Phase 7 follow-up #243 — CachedTagUpstreamSource + Phase7EngineComposer

Ships the composition kernel that maps Config DB rows (Script / VirtualTag /
ScriptedAlarm) to the runtime definitions VirtualTagEngine + ScriptedAlarmEngine
consume, builds the engine instances, and wires OnEvent → historian-sink routing.

## src/ZB.MOM.WW.OtOpcUa.Server/Phase7/

- CachedTagUpstreamSource — implements both Core.VirtualTags.ITagUpstreamSource and
  Core.ScriptedAlarms.ITagUpstreamSource (identical shape, distinct namespaces) on one
  concrete type so the composer can hand one instance to both engines. Thread-safe
  ConcurrentDictionary value cache with synchronous ReadTag + fire-on-write
  Push(path, snapshot) that fans out to every observer registered via SubscribeTag.
  Unknown-path reads return a BadNodeIdUnknown-quality snapshot (status 0x80340000)
  so scripts branch on quality naturally.
- Phase7EngineComposer.Compose(scripts, virtualTags, scriptedAlarms, upstream,
  alarmStateStore, historianSink, rootScriptLogger, loggerFactory) — single static
  entry point that:
  * Indexes scripts by ScriptId, resolves VirtualTag.ScriptId + ScriptedAlarm.PredicateScriptId
    to full SourceCode
  * Projects DB rows to VirtualTagDefinition + ScriptedAlarmDefinition (mapping
    DataType string → DriverDataType enum, AlarmType string → AlarmKind enum,
    Severity 1..1000 → AlarmSeverity bucket matching the OPC UA Part 9 bands
    that AbCipAlarmProjection + OpcUaClient MapSeverity already use)
  * Constructs VirtualTagEngine + loads definitions (throws InvalidOperationException
    with the list of scripts that failed to compile — aggregated like Streams B+C)
  * Constructs ScriptedAlarmEngine + loads definitions + wires OnEvent →
    IAlarmHistorianSink.EnqueueAsync using ScriptedAlarmEvent.Emission as the event
    kind + Condition.LastAckUser/LastAckComment for audit fields
  * Returns Phase7ComposedSources with Disposables list the caller owns

Empty Phase 7 config returns Phase7ComposedSources.Empty so deployments without
scripts / alarms behave exactly as pre-Phase-7. Non-null sources flow into
OpcUaApplicationHost's virtualReadable / scriptedAlarmReadable plumbing landed by
task #239 — DriverNodeManager then dispatches reads by NodeSourceKind per PR #186.

## Tests — 12/12

CachedTagUpstreamSourceTests (6):
- Unknown-path read returns BadNodeIdUnknown-quality snapshot
- Push-then-Read returns cached value
- Push fans out to subscribers in registration order
- Push to one path doesn't fire another path's observer
- Dispose of subscription handle stops fan-out
- Satisfies both Core.VirtualTags + Core.ScriptedAlarms ITagUpstreamSource interfaces

Phase7EngineComposerTests (6):
- Empty rows → Phase7ComposedSources.Empty (both sources null)
- VirtualTag rows → VirtualReadable non-null + Disposables populated
- Missing script reference throws InvalidOperationException with the missing ScriptId
  in the message
- Disabled VirtualTag row skipped by projection
- TimerIntervalMs → TimeSpan.FromMilliseconds round-trip
- Severity 1..1000 maps to Low/Medium/High/Critical at 250/500/750 boundaries
  (matches AbCipAlarmProjection + OpcUaClient.MapSeverity banding)

## Scope — what this PR does NOT do

The composition kernel is the tricky part; the remaining wiring is three narrower
follow-ups that each build on this PR:

- task #244 — driver-bridge feed that populates CachedTagUpstreamSource from live
  driver subscriptions. Without this, ctx.GetTag returns BadNodeIdUnknown even when
  the driver has a fresh value.
- task #245 — ScriptedAlarmReadable adapter exposing each alarm's current Active
  state as IReadable. Phase7EngineComposer.Compose currently returns
  ScriptedAlarmReadable=null so reads on Source=ScriptedAlarm variables return
  BadNotFound per the ADR-002 "misconfiguration not silent fallback" signal.
- task #246 — Program.cs call to Phase7EngineComposer.Compose with config rows
  loaded from the sealed-cache DB read, plus SqliteStoreAndForwardSink lifecycle
  wiring at %ProgramData%/OtOpcUa/alarm-historian-queue.db with the Galaxy.Host
  IPC writer from Stream D.

Task #240 (live OPC UA E2E smoke) depends on all three follow-ups landing.

ZB.MOM.WW.OtOpcUa.slnx

@@ -36,6 +36,7 @@
         <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/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.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/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;
+                    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.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 +30,14 @@ 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).
+    private readonly ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? _virtualReadable;
+    private readonly ZB.MOM.WW.OtOpcUa.Core.Abstractions.IReadable? _scriptedAlarmReadable;
+
     private readonly ILoggerFactory _loggerFactory;
     private readonly ILogger<OpcUaApplicationHost> _logger;
     private ApplicationInstance? _application;
@@ -45,7 +53,9 @@ 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;
@@ -57,6 +67,8 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
         _tierLookup = tierLookup;
         _resilienceConfigLookup = resilienceConfigLookup;
         _equipmentContentLookup = equipmentContentLookup;
+        _virtualReadable = virtualReadable;
+        _scriptedAlarmReadable = scriptedAlarmReadable;
         _loggerFactory = loggerFactory;
         _logger = logger;
     }
@@ -85,7 +97,8 @@ 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/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/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);
+        }
+
+        ScriptedAlarmSource? alarmSource = 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();
+            alarmSource = new ScriptedAlarmSource(alarmEngine);
+            disposables.Add(alarmEngine);
+            disposables.Add(alarmSource);
+        }
+
+        // ScriptedAlarmSource is an IAlarmSource, not an IReadable — scripted-alarm
+        // variable-read dispatch (task #245) needs a dedicated engine-state adapter. Until
+        // that ships, reads against Source=ScriptedAlarm nodes return BadNotFound per the
+        // DriverNodeManager null-check path (the ADR-002 "misconfiguration not silent
+        // fallback" signal). The alarm event stream still fires via IAlarmSource.
+        return new Phase7ComposedSources(vtSource, ScriptedAlarmReadable: null, 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/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.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/Phase7EngineComposerTests.cs

@@ -0,0 +1,143 @@
+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.Disposables.Count.ShouldBeGreaterThan(0);
+    }
+
+    [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}");
+        }
+    }
+}
+