays(31);
+        await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.GetStatus().DeadLetterDepth.ShouldBe(0, "purged past retention");
+    }
+
+    [Fact]
+    public async Task RetryDeadLettered_requeues_for_retry()
+    {
+        var writer = new FakeWriter();
+        writer.NextOutcomePerEvent.Enqueue(HistorianWriteOutcome.PermanentFail);
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("bad"), CancellationToken.None);
+        await sink.DrainOnceAsync(CancellationToken.None);
+        sink.GetStatus().DeadLetterDepth.ShouldBe(1);
+
+        var revived = sink.RetryDeadLettered();
+        revived.ShouldBe(1);
+
+        var status = sink.GetStatus();
+        status.QueueDepth.ShouldBe(1);
+        status.DeadLetterDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task Backoff_ladder_caps_at_60s()
+    {
+        var writer = new FakeWriter { DefaultOutcome = HistorianWriteOutcome.RetryPlease };
+        using var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+
+        await sink.EnqueueAsync(Event("A1"), CancellationToken.None);
+
+        // 10 retry rounds — ladder should cap at 60s.
+        for (var i = 0; i < 10; i++)
+            await sink.DrainOnceAsync(CancellationToken.None);
+
+        sink.CurrentBackoff.ShouldBe(TimeSpan.FromSeconds(60));
+    }
+
+    [Fact]
+    public void NullAlarmHistorianSink_reports_disabled_status()
+    {
+        var s = NullAlarmHistorianSink.Instance.GetStatus();
+        s.DrainState.ShouldBe(HistorianDrainState.Disabled);
+        s.QueueDepth.ShouldBe(0);
+    }
+
+    [Fact]
+    public async Task NullAlarmHistorianSink_swallows_enqueue()
+    {
+        // Should not throw or persist anything.
+        await NullAlarmHistorianSink.Instance.EnqueueAsync(Event("A1"), CancellationToken.None);
+    }
+
+    [Fact]
+    public void Ctor_rejects_bad_args()
+    {
+        var w = new FakeWriter();
+        Should.Throw<ArgumentException>(() => new SqliteStoreAndForwardSink("", w, _log));
+        Should.Throw<ArgumentNullException>(() => new SqliteStoreAndForwardSink(_dbPath, null!, _log));
+        Should.Throw<ArgumentNullException>(() => new SqliteStoreAndForwardSink(_dbPath, w, null!));
+        Should.Throw<ArgumentOutOfRangeException>(() => new SqliteStoreAndForwardSink(_dbPath, w, _log, batchSize: 0));
+        Should.Throw<ArgumentOutOfRangeException>(() => new SqliteStoreAndForwardSink(_dbPath, w, _log, capacity: 0));
+    }
+
+    [Fact]
+    public async Task Disposed_sink_rejects_enqueue()
+    {
+        var writer = new FakeWriter();
+        var sink = new SqliteStoreAndForwardSink(_dbPath, writer, _log);
+        sink.Dispose();
+
+        await Should.ThrowAsync<ObjectDisposedException>(
+            () => sink.EnqueueAsync(Event("A1"), CancellationToken.None));
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests/ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net10.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <IsPackable>false</IsPackable>
+        <IsTestProject>true</IsTestProject>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.Tests</RootNamespace>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="xunit.v3" Version="1.1.0"/>
+        <PackageReference Include="Shouldly" Version="4.3.0"/>
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0"/>
+        <PackageReference Include="xunit.runner.visualstudio" Version="3.0.2">
+            <PrivateAssets>all</PrivateAssets>
+            <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+        </PackageReference>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-37gx-xxp4-5rgx"/>
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-w3x6-4m5h-cxqf"/>
+    </ItemGroup>
+
+</Project>

tests/ZB.MOM.WW.OtOpcUa.Core.Tests/OpcUa/EquipmentNodeWalkerTests.cs

@@ -147,6 +147,117 @@ public sealed class EquipmentNodeWalkerTests
         variable.AttributeInfo.DriverDataType.ShouldBe(DriverDataType.String);
     }
 
+    [Fact]
+    public void Walk_Emits_VirtualTag_Variables_With_Virtual_Source_Discriminator()
+    {
+        var eq = Eq("eq-1", "line-1", "oven-3");
+        var vtag = new VirtualTag
+        {
+            VirtualTagRowId = Guid.NewGuid(), GenerationId = 1,
+            VirtualTagId = "vt-1", EquipmentId = "eq-1", Name = "LineRate",
+            DataType = "Float32", ScriptId = "scr-1", Historize = true,
+        };
+        var content = new EquipmentNamespaceContent(
+            [Area("area-1", "warsaw")], [Line("line-1", "area-1", "line-a")],
+            [eq], [], VirtualTags: [vtag]);
+
+        var rec = new RecordingBuilder("root");
+        EquipmentNodeWalker.Walk(rec, content);
+
+        var equipmentNode = rec.Children[0].Children[0].Children[0];
+        var v = equipmentNode.Variables.Single(x => x.BrowseName == "LineRate");
+        v.AttributeInfo.Source.ShouldBe(NodeSourceKind.Virtual);
+        v.AttributeInfo.VirtualTagId.ShouldBe("vt-1");
+        v.AttributeInfo.ScriptedAlarmId.ShouldBeNull();
+        v.AttributeInfo.IsHistorized.ShouldBeTrue();
+        v.AttributeInfo.DriverDataType.ShouldBe(DriverDataType.Float32);
+    }
+
+    [Fact]
+    public void Walk_Emits_ScriptedAlarm_Variables_With_ScriptedAlarm_Source_And_IsAlarm()
+    {
+        var eq = Eq("eq-1", "line-1", "oven-3");
+        var alarm = new ScriptedAlarm
+        {
+            ScriptedAlarmRowId = Guid.NewGuid(), GenerationId = 1,
+            ScriptedAlarmId = "al-1", EquipmentId = "eq-1", Name = "HighTemp",
+            AlarmType = "LimitAlarm", MessageTemplate = "{Temp} exceeded",
+            PredicateScriptId = "scr-9", Severity = 800,
+        };
+        var content = new EquipmentNamespaceContent(
+            [Area("area-1", "warsaw")], [Line("line-1", "area-1", "line-a")],
+            [eq], [], ScriptedAlarms: [alarm]);
+
+        var rec = new RecordingBuilder("root");
+        EquipmentNodeWalker.Walk(rec, content);
+
+        var v = rec.Children[0].Children[0].Children[0].Variables.Single(x => x.BrowseName == "HighTemp");
+        v.AttributeInfo.Source.ShouldBe(NodeSourceKind.ScriptedAlarm);
+        v.AttributeInfo.ScriptedAlarmId.ShouldBe("al-1");
+        v.AttributeInfo.VirtualTagId.ShouldBeNull();
+        v.AttributeInfo.IsAlarm.ShouldBeTrue();
+        v.AttributeInfo.DriverDataType.ShouldBe(DriverDataType.Boolean);
+    }
+
+    [Fact]
+    public void Walk_Skips_Disabled_VirtualTags_And_Alarms()
+    {
+        var eq = Eq("eq-1", "line-1", "oven-3");
+        var vtag = new VirtualTag
+        {
+            VirtualTagRowId = Guid.NewGuid(), GenerationId = 1,
+            VirtualTagId = "vt-1", EquipmentId = "eq-1", Name = "Disabled",
+            DataType = "Float32", ScriptId = "scr-1", Enabled = false,
+        };
+        var alarm = new ScriptedAlarm
+        {
+            ScriptedAlarmRowId = Guid.NewGuid(), GenerationId = 1,
+            ScriptedAlarmId = "al-1", EquipmentId = "eq-1", Name = "DisabledAlarm",
+            AlarmType = "LimitAlarm", MessageTemplate = "x",
+            PredicateScriptId = "scr-9", Enabled = false,
+        };
+        var content = new EquipmentNamespaceContent(
+            [Area("area-1", "warsaw")], [Line("line-1", "area-1", "line-a")],
+            [eq], [], VirtualTags: [vtag], ScriptedAlarms: [alarm]);
+
+        var rec = new RecordingBuilder("root");
+        EquipmentNodeWalker.Walk(rec, content);
+
+        rec.Children[0].Children[0].Children[0].Variables.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void Walk_Null_VirtualTags_And_ScriptedAlarms_Is_Safe()
+    {
+        // Backwards-compat — callers that don't populate the new collections still work.
+        var eq = Eq("eq-1", "line-1", "oven-3");
+        var content = new EquipmentNamespaceContent(
+            [Area("area-1", "warsaw")], [Line("line-1", "area-1", "line-a")], [eq], []);
+
+        var rec = new RecordingBuilder("root");
+        EquipmentNodeWalker.Walk(rec, content);  // must not throw
+
+        rec.Children[0].Children[0].Children[0].Variables.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void Driver_tag_default_NodeSourceKind_is_Driver()
+    {
+        var eq = Eq("eq-1", "line-1", "oven-3");
+        var tag = NewTag("t-1", "Temp", "Int32", "plc-01", "eq-1");
+        var content = new EquipmentNamespaceContent(
+            [Area("area-1", "warsaw")], [Line("line-1", "area-1", "line-a")],
+            [eq], [tag]);
+
+        var rec = new RecordingBuilder("root");
+        EquipmentNodeWalker.Walk(rec, content);
+
+        var v = rec.Children[0].Children[0].Children[0].Variables.Single();
+        v.AttributeInfo.Source.ShouldBe(NodeSourceKind.Driver);
+        v.AttributeInfo.VirtualTagId.ShouldBeNull();
+        v.AttributeInfo.ScriptedAlarmId.ShouldBeNull();
+    }
+
     // ----- builders for test seed rows -----
 
     private static UnsArea Area(string id, string name) => new()

tests/ZB.MOM.WW.OtOpcUa.Server.Tests/DriverNodeManagerSourceDispatchTests.cs

@@ -0,0 +1,89 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Server.OpcUa;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests;
+
+/// <summary>
+///     Phase 7 Stream G follow-up — verifies the NodeSourceKind dispatch kernel that
+///     DriverNodeManager's OnReadValue + OnWriteValue use to route per-node calls to
+///     the right backend per ADR-002. Pure functions; no OPC UA stack required.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class DriverNodeManagerSourceDispatchTests
+{
+    private sealed class FakeReadable : IReadable
+    {
+        public string Name { get; init; } = "";
+        public Task<IReadOnlyList<DataValueSnapshot>> ReadAsync(
+            IReadOnlyList<string> fullReferences, CancellationToken cancellationToken) =>
+            Task.FromResult<IReadOnlyList<DataValueSnapshot>>([]);
+    }
+
+    [Fact]
+    public void Driver_source_routes_to_driver_readable()
+    {
+        var drv = new FakeReadable { Name = "drv" };
+        var vt = new FakeReadable { Name = "vt" };
+        var al = new FakeReadable { Name = "al" };
+
+        DriverNodeManager.SelectReadable(NodeSourceKind.Driver, drv, vt, al).ShouldBeSameAs(drv);
+    }
+
+    [Fact]
+    public void Virtual_source_routes_to_virtual_readable()
+    {
+        var drv = new FakeReadable();
+        var vt = new FakeReadable();
+        var al = new FakeReadable();
+
+        DriverNodeManager.SelectReadable(NodeSourceKind.Virtual, drv, vt, al).ShouldBeSameAs(vt);
+    }
+
+    [Fact]
+    public void ScriptedAlarm_source_routes_to_alarm_readable()
+    {
+        var drv = new FakeReadable();
+        var vt = new FakeReadable();
+        var al = new FakeReadable();
+
+        DriverNodeManager.SelectReadable(NodeSourceKind.ScriptedAlarm, drv, vt, al).ShouldBeSameAs(al);
+    }
+
+    [Fact]
+    public void Virtual_source_without_virtual_readable_returns_null()
+    {
+        // Engine not wired → dispatch layer surfaces BadNotFound (the null propagates
+        // through to the OnReadValue null-check).
+        DriverNodeManager.SelectReadable(
+            NodeSourceKind.Virtual, driverReadable: new FakeReadable(),
+            virtualReadable: null, scriptedAlarmReadable: null).ShouldBeNull();
+    }
+
+    [Fact]
+    public void ScriptedAlarm_source_without_alarm_readable_returns_null()
+    {
+        DriverNodeManager.SelectReadable(
+            NodeSourceKind.ScriptedAlarm, driverReadable: new FakeReadable(),
+            virtualReadable: new FakeReadable(), scriptedAlarmReadable: null).ShouldBeNull();
+    }
+
+    [Fact]
+    public void Driver_source_without_driver_readable_returns_null()
+    {
+        // Pre-existing BadNotReadable behavior — unchanged by Phase 7 wiring.
+        DriverNodeManager.SelectReadable(
+            NodeSourceKind.Driver, driverReadable: null,
+            virtualReadable: new FakeReadable(), scriptedAlarmReadable: new FakeReadable()).ShouldBeNull();
+    }
+
+    [Fact]
+    public void IsWriteAllowedBySource_only_Driver_returns_true()
+    {
+        // Plan decision #6 — OPC UA writes to virtual tags / scripted alarms rejected.
+        DriverNodeManager.IsWriteAllowedBySource(NodeSourceKind.Driver).ShouldBeTrue();
+        DriverNodeManager.IsWriteAllowedBySource(NodeSourceKind.Virtual).ShouldBeFalse();
+        DriverNodeManager.IsWriteAllowedBySource(NodeSourceKind.ScriptedAlarm).ShouldBeFalse();
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Server.Tests/Phase7/CachedTagUpstreamSourceTests.cs

@@ -0,0 +1,83 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests.Phase7;
+
+/// <summary>
+///     Covers the Phase 7 driver-to-engine bridge cache (task #243). Verifies the
+///     cache serves last-known values synchronously, fans out Push updates to
+///     subscribers, and cleans up on Dispose.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class CachedTagUpstreamSourceTests
+{
+    private static DataValueSnapshot Snap(object? v) =>
+        new(v, 0u, DateTime.UtcNow, DateTime.UtcNow);
+
+    [Fact]
+    public void ReadTag_unknown_path_returns_BadNodeIdUnknown_snapshot()
+    {
+        var c = new CachedTagUpstreamSource();
+        var snap = c.ReadTag("/nowhere");
+        snap.Value.ShouldBeNull();
+        snap.StatusCode.ShouldBe(CachedTagUpstreamSource.UpstreamNotConfigured);
+    }
+
+    [Fact]
+    public void Push_then_Read_returns_cached_value()
+    {
+        var c = new CachedTagUpstreamSource();
+        c.Push("/Line1/Temp", Snap(42));
+        c.ReadTag("/Line1/Temp").Value.ShouldBe(42);
+    }
+
+    [Fact]
+    public void Push_fans_out_to_subscribers_in_registration_order()
+    {
+        var c = new CachedTagUpstreamSource();
+        var events = new List<string>();
+        c.SubscribeTag("/X", (p, s) => events.Add($"A:{p}:{s.Value}"));
+        c.SubscribeTag("/X", (p, s) => events.Add($"B:{p}:{s.Value}"));
+
+        c.Push("/X", Snap(7));
+
+        events.ShouldBe(["A:/X:7", "B:/X:7"]);
+    }
+
+    [Fact]
+    public void Push_to_different_path_does_not_fire_foreign_observer()
+    {
+        var c = new CachedTagUpstreamSource();
+        var fired = 0;
+        c.SubscribeTag("/X", (_, _) => fired++);
+
+        c.Push("/Y", Snap(1));
+        fired.ShouldBe(0);
+    }
+
+    [Fact]
+    public void Dispose_of_subscription_stops_fan_out()
+    {
+        var c = new CachedTagUpstreamSource();
+        var fired = 0;
+        var sub = c.SubscribeTag("/X", (_, _) => fired++);
+
+        c.Push("/X", Snap(1));
+        sub.Dispose();
+        c.Push("/X", Snap(2));
+
+        fired.ShouldBe(1);
+    }
+
+    [Fact]
+    public void Satisfies_both_VirtualTag_and_ScriptedAlarm_upstream_interfaces()
+    {
+        var c = new CachedTagUpstreamSource();
+        // Single instance is assignable to both — the composer passes it through for
+        // both engine constructors per the task #243 wiring.
+        ((Core.VirtualTags.ITagUpstreamSource)c).ShouldNotBeNull();
+        ((Core.ScriptedAlarms.ITagUpstreamSource)c).ShouldNotBeNull();
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Server.Tests/Phase7/DriverSubscriptionBridgeTests.cs

@@ -0,0 +1,226 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests.Phase7;
+
+/// <summary>
+///     Task #244 — covers the bridge that pumps live driver <c>OnDataChange</c>
+///     notifications into the Phase 7 <see cref="CachedTagUpstreamSource"/>.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class DriverSubscriptionBridgeTests
+{
+    private sealed class FakeDriver : ISubscribable
+    {
+        public List<IReadOnlyList<string>> SubscribeCalls { get; } = [];
+        public List<ISubscriptionHandle> Unsubscribed { get; } = [];
+        public ISubscriptionHandle? LastHandle { get; private set; }
+        public event EventHandler<DataChangeEventArgs>? OnDataChange;
+
+        public Task<ISubscriptionHandle> SubscribeAsync(
+            IReadOnlyList<string> fullReferences, TimeSpan publishingInterval, CancellationToken cancellationToken)
+        {
+            SubscribeCalls.Add(fullReferences);
+            LastHandle = new Handle($"sub-{SubscribeCalls.Count}");
+            return Task.FromResult(LastHandle);
+        }
+
+        public Task UnsubscribeAsync(ISubscriptionHandle handle, CancellationToken cancellationToken)
+        {
+            Unsubscribed.Add(handle);
+            return Task.CompletedTask;
+        }
+
+        public void Fire(string fullRef, object value)
+        {
+            OnDataChange?.Invoke(this, new DataChangeEventArgs(
+                LastHandle!, fullRef,
+                new DataValueSnapshot(value, 0u, DateTime.UtcNow, DateTime.UtcNow)));
+        }
+
+        private sealed record Handle(string DiagnosticId) : ISubscriptionHandle;
+    }
+
+    [Fact]
+    public async Task StartAsync_calls_SubscribeAsync_with_distinct_fullRefs()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var driver = new FakeDriver();
+        await using var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        await bridge.StartAsync(new[]
+        {
+            new DriverFeed(driver,
+                new Dictionary<string, string>
+                {
+                    ["/Site/L1/A/Temp"] = "DR.Temp",
+                    ["/Site/L1/A/Pressure"] = "DR.Pressure",
+                },
+                TimeSpan.FromSeconds(1)),
+        }, CancellationToken.None);
+
+        driver.SubscribeCalls.Count.ShouldBe(1);
+        driver.SubscribeCalls[0].ShouldContain("DR.Temp");
+        driver.SubscribeCalls[0].ShouldContain("DR.Pressure");
+    }
+
+    [Fact]
+    public async Task OnDataChange_pushes_to_cache_keyed_by_UNS_path()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var driver = new FakeDriver();
+        await using var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        await bridge.StartAsync(new[]
+        {
+            new DriverFeed(driver,
+                new Dictionary<string, string> { ["/Site/L1/A/Temp"] = "DR.Temp" },
+                TimeSpan.FromSeconds(1)),
+        }, CancellationToken.None);
+
+        driver.Fire("DR.Temp", 42.5);
+
+        sink.ReadTag("/Site/L1/A/Temp").Value.ShouldBe(42.5);
+    }
+
+    [Fact]
+    public async Task OnDataChange_with_unmapped_fullRef_is_ignored()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var driver = new FakeDriver();
+        await using var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        await bridge.StartAsync(new[]
+        {
+            new DriverFeed(driver,
+                new Dictionary<string, string> { ["/p"] = "DR.A" },
+                TimeSpan.FromSeconds(1)),
+        }, CancellationToken.None);
+
+        driver.Fire("DR.B", 99);  // not in map
+
+        sink.ReadTag("/p").StatusCode.ShouldBe(CachedTagUpstreamSource.UpstreamNotConfigured,
+            "unmapped fullRef shouldn't pollute the cache");
+    }
+
+    [Fact]
+    public async Task Empty_PathToFullRef_skips_SubscribeAsync_call()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var driver = new FakeDriver();
+        await using var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        await bridge.StartAsync(new[]
+        {
+            new DriverFeed(driver, new Dictionary<string, string>(), TimeSpan.FromSeconds(1)),
+        }, CancellationToken.None);
+
+        driver.SubscribeCalls.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public async Task DisposeAsync_unsubscribes_each_active_subscription()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var driver = new FakeDriver();
+        var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        await bridge.StartAsync(new[]
+        {
+            new DriverFeed(driver,
+                new Dictionary<string, string> { ["/p"] = "DR.A" },
+                TimeSpan.FromSeconds(1)),
+        }, CancellationToken.None);
+
+        await bridge.DisposeAsync();
+
+        driver.Unsubscribed.Count.ShouldBe(1);
+        driver.Unsubscribed[0].ShouldBeSameAs(driver.LastHandle);
+    }
+
+    [Fact]
+    public async Task DisposeAsync_unhooks_OnDataChange_so_post_dispose_events_dont_push()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var driver = new FakeDriver();
+        var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        await bridge.StartAsync(new[]
+        {
+            new DriverFeed(driver,
+                new Dictionary<string, string> { ["/p"] = "DR.A" },
+                TimeSpan.FromSeconds(1)),
+        }, CancellationToken.None);
+
+        await bridge.DisposeAsync();
+        driver.Fire("DR.A", 999);  // post-dispose event
+
+        sink.ReadTag("/p").StatusCode.ShouldBe(CachedTagUpstreamSource.UpstreamNotConfigured);
+    }
+
+    [Fact]
+    public async Task StartAsync_called_twice_throws()
+    {
+        var sink = new CachedTagUpstreamSource();
+        await using var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+        await bridge.StartAsync(Array.Empty<DriverFeed>(), CancellationToken.None);
+
+        await Should.ThrowAsync<InvalidOperationException>(
+            () => bridge.StartAsync(Array.Empty<DriverFeed>(), CancellationToken.None));
+    }
+
+    [Fact]
+    public async Task DisposeAsync_is_idempotent()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+        await bridge.DisposeAsync();
+        await bridge.DisposeAsync();  // must not throw
+    }
+
+    [Fact]
+    public async Task Subscribe_failure_unhooks_handler_and_propagates()
+    {
+        var sink = new CachedTagUpstreamSource();
+        var failingDriver = new ThrowingDriver();
+        await using var bridge = new DriverSubscriptionBridge(sink, NullLogger<DriverSubscriptionBridge>.Instance);
+
+        var feeds = new[]
+        {
+            new DriverFeed(failingDriver,
+                new Dictionary<string, string> { ["/p"] = "DR.A" },
+                TimeSpan.FromSeconds(1)),
+        };
+
+        await Should.ThrowAsync<InvalidOperationException>(
+            () => bridge.StartAsync(feeds, CancellationToken.None));
+
+        // Handler should be unhooked — firing now would NPE if it wasn't (event has 0 subs).
+        failingDriver.HasAnyHandlers.ShouldBeFalse(
+            "handler must be removed when SubscribeAsync throws so it doesn't leak");
+    }
+
+    [Fact]
+    public void Null_sink_or_logger_rejected()
+    {
+        Should.Throw<ArgumentNullException>(() => new DriverSubscriptionBridge(null!, NullLogger<DriverSubscriptionBridge>.Instance));
+        Should.Throw<ArgumentNullException>(() => new DriverSubscriptionBridge(new CachedTagUpstreamSource(), null!));
+    }
+
+    private sealed class ThrowingDriver : ISubscribable
+    {
+        private EventHandler<DataChangeEventArgs>? _handler;
+        public bool HasAnyHandlers => _handler is not null;
+        public event EventHandler<DataChangeEventArgs>? OnDataChange
+        {
+            add => _handler = (EventHandler<DataChangeEventArgs>?)Delegate.Combine(_handler, value);
+            remove => _handler = (EventHandler<DataChangeEventArgs>?)Delegate.Remove(_handler, value);
+        }
+        public Task<ISubscriptionHandle> SubscribeAsync(IReadOnlyList<string> _, TimeSpan __, CancellationToken ___) =>
+            throw new InvalidOperationException("driver offline");
+        public Task UnsubscribeAsync(ISubscriptionHandle _, CancellationToken __) => Task.CompletedTask;
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Server.Tests/Phase7/Phase7ComposerMappingTests.cs

@@ -0,0 +1,93 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
+using ZB.MOM.WW.OtOpcUa.Core.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests.Phase7;
+
+/// <summary>
+///     Task #246 — covers the deterministic mapping inside <see cref="Phase7Composer"/>
+///     that turns <see cref="EquipmentNamespaceContent"/> into the path → fullRef map
+///     <see cref="DriverFeed.PathToFullRef"/> consumes. Pure function; no DI / DB needed.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class Phase7ComposerMappingTests
+{
+    private static UnsArea Area(string id, string name) =>
+        new() { UnsAreaId = id, ClusterId = "c", Name = name, GenerationId = 1 };
+
+    private static UnsLine Line(string id, string areaId, string name) =>
+        new() { UnsLineId = id, UnsAreaId = areaId, Name = name, GenerationId = 1 };
+
+    private static Equipment Eq(string id, string lineId, string name) => new()
+    {
+        EquipmentRowId = Guid.NewGuid(), GenerationId = 1, EquipmentId = id,
+        EquipmentUuid = Guid.NewGuid(), DriverInstanceId = "drv",
+        UnsLineId = lineId, Name = name, MachineCode = "m",
+    };
+
+    private static Tag T(string id, string name, string fullRef, string equipmentId) => new()
+    {
+        TagRowId = Guid.NewGuid(), GenerationId = 1, TagId = id,
+        DriverInstanceId = "drv", EquipmentId = equipmentId,
+        Name = name, DataType = "Float32",
+        AccessLevel = TagAccessLevel.Read, TagConfig = fullRef,
+    };
+
+    [Fact]
+    public void Maps_tag_to_UNS_path_walker_emits()
+    {
+        var content = new EquipmentNamespaceContent(
+            Areas: [Area("a1", "warsaw")],
+            Lines: [Line("l1", "a1", "oven-line")],
+            Equipment: [Eq("e1", "l1", "oven-3")],
+            Tags: [T("t1", "Temp", "DR.Temp", "e1")]);
+
+        var map = Phase7Composer.MapPathsToFullRefs(content);
+
+        map.ShouldContainKeyAndValue("/warsaw/oven-line/oven-3/Temp", "DR.Temp");
+    }
+
+    [Fact]
+    public void Skips_tag_with_null_EquipmentId()
+    {
+        var content = new EquipmentNamespaceContent(
+            [Area("a1", "warsaw")], [Line("l1", "a1", "ol")], [Eq("e1", "l1", "ov")],
+            [T("t1", "Bare", "DR.Bare", null!)]);  // SystemPlatform-style orphan
+
+        Phase7Composer.MapPathsToFullRefs(content).ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void Skips_tag_pointing_at_unknown_Equipment()
+    {
+        var content = new EquipmentNamespaceContent(
+            [Area("a1", "warsaw")], [Line("l1", "a1", "ol")], [Eq("e1", "l1", "ov")],
+            [T("t1", "Lost", "DR.Lost", "e-missing")]);
+
+        Phase7Composer.MapPathsToFullRefs(content).ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void Maps_multiple_tags_under_same_equipment_distinctly()
+    {
+        var content = new EquipmentNamespaceContent(
+            [Area("a1", "site")], [Line("l1", "a1", "line1")], [Eq("e1", "l1", "cell")],
+            [T("t1", "Temp", "DR.T", "e1"), T("t2", "Pressure", "DR.P", "e1")]);
+
+        var map = Phase7Composer.MapPathsToFullRefs(content);
+
+        map.Count.ShouldBe(2);
+        map["/site/line1/cell/Temp"].ShouldBe("DR.T");
+        map["/site/line1/cell/Pressure"].ShouldBe("DR.P");
+    }
+
+    [Fact]
+    public void Empty_content_yields_empty_map()
+    {
+        Phase7Composer.MapPathsToFullRefs(new EquipmentNamespaceContent([], [], [], []))
+            .ShouldBeEmpty();
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Server.Tests/Phase7/Phase7EngineComposerTests.cs

@@ -0,0 +1,162 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Serilog;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests.Phase7;
+
+/// <summary>
+///     Phase 7 follow-up (task #243) — verifies the composer that maps Config DB
+///     rows to runtime engine definitions + wires up VirtualTagEngine +
+///     ScriptedAlarmEngine + historian routing.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class Phase7EngineComposerTests
+{
+    private static Script ScriptRow(string id, string source) => new()
+    {
+        ScriptRowId = Guid.NewGuid(), GenerationId = 1,
+        ScriptId = id, Name = id, SourceCode = source, SourceHash = "h",
+    };
+
+    private static VirtualTag VtRow(string id, string scriptId) => new()
+    {
+        VirtualTagRowId = Guid.NewGuid(), GenerationId = 1,
+        VirtualTagId = id, EquipmentId = "eq-1", Name = id,
+        DataType = "Float32", ScriptId = scriptId,
+    };
+
+    private static ScriptedAlarm AlarmRow(string id, string scriptId) => new()
+    {
+        ScriptedAlarmRowId = Guid.NewGuid(), GenerationId = 1,
+        ScriptedAlarmId = id, EquipmentId = "eq-1", Name = id,
+        AlarmType = "LimitAlarm", Severity = 500,
+        MessageTemplate = "x", PredicateScriptId = scriptId,
+    };
+
+    [Fact]
+    public void Compose_empty_rows_returns_Empty_sentinel()
+    {
+        var result = Phase7EngineComposer.Compose(
+            scripts: [],
+            virtualTags: [],
+            scriptedAlarms: [],
+            upstream: new CachedTagUpstreamSource(),
+            alarmStateStore: new InMemoryAlarmStateStore(),
+            historianSink: NullAlarmHistorianSink.Instance,
+            rootScriptLogger: new LoggerConfiguration().CreateLogger(),
+            loggerFactory: NullLoggerFactory.Instance);
+
+        result.ShouldBeSameAs(Phase7ComposedSources.Empty);
+        result.VirtualReadable.ShouldBeNull();
+        result.ScriptedAlarmReadable.ShouldBeNull();
+    }
+
+    [Fact]
+    public void Compose_VirtualTag_rows_returns_non_null_VirtualReadable()
+    {
+        var scripts = new[] { ScriptRow("scr-1", "return 1;") };
+        var vtags = new[] { VtRow("vt-1", "scr-1") };
+
+        var result = Phase7EngineComposer.Compose(
+            scripts, vtags, [],
+            upstream: new CachedTagUpstreamSource(),
+            alarmStateStore: new InMemoryAlarmStateStore(),
+            historianSink: NullAlarmHistorianSink.Instance,
+            rootScriptLogger: new LoggerConfiguration().CreateLogger(),
+            loggerFactory: NullLoggerFactory.Instance);
+
+        result.VirtualReadable.ShouldNotBeNull();
+        result.ScriptedAlarmReadable.ShouldBeNull("no alarms configured");
+        result.Disposables.Count.ShouldBeGreaterThan(0);
+    }
+
+    [Fact]
+    public void Compose_ScriptedAlarm_rows_returns_non_null_ScriptedAlarmReadable()
+    {
+        var scripts = new[] { ScriptRow("scr-1", "return false;") };
+        var alarms = new[] { AlarmRow("al-1", "scr-1") };
+
+        var result = Phase7EngineComposer.Compose(
+            scripts, [], alarms,
+            upstream: new CachedTagUpstreamSource(),
+            alarmStateStore: new InMemoryAlarmStateStore(),
+            historianSink: NullAlarmHistorianSink.Instance,
+            rootScriptLogger: new LoggerConfiguration().CreateLogger(),
+            loggerFactory: NullLoggerFactory.Instance);
+
+        result.ScriptedAlarmReadable.ShouldNotBeNull("task #245 — alarm Active state readable");
+        result.VirtualReadable.ShouldBeNull();
+    }
+
+    [Fact]
+    public void Compose_missing_script_reference_throws_with_actionable_message()
+    {
+        var vtags = new[] { VtRow("vt-1", "scr-missing") };
+
+        Should.Throw<InvalidOperationException>(() =>
+            Phase7EngineComposer.Compose(
+                scripts: [],
+                vtags, [],
+                upstream: new CachedTagUpstreamSource(),
+                alarmStateStore: new InMemoryAlarmStateStore(),
+                historianSink: NullAlarmHistorianSink.Instance,
+                rootScriptLogger: new LoggerConfiguration().CreateLogger(),
+                loggerFactory: NullLoggerFactory.Instance))
+            .Message.ShouldContain("scr-missing");
+    }
+
+    [Fact]
+    public void Compose_disabled_VirtualTag_is_skipped()
+    {
+        var scripts = new[] { ScriptRow("scr-1", "return 1;") };
+        var disabled = VtRow("vt-1", "scr-1");
+        disabled.Enabled = false;
+
+        var defs = Phase7EngineComposer.ProjectVirtualTags(
+            new[] { disabled },
+            new Dictionary<string, Script> { ["scr-1"] = scripts[0] }).ToList();
+
+        defs.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void ProjectVirtualTags_maps_timer_interval_milliseconds_to_TimeSpan()
+    {
+        var scripts = new[] { ScriptRow("scr-1", "return 1;") };
+        var vt = VtRow("vt-1", "scr-1");
+        vt.TimerIntervalMs = 2500;
+
+        var def = Phase7EngineComposer.ProjectVirtualTags(
+            new[] { vt },
+            new Dictionary<string, Script> { ["scr-1"] = scripts[0] }).Single();
+
+        def.TimerInterval.ShouldBe(TimeSpan.FromMilliseconds(2500));
+    }
+
+    [Fact]
+    public void ProjectScriptedAlarms_maps_Severity_numeric_to_AlarmSeverity_bucket()
+    {
+        var scripts = new[] { ScriptRow("scr-1", "return true;") };
+
+        var buckets = new[] { (1, AlarmSeverity.Low), (250, AlarmSeverity.Low),
+                               (251, AlarmSeverity.Medium), (500, AlarmSeverity.Medium),
+                               (501, AlarmSeverity.High), (750, AlarmSeverity.High),
+                               (751, AlarmSeverity.Critical), (1000, AlarmSeverity.Critical) };
+        foreach (var (input, expected) in buckets)
+        {
+            var row = AlarmRow("a1", "scr-1");
+            row.Severity = input;
+            var def = Phase7EngineComposer.ProjectScriptedAlarms(
+                new[] { row },
+                new Dictionary<string, Script> { ["scr-1"] = scripts[0] }).Single();
+            def.Severity.ShouldBe(expected, $"severity {input} should map to {expected}");
+        }
+    }
+}
+

tests/ZB.MOM.WW.OtOpcUa.Server.Tests/Phase7/ScriptedAlarmReadableTests.cs

@@ -0,0 +1,120 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Serilog;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.ScriptedAlarms;
+using ZB.MOM.WW.OtOpcUa.Core.Scripting;
+using ZB.MOM.WW.OtOpcUa.Server.Phase7;
+
+namespace ZB.MOM.WW.OtOpcUa.Server.Tests.Phase7;
+
+/// <summary>
+///     Task #245 — covers the IReadable adapter that surfaces each scripted alarm's
+///     live <c>ActiveState</c> so OPC UA variable reads on Source=ScriptedAlarm nodes
+///     return the predicate truth instead of BadNotFound.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class ScriptedAlarmReadableTests
+{
+    private static (ScriptedAlarmEngine engine, CachedTagUpstreamSource upstream) BuildEngineWith(
+        params (string alarmId, string predicateSource)[] alarms)
+    {
+        var upstream = new CachedTagUpstreamSource();
+        var logger = new LoggerConfiguration().CreateLogger();
+        var factory = new ScriptLoggerFactory(logger);
+        var engine = new ScriptedAlarmEngine(upstream, new InMemoryAlarmStateStore(), factory, logger);
+        var defs = alarms.Select(a => new ScriptedAlarmDefinition(
+            AlarmId: a.alarmId,
+            EquipmentPath: "/eq",
+            AlarmName: a.alarmId,
+            Kind: AlarmKind.LimitAlarm,
+            Severity: AlarmSeverity.Medium,
+            MessageTemplate: "x",
+            PredicateScriptSource: a.predicateSource)).ToList();
+        engine.LoadAsync(defs, CancellationToken.None).GetAwaiter().GetResult();
+        return (engine, upstream);
+    }
+
+    [Fact]
+    public async Task Reads_return_false_for_newly_loaded_alarm_with_inactive_predicate()
+    {
+        var (engine, _) = BuildEngineWith(("a1", "return false;"));
+        using var _e = engine;
+        var readable = new ScriptedAlarmReadable(engine);
+
+        var result = await readable.ReadAsync(["a1"], CancellationToken.None);
+
+        result.Count.ShouldBe(1);
+        result[0].Value.ShouldBe(false);
+        result[0].StatusCode.ShouldBe(0u, "Good quality when the engine has state");
+    }
+
+    [Fact]
+    public async Task Reads_return_true_when_predicate_evaluates_to_active()
+    {
+        var (engine, upstream) = BuildEngineWith(
+            ("tempAlarm", "return ctx.GetTag(\"/Site/Line/Cell/Temp\").Value is double d && d > 100;"));
+        using var _e = engine;
+
+        // Seed the upstream value + nudge the engine so the alarm transitions to Active.
+        upstream.Push("/Site/Line/Cell/Temp",
+            new DataValueSnapshot(150.0, 0u, DateTime.UtcNow, DateTime.UtcNow));
+
+        // Allow the engine's change-driven cascade to run.
+        await Task.Delay(50);
+
+        var readable = new ScriptedAlarmReadable(engine);
+        var result = await readable.ReadAsync(["tempAlarm"], CancellationToken.None);
+
+        result[0].Value.ShouldBe(true);
+    }
+
+    [Fact]
+    public async Task Reads_return_BadNodeIdUnknown_for_missing_alarm()
+    {
+        var (engine, _) = BuildEngineWith(("a1", "return false;"));
+        using var _e = engine;
+        var readable = new ScriptedAlarmReadable(engine);
+
+        var result = await readable.ReadAsync(["a-not-loaded"], CancellationToken.None);
+
+        result[0].Value.ShouldBeNull();
+        result[0].StatusCode.ShouldBe(0x80340000u,
+            "BadNodeIdUnknown surfaces a misconfiguration, not a silent false");
+    }
+
+    [Fact]
+    public async Task Reads_batch_round_trip_preserves_order()
+    {
+        var (engine, _) = BuildEngineWith(
+            ("a1", "return false;"),
+            ("a2", "return false;"));
+        using var _e = engine;
+        var readable = new ScriptedAlarmReadable(engine);
+
+        var result = await readable.ReadAsync(["a2", "missing", "a1"], CancellationToken.None);
+
+        result.Count.ShouldBe(3);
+        result[0].Value.ShouldBe(false);               // a2
+        result[1].StatusCode.ShouldBe(0x80340000u);    // missing
+        result[2].Value.ShouldBe(false);               // a1
+    }
+
+    [Fact]
+    public void Null_engine_rejected()
+    {
+        Should.Throw<ArgumentNullException>(() => new ScriptedAlarmReadable(null!));
+    }
+
+    [Fact]
+    public async Task Null_fullReferences_rejected()
+    {
+        var (engine, _) = BuildEngineWith(("a1", "return false;"));
+        using var _e = engine;
+        var readable = new ScriptedAlarmReadable(engine);
+
+        await Should.ThrowAsync<ArgumentNullException>(
+            () => readable.ReadAsync(null!, CancellationToken.None));
+    }
+}