Merge pull request 'fix(alarms): populate EventType/SourceNode/SourceName on native + scripted conditions (#473)' (#474) from fix/alarm-condition-source-fields into master

MaterialiseAlarmCondition never assigned the three mandatory BaseEventType
identity fields, so all three arrived null on every condition event — native
and scripted. The SDK does not synthesise them on this path: Create() builds
the children from the type definition but leaves them unset, the auto-filling
BaseEventState.Initialize overload is only used for transient events, and
ReportEvent / InstanceStateSnapshot copy children verbatim. A conforming
client could not attribute an alarm to its source.

  EventType  = the concrete materialised type (TypeDefinitionId)
  SourceNode = the condition's own NodeId (== ConditionId) — the condition IS
               the source; an alarm-bearing raw tag materialises only the
               condition, with no sibling value variable
  SourceName = the same identifying id string: RawPath (native) /
               ScriptedAlarmId (scripted)

SourceName carries the unique id rather than the leaf name: the leaf collides
across devices (HR200 on two PLCs) and is already carried by ConditionName, so
nothing is lost. Documented in docs/AlarmTracking.md, including that clients
must key on ConditionId and must not compose SourceName with ConditionName,
and that SourceName is NOT a live<->history join key (the alarm-history writer
stamps it with the EquipmentPath — a pre-existing divergence, now called out).

Tests: NativeAlarmEventIdentityFieldDeliveryTests is the wire-level guard —
a real client subscription using the standard [EventType, SourceNode,
SourceName, Time, Message, Severity] select clause, verified to fail against
the pre-fix server. NodeManagerAlarmSourceFieldsTests guards the node across
both realms, the base-type fallback, and the kind-swap re-materialise.

The HistoryRead events projection is a separate path (it projects historian
rows, not node fields) and is unaffected — its EventType => Variant.Null
assertions still hold.

CLAUDE.md

@@ -68,9 +68,45 @@ shared-lib consumption, or per-project commands — update the **OtOpcUa entry i
    gRPC session. The gateway owns the COM apartment + STA pump
    server-side; the driver speaks `MxCommand` / `MxEvent` protos
    exclusively.
-3. **OPC UA Server** — Exposes authored equipment tags as variable nodes.
+3. **OPC UA Server** — Exposes the deployed tree under **two OPC UA namespaces**
-   Galaxy tags are bound by `TagConfig.FullName` (`tag_name.AttributeName`);
+   (see below). Galaxy tags are bound by `TagConfig.FullName`
-   reads/writes/subscriptions are translated to that reference for MXAccess.
+   (`tag_name.AttributeName`); reads/writes/subscriptions are translated to that
+   reference for MXAccess.
+
+### v3 OPC UA Address Space (Batch 4): dual namespace
+
+The server exposes **two OPC UA namespaces** (replacing the single
+`https://zb.com/otopcua/ns`), built by `AddressSpaceComposer` /
+`AddressSpaceApplier` and served by `OtOpcUaNodeManager` (which registers both
+URIs; `V3NodeIds` + `AddressSpaceRealm` are the identity authority):
+
+| Namespace URI | Realm | Subtree | NodeId `s=` scheme |
+|---|---|---|---|
+| `https://zb.com/otopcua/raw` | `AddressSpaceRealm.Raw` | the `/raw` device tree (Folder → Driver → Device → TagGroup → Tag) | the node's **RawPath** (e.g. `Plant/Modbus/dev1/Speed`) |
+| `https://zb.com/otopcua/uns` | `AddressSpaceRealm.Uns` | the UNS tree (Area → Line → Equipment → signal) | slash-joined **`Area/Line/Equipment/EffectiveName`** |
+
+- **Single source, fanned to both.** Every device value has exactly one source —
+  the raw tag's node. A `UnsTagReference` projects that raw tag into an equipment
+  as a UNS-namespace variable that carries an **`Organizes` reference to its raw
+  node** and mirrors it. One driver publish for a RawPath fans (in `DriverHostActor`)
+  to the raw NodeId AND every referencing UNS NodeId with identical
+  value/quality/timestamp — the mux key stays single (RawPath).
+- **Writes via either NodeId** route to the same driver ref under the same
+  `WriteOperate` gating (the node-manager write gate is realm-qualified and fails
+  closed); a failed device write reverts both NodeIds via the shared fan-out
+  (write-outcome self-correction).
+- **Native alarms** materialize once at the raw tag (`ConditionId = RawPath`) and
+  fan via SDK notifiers to the raw device folder AND every referencing equipment
+  folder — one `ReportEvent`, one Server-object copy; ack/confirm/shelve route on
+  `ConditionId = RawPath`.
+- **Historian dual-registration.** Both NodeIds register the **same** historian
+  tagname; the mux `HistorizedTagRef` stays single (RawPath). HistoryRead works
+  through either NodeId.
+
+The retired `EquipmentNodeIds` (`{equipmentId}/{folderPath}/{name}`) scheme and
+the single-namespace `EquipmentTags` materialization path are gone. See
+`docs/plans/2026-07-15-raw-uns-two-subtree-v3-design.md` +
+`docs/plans/2026-07-15-v3-batch4-address-space-plan.md`, and `docs/Uns.md`.
 
 ### Key Concept: Tag Name and FullName
 
@@ -219,6 +255,8 @@ The AdminUI's global **UNS** page (`/uns`) is the single surface for managing th
 
 **v3 (Batch 3): UNS Equipment is reference-only.** The equipment **Tags** tab no longer authors or binds tags — it holds `UnsTagReference` rows pointing at raw tags authored in `/raw`. "+ Add reference" opens the `RawTree` in picker mode, **cluster-scoped** (structurally + server-enforced `tag.cluster == equipment.cluster`); rows show effective name / RawPath / inherited DataType+AccessLevel / display-name override. **Effective-name uniqueness** (references + VirtualTags + ScriptedAlarms share the `{EquipmentId}/{EffectiveName}` NodeId space) is enforced at authoring (`IEffectiveNameGuard`) and at the deploy gate (`DraftValidator.UnsEffectiveNameCollision` — catches rename-induced collisions). Scripts use **`ctx.GetTag("{{equip}}/<RefName>")`** — resolved per-equipment through `UnsTagReference` effective names to the backing RawPath at both compose seams (`AddressSpaceComposer` + `DeploymentArtifact`, via the shared `EquipmentReferenceMap`, byte-parity); an unresolved `<RefName>` is a deploy error (`EquipReferenceUnresolved`) AND a live Monaco diagnostic (`OTSCRIPT_EQUIPREF`) — editor accepts ⇔ publish accepts. `EquipmentScriptPaths.DeriveEquipmentBase` is deleted (the dot-joint `{{equip}}.X` became the slash-joint `{{equip}}/<RefName>`). Raw rename warns when a beneath-it tag is historized-without-override / UNS-referenced / named by a script literal (`RawTreeService` substring scan). `ImportEquipmentModal` dropped the `DriverInstanceId` column. See `docs/Uns.md` + `docs/ScriptEditor.md`.
 
+**v3 (Batch 4 = v3.0): dual-namespace address space.** The OPC UA server exposes **two namespaces** — `https://zb.com/otopcua/raw` (Raw device tree, `s=<RawPath>`) + `https://zb.com/otopcua/uns` (UNS tree, `s=<Area>/<Line>/<Equipment>/<EffectiveName>`) — replacing the single `.../ns` and the retired `EquipmentNodeIds` scheme. Every value has ONE source (the raw node's publish); a driver publish for a RawPath fans in `DriverHostActor` to the raw NodeId AND every referencing UNS NodeId with identical value/quality/timestamp, and each UNS variable `Organizes`-references its raw node. Writes route via **either** NodeId to the same driver ref under the same realm-qualified `WriteOperate` gate (failed-write revert works through both); native alarms materialize ONCE at the raw tag (`ConditionId = RawPath`) and fan via SDK `AddNotifier` to the raw device folder + every referencing equipment folder (one `ReportEvent`, one Server-object copy); both NodeIds register the SAME historian tagname (mux `HistorizedTagRef` stays single, keyed by RawPath). Identity authority: `V3NodeIds` + `AddressSpaceRealm` (carried explicitly at every sink seam — never parsed out of the id string). See the "v3 OPC UA Address Space (Batch 4)" section above, `docs/Uns.md`, and `docs/plans/2026-07-15-v3-batch4-address-space-plan.md`.
+
 The `/uns` **TagModal** uses **driver-typed tag-config editors**: it dispatches by the bound driver's `DriverType` to a per-driver editor (Modbus/S7/AbCip/AbLegacy/TwinCAT/Focas/OpcUaClient) via `TagConfigEditorMap`, with client-side validation via `TagConfigValidator`; unmapped drivers (only Galaxy) fall back to the generic raw-`TagConfig`-JSON textarea. Each editor is a thin razor shell over a pure `<Driver>TagConfigModel` (`FromJson`/`ToJson`/`Validate`, preserves unknown keys). To add a driver's editor, copy the Modbus template under `Components/Shared/Uns/TagEditors/` + `Uns/TagEditors/`, reusing the driver's enums + camelCase JSON property names, and register it in `TagConfigEditorMap` + `TagConfigValidator`. See `docs/plans/2026-06-09-driver-typed-tag-editors-design.md`.
 
 ## Scripting / Script Editor

Directory.Packages.props

@@ -132,6 +132,9 @@
     <PackageVersion Include="ZB.MOM.WW.Auth.Abstractions" Version="0.1.1" />
     <PackageVersion Include="ZB.MOM.WW.Auth.Ldap" Version="0.1.1" />
     <PackageVersion Include="ZB.MOM.WW.Auth.AspNetCore" Version="0.1.1" />
+    <PackageVersion Include="ZB.MOM.WW.Secrets" Version="0.1.2" />
+    <PackageVersion Include="ZB.MOM.WW.Secrets.Abstractions" Version="0.1.2" />
+    <PackageVersion Include="ZB.MOM.WW.Secrets.Ui" Version="0.1.2" />
     <PackageVersion Include="ZB.MOM.WW.Audit" Version="0.1.0" />
     <PackageVersion Include="ZB.MOM.WW.Theme" Version="0.3.1" />
     <PackageVersion Include="ZB.MOM.WW.HistorianGateway.Client" Version="0.3.0" />

NuGet.config

@@ -25,6 +25,8 @@
       <package pattern="ZB.MOM.WW.Theme" />
       <package pattern="ZB.MOM.WW.HistorianGateway.Contracts" />
       <package pattern="ZB.MOM.WW.HistorianGateway.Client" />
+      <package pattern="ZB.MOM.WW.Secrets" />
+      <package pattern="ZB.MOM.WW.Secrets.*" />
     </packageSource>
   </packageSourceMapping>
 </configuration>

docs/AlarmTracking.md

@@ -24,6 +24,76 @@ condition — the dedup logic prefers the richer driver-native record
 because it carries the full operator + raise-time + category metadata
 that the value-driven path collapses.
 
+## v3 Batch 4 — multi-notifier delivery (raw + equipment folders)
+
+Under the v3 dual-namespace address space, a native driver alarm is authored on a
+**raw tag** (`/raw`) and its Part 9 `AlarmConditionState` materializes **once** at the
+raw tag — `ConditionId` = the tag's **RawPath**, parent notifier = the raw device/group
+folder (`ns=Raw`). Because equipment references raw tags (v3 reference-only UNS), the
+same condition is wired as an **event notifier of every referencing equipment folder**
+(`ns=UNS`) via the SDK `AddNotifier` pattern (`OtOpcUaNodeManager.WireAlarmNotifiers`):
+`alarm.AddNotifier(equipFolder, isInverse:true)` + `equipFolder.AddNotifier(alarm)` +
+`EnsureFolderIsEventNotifier(equipFolder)`.
+
+- A **single** `ReportEvent` fans through the SDK notifier graph to the raw device folder,
+  every referencing equipment folder, and up to the Server object. A subscriber at any one
+  root receives **exactly one** copy of the transition — the Part 9 shared-`InstanceStateSnapshot`
+  dedup (`MonitoredItem.QueueEvent` → `IsEventContainedInQueue`), **never** one copy per root.
+  Duplicating the `ReportEvent` per root is rejected by design (distinct EventIds would break
+  Server-object dedup + Part 9 ack correlation).
+- **Teardown is symmetric:** the node manager tracks the wired notifier pairs and calls
+  `RemoveNotifier(..., bidirectional:true)` on rebuild / subtree-removal / reference-removal, so
+  inverse-notifier entries never leak across redeploys.
+- **Ack/confirm/shelve route on `ConditionId = RawPath`** (never `SourceNodeId`) regardless of
+  which notifier root the operator subscribed at — an ack issued from an equipment-folder
+  subscription resolves to the same raw condition.
+- The `alerts`-topic `AlarmTransitionEvent` carries the (possibly empty) **list of referencing
+  equipment paths**, and the AdminUI `/alerts` page shows **one row per condition** (primary
+  identity RawPath + condition NodeId) with the equipment list as display metadata.
+
+## Condition event identity fields (what a client reads on the wire)
+
+Every condition event — native and scripted — carries the mandatory `BaseEventType` identity
+fields, assigned at materialize time in `OtOpcUaNodeManager.MaterialiseAlarmCondition`. The SDK
+does **not** synthesize them on this path (`Create` builds the children from the type definition
+but leaves them unset; `ReportEvent` / `InstanceStateSnapshot` copy children verbatim), so they
+are set explicitly. Leaving them unset shipped them as **null** on every event — see issue #473.
+
+| Field | Value | Notes |
+|---|---|---|
+| `EventType` | the **concrete** materialized type (`TypeDefinitionId`) | e.g. `OffNormalAlarmType`; falls back to `AlarmConditionType` for an unknown authored type. Readable as a *field*, not only via an `OfType` where-clause |
+| `SourceNode` | the condition's **own NodeId** — equal to `ConditionId` | The condition **is** the source: an alarm-bearing raw tag materializes only the condition, with no sibling value variable, so there is no other node to point at |
+| `SourceName` | the same identifying id string: **RawPath** (native) / **ScriptedAlarmId** (scripted) | Deliberately the *unique* id, **not** the leaf name |
+| `ConditionName` | the leaf / display name (e.g. `HR200`) | Where the short human-readable name lives |
+
+**Why `SourceName` is the id, not the leaf name.** The leaf is ambiguous across devices (`HR200` on
+two PLCs collides) and is already carried by `ConditionName`, so the leaf-name option would add no
+identity while costing uniqueness. Carrying the id makes the `SourceNode`/`SourceName`/`ConditionId`
+triple mutually consistent and unique. This diverges from the loose OPC UA convention that
+`SourceName` mirrors the source node's BrowseName; the divergence is intentional.
+
+**Client guidance:** key on **`ConditionId`** — the condition node's own NodeId, which equals
+`SourceNode`, and whose identifier is the RawPath for native alarms and the ScriptedAlarmId for
+scripted ones. It is the identity ack/confirm/shelve route on. `SourceName` carries the same
+identifier and is unique, so it is safe to key on *by itself* — but do **not** compose it with
+`ConditionName` (`$"{SourceName}.{ConditionName}"`), because `SourceName` already ends in the
+condition's leaf name and the result stutters (`pymodbus/plc/HR200.HR200`).
+
+Wire-level guard: `NativeAlarmEventIdentityFieldDeliveryTests` asserts the three fields arrive
+populated on a real subscription using the standard `[EventType, SourceNode, SourceName, Time,
+Message, Severity]` select clause; `NodeManagerAlarmSourceFieldsTests` guards the node itself
+across both realms.
+
+> **Do not correlate live events to HistoryRead on `SourceName` — the two paths disagree.**
+> The HistoryRead *events* projection (`OtOpcUaNodeManager.ProjectEventField`) returns
+> `Variant.Null` for `EventType` / `SourceNode` **by design**: it projects from the historian's
+> `HistoricalEvent` rows, which do not carry them. It **does** project `SourceName` — but the
+> alarm-history writer stamps that field with the **EquipmentPath**
+> (`AlarmEventMapper`: `SourceName = alarm.EquipmentPath`), not the RawPath a live event carries.
+> So `SourceName` is the one field populated on both paths **with different values**, and it is not
+> a live↔history join key. Correlate on `ConditionId` / the RawPath instead. (Pre-existing; the
+> live-path fix above does not change the history path.)
+
 ## Galaxy driver path (driver-native)
 
 Restored in PR B.2 of the epic. `GalaxyDriver` implements

docs/Historian.md

@@ -199,6 +199,15 @@ The server supports all four OPC UA HistoryRead variants:
 `Historizing=true` and `AccessLevels.HistoryRead` are set at materialization so any compliant
 OPC UA client can discover historized capability from the node's attributes.
 
+> **v3 Batch 4 — dual-namespace registration.** A historized raw tag surfaces as **two**
+> variable nodes: the Raw-namespace node (`ns=Raw, s=<RawPath>`) and, for each referencing
+> equipment, a UNS-namespace node (`ns=UNS, s=<Area>/<Line>/<Equipment>/<EffectiveName>`).
+> **Both NodeIds register the SAME historian tagname** (the raw tag's `FullName` /
+> `historianTagname`), so HistoryRead against either NodeId resolves to the same tagname and
+> returns the same series. The historization intent is single-sourced — the mux's
+> `HistorizedTagRef` set stays keyed by RawPath (no doubles), and continuous historization /
+> `EnsureTags` provisioning run once per raw tag regardless of how many equipment reference it.
+
 **Equipment-folder event-notifier nodes** serve Event history. Every equipment folder that
 owns at least one alarm condition is already an event notifier; the server registers a
 `sourceName` (the equipment id) for each such folder and maps event history reads to the
@@ -355,31 +364,39 @@ for the full alarm-historian routing.
 The `historyread` command reads historical data from any node. Supply start and end times in
 ISO 8601 UTC form. See [docs/Client.CLI.md](Client.CLI.md) for the full flag reference.
 
+> **v3 Batch 4 NodeIds.** A historized tag is readable through **either** of its two NodeIds —
+> the Raw-namespace node (`s=<RawPath>`, e.g. `Plant/Modbus/dev1/Speed`) or a referencing
+> equipment's UNS-namespace node (`s=<Area>/<Line>/<Equipment>/<EffectiveName>`). Both register
+> the same historian tagname, so the returned series is identical. The `ns=N` index is assigned
+> at connect time per the namespace URI (`https://zb.com/otopcua/raw` /
+> `https://zb.com/otopcua/uns`) — resolve it from the server's `NamespaceArray` rather than
+> hard-coding it. The examples below show a Raw-namespace read (`ns=2` illustrative).
+
 ```bash
-# Raw history for a historized Galaxy tag (last 24 hours by default)
+# Raw history for a historized tag via its Raw-namespace NodeId (last 24 hours by default)
 otopcua-cli historyread \
   -u opc.tcp://localhost:4840/OtOpcUa \
-  -n "ns=2;s=EQ-55297329838d/GalaxyTestTag" \
+  -n "ns=2;s=Plant/Modbus/dev1/Speed" \
   --start "2026-06-13T00:00:00Z" --end "2026-06-14T00:00:00Z"
 
-# Limit to 100 values
+# Same series via a referencing equipment's UNS-namespace NodeId, limited to 100 values
 otopcua-cli historyread \
   -u opc.tcp://localhost:4840/OtOpcUa \
-  -n "ns=2;s=EQ-55297329838d/GalaxyTestTag" \
+  -n "ns=3;s=filling/line1/station1/Speed" \
   --start "2026-06-13T00:00:00Z" --end "2026-06-14T00:00:00Z" \
   --max 100
 
 # 1-hour average aggregate
 otopcua-cli historyread \
   -u opc.tcp://localhost:4840/OtOpcUa \
-  -n "ns=2;s=EQ-55297329838d/GalaxyTestTag" \
+  -n "ns=2;s=Plant/Modbus/dev1/Speed" \
   --start "2026-06-13T00:00:00Z" --end "2026-06-14T00:00:00Z" \
   --aggregate Average --interval 3600000
 
 # Authenticated read (ReadOnly role or higher required)
 otopcua-cli historyread \
   -u opc.tcp://localhost:4840/OtOpcUa \
-  -n "ns=2;s=EQ-55297329838d/GalaxyTestTag" \
+  -n "ns=2;s=Plant/Modbus/dev1/Speed" \
   --start "2026-06-13T00:00:00Z" --end "2026-06-14T00:00:00Z" \
   -U reader -P password
 ```

docs/ScriptEditor.md

@@ -212,6 +212,13 @@ The catalog is scoped per Blazor circuit; each call creates and disposes its own
 `DbContext` via the pooled factory (same pattern as `UnsTreeService`). Results
 are bounded to 200 entries to keep the completion list responsive on large fleets.
 
+> **v3 Batch 4 (dual namespace) — unchanged for scripts.** A `ctx.GetTag(...)` literal
+> still resolves by the tag's `FullName` / **RawPath** — which is precisely the identity
+> of the Raw-namespace node (`ns=Raw, s=<RawPath>`). A `{{equip}}/<RefName>` token resolves
+> through the equipment's `UnsTagReference` to that same backing RawPath (see below), so
+> scripts key off the single value source regardless of the UNS projection. The dual
+> namespace changes only the OPC UA address-space surface, not script tag-path semantics.
+
 ### Literal gate
 
 `TryGetTagPathLiteral` identifies the tag-path context by climbing from the

docs/ScriptedAlarms.md

@@ -127,9 +127,25 @@ object alongside the usual `"FullName"`:
 (unchanged behaviour). `"alarm"` **present** → the tag materialises as a Part 9
 `AlarmConditionState` under its equipment folder **instead of** a value variable.
 No EF/schema change is required; the intent rides in the schemaless `TagConfig`
-blob and is parsed byte-parity in both the compose (`Phase7Composer`) and deploy
+blob and is parsed byte-parity in both the compose (`AddressSpaceComposer`) and deploy
 (`DeploymentArtifact`) paths.
 
+> **v3 Batch 4 — multi-notifier fan-out.** The `"alarm"` object now rides on a **raw
+> tag** authored in `/raw` (referenced into equipment), and the Part 9 condition
+> materializes **once at the raw tag** — its `ConditionId` is the tag's **RawPath**, its
+> parent notifier is the raw device/group folder. For **each referencing equipment**, the
+> node manager (`WireAlarmNotifiers`) wires the SDK `AddNotifier` pattern
+> (`alarm.AddNotifier(equipFolder, isInverse:true)` + `equipFolder.AddNotifier(alarm)` +
+> `EnsureFolderIsEventNotifier(equipFolder)`) so the single condition fans to the raw device
+> folder AND every equipment folder. A **single** `ReportEvent` fans to all notifier roots —
+> a Server-object subscriber sees **exactly one** copy (the Part 9 shared-snapshot dedup),
+> never one-per-root. Teardown is symmetric (`RemoveNotifier(..., bidirectional:true)` on
+> rebuild / reference removal) so inverse-notifier entries never leak across redeploys.
+> Ack/confirm/shelve route on **`ConditionId = RawPath`** (never `SourceNodeId`), and the
+> `/alerts` row lists the referencing equipment paths. See
+> [AlarmTracking.md](AlarmTracking.md) and the WP4 section of
+> `docs/plans/2026-07-15-v3-batch4-address-space-plan.md`.
+
 ### TagConfig alarm fields
 
 | Field | Values | Default |
@@ -208,9 +224,10 @@ native alarm transitions identically. Publication to the `alerts` topic is
 the OPC UA condition-node write is ungated on all nodes so a Secondary stays warm
 for failover.
 
-The alarm is authored on the `Tags` tab of the equipment page (`/uns/equipment/{id}`)
+The alarm is authored on the **raw tag** in `/raw` by including the `"alarm"` object in the
-by editing the tag's raw `TagConfig` JSON to include the `"alarm"` object. No
+tag's `TagConfig` JSON (v3 Batch 4 — equipment no longer authors tags; it references raw
-other configuration is required.
+tags). No other configuration is required: any equipment that references the raw tag
+automatically receives the alarm at its equipment folder via the multi-notifier fan-out above.
 
 ### Native-alarm OPC UA operator operations
 

docs/Uns.md

@@ -110,6 +110,41 @@ UNS-referenced, or named by a script literal — see [`Raw.md`](Raw.md).
 `GalaxyMxGateway` driver in `/raw`, referenced into equipment like any other raw
 tag. There is no separate alias concept or `SystemPlatform`-kind namespace.
 
+### OPC UA address-space projection (v3 Batch 4 — dual namespace)
+
+> **v3 (Batch 4):** the server now exposes the address space under **two OPC UA
+> namespaces** instead of the old single `https://zb.com/otopcua/ns`:
+>
+> | Namespace URI | Subtree | NodeId `s=` scheme |
+> |---|---|---|
+> | `https://zb.com/otopcua/raw` | the `/raw` device tree (Folder → Driver → Device → TagGroup → Tag) | the node's **RawPath** (e.g. `Plant/Modbus/dev1/Speed`) |
+> | `https://zb.com/otopcua/uns` | the UNS tree (Area → Line → Equipment → signal) | the slash-joined **`Area/Line/Equipment/EffectiveName`** |
+
+Every device value has **exactly one source** — the raw tag's node in the Raw
+namespace. A `UnsTagReference` projects that raw tag into an equipment as a
+**UNS-namespace variable** whose NodeId leaf is the reference's **effective name**
+(the display-name override else the raw tag's `Name`). The UNS variable does not
+bind a driver of its own: it carries an **`Organizes` reference to its backing raw
+node** and mirrors it. A single driver publish for a RawPath **fans out** to the
+raw NodeId AND every referencing UNS NodeId with identical value / quality /
+source-timestamp — the two NodeIds never drift.
+
+- **Reads / subscriptions** work through either NodeId and return the same data.
+- **Writes** route through either NodeId to the same backing driver ref under the
+  **same `WriteOperate` gating** (a UNS write is neither more nor less privileged
+  than the raw write it fans from); a failed device write reverts both NodeIds via
+  the shared fan-out.
+- **HistoryRead** works through either NodeId and returns the same series — both
+  NodeIds register the **same historian tagname** (see [`Historian.md`](Historian.md)).
+- **Native alarms** materialize once at the raw tag (`ConditionId = RawPath`) and
+  fan via SDK notifiers to the raw device folder AND every referencing equipment
+  folder — see [`ScriptedAlarms.md`](ScriptedAlarms.md) / [`AlarmTracking.md`](AlarmTracking.md).
+
+Note the two distinct identity strings: the wire **NodeId** is the path
+`Area/Line/Equipment/EffectiveName`, while the **effective-name uniqueness key**
+above is `{EquipmentId}/{EffectiveName}` (the logical per-equipment collision
+space the guards enforce). They are related but not the same string.
+
 ### Virtual tags
 
 A virtual tag is bound to an equipment and driven by a **script** (no driver).

docs/operations/2026-07-16-secrets-clustered-master-key.md

@@ -0,0 +1,177 @@
+# Secrets: Clustered Master-Key Posture (All Roles)
+
+## Purpose
+
+`ZB.MOM.WW.Secrets` resolves `${secret:...}` tokens in `appsettings.*.json` via a
+pre-host expander (`SecretReferenceExpander.ExpandConfigurationAsync`, wired in
+`src/Server/ZB.MOM.WW.OtOpcUa.Host/Program.cs`) that runs at **every** OtOpcUa node
+boot, before the host is built. It reads rows from an envelope-encrypted SQLite
+store (`Secrets:SqlitePath`) unwrapped with a key-encryption key (KEK) sourced per
+`Secrets:MasterKey:Source`. The runtime `ISecretResolver` (`AddZbSecrets`) is also
+registered unconditionally, independent of node role.
+
+OtOpcUa is Akka.NET-clustered (`builder.Services.AddAkka("otopcua", (ab, sp) => { ... })`
+in `Program.cs`), with roles parsed by `RoleParser` (`src/Core/ZB.MOM.WW.OtOpcUa.Cluster/RoleParser.cs`):
+`admin`, `driver`, `dev`. A node can carry any combination of these roles (e.g. a
+fused admin+driver node, or a driver-only node). This runbook covers what a
+production deployment needs so that secret resolution behaves identically on
+**every node regardless of role** — not just admin nodes. That matters here more
+than it might elsewhere: the pre-host expander and the runtime resolver both run
+unconditionally on driver-only nodes too, and driver-only nodes are the ones that
+will resolve Layer-B `DriverConfig` secret references (coming in Slice 2) at
+runtime, not just at boot. It does **not** change any code; it is an
+operations/deployment posture, delivered out-of-band from the committed config.
+
+## The two hard requirements
+
+For the pre-host expander (and the runtime resolver) to resolve the same
+plaintext secret on every node, no matter its role:
+
+1. **Identical KEK on every node.** All nodes — admin, driver, and any fused
+   combination — must unwrap the store with the exact same master key. A
+   per-node KEK (e.g. a per-box DPAPI-protected key) would make each node
+   decrypt every *other* node's ciphertext rows to garbage.
+2. **Identical store rows on every node.** All nodes must read the same SQLite
+   database (same file, or a replicated/shared copy with the same rows) — not
+   independently-seeded stores that happen to share a KEK.
+
+`ZB.MOM.WW.Secrets` ships a SQLite-only `ISecretStore` with a `NoOpSecretReplicator`
+— there is no built-in cross-node replication today. Meeting both requirements in
+production is a deployment concern, covered below.
+
+## Recommended interim posture (G-5)
+
+Until real replication exists (G-7, below), the recommended production posture is:
+
+- **`Secrets:MasterKey:Source = File`**, with `FilePath` pointing at a **read-only
+  key file that is identical on every node of every role** — a base64-encoded
+  32-byte key, generated out-of-band (e.g. `openssl rand -base64 32`), distributed
+  to each node's filesystem/secret-mount by the deployment tooling, and **never
+  committed** to the repo. Treat it with the same discipline as any other
+  production secret (restrictive file ACLs, no logging, rotated via a future
+  KEK-rotation runbook — not yet built).
+- **`Secrets:SqlitePath`** pointing at a **single shared or replicated volume**
+  that every node mounts (admin, driver, and dev/fused alike), so every node's
+  migrator opens and reads the same rows at boot.
+
+Writes to the store are rare and human-driven — an operator using the
+`/admin/secrets` UI (admin nodes only) or the `ZB.MOM.WW.Secrets` CLI — while
+reads happen on every node's boot and on the `ResolveCacheTtl` refresh cycle,
+regardless of role. The access pattern is read-mostly / effectively
+single-writer, which is what makes a shared SQLite volume viable as an interim
+posture (see caveat below).
+
+## How it's delivered (do NOT commit these values)
+
+The File-KEK + shared-store posture is supplied per-node at deployment time —
+**never** by editing the committed `appsettings.json` or the role-overlay files
+(`appsettings.admin.json`, `appsettings.driver.json`, `appsettings.admin-driver.json`).
+Those committed overlays are also consumed by local dev and the
+`TwoNodeClusterHarness` integration tests, so hardcoding a `Source=File` path
+into them would break every dev/test/CI boot. Two acceptable delivery
+mechanisms instead:
+
+**Option A — environment variable overrides** (Windows Service / NSSM env block,
+container `env_file`, etc.), applied identically on every node regardless of role:
+
+```
+# production deployment — do not commit to the dev appsettings
+Secrets__MasterKey__Source=File
+Secrets__MasterKey__FilePath=/run/secrets/otopcua-master.key
+Secrets__SqlitePath=/shared/secrets/otopcua-secrets.db
+```
+
+**Option B — a production-only config layer** that is *not* the committed dev
+base (e.g. an untracked `appsettings.Production.json` deployed alongside the
+binaries, or an orchestrator-injected config mount):
+
+```jsonc
+// production deployment — do not commit to the dev appsettings
+{
+  "Secrets": {
+    "MasterKey": {
+      "Source": "File",
+      "FilePath": "/run/secrets/otopcua-master.key"
+    },
+    "SqlitePath": "/shared/secrets/otopcua-secrets.db"
+  }
+}
+```
+
+Either way, the file/path referenced must exist and be identical on every node
+**before** that node boots — the pre-host expander runs unconditionally on every
+role and will throw (`SecretNotFoundException` / migration failure) if the store
+or key is missing.
+
+## Caveat: SQLite over a shared volume is not real replication
+
+SQLite's file-locking model does not tolerate concurrent multi-writer access well
+over network filesystems (SMB/NFS locking is unreliable, and even on a clustered
+block volume only one writer should be active at a time). The interim posture
+above is acceptable because:
+
+- Reads dominate (every node's boot + cache-refresh cycle, across every role).
+- Writes are rare, human-initiated, and effectively single-writer in practice
+  (an operator runs the CLI/UI against one admin node at a time).
+
+It is **not** a substitute for real replication, and it is not safe if multiple
+nodes attempt concurrent writes. Do not build automation that writes secrets
+from more than one node simultaneously.
+
+## Data Protection is independent — do not touch it here
+
+OtOpcUa's cookie/session protection already has its own clustered-key story:
+`AddDataProtection().PersistKeysToDbContext<OtOpcUaConfigDbContext>()`
+(`src/Server/ZB.MOM.WW.OtOpcUa.Security/ServiceCollectionExtensions.cs:73-75`),
+which shares the Data Protection key ring across every node via the existing
+ConfigDb. That mechanism is unrelated to `ZB.MOM.WW.Secrets`' envelope encryption
+(KEK + SQLite store) and must **not** be reconfigured as part of secrets-adoption
+work — doing so risks invalidating active sessions for an unrelated reason.
+
+It is, however, the model for where the *next* iteration of secret storage
+should go — see the G-7 hand-off below.
+
+## The G-7 hand-off
+
+The posture above is an interim, ops-only workaround. The long-term shape,
+tracked as **G-7** in `scadaproj/components/secrets/GAPS.md`, is a
+ConfigDb-backed `ISecretStore` that mirrors the pattern OtOpcUa already uses for
+the Data Protection key ring:
+
+```csharp
+services.AddDataProtection()
+    .PersistKeysToDbContext<OtOpcUaConfigDbContext>()
+    .SetApplicationName("OtOpcUa");
+```
+
+(`src/Server/ZB.MOM.WW.OtOpcUa.Security/ServiceCollectionExtensions.cs:73-75`).
+`OtOpcUaConfigDbContext` already gives every node — admin, driver, and dev/fused
+alike — a single MS SQL-backed source of truth for the Data Protection key ring;
+the secret store is the natural next tenant of that same shared database instead
+of a shared SQLite file. Building this requires new `ZB.MOM.WW.Secrets` library
+code (a ConfigDb-backed `ISecretStore` implementation) that does not exist yet,
+overlaps the G-7 tracking item, and is explicitly **deferred there** — it is not
+built as part of this cut. This runbook's shared-SQLite-volume posture is the
+bridge until G-7 lands.
+
+## Dev/test/default posture (unchanged)
+
+The committed default in `appsettings.json` is:
+
+```json
+"Secrets": {
+  "SqlitePath": "otopcua-secrets.db",
+  "MasterKey": { "Source": "Environment", "EnvVarName": "ZB_SECRETS_MASTER_KEY" },
+  "RunMigrationsOnStartup": true
+}
+```
+
+This is dev-safe: `Source=Environment` needs no filesystem key, and the SQLite
+path is relative to the working directory, so local dev, the role-overlay
+appsettings (`appsettings.admin.json`, `appsettings.driver.json`,
+`appsettings.admin-driver.json`), and the `TwoNodeClusterHarness` integration
+tests all boot cleanly with no external mount. The File-KEK + shared-volume
+posture in this runbook applies only to real clustered production deployments —
+it must never be baked into the committed dev/role-overlay base, because the
+expander runs unconditionally at every node boot (any role) and would break
+dev/CI if pointed at a nonexistent `/shared` mount.

docs/plans/2026-07-16-v3-batch4-PR.md

@@ -0,0 +1,115 @@
+# v3 Batch 4 — dual-namespace address space + raw-only runtime binding (= v3.0)
+
+Implements `docs/plans/2026-07-15-v3-batch4-address-space-plan.md` (B4-WP1–WP5), executed via the
+`/v3-batch 4` coordinator: contracts-first fan-out, worktree-isolated Opus agents per wave, a
+code-reviewer pass + green build/test after each wave, then the non-negotiable **7-leg v3.0 live gate**
+on docker-dev + Client.CLI. **This batch lights up the address space** — v3.0.
+
+## What landed
+
+- **Contracts** (`a1a56e22`) — two namespace URIs (`…/otopcua/raw`, `…/otopcua/uns`, replacing the single
+  `…/ns`), `V3NodeIds` (raw = `s=<RawPath>`, UNS = `s=<Area>/<Line>/<Equipment>/<EffectiveName>`), and the
+  `AddressSpaceRealm` (`Raw | Uns`) discriminator carried at every sink seam.
+- **Wave A** (2 agents ∥):
+  - **WP1** — composer/planner un-darkened: emit the **Raw** subtree (Folder→Driver→Device→TagGroup→Tag,
+    tags as `(realm=Raw, s=RawPath)`) + the **UNS** subtree (each `UnsTagReference` a Variable
+    `(realm=Uns, s=Area/Line/Equipment/EffectiveName)` carrying its backing RawPath + an `Organizes`
+    UNS→Raw ref); native-alarm plans at the **raw** tag (ConditionId=RawPath) carrying referencing-equipment
+    paths; per-realm planner diff (raw rename = remove+add Raw + re-point UNS); reactivated the Batch-1-skipped
+    `EquipmentNamespaceMaterializationTests`.
+  - **WP2** — node manager registers both namespaces; `AddressSpaceRealm` on every node-naming sink method
+    (maps keyed by ns-qualified NodeId so a Raw + UNS node sharing a bare `s=` id stay distinct; historized
+    UNS node registers the **same** tagname, mux single by RawPath); everything **forwarded through
+    `DeferredAddressSpaceSink`** + reflection guard extended (the forwarding trap). **M1 fix**: new
+    `AddReference` sink seam wiring the `Organizes` UNS→Raw edge bidirectionally (idempotent, missing-endpoint
+    no-op, forwarded + reflection-covered).
+- **Wave B** (1 agent — the delicate one):
+  - **WP3** — applier materializes both realms + wires the Organizes edge; `DriverHostActor` dual-NodeId
+    registration + single-source fan-out (drift-free — one publish → raw NodeId AND every referencing UNS
+    NodeId, identical value/quality/timestamp); write routing + failed-write revert through both NodeIds;
+    `EquipmentNodeIds` retired; transitional realm defaults removed from the sink surface. **Review fixes**:
+    **H1** realm-qualified `(realm, bareId)` write-routing key (a raw RawPath that coincidentally equals a UNS
+    path can no longer misroute a write); **M1** coherent-dormant discovery-injection guard; **M2** dual-node
+    self-correction tests; **L1** node-manager routing defaults removed (~180 call sites); byte-parity
+    round-trip test.
+- **Wave C** (2 agents ∥):
+  - **WP4** — multi-notifier native alarms: one condition at the raw tag, `AddNotifier`-fanned to the raw
+    device folder + every referencing equipment folder, **one `ReportEvent`** (exactly one Server-object copy —
+    proven by an over-the-wire event-delivery test), teardown symmetry (`RemoveNotifier(bidirectional:true)` on
+    rebuild/condition-removal/subtree-removal + reconcile), ack/confirm/shelve still on ConditionId=RawPath;
+    `AlarmTransitionEvent` + `/alerts` gain the referencing-equipment list. **Review fixes**: M1 event-delivery
+    test, M2 resolution-failure meter + composer↔applier path-agreement test, M3 reconcile, L1/L3.
+  - **WP5** — over-the-wire dual-namespace integration tests (`DualNamespaceAddressSpaceTests`) + 2-node
+    harness materialization round-trip; docs (`CLAUDE.md`, `docs/Uns.md`, `docs/ScriptEditor.md`,
+    `docs/Historian.md`, `docs/ScriptedAlarms.md`, `docs/AlarmTracking.md`).
+- **Coordinator seam-fix** — threaded `ReferencingEquipmentPaths` into `DriverHostActor.ForwardNativeAlarm`'s
+  `AlarmTransitionEvent` so `/alerts` chips populate in production (WP3-owned file WP4 couldn't edit).
+- **Live-gate bug fix** — the gate caught a genuine prod-inert defect: **Equipment VirtualTags never resolved
+  live** (a redeploy resets the VT's UNS node to `BadWaitingForInitialData`, but a surviving unchanged-plan
+  `VirtualTagActor` keeps its value-dedup state and suppresses the re-publish → the reset node stays Bad
+  forever with a static dependency). Fix: `ReassertValue` on apply re-emits the last value after the node
+  reset. Regression test fail-before/pass-after; live-verified Good. (Reviewer follow-ups: reassert skips
+  historian re-record (M1); scripted-alarm redeploy recovery (M2); comment (LOW-3).)
+
+## Reviewer verdict per wave
+
+No HIGH survived any wave. Wave A: forwarding trap verified solid (DispatchProxy guard catches unforwarded
+methods), collision-free ns-qualified keying, planner raw-rename-repoints-UNS holds; M1 (Organizes seam) fixed.
+Wave B: **H1** write-route realm collision fixed with a regression test; M1/M2/L1 fixed. Wave C: single-ReportEvent
++ teardown symmetry + forwarding trap all confirmed; M1/M2/M3/L1/L3 fixed. VT-fix review: ordering confirmed real,
+dedup/02-S13 semantics intact; M1/M2/LOW-3 closed.
+
+## v3.0 live gate (docker-dev `:9200` / `opc.tcp://:4840`+`:4841`, both centrals rebuilt on Batch-4 code)
+
+1. **Browse both namespaces** — `ns=2` Raw tree (`pymodbus/plc/HR200`, `s=<RawPath>`) + `ns=3` UNS tree
+   (`gatearea/gateline/gateequip/MainPressure`, effective names); both materialize `failed=0`.
+2. **Single-source fan-out** — `MainPressure` (UNS) = `HR200` (Raw) = **1234**, identical value AND timestamp;
+   Calculation tag `Cval` computes (=1235); the `{{equip}}/MainPressure` VirtualTag reads Good (post-fix).
+3. **Writes** — write **4242** via the UNS NodeId → read-back **4242** via the raw NodeId; write **777** via the
+   raw NodeId; `opc-readonly` rejected **0x801F0000** on the UNS NodeId (role gating symmetric). Failed-write
+   dual-node revert is unit-covered (`exception_injector` fixture not provisioned on this rig).
+4. **History** — HistoryRead via the raw NodeId and the UNS NodeId both return **GoodNoData** under the same
+   historian tagname (Null source — no gateway on docker-dev); provisioning tally `dispatched=1 … failed=0`.
+5. **Alarms (multi-notifier)** — the native alarm materialized as a Part 9 **AlarmCondition** at the raw tag
+   (ConditionId = RawPath); the **equipment folder** accepts an alarm subscription + ConditionRefresh, proving
+   it is a live event-notifier wired to the raw condition; the Server object likewise. The transition delivery
+   (exactly-one Server copy + delivery at both notifiers + ack) is covered by the over-the-wire
+   `NativeAlarmMultiNotifierEventDeliveryTests` — docker-dev has no `IAlarmSource` driver (only Galaxy is one)
+   so a live transition can't be tripped on the rig.
+6. **Rename cascade** — renamed `HR200`→`HR200X` + deployed: old raw NodeId gone, new present; the UNS
+   reference `MainPressure` follows automatically; the `{{equip}}` VirtualTag keeps working and tracks the
+   renamed tag live (3610→3611 Good); the **absolute** RawPath script literal (`Cval`) now fails **Bad
+   0x80000000**. (Caveat: a raw-tag rename needs a node recreate/restart to hot-rebind the renamed tag's live
+   driver value — the pre-existing deploy-THEN-recreate pattern for structural edits.)
+7. **Redundancy** — ServiceLevel split **central-1 = 250 / central-2 = 240** (both Good) — the Primary/Secondary
+   differentiation is intact with the second namespace present; single-emit-per-condition is unit-covered (the
+   alarm-emit gate is Primary-only).
+
+## Tests
+
+Full solution builds **0 errors**. Commons 306, Configuration 121, OpcUaServer 375/4-skip (+ OpcUaServer.IntegrationTests
+dual-namespace + event-delivery), Runtime 377 (+ VT reassert regression), AdminUI 659, Host.IntegrationTests green
+(the pre-existing Batch-2 `Calculation`-probe stale test fixed here). The remaining Runtime skips are legacy
+`EquipmentTags`-model dark tests + the dormant discovery-injection scenarios (accurate skip reasons).
+
+## Documented follow-ups (non-blocking)
+
+- **Scripted-alarm redeploy recovery (CONFIRMED pre-existing bug, deferred — deserves its own careful fix).**
+  The scripted-alarm Part 9 condition node has the same redeploy-reset race the VT `ReassertValue` fix closed:
+  `RebuildAddressSpace` clears `_alarmConditions` and `MaterialiseScriptedAlarms` recreates each condition
+  fresh/normal, but `ScriptedAlarmEngine.LoadAsync` reloads from the persisted state and yields
+  `EmissionKind.None` for a still-active condition (dropped by `OnEngineEmission`), so an **active scripted
+  alarm with static dependencies under-reports as normal after a full-rebuild deploy until its next real
+  transition** (the known "snapshot-is-one-shot / restart-to-re-deliver" gotcha — NOT a Batch-4 regression).
+  Deferred because the fix is a Core-engine emission-contract change carrying **double-alarm-history risk**
+  (a naive re-emit would append a duplicate AVEVA/historian row per deploy — the alarm analogue of the VT M1
+  historian issue). Proposed shape: a host-driven, node-only `AlarmStateUpdate` re-assert in `OnAlarmsLoaded`
+  (same safe post-materialise ordering as the VT fix), reusing `_engine.GetState(alarmId)` + `LoadedAlarmIds`,
+  **never touching the `alerts` topic**.
+- Raw-tag rename hot-rebind of the renamed tag's live value without a recreate (today: deploy-THEN-recreate).
+- Absolute-path Monaco completion → RawPath (from Batch 3; the `{{equip}}/` completion works).
+- Cross-repo (post-merge): ScadaBridge Data-Connection-Layer NodeId/namespace cutover (raw `s=<RawPath>` /
+  UNS `s=<Area>/<Line>/<Equipment>/<EffectiveName>`, retired `EquipmentNodeIds`) + the umbrella index
+  `../scadaproj/CLAUDE.md` OtOpcUa entry.
+
+https://claude.ai/code/session_01LVneM3eh1UtJxEisFXgmox

docs/security.md

@@ -380,6 +380,55 @@ polling the node.
 
 ---
 
+## Config secrets (`${secret:}` delivery)
+
+OtOpcUa never commits secret values to `appsettings*.json`. Every real secret is
+supplied at deploy time — either as a plain environment variable, or as a
+`${secret:<name>}` token backed by the shared **`ZB.MOM.WW.Secrets`** encrypted store.
+
+A pre-host expander (`SecretReferenceExpander.ExpandConfigurationAsync`, wired in
+`OtOpcUa.Host/Program.cs`) walks the assembled configuration and rewrites every
+`${secret:<name>}` token into its resolved plaintext **before** the host is built —
+so every downstream binder/validator (`AddZbSerilog`, `AddOtOpcUaConfigDb`, the first
+`ValidateOnStart`) sees resolved values. The store's key-encryption key (KEK) comes from
+the `ZB_SECRETS_MASTER_KEY` environment variable (`Secrets:MasterKey:Source=Environment`);
+the encrypted SQLite store lives at `Secrets:SqlitePath`.
+
+The expander is **fail-closed and section-agnostic**: a `${secret:<name>}` token whose
+secret is absent throws `SecretNotFoundException` at startup, regardless of which feature
+owns the key or whether that feature is enabled. Keys prefixed with `_` (comment keys) are
+skipped, so a `${secret:...}` example inside a `_…Comment` value is never resolved.
+
+The five config secrets and their canonical secret names:
+
+| Config key | Owner | Secret name |
+|---|---|---|
+| `Security:Jwt:SigningKey` | `JwtOptions` | `otopcua/jwt/signing-key` |
+| `Security:Ldap:ServiceAccountPassword` | `LdapOptions` | `otopcua/ldap/service-account-password` |
+| `Security:DeployApiKey` | `DeployApiEndpoints` | `otopcua/deploy/api-key` |
+| `ConnectionStrings:ConfigDb` | `AddOtOpcUaConfigDb` | `otopcua/sql/configdb-connstr` |
+| `ServerHistorian:ApiKey` | `ServerHistorianOptions` | `otopcua/historian/api-key` |
+
+**Delivery.** By default these are delivered as plain environment variables (e.g.
+`ServerHistorian__ApiKey=histgw_…`), never committed. To deliver one from the encrypted
+store instead, seed it once with the `secret` CLI (from `ZB.MOM.WW.Secrets`), then supply
+the token in place of the literal — via env var or a deployment appsettings overlay:
+
+```
+secret set otopcua/historian/api-key <value>       # seed the encrypted store first
+ServerHistorian__ApiKey='${secret:otopcua/historian/api-key}'
+```
+
+Only switch a value to a `${secret:}` token **after** the secret is seeded — an unseeded
+token fails the boot fail-closed. Do not commit the KEK (`ZB_SECRETS_MASTER_KEY`) or any
+secret value.
+
+For the production posture needed so every clustered node (admin, driver, and any
+fused role) resolves the same secrets from the same store, see
+[`docs/operations/2026-07-16-secrets-clustered-master-key.md`](operations/2026-07-16-secrets-clustered-master-key.md).
+
+---
+
 ## Troubleshooting
 
 ### Certificate trust failure

src/Core/ZB.MOM.WW.OtOpcUa.Commons/Messages/Alerts/AlarmTransitionEvent.cs

@@ -17,6 +17,7 @@ namespace ZB.MOM.WW.OtOpcUa.Commons.Messages.Alerts;
 /// <param name="AlarmTypeName">OPC UA Part 9 condition subtype name — one of <c>LimitAlarm</c> / <c>DiscreteAlarm</c> / <c>OffNormalAlarm</c> / <c>AlarmCondition</c> (the base type, used as the default). The historian feed maps this onto the durable alarm-type column.</param>
 /// <param name="Comment">Operator-supplied comment on ack / confirm / comment transitions; <c>null</c> for engine-driven transitions (Activated / Cleared / Shelved / …) that carry no comment.</param>
 /// <param name="HistorizeToAveva">When <c>false</c>, the durable historian sink suppresses this transition (the live <c>alerts</c> fan-out is unaffected); <c>null</c> or <c>true</c> historize. <c>null</c> is the cross-version/rolling-restart case: an old-format message missing the field deserializes to <c>null</c> (CLR default for <c>bool?</c>) and is historized (safe default-on), matching the <c>AlarmTypeName</c> null-coalesce in <c>HistorianAdapterActor.Translate</c>. The producer (<c>ScriptedAlarmHostActor</c>) always sets a concrete <c>true</c>/<c>false</c>.</param>
+/// <param name="ReferencingEquipmentPaths">v3 Batch 4 (multi-notifier native alarms) — the (possibly empty) list of UNS equipment-folder paths (<c>Area/Line/Equipment</c>) that reference the alarm's backing raw tag. A native alarm is a SINGLE Part 9 condition materialised once at the raw tag (its <see cref="AlarmId"/> is the RawPath); the same condition fans events to every referencing equipment's UNS folder via SDK notifiers, and this list is carried so <c>/alerts</c> shows the one condition row with all its referencing equipment as display metadata. Empty for scripted alarms (they are per-equipment) and for a native alarm whose raw tag no equipment references. Defaults empty so every existing producer + rolling-restart deserialization keeps compiling / working.</param>
 public sealed record AlarmTransitionEvent(
     string AlarmId,
     string EquipmentPath,
@@ -28,4 +29,5 @@ public sealed record AlarmTransitionEvent(
     DateTime TimestampUtc,
     string AlarmTypeName = "AlarmCondition",
     string? Comment = null,
-    bool? HistorizeToAveva = null);
+    bool? HistorizeToAveva = null,
+    IReadOnlyList<string>? ReferencingEquipmentPaths = null);

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/AddressSpaceRealm.cs

@@ -0,0 +1,18 @@
+namespace ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+
+/// <summary>
+///     Which of the two v3 OPC UA namespaces a node lives in. Carried explicitly alongside a
+///     node's <c>s=</c> identifier at every address-space sink seam so the namespace is chosen at
+///     the call site, never parsed back out of the id string (explicit beats inferred).
+///     <see cref="V3NodeIds.NamespaceUri"/> maps each realm to its namespace URI.
+/// </summary>
+public enum AddressSpaceRealm
+{
+    /// <summary>The device-oriented Raw tree (Folder→Driver→Device→TagGroup→Tag); a node's
+    /// <c>s=</c> id is its <see cref="ZB.MOM.WW.OtOpcUa.Commons.Types.RawPaths">RawPath</see>.</summary>
+    Raw,
+
+    /// <summary>The equipment-oriented UNS tree (Area→Line→Equipment→signal); a node's <c>s=</c>
+    /// id is the slash-joined <c>Area/Line/Equipment[/EffectiveName]</c>.</summary>
+    Uns,
+}

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/DeferredAddressSpaceSink.cs

@@ -23,30 +23,41 @@ public sealed class DeferredAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgical
         _inner = sink ?? NullOpcUaAddressSpaceSink.Instance;
 
     /// <inheritdoc />
-    public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc)
+    public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm)
-        => _inner.WriteValue(nodeId, value, quality, sourceTimestampUtc);
+        => _inner.WriteValue(nodeId, value, quality, sourceTimestampUtc, realm);
 
     /// <inheritdoc />
-    public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
+    public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm)
-        => _inner.WriteAlarmCondition(alarmNodeId, state, sourceTimestampUtc);
+        => _inner.WriteAlarmCondition(alarmNodeId, state, sourceTimestampUtc, realm);
 
     /// <inheritdoc />
-    public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false)
+    public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false)
-        => _inner.MaterialiseAlarmCondition(alarmNodeId, equipmentNodeId, displayName, alarmType, severity, isNative);
+        => _inner.MaterialiseAlarmCondition(alarmNodeId, equipmentNodeId, displayName, alarmType, severity, realm, isNative);
 
     /// <inheritdoc />
-    public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
+    // Forward the WP4 multi-notifier wiring to the inner sink. Without this the native-alarm fan-out to the
-        => _inner.EnsureFolder(folderNodeId, parentNodeId, displayName);
+    // referencing equipment folders ships INERT on every driver-role host (actors inject THIS wrapper, not the
+    // inner SdkAddressSpaceSink) — the F10b / PR#423 forwarding trap the reflection guard exists to catch.
+    public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm)
+        => _inner.WireAlarmNotifiers(alarmNodeId, alarmRealm, notifierFolderNodeIds, notifierFolderRealm);
 
     /// <inheritdoc />
-    public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+    public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm)
-        => _inner.EnsureVariable(variableNodeId, parentFolderNodeId, displayName, dataType, writable, historianTagname, isArray, arrayLength);
+        => _inner.EnsureFolder(folderNodeId, parentNodeId, displayName, realm);
+
+    /// <inheritdoc />
+    public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+        => _inner.EnsureVariable(variableNodeId, parentFolderNodeId, displayName, dataType, writable, realm, historianTagname, isArray, arrayLength);
 
     /// <inheritdoc />
     public void RebuildAddressSpace() => _inner.RebuildAddressSpace();
 
     /// <inheritdoc />
-    public void RaiseNodesAddedModelChange(string affectedNodeId) => _inner.RaiseNodesAddedModelChange(affectedNodeId);
+    public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm) => _inner.RaiseNodesAddedModelChange(affectedNodeId, realm);
+
+    /// <inheritdoc />
+    public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes")
+        => _inner.AddReference(sourceNodeId, sourceRealm, targetNodeId, targetRealm, referenceType);
 
     /// <inheritdoc />
     // Forwards to the inner sink when it supports the surgical capability; returns false otherwise —
@@ -55,9 +66,9 @@ public sealed class DeferredAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgical
     // Without this forward the surgical optimization is inert on every driver-role host, because
     // actors inject THIS wrapper, not the inner sink. ALL six args (including the DataType/array-shape
     // ones) MUST be forwarded — a partial forward silently drops the shape update on every driver-role host.
-    public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
+    public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength, AddressSpaceRealm realm)
         => _inner is ISurgicalAddressSpaceSink surgical
-           && surgical.UpdateTagAttributes(variableNodeId, writable, historianTagname, dataType, isArray, arrayLength);
+           && surgical.UpdateTagAttributes(variableNodeId, writable, historianTagname, dataType, isArray, arrayLength, realm);
 
     /// <inheritdoc />
     // Forwards to the inner sink when it supports the surgical capability; returns false otherwise —
@@ -65,9 +76,9 @@ public sealed class DeferredAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgical
     // sink that isn't surgical — so the caller (AddressSpaceApplier) falls back to a full rebuild.
     // Without this forward the rename-refresh optimization is inert on every driver-role host, because
     // actors inject THIS wrapper, not the inner sink.
-    public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+    public bool UpdateFolderDisplayName(string folderNodeId, string displayName, AddressSpaceRealm realm)
         => _inner is ISurgicalAddressSpaceSink surgical
-           && surgical.UpdateFolderDisplayName(folderNodeId, displayName);
+           && surgical.UpdateFolderDisplayName(folderNodeId, displayName, realm);
 
     // R2-07 T7 — surgical remove forwards. Same capability-sniffing pattern as UpdateTagAttributes /
     // UpdateFolderDisplayName: forward when the inner sink supports the surgical capability; return false
@@ -75,14 +86,14 @@ public sealed class DeferredAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgical
     // (AddressSpaceApplier) falls back to a full rebuild. Without these forwards the surgical remove path is
     // inert on every driver-role host — the F10b / PR#423 trap the reflection guard exists to catch.
     /// <inheritdoc />
-    public bool RemoveVariableNode(string variableNodeId)
+    public bool RemoveVariableNode(string variableNodeId, AddressSpaceRealm realm)
-        => _inner is ISurgicalAddressSpaceSink surgical && surgical.RemoveVariableNode(variableNodeId);
+        => _inner is ISurgicalAddressSpaceSink surgical && surgical.RemoveVariableNode(variableNodeId, realm);
 
     /// <inheritdoc />
-    public bool RemoveAlarmConditionNode(string alarmNodeId)
+    public bool RemoveAlarmConditionNode(string alarmNodeId, AddressSpaceRealm realm)
-        => _inner is ISurgicalAddressSpaceSink surgical && surgical.RemoveAlarmConditionNode(alarmNodeId);
+        => _inner is ISurgicalAddressSpaceSink surgical && surgical.RemoveAlarmConditionNode(alarmNodeId, realm);
 
     /// <inheritdoc />
-    public bool RemoveEquipmentSubtree(string equipmentNodeId)
+    public bool RemoveEquipmentSubtree(string equipmentNodeId, AddressSpaceRealm realm)
-        => _inner is ISurgicalAddressSpaceSink surgical && surgical.RemoveEquipmentSubtree(equipmentNodeId);
+        => _inner is ISurgicalAddressSpaceSink surgical && surgical.RemoveEquipmentSubtree(equipmentNodeId, realm);
 }

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/EquipmentNodeIds.cs

@@ -1,31 +0,0 @@
-namespace ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
-
-/// <summary>
-///     Single source of truth for equipment-namespace OPC UA NodeId strings. The variable NodeId is
-///     FOLDER-SCOPED (<c>{parent}/{Name}</c>), NOT the driver-side FullName — a driver wire ref is not
-///     unique across identical machines, so FullName-as-NodeId would collide in the sink. Used by the
-///     materialiser (AddressSpaceApplier), the VirtualTag publish map, and the driver live-value router so all
-///     three agree on the exact NodeId a variable was placed at.
-/// </summary>
-public static class EquipmentNodeIds
-{
-    /// <summary>The sub-folder NodeId under an equipment for a non-empty FolderPath: <c>{equipmentId}/{folderPath}</c>.</summary>
-    /// <param name="equipmentId">The owning equipment's NodeId.</param>
-    /// <param name="folderPath">The tag/vtag FolderPath (must be non-empty for this to be meaningful).</param>
-    /// <returns>The sub-folder NodeId string.</returns>
-    public static string SubFolder(string equipmentId, string folderPath) => $"{equipmentId}/{folderPath}";
-
-    /// <summary>
-    ///     The folder-scoped variable NodeId: <c>{parent}/{name}</c> where <c>parent = equipmentId</c> when
-    ///     <paramref name="folderPath"/> is null/empty, else <see cref="SubFolder"/>.
-    /// </summary>
-    /// <param name="equipmentId">The owning equipment's NodeId.</param>
-    /// <param name="folderPath">The tag/vtag FolderPath, or null/empty for "directly under the equipment".</param>
-    /// <param name="name">The tag/vtag Name (the leaf browse segment).</param>
-    /// <returns>The folder-scoped variable NodeId string.</returns>
-    public static string Variable(string equipmentId, string? folderPath, string name)
-    {
-        var parent = string.IsNullOrWhiteSpace(folderPath) ? equipmentId : SubFolder(equipmentId, folderPath);
-        return $"{parent}/{name}";
-    }
-}

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaAddressSpaceSink.cs

@@ -13,7 +13,11 @@ public interface IOpcUaAddressSpaceSink
     /// <param name="value">The value to write.</param>
     /// <param name="quality">The quality status of the value.</param>
     /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-    void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc);
+    /// <param name="realm">Which of the two v3 namespaces (<see cref="AddressSpaceRealm.Raw"/> device tree or
+    /// <see cref="AddressSpaceRealm.Uns"/> equipment tree) the <paramref name="nodeId"/> lives in — the sink
+    /// resolves the namespace index from the realm rather than parsing it out of the id string. WP3's fan-out
+    /// calls this once per NodeId (raw + every referencing UNS node) with the matching realm.</param>
+    void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm);
 
     /// <summary>Write an alarm-condition's full Part 9 state. When a real condition node has been
     /// materialised for <paramref name="alarmNodeId"/> via <see cref="MaterialiseAlarmCondition"/>,
@@ -25,7 +29,9 @@ public interface IOpcUaAddressSpaceSink
     /// <param name="alarmNodeId">The OPC UA node ID of the alarm (== ScriptedAlarmId for materialised conditions).</param>
     /// <param name="state">The full condition state to project onto the node.</param>
     /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-    void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc);
+    /// <param name="realm">The namespace realm <paramref name="alarmNodeId"/> lives in (must match the realm
+    /// the condition was materialised under).</param>
+    void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm);
 
     /// <summary>
     ///     Materialise a real OPC UA Part 9 alarm-condition node under its equipment folder so clients
@@ -41,7 +47,31 @@ public interface IOpcUaAddressSpaceSink
     /// <param name="isNative">When true this is a driver-fed (native, e.g. Galaxy) equipment-tag alarm; when
     /// false (default) it is a scripted alarm. The node manager tracks native condition node ids so a later
     /// task can route a native condition's inbound Acknowledge to the driver instead of the scripted engine.</param>
-    void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false);
+    /// <param name="realm">The namespace realm the condition (and its parent folder <paramref name="equipmentNodeId"/>)
+    /// live in.</param>
+    void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false);
+
+    /// <summary>
+    ///     v3 Batch 4 (multi-notifier native alarms) — wire an already-materialised native alarm condition
+    ///     (<paramref name="alarmNodeId"/>, materialised at the raw tag via <see cref="MaterialiseAlarmCondition"/>
+    ///     with ConditionId = the RawPath) as an event notifier of EACH referencing equipment's UNS folder, so
+    ///     the condition's <b>single</b> <c>ReportEvent</c> fans one event to every referencing equipment root
+    ///     WITHOUT re-reporting per root (distinct EventIds would break Server-object dedup + Part 9 ack
+    ///     correlation). Per folder the sink wires the SDK's bidirectional notifier pattern
+    ///     (<c>alarm.AddNotifier(isInverse:true, folder)</c> + <c>folder.AddNotifier(isInverse:false, alarm)</c>)
+    ///     and promotes the folder to an event notifier. <b>Idempotent</b> (a re-wire of the same pair updates,
+    ///     never duplicates); a <b>missing endpoint is a no-op</b> (logged, never thrown) so a mid-rebuild race
+    ///     can't fault a deploy. The sink tracks each wired pair so a later rebuild / condition-removal /
+    ///     equipment-subtree-removal tears the notifier down bidirectionally (no inverse-notifier entry leaks
+    ///     across redeploys).
+    /// </summary>
+    /// <param name="alarmNodeId">The native alarm condition's node id (== the backing tag's RawPath).</param>
+    /// <param name="alarmRealm">The namespace realm the condition lives in (Raw for native alarms).</param>
+    /// <param name="notifierFolderNodeIds">The equipment folder node ids (their <c>s=</c> ids) to wire as
+    /// extra event-notifier roots for this condition. An unknown / not-yet-materialised folder id is skipped.</param>
+    /// <param name="notifierFolderRealm">The namespace realm the notifier folders live in (Uns for equipment folders).</param>
+    void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm,
+                            IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm);
 
     /// <summary>
     ///     Ensure a folder node exists under the given parent. Used by <c>AddressSpaceApplier</c> to
@@ -52,7 +82,8 @@ public interface IOpcUaAddressSpaceSink
     /// <param name="folderNodeId">The OPC UA node ID for the folder.</param>
     /// <param name="parentNodeId">The parent folder node ID, or null for namespace root.</param>
     /// <param name="displayName">The display name for the folder.</param>
-    void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName);
+    /// <param name="realm">The namespace realm the folder (and its <paramref name="parentNodeId"/>) live in.</param>
+    void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm);
 
     /// <summary>
     ///     Ensure a Variable node exists at <paramref name="variableNodeId"/>, parented under
@@ -77,7 +108,10 @@ public interface IOpcUaAddressSpaceSink
     /// rank + dimensions carry the array-ness.</param>
     /// <param name="arrayLength">The declared length of the 1-D array when <paramref name="isArray"/> is
     /// true; ignored for scalars. Null ⇒ length 0 (unbounded).</param>
-    void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null);
+    /// <param name="realm">The namespace realm the variable (and its <paramref name="parentFolderNodeId"/>) live
+    /// in. A historized UNS reference node registers the SAME <paramref name="historianTagname"/> as its backing
+    /// raw node — both NodeIds map to one tagname — so this call carries the shared tagname per realm.</param>
+    void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null);
 
     /// <summary>
     ///     Tear down + repopulate the address space. Called by <c>OpcUaPublishActor</c> after a
@@ -91,7 +125,28 @@ public interface IOpcUaAddressSpaceSink
     ///     (Part 3 GeneralModelChangeEvent, verb NodeAdded).
     /// </summary>
     /// <param name="affectedNodeId">The node under which discovered nodes were added.</param>
-    void RaiseNodesAddedModelChange(string affectedNodeId);
+    /// <param name="realm">The namespace realm <paramref name="affectedNodeId"/> lives in.</param>
+    void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm);
+
+    /// <summary>
+    ///     Add an OPC UA reference from an already-materialised source node to an already-materialised
+    ///     target node, both realm-qualified. Used by <c>AddressSpaceApplier</c> to link each UNS reference
+    ///     Variable (source, <see cref="AddressSpaceRealm.Uns"/>) to its backing Raw node (target,
+    ///     <see cref="AddressSpaceRealm.Raw"/>) with an <c>Organizes</c> edge, so the UNS variable
+    ///     browse-resolves to its raw source (and the raw node back via the inverse). The edge is wired
+    ///     bidirectionally (forward on the source, inverse on the target) so browse resolves both ways.
+    ///     <b>Idempotent</b> (an existing edge is not duplicated); a <b>missing endpoint is a no-op</b>
+    ///     (logged, never thrown) so a mid-rebuild race can't fault a deploy.
+    /// </summary>
+    /// <param name="sourceNodeId">The source node's <c>s=</c> id (the referencing node — e.g. the UNS variable).</param>
+    /// <param name="sourceRealm">The namespace realm <paramref name="sourceNodeId"/> lives in.</param>
+    /// <param name="targetNodeId">The target node's <c>s=</c> id (the referenced node — e.g. the backing Raw node).</param>
+    /// <param name="targetRealm">The namespace realm <paramref name="targetNodeId"/> lives in.</param>
+    /// <param name="referenceType">The hierarchical reference type name — <c>Organizes</c> (default),
+    /// <c>HasComponent</c>, or <c>HasProperty</c>; unknown names fall back to <c>Organizes</c>.</param>
+    void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm,
+                      string targetNodeId, AddressSpaceRealm targetRealm,
+                      string referenceType = "Organizes");
 }
 
 /// <summary>OPC UA status code projection — Good / Uncertain / Bad. Real SDK has finer-grained
@@ -106,23 +161,29 @@ public sealed class NullOpcUaAddressSpaceSink : IOpcUaAddressSpaceSink
     private NullOpcUaAddressSpaceSink() { }
 
     /// <inheritdoc />
-    public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+    public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
 
     /// <inheritdoc />
-    public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc) { }
+    public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
 
     /// <inheritdoc />
-    public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+    public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
 
     /// <inheritdoc />
-    public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName) { }
+    public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
 
     /// <inheritdoc />
-    public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+    public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm) { }
+
+    /// <inheritdoc />
+    public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
 
     /// <inheritdoc />
     public void RebuildAddressSpace() { }
 
     /// <inheritdoc />
-    public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+    public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm) { }
+
+    /// <inheritdoc />
+    public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
 }

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/IOpcUaNodeWriteGateway.cs

@@ -11,11 +11,17 @@ public interface IOpcUaNodeWriteGateway
 {
     /// <summary>Route a write of <paramref name="value"/> to the driver backing node
     /// <paramref name="nodeId"/>; the returned task resolves with the device-write outcome.</summary>
-    /// <param name="nodeId">The folder-scoped equipment-variable node id being written.</param>
+    /// <param name="nodeId">The full ns-qualified node id being written (<c>node.NodeId.ToString()</c>).</param>
     /// <param name="value">The value the client wrote.</param>
+    /// <param name="realm">Which of the two v3 namespaces (<see cref="AddressSpaceRealm.Raw"/> device tree or
+    /// <see cref="AddressSpaceRealm.Uns"/> equipment tree) <paramref name="nodeId"/> lives in — the node
+    /// manager resolves it from the node's namespace index (<c>RealmOf</c>). It is REQUIRED for correct
+    /// routing: a raw <c>s=&lt;RawPath&gt;</c> and a UNS <c>s=&lt;Area/Line/Equip/Eff&gt;</c> can collide as bare
+    /// strings, so the routing map is keyed by <c>(realm, bareId)</c> — dropping the realm would let an
+    /// operator write route to the WRONG driver ref.</param>
     /// <param name="ct">Cancellation token.</param>
     /// <returns>A task resolving to the device-write outcome.</returns>
-    Task<NodeWriteOutcome> WriteAsync(string nodeId, object? value, CancellationToken ct);
+    Task<NodeWriteOutcome> WriteAsync(string nodeId, object? value, AddressSpaceRealm realm, CancellationToken ct);
 }
 
 /// <summary>Outcome of routing an inbound node write to the backing driver.</summary>
@@ -31,6 +37,6 @@ public sealed class NullOpcUaNodeWriteGateway : IOpcUaNodeWriteGateway
     public static readonly NullOpcUaNodeWriteGateway Instance = new();
     private NullOpcUaNodeWriteGateway() { }
     /// <inheritdoc />
-    public Task<NodeWriteOutcome> WriteAsync(string nodeId, object? value, CancellationToken ct) =>
+    public Task<NodeWriteOutcome> WriteAsync(string nodeId, object? value, AddressSpaceRealm realm, CancellationToken ct) =>
         Task.FromResult(new NodeWriteOutcome(false, "writes unavailable"));
 }

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/ISurgicalAddressSpaceSink.cs

@@ -21,8 +21,10 @@ public interface ISurgicalAddressSpaceSink
     /// <param name="dataType">The OPC UA built-in data type name (e.g. "Boolean", "Int32", "Float").</param>
     /// <param name="isArray">When true the node is a 1-D array (ValueRank=OneDimension); when false scalar.</param>
     /// <param name="arrayLength">The declared length of the 1-D array when <paramref name="isArray"/> is true; ignored for scalars.</param>
+    /// <param name="realm">The namespace realm <paramref name="variableNodeId"/> lives in — the sink resolves the
+    /// namespace index from the realm rather than parsing it out of the id string.</param>
     /// <returns>True when the in-place update was applied; false when the node is missing (caller rebuilds).</returns>
-    bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength);
+    bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength, AddressSpaceRealm realm);
 
     /// <summary>Update an existing folder node's <c>DisplayName</c> IN PLACE, notifying subscribers
     /// (ClearChangeMasks) without a rebuild — used by AddressSpaceApplier to apply a UNS Area / Line
@@ -32,8 +34,9 @@ public interface ISurgicalAddressSpaceSink
     /// should rebuild instead).</summary>
     /// <param name="folderNodeId">The node id of the folder whose display name to update in place.</param>
     /// <param name="displayName">The new display name to apply.</param>
+    /// <param name="realm">The namespace realm <paramref name="folderNodeId"/> lives in.</param>
     /// <returns>True when the in-place update was applied; false when the folder is missing (caller rebuilds).</returns>
-    bool UpdateFolderDisplayName(string folderNodeId, string displayName);
+    bool UpdateFolderDisplayName(string folderNodeId, string displayName, AddressSpaceRealm realm);
 
     /// <summary>Remove ONE existing value-variable node IN PLACE (detach from its parent, drop it from the
     /// predefined-node set, drop any historized-tagname registration), then raise a Part 3
@@ -43,8 +46,9 @@ public interface ISurgicalAddressSpaceSink
     /// re-subscription attempts get BadNodeIdUnknown from the SDK. Returns false when the node id is unknown
     /// (the node-manager maps drifted from the plan — caller falls back to a full rebuild).</summary>
     /// <param name="variableNodeId">The folder-scoped node id of the variable to remove in place.</param>
+    /// <param name="realm">The namespace realm <paramref name="variableNodeId"/> lives in.</param>
     /// <returns>True when the node was removed; false when the id is unknown (caller rebuilds).</returns>
-    bool RemoveVariableNode(string variableNodeId);
+    bool RemoveVariableNode(string variableNodeId, AddressSpaceRealm realm);
 
     /// <summary>Remove ONE existing Part 9 alarm-condition node IN PLACE (detach, drop from the
     /// predefined-node set, clear the native-alarm flag), then raise NodeDeleted outside the lock. The
@@ -52,8 +56,9 @@ public interface ISurgicalAddressSpaceSink
     /// stops replaying on ConditionRefresh. Returns false when the condition id is unknown (caller
     /// rebuilds).</summary>
     /// <param name="alarmNodeId">The alarm condition node id (== ScriptedAlarmId, or a native alarm tag's folder-scoped id).</param>
+    /// <param name="realm">The namespace realm <paramref name="alarmNodeId"/> lives in.</param>
     /// <returns>True when the condition was removed; false when the id is unknown (caller rebuilds).</returns>
-    bool RemoveAlarmConditionNode(string alarmNodeId);
+    bool RemoveAlarmConditionNode(string alarmNodeId, AddressSpaceRealm realm);
 
     /// <summary>Remove an equipment folder AND its entire descendant subtree (sub-folders, value variables,
     /// condition nodes) IN PLACE: per-descendant map/registration cleanup (variables, historized tagnames,
@@ -62,6 +67,7 @@ public interface ISurgicalAddressSpaceSink
     /// the equipment folder outside the lock. Returns false when the folder id is unknown (caller
     /// rebuilds).</summary>
     /// <param name="equipmentNodeId">The equipment folder node id whose entire subtree to remove.</param>
+    /// <param name="realm">The namespace realm <paramref name="equipmentNodeId"/> lives in.</param>
     /// <returns>True when the subtree was removed; false when the id is unknown (caller rebuilds).</returns>
-    bool RemoveEquipmentSubtree(string equipmentNodeId);
+    bool RemoveEquipmentSubtree(string equipmentNodeId, AddressSpaceRealm realm);
 }

src/Core/ZB.MOM.WW.OtOpcUa.Commons/OpcUa/V3NodeIds.cs

@@ -0,0 +1,110 @@
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+
+namespace ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+
+/// <summary>
+///     v3 dual-namespace NodeId + namespace-URI authority. Two OPC UA namespaces expose the same
+///     underlying values under two identity schemes:
+///     <list type="bullet">
+///       <item><b>Raw</b> (<see cref="RawNamespaceUri"/>): the device-oriented tree
+///         Folder→Driver→Device→TagGroup→Tag. A node's <c>s=</c> identifier IS its
+///         <see cref="RawPaths">RawPath</see> — folders/drivers/devices/groups included (each keys
+///         on its own RawPath prefix).</item>
+///       <item><b>Uns</b> (<see cref="UnsNamespaceUri"/>): the equipment-oriented tree
+///         Area→Line→Equipment→signal. A node's <c>s=</c> identifier is the slash-joined
+///         <c>Area/Line/Equipment[/EffectiveName]</c>.</item>
+///     </list>
+///     These replace the single <c>https://zb.com/otopcua/ns</c> namespace and the retired
+///     <c>EquipmentNodeIds</c> ({equipmentId}/{folderPath}/{name}) scheme. Realm travels alongside
+///     the identifier as an <see cref="AddressSpaceRealm"/> at every sink seam — the namespace is
+///     never parsed back out of the id string. Both schemes share <see cref="RawPaths.Separator"/>
+///     and its ordinal, case-sensitive segment charset so identity is enforced in one place.
+/// </summary>
+public static class V3NodeIds
+{
+    /// <summary>The Raw namespace URI (device-oriented subtree).</summary>
+    public const string RawNamespaceUri = "https://zb.com/otopcua/raw";
+
+    /// <summary>The UNS namespace URI (equipment-oriented subtree).</summary>
+    public const string UnsNamespaceUri = "https://zb.com/otopcua/uns";
+
+    /// <summary>The namespace URI for a realm.</summary>
+    /// <param name="realm">The address-space realm.</param>
+    /// <returns>The realm's namespace URI.</returns>
+    /// <exception cref="ArgumentOutOfRangeException">Unknown realm.</exception>
+    public static string NamespaceUri(AddressSpaceRealm realm) => realm switch
+    {
+        AddressSpaceRealm.Raw => RawNamespaceUri,
+        AddressSpaceRealm.Uns => UnsNamespaceUri,
+        _ => throw new ArgumentOutOfRangeException(nameof(realm), realm, "Unknown address-space realm."),
+    };
+
+    // ----- Raw realm -----
+
+    /// <summary>
+    ///     The Raw-namespace <c>s=</c> identifier for a raw node — identical to its
+    ///     <see cref="RawPaths">RawPath</see> (folders, drivers, devices, groups, and tags all key
+    ///     on their own RawPath). A pass-through seam so call sites read intent rather than a bare
+    ///     string; the argument is expected to already be a RawPaths-built path.
+    /// </summary>
+    /// <param name="rawPath">The (already-built) RawPath.</param>
+    /// <returns>The Raw-namespace <c>s=</c> identifier (== <paramref name="rawPath"/>).</returns>
+    public static string Raw(string rawPath)
+    {
+        ArgumentException.ThrowIfNullOrEmpty(rawPath);
+        return rawPath;
+    }
+
+    // ----- Uns realm -----
+
+    /// <summary>
+    ///     The UNS-namespace <c>s=</c> identifier for a folder or variable, slash-joined from
+    ///     ordered segments (Area, then Line, then Equipment, then an optional EffectiveName).
+    ///     Every segment is validated via <see cref="RawPaths.ValidateSegment"/> (no embedded
+    ///     separator, no leading/trailing whitespace) so a UNS id round-trips like a RawPath.
+    /// </summary>
+    /// <param name="segments">The ordered, non-empty segments (Area → leaf).</param>
+    /// <returns>The slash-joined UNS <c>s=</c> identifier.</returns>
+    /// <exception cref="ArgumentException">A segment is invalid, or the sequence is empty.</exception>
+    public static string Uns(params string[] segments) => UnsFromSegments(segments);
+
+    /// <summary>Build a UNS <c>s=</c> identifier from ordered segments. See <see cref="Uns(string[])"/>.</summary>
+    /// <param name="segments">The ordered, non-empty segments (Area → leaf).</param>
+    /// <returns>The slash-joined UNS <c>s=</c> identifier.</returns>
+    public static string Uns(IEnumerable<string> segments) => UnsFromSegments(segments);
+
+    /// <summary>
+    ///     Append a child segment (a Line under an Area, an Equipment under a Line, an
+    ///     EffectiveName under an Equipment) to an already-built UNS path.
+    /// </summary>
+    /// <param name="parentUnsPath">The parent UNS path (assumed already valid).</param>
+    /// <param name="childSegment">The child segment to append.</param>
+    /// <returns>The combined UNS <c>s=</c> identifier.</returns>
+    /// <exception cref="ArgumentException">The child segment is invalid, or the parent is blank.</exception>
+    public static string UnsChild(string parentUnsPath, string childSegment)
+    {
+        ArgumentException.ThrowIfNullOrEmpty(parentUnsPath);
+        var error = RawPaths.ValidateSegment(childSegment);
+        if (error is not null)
+            throw new ArgumentException($"Invalid UNS NodeId segment ('{childSegment}'): {error}", nameof(childSegment));
+
+        return parentUnsPath + RawPaths.Separator + childSegment;
+    }
+
+    private static string UnsFromSegments(IEnumerable<string> segments)
+    {
+        ArgumentNullException.ThrowIfNull(segments);
+        var list = segments as IReadOnlyList<string> ?? segments.ToList();
+        if (list.Count == 0)
+            throw new ArgumentException("A UNS NodeId must have at least one segment.", nameof(segments));
+
+        for (var i = 0; i < list.Count; i++)
+        {
+            var error = RawPaths.ValidateSegment(list[i]);
+            if (error is not null)
+                throw new ArgumentException($"Invalid UNS NodeId segment at index {i} ('{list[i]}'): {error}", nameof(segments));
+        }
+
+        return string.Join(RawPaths.Separator, list);
+    }
+}

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser/GalaxyDriverBrowser.cs

@@ -5,6 +5,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using ZB.MOM.WW.MxGateway.Client;
 using ZB.MOM.WW.OtOpcUa.Commons.Browsing;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser;
 
@@ -34,11 +35,14 @@ public sealed class GalaxyDriverBrowser : IDriverBrowser
     };
 
     private readonly ILogger<GalaxyDriverBrowser> _logger;
+    private readonly ISecretResolver _secretResolver;
 
     /// <summary>Creates a new browser. Logger defaults to <see cref="NullLogger{T}"/>.</summary>
+    /// <param name="secretResolver">Resolves the <c>secret:</c> arm of <c>Gateway.ApiKeySecretRef</c> (DI-injected).</param>
     /// <param name="logger">Optional logger; null is allowed for unit-test construction.</param>
-    public GalaxyDriverBrowser(ILogger<GalaxyDriverBrowser>? logger = null)
+    public GalaxyDriverBrowser(ISecretResolver secretResolver, ILogger<GalaxyDriverBrowser>? logger = null)
     {
+        _secretResolver = secretResolver ?? throw new ArgumentNullException(nameof(secretResolver));
         _logger = logger ?? NullLogger<GalaxyDriverBrowser>.Instance;
     }
 
@@ -68,7 +72,7 @@ public sealed class GalaxyDriverBrowser : IDriverBrowser
         if (string.IsNullOrWhiteSpace(opts.MxAccess.ClientName))
             throw new InvalidOperationException("Galaxy browser requires MxAccess.ClientName.");
 
-        var clientOpts = BuildClientOptions(opts.Gateway);
+        var clientOpts = await BuildClientOptionsAsync(opts.Gateway, cancellationToken).ConfigureAwait(false);
 
         // 30s wall-clock budget for the connect phase, linked to the caller's token so
         // an AdminUI cancel still wins early.
@@ -116,13 +120,21 @@ public sealed class GalaxyDriverBrowser : IDriverBrowser
     ///     Build the gateway client options from the form's Gateway section. Mirrors the
     ///     runtime driver's <c>GalaxyDriver.BuildClientOptions</c> field-for-field so the
     ///     gateway sees an identical option shape. The API-key reference is resolved via
-    ///     the shared <see cref="GalaxySecretRef.ResolveApiKey"/> in Driver.Galaxy.Contracts
+    ///     the shared <see cref="GalaxySecretRef.ResolveApiKeyAsync"/> in Driver.Galaxy.Contracts
     ///     (the same resolver the runtime driver uses), so browse and runtime stay in lock-step.
+    ///     The <c>secret:</c> arm is async, so the key is resolved into a local before the
+    ///     object initializer (you can't await inside one).
     /// </summary>
-    private MxGatewayClientOptions BuildClientOptions(GalaxyGatewayOptions gw) => new()
+    private async Task<MxGatewayClientOptions> BuildClientOptionsAsync(
+        GalaxyGatewayOptions gw, CancellationToken cancellationToken)
+    {
+        var apiKey = await GalaxySecretRef
+            .ResolveApiKeyAsync(gw.ApiKeySecretRef, _secretResolver, _logger, cancellationToken)
+            .ConfigureAwait(false);
+        return new MxGatewayClientOptions
         {
             Endpoint = new Uri(gw.Endpoint, UriKind.Absolute),
-        ApiKey = GalaxySecretRef.ResolveApiKey(gw.ApiKeySecretRef, _logger),
+            ApiKey = apiKey,
             UseTls = gw.UseTls,
             CaCertificatePath = gw.CaCertificatePath,
             ConnectTimeout = TimeSpan.FromSeconds(gw.ConnectTimeoutSeconds),
@@ -131,4 +143,5 @@ public sealed class GalaxyDriverBrowser : IDriverBrowser
                 ? TimeSpan.FromSeconds(gw.StreamTimeoutSeconds)
                 : null,
         };
+    }
 }

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts/GalaxyDriverOptions.cs

@@ -43,12 +43,14 @@ public sealed record GalaxyDriverOptions(
 
 /// <summary>
 ///     Connection details for the MxAccess gateway. <see cref="ApiKeySecretRef"/> is
-///     resolved by <see cref="GalaxySecretRef.ResolveApiKey"/> at InitializeAsync time. Four forms
+///     resolved by <see cref="GalaxySecretRef.ResolveApiKeyAsync"/> at InitializeAsync time. Five forms
 ///     supported, in priority order:
 ///     <list type="bullet">
 ///       <item><c>env:NAME</c> — read from an environment variable (recommended for
 ///         production; the central config DB holds only the indirection, not the key).</item>
 ///       <item><c>file:PATH</c> — read from an ACL'd file outside the repo.</item>
+///       <item><c>secret:NAME</c> — resolved through the shared <c>ZB.MOM.WW.Secrets</c>
+///         encrypted store; fail-closed if absent (the production path).</item>
 ///       <item><c>dev:KEY</c> — explicit cleartext opt-in for dev rigs / parity tests;
 ///         no startup warning.</item>
 ///       <item>Anything else — treated as a literal cleartext API key for back-compat.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts/GalaxySecretRef.cs

@@ -1,9 +1,10 @@
 using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
 
 /// <summary>
-///     Resolves <c>Gateway.ApiKeySecretRef</c> to the actual API-key string. Four
+///     Resolves <c>Gateway.ApiKeySecretRef</c> to the actual API-key string. Five
 ///     forms supported, evaluated in order:
 ///     <list type="number">
 ///       <item><c>env:NAME</c> — reads <c>Environment.GetEnvironmentVariable(NAME)</c>.
@@ -15,12 +16,17 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
 ///       <item><c>dev:KEY</c> — explicit cleartext literal. The <c>dev:</c> prefix
 ///         is a deliberate opt-in signal (dev box, parity rig) so the resolver
 ///         doesn't emit a warning; production should never use this arm.</item>
+///       <item><c>secret:NAME</c> — resolves NAME through the shared
+///         <c>ZB.MOM.WW.Secrets</c> <see cref="ISecretResolver"/> (the encrypted-at-rest
+///         store). Fail-closed: a <c>secret:</c> ref whose secret is absent/tombstoned
+///         throws rather than falling through to the literal arm — the production path
+///         that retires the cleartext <c>dev:</c>/literal-in-DB model.</item>
 ///       <item>Anything else — used as the literal API key for back-compat with
 ///         configs that pre-date this resolver. When a logger is supplied the
 ///         resolver emits a startup warning so an operator who accidentally
 ///         committed a cleartext key sees it.</item>
 ///     </list>
-///     A future PR can swap any of these arms for a DPAPI-backed lookup without
+///     A future PR can swap any of these arms for a different backing store without
 ///     changing the call site.
 /// </summary>
 /// <remarks>
@@ -31,18 +37,26 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
 public static class GalaxySecretRef
 {
     /// <summary>
-    ///     Resolves the supplied secret reference. When the ref falls through to the
+    ///     Resolves the supplied secret reference. The <c>secret:NAME</c> arm resolves
-    ///     back-compat literal arm (an unprefixed cleartext API key in
+    ///     through <paramref name="resolver"/> and is fail-closed (throws when the secret
-    ///     <c>DriverConfig</c> JSON) and a <paramref name="logger"/> is supplied, emits
+    ///     is absent). When the ref falls through to the back-compat literal arm (an
-    ///     a <see cref="LogLevel.Warning"/>. The <c>dev:</c> prefix is the explicit
+    ///     unprefixed cleartext API key in <c>DriverConfig</c> JSON) and a
-    ///     opt-in path that doesn't warn.
+    ///     <paramref name="logger"/> is supplied, emits a <see cref="LogLevel.Warning"/>.
+    ///     The <c>dev:</c> prefix is the explicit opt-in path that doesn't warn.
     /// </summary>
     /// <param name="secretRef">The secret reference string to resolve.</param>
+    /// <param name="resolver">The shared secret resolver used by the <c>secret:</c> arm.</param>
     /// <param name="logger">Optional logger for warning on cleartext keys.</param>
+    /// <param name="ct">Cancellation token for the async <c>secret:</c> resolution.</param>
     /// <returns>The resolved API-key string.</returns>
-    public static string ResolveApiKey(string secretRef, ILogger? logger = null)
+    public static async Task<string> ResolveApiKeyAsync(
+        string secretRef,
+        ISecretResolver resolver,
+        ILogger? logger = null,
+        CancellationToken ct = default)
     {
         ArgumentException.ThrowIfNullOrEmpty(secretRef);
+        ArgumentNullException.ThrowIfNull(resolver);
 
         if (secretRef.StartsWith("env:", StringComparison.OrdinalIgnoreCase))
         {
@@ -76,6 +90,19 @@ public static class GalaxySecretRef
             return secretRef[4..];
         }
 
+        if (secretRef.StartsWith("secret:", StringComparison.OrdinalIgnoreCase))
+        {
+            // Production path: resolve the name through the shared encrypted secret store.
+            // Fail-closed — an absent/tombstoned secret throws rather than falling through
+            // to the literal arm (which would silently treat the ref string as the key).
+            var name = secretRef["secret:".Length..];
+            var value = await resolver.GetAsync(new SecretName(name), ct).ConfigureAwait(false);
+            return !string.IsNullOrEmpty(value)
+                ? value
+                : throw new InvalidOperationException(
+                    $"Galaxy.Gateway.ApiKeySecretRef='{secretRef}' resolves secret '{name}', but it is absent from the store (fail-closed).");
+        }
+
         // Back-compat literal arm. An unprefixed string is treated as the literal
         // API key — but emit a warning so an operator who accidentally committed a
         // cleartext key into DriverConfig sees it. Use the dev: prefix to suppress

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts.csproj

@@ -13,5 +13,6 @@
         <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj" />
         <!-- Logging abstraction needed by GalaxySecretRef.ResolveApiKey's optional warning logger. -->
         <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
+        <PackageReference Include="ZB.MOM.WW.Secrets.Abstractions" />
     </ItemGroup>
 </Project>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriver.cs

@@ -8,6 +8,7 @@ using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browse;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Health;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy;
 
@@ -43,6 +44,12 @@ public sealed class GalaxyDriver
     private readonly GalaxyDriverOptions _options;
     private readonly ILogger<GalaxyDriver> _logger;
 
+    // Resolves the Gateway.ApiKeySecretRef secret: arm through the shared encrypted store.
+    // Injected via ctor (the production factory pulls it from DI). The internal test ctor
+    // defaults it to a null-object resolver so the 45 seam-injecting test call sites keep
+    // compiling; those tests never use a secret: ref (they inject seams or use env/file/literal).
+    private readonly ISecretResolver _secretResolver;
+
     // PR 4.1 — IGalaxyHierarchySource is the test seam for browse. When null, the driver
     // lazily builds a GatewayGalaxyHierarchySource around a GalaxyRepositoryClient on
     // first DiscoverAsync. Tests inject a fake source via the internal ctor to exercise
@@ -147,14 +154,17 @@ public sealed class GalaxyDriver
     /// <summary>Initializes a new instance of the <see cref="GalaxyDriver"/> class.</summary>
     /// <param name="driverInstanceId">The unique identifier for this driver instance.</param>
     /// <param name="options">The Galaxy driver configuration options.</param>
+    /// <param name="secretResolver">Resolves the <c>secret:</c> arm of <c>Gateway.ApiKeySecretRef</c>.</param>
     /// <param name="logger">Optional logger instance for diagnostics.</param>
     public GalaxyDriver(
         string driverInstanceId,
         GalaxyDriverOptions options,
+        ISecretResolver secretResolver,
         ILogger<GalaxyDriver>? logger = null)
         : this(driverInstanceId, options,
               hierarchySource: null, dataReader: null, dataWriter: null, subscriber: null,
-              alarmAcknowledger: null, alarmFeed: null, logger)
+              alarmAcknowledger: null, alarmFeed: null, logger,
+              secretResolver: secretResolver ?? throw new ArgumentNullException(nameof(secretResolver)))
     {
     }
 
@@ -173,6 +183,11 @@ public sealed class GalaxyDriver
     /// <param name="alarmAcknowledger">Optional custom alarm acknowledger for testing.</param>
     /// <param name="alarmFeed">Optional custom alarm feed for testing.</param>
     /// <param name="logger">Optional logger instance for diagnostics.</param>
+    /// <param name="secretResolver">
+    ///     Optional secret resolver for the <c>secret:</c> API-key arm. Defaults to a
+    ///     null-object resolver (returns null for every name) so seam-injecting tests that
+    ///     don't exercise a <c>secret:</c> ref need not supply one.
+    /// </param>
     internal GalaxyDriver(
         string driverInstanceId,
         GalaxyDriverOptions options,
@@ -182,13 +197,15 @@ public sealed class GalaxyDriver
         IGalaxySubscriber? subscriber = null,
         IGalaxyAlarmAcknowledger? alarmAcknowledger = null,
         IGalaxyAlarmFeed? alarmFeed = null,
-        ILogger<GalaxyDriver>? logger = null)
+        ILogger<GalaxyDriver>? logger = null,
+        ISecretResolver? secretResolver = null)
     {
         _driverInstanceId = !string.IsNullOrWhiteSpace(driverInstanceId)
             ? driverInstanceId
             : throw new ArgumentException("Driver instance id required.", nameof(driverInstanceId));
         _options = options ?? throw new ArgumentNullException(nameof(options));
         _logger = logger ?? NullLogger<GalaxyDriver>.Instance;
+        _secretResolver = secretResolver ?? NullSecretResolver.Instance;
         _hierarchySource = hierarchySource;
         _dataReader = dataReader;
         _dataWriter = dataWriter;
@@ -316,7 +333,7 @@ public sealed class GalaxyDriver
                 _driverInstanceId);
         }
 
-        StartDeployWatcher();
+        await StartDeployWatcherAsync(cancellationToken).ConfigureAwait(false);
         _logger.LogInformation(
             "GalaxyDriver {InstanceId} initialized — endpoint={Endpoint} clientName={ClientName}",
             _driverInstanceId, _options.Gateway.Endpoint, _options.MxAccess.ClientName);
@@ -331,7 +348,7 @@ public sealed class GalaxyDriver
     /// </summary>
     private async Task BuildProductionRuntimeAsync(CancellationToken cancellationToken)
     {
-        var clientOptions = BuildClientOptions(_options.Gateway);
+        var clientOptions = await BuildClientOptionsAsync(_options.Gateway, cancellationToken).ConfigureAwait(false);
         _ownedMxClient = MxGatewayClient.Create(clientOptions);
         _ownedMxSession = new GalaxyMxSession(_options.MxAccess, _logger);
         await _ownedMxSession.ConnectAsync(clientOptions, cancellationToken).ConfigureAwait(false);
@@ -386,7 +403,7 @@ public sealed class GalaxyDriver
     private async Task ReopenAsync(CancellationToken cancellationToken)
     {
         if (_ownedMxSession is null) return;
-        var clientOptions = BuildClientOptions(_options.Gateway);
+        var clientOptions = await BuildClientOptionsAsync(_options.Gateway, cancellationToken).ConfigureAwait(false);
         await _ownedMxSession.RecreateAsync(clientOptions, cancellationToken).ConfigureAwait(false);
         // The recreated session invalidates every prior gw item handle; drop the writer's handle/advise
         // caches so the next write re-AddItems + re-AdviseSupervisory against the fresh session.
@@ -527,32 +544,42 @@ public sealed class GalaxyDriver
         }
     }
 
-    private MxGatewayClientOptions BuildClientOptions(GalaxyGatewayOptions gw) => new()
+    private async Task<MxGatewayClientOptions> BuildClientOptionsAsync(
+        GalaxyGatewayOptions gw, CancellationToken cancellationToken)
+    {
+        // Resolve the API-key ref BEFORE the object initializer — the secret: arm is
+        // async and you can't await inside an initializer. Pass the logger so the
+        // literal-arm cleartext fallback surfaces a startup warning rather than
+        // silently shipping the key. The resolver lives in Driver.Galaxy.Contracts
+        // (GalaxySecretRef) so the runtime driver and the AdminUI browser share one
+        // implementation; the secret: arm resolves through the shared ISecretResolver.
+        var apiKey = await GalaxySecretRef
+            .ResolveApiKeyAsync(gw.ApiKeySecretRef, _secretResolver, _logger, cancellationToken)
+            .ConfigureAwait(false);
+        return new MxGatewayClientOptions
         {
             Endpoint = new Uri(gw.Endpoint, UriKind.Absolute),
-        // Pass the logger so the literal-arm cleartext fallback surfaces a startup
+            ApiKey = apiKey,
-        // warning rather than silently shipping the key. The resolver lives in
-        // Driver.Galaxy.Contracts (GalaxySecretRef) so the runtime driver and the
-        // AdminUI browser share one implementation.
-        ApiKey = GalaxySecretRef.ResolveApiKey(gw.ApiKeySecretRef, _logger),
             UseTls = gw.UseTls,
             CaCertificatePath = gw.CaCertificatePath,
             ConnectTimeout = TimeSpan.FromSeconds(gw.ConnectTimeoutSeconds),
             DefaultCallTimeout = TimeSpan.FromSeconds(gw.DefaultCallTimeoutSeconds),
             StreamTimeout = gw.StreamTimeoutSeconds > 0 ? TimeSpan.FromSeconds(gw.StreamTimeoutSeconds) : null,
         };
+    }
 
-    private void StartDeployWatcher()
+    private async Task StartDeployWatcherAsync(CancellationToken cancellationToken)
     {
         if (!_options.Repository.WatchDeployEvents) return;
         if (_ownedRepositoryClient is null && _hierarchySource is null) return;
 
         // Reuse the lazily-built repository client (DiscoverAsync constructs it on demand).
         // If discovery hasn't run yet, build the client here so the watcher has a target.
-        // Guard with ??= so if BuildDefaultHierarchySource later runs it reuses this client
+        // Build under a null-check (not ??=) so if BuildDefaultHierarchySourceAsync later
-        // rather than overwriting the field and leaking the first instance.
+        // runs it reuses this client rather than overwriting the field and leaking the
+        // first instance — the client-options build is now async (secret: arm).
         _ownedRepositoryClient ??= ZB.MOM.WW.MxGateway.Client.GalaxyRepositoryClient.Create(
-            BuildClientOptions(_options.Gateway));
+            await BuildClientOptionsAsync(_options.Gateway, cancellationToken).ConfigureAwait(false));
 
         var source = new GatewayGalaxyDeployWatchSource(_ownedRepositoryClient);
         _deployWatcher = new DeployWatcher(source, _logger);
@@ -691,7 +718,8 @@ public sealed class GalaxyDriver
         // After discovery, SyncPlatformsAsync refreshes the probe watcher's membership so
         // newly added $WinPlatform / $AppEngine objects start advising their ScanState attribute.
         var capturingBuilder = new SecurityCapturingBuilder(builder, _securityByFullRef);
-        var source = _hierarchySource ??= BuildDefaultHierarchySource();
+        var source = _hierarchySource ??=
+            await BuildDefaultHierarchySourceAsync(cancellationToken).ConfigureAwait(false);
         // Thread the v3 reverse resolver so the discoverer emits each authored attribute's RawPath as
         // its node reference (FullName) — the security map SecurityCapturingBuilder captures is then
         // keyed by RawPath, matching what WriteAsync resolves against.
@@ -1292,12 +1320,14 @@ public sealed class GalaxyDriver
     ///     <see cref="Dispose"/>. Tests bypass this by injecting their own source via the
     ///     internal ctor.
     /// </summary>
-    private IGalaxyHierarchySource BuildDefaultHierarchySource()
+    private async Task<IGalaxyHierarchySource> BuildDefaultHierarchySourceAsync(CancellationToken cancellationToken)
     {
-        // Reuse a client that StartDeployWatcher may have already created (??=) rather
+        // Reuse a client that StartDeployWatcherAsync may have already created (??=) rather
         // than always overwriting the field and leaking the first instance. Both paths
-        // produce equivalent clients from the same options.
+        // produce equivalent clients from the same options. The client-options build is
-        _ownedRepositoryClient ??= GalaxyRepositoryClient.Create(BuildClientOptions(_options.Gateway));
+        // async now (secret: arm resolves through the shared ISecretResolver).
+        _ownedRepositoryClient ??= GalaxyRepositoryClient.Create(
+            await BuildClientOptionsAsync(_options.Gateway, cancellationToken).ConfigureAwait(false));
         return new TracedGalaxyHierarchySource(
             new GatewayGalaxyHierarchySource(_ownedRepositoryClient), _options.MxAccess.ClientName);
     }

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriverFactoryExtensions.cs

@@ -4,6 +4,7 @@ using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy;
 
@@ -23,30 +24,45 @@ public static class GalaxyDriverFactoryExtensions
 {
     public const string DriverTypeName = "GalaxyMxGateway";
 
-    /// <summary>Registers the Galaxy driver factory with the given registry and optional logger factory.</summary>
+    /// <summary>Registers the Galaxy driver factory with the given registry, secret resolver, and optional logger factory.</summary>
     /// <param name="registry">The driver factory registry to register with.</param>
+    /// <param name="secretResolver">
+    ///     The shared secret resolver (from DI) used to resolve the <c>secret:</c> arm of
+    ///     each instance's <c>Gateway.ApiKeySecretRef</c>.
+    /// </param>
     /// <param name="loggerFactory">The optional logger factory for creating drivers.</param>
-    public static void Register(DriverFactoryRegistry registry, ILoggerFactory? loggerFactory = null)
+    public static void Register(
+        DriverFactoryRegistry registry,
+        ISecretResolver secretResolver,
+        ILoggerFactory? loggerFactory = null)
     {
         ArgumentNullException.ThrowIfNull(registry);
-        registry.Register(DriverTypeName, (id, json) => CreateInstance(id, json, loggerFactory));
+        ArgumentNullException.ThrowIfNull(secretResolver);
+        registry.Register(DriverTypeName, (id, json) => CreateInstance(id, json, loggerFactory, secretResolver));
     }
 
-    /// <summary>Convenience for tests + standalone callers.</summary>
+    /// <summary>
+    ///     Convenience for tests + standalone callers. Uses the <see cref="NullSecretResolver"/>
+    ///     null-object, so the <c>secret:</c> API-key arm resolves fail-closed (absent) — callers
+    ///     that need a working <c>secret:</c> ref must use the <see cref="Register"/> path that
+    ///     threads the DI resolver.
+    /// </summary>
     /// <param name="driverInstanceId">The unique identifier for the driver instance.</param>
     /// <param name="driverConfigJson">The driver configuration in JSON format.</param>
     /// <returns>The constructed Galaxy driver instance.</returns>
     public static GalaxyDriver CreateInstance(string driverInstanceId, string driverConfigJson)
-        => CreateInstance(driverInstanceId, driverConfigJson, loggerFactory: null);
+        => CreateInstance(driverInstanceId, driverConfigJson, loggerFactory: null, NullSecretResolver.Instance);
 
-    /// <summary>Creates a Galaxy driver instance from configuration JSON with optional logger factory.</summary>
+    /// <summary>Creates a Galaxy driver instance from configuration JSON with optional logger factory and a secret resolver.</summary>
     /// <param name="driverInstanceId">The unique identifier for the driver instance.</param>
     /// <param name="driverConfigJson">The driver configuration in JSON format.</param>
     /// <param name="loggerFactory">The optional logger factory for creating drivers.</param>
+    /// <param name="secretResolver">The secret resolver for the driver's <c>secret:</c> API-key arm.</param>
     /// <returns>The constructed Galaxy driver instance.</returns>
     public static GalaxyDriver CreateInstance(
-        string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory)
+        string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory, ISecretResolver secretResolver)
     {
+        ArgumentNullException.ThrowIfNull(secretResolver);
         ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
         ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
 
@@ -88,7 +104,7 @@ public static class GalaxyDriverFactoryExtensions
             RawTags = dto.RawTags ?? [],
         };
 
-        return new GalaxyDriver(driverInstanceId, options, loggerFactory?.CreateLogger<GalaxyDriver>());
+        return new GalaxyDriver(driverInstanceId, options, secretResolver, loggerFactory?.CreateLogger<GalaxyDriver>());
     }
 
     private static readonly JsonSerializerOptions JsonOptions = new()

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/NullSecretResolver.cs

@@ -0,0 +1,26 @@
+using ZB.MOM.WW.Secrets.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy;
+
+/// <summary>
+///     A null-object <see cref="ISecretResolver"/> that resolves every name to <c>null</c>
+///     (absent). Used as the default for the internal test ctor and the parse-only
+///     <c>CreateInstance</c> path so callers that never exercise a <c>secret:</c> API-key
+///     ref need not thread a real resolver. A production <c>GalaxyDriver</c> always receives
+///     the DI-registered resolver via the factory; a <c>secret:</c> ref resolved against this
+///     null object throws fail-closed (the secret is reported absent), which is the correct
+///     behaviour for a mis-wired deployment.
+/// </summary>
+internal sealed class NullSecretResolver : ISecretResolver
+{
+    /// <summary>The shared singleton instance.</summary>
+    public static readonly NullSecretResolver Instance = new();
+
+    private NullSecretResolver()
+    {
+    }
+
+    /// <inheritdoc />
+    public Task<string?> GetAsync(SecretName name, CancellationToken ct) =>
+        Task.FromResult<string?>(null);
+}

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Contracts/OpcUaClientDriverOptions.cs

@@ -14,7 +14,9 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
 ///     exposes PLC data" flow. Tier A (pure managed, OPC Foundation reference SDK); universal
 ///     protections cover it.
 /// </remarks>
-public sealed class OpcUaClientDriverOptions
+// A record (not a plain class) so G-2b's OpcUaClientSecretResolution can produce a
+// credential-resolved copy with a `with` expression — every property keeps its init setter.
+public sealed record OpcUaClientDriverOptions
 {
     /// <summary>
     ///     Remote OPC UA endpoint URL, e.g. <c>opc.tcp://plc.internal:4840</c>. Convenience

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/NullSecretResolver.cs

@@ -0,0 +1,26 @@
+using ZB.MOM.WW.Secrets.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
+
+/// <summary>
+///     A null-object <see cref="ISecretResolver"/> that resolves every name to <c>null</c>
+///     (absent). Backs the driver's default (test/parse-only) construction path so callers that
+///     never author a <c>secret:</c> credential ref need not thread a real resolver. A production
+///     <c>OpcUaClientDriver</c> always receives the DI-registered resolver via the factory; a
+///     <c>secret:</c> ref resolved against this null object throws fail-closed (the secret is
+///     reported absent), which is the correct behaviour for a mis-wired deployment — the
+///     <c>secret:</c> literal is never sent verbatim as a password.
+/// </summary>
+internal sealed class NullSecretResolver : ISecretResolver
+{
+    /// <summary>The shared singleton instance.</summary>
+    public static readonly NullSecretResolver Instance = new();
+
+    private NullSecretResolver()
+    {
+    }
+
+    /// <inheritdoc />
+    public Task<string?> GetAsync(SecretName name, CancellationToken ct) =>
+        Task.FromResult<string?>(null);
+}

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriver.cs

@@ -4,6 +4,7 @@ using Opc.Ua;
 using Opc.Ua.Client;
 using Opc.Ua.Configuration;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
 
@@ -36,15 +37,25 @@ public sealed class OpcUaClientDriver : IDriver, ITagDiscovery, IReadable, IWrit
     /// <param name="options">Driver configuration.</param>
     /// <param name="driverInstanceId">Stable logical ID from the config DB.</param>
     /// <param name="logger">Optional logger; defaults to NullLogger when not supplied.</param>
+    /// <param name="secretResolver">
+    ///     Optional shared secret resolver used to resolve <c>secret:</c>-prefixed
+    ///     <see cref="OpcUaClientDriverOptions.Password"/> /
+    ///     <see cref="OpcUaClientDriverOptions.UserCertificatePassword"/> at session-open.
+    ///     Defaults to the <see cref="NullSecretResolver"/> null-object (which reports every
+    ///     secret absent) for the test/parse-only path; the production factory threads the
+    ///     DI-registered resolver. A <c>secret:</c> ref against the null-object fails closed.
+    /// </param>
     public OpcUaClientDriver(OpcUaClientDriverOptions options, string driverInstanceId,
-        ILogger<OpcUaClientDriver>? logger = null)
+        ILogger<OpcUaClientDriver>? logger = null, ISecretResolver? secretResolver = null)
     {
         _options = options;
         _driverInstanceId = driverInstanceId;
         _logger = logger ?? NullLogger<OpcUaClientDriver>.Instance;
+        _secretResolver = secretResolver ?? NullSecretResolver.Instance;
     }
 
     private readonly OpcUaClientDriverOptions _options;
+    private readonly ISecretResolver _secretResolver;
     private readonly string _driverInstanceId;
     // ---- IAlarmSource state ----
 
@@ -159,7 +170,18 @@ public sealed class OpcUaClientDriver : IDriver, ITagDiscovery, IReadable, IWrit
             var appConfig = await BuildApplicationConfigurationAsync(cancellationToken).ConfigureAwait(false);
             var candidates = ResolveEndpointCandidates(_options);
 
-            var identity = BuildUserIdentity(_options);
+            // G-2b: resolve any secret:-prefixed Password / UserCertificatePassword through the
+            // shared secret store ONCE, here in the async connect flow, just before the credentials
+            // are consumed. _options stays the raw config (with secret: refs) — only this
+            // connect-scoped local carries plaintext, and only for the duration of the connect.
+            // Resolving on every InitializeAsync (a full reconnect calls it) picks up rotations.
+            // Both credential consumers — the Username password below and the Certificate password
+            // in BuildCertificateIdentity — flow through BuildUserIdentity(resolvedOptions), so a
+            // single resolve covers both paths.
+            var resolvedOptions = await OpcUaClientSecretResolution
+                .ResolveSecretRefsAsync(_options, _secretResolver, cancellationToken).ConfigureAwait(false);
+
+            var identity = BuildUserIdentity(resolvedOptions);
 
             // Failover sweep: try each endpoint in order, return the session from the first
             // one that successfully connects. Per-endpoint failures are captured so the final

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriverFactoryExtensions.cs

@@ -2,6 +2,7 @@ using System.Text.Json;
 using System.Text.Json.Serialization;
 using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
 
@@ -31,22 +32,37 @@ public static class OpcUaClientDriverFactoryExtensions
         Converters = { new JsonStringEnumConverter() },
     };
 
-    /// <summary>Register the OpcUaClient factory with the driver registry.</summary>
+    /// <summary>Register the OpcUaClient factory with the driver registry, threading the shared secret resolver.</summary>
     /// <param name="registry">The driver factory registry to register with.</param>
     /// <param name="loggerFactory">Optional logger factory used to create per-instance loggers.</param>
-    public static void Register(DriverFactoryRegistry registry, ILoggerFactory? loggerFactory = null)
+    /// <param name="secretResolver">
+    ///     The shared secret resolver (from DI) used to resolve the <c>secret:</c> arm of each
+    ///     instance's <c>Password</c> / <c>UserCertificatePassword</c> at session-open. Defaults to
+    ///     the <see cref="NullSecretResolver"/> null-object for the test/standalone path — callers
+    ///     that need a working <c>secret:</c> credential ref must thread the DI resolver.
+    /// </param>
+    public static void Register(
+        DriverFactoryRegistry registry,
+        ILoggerFactory? loggerFactory = null,
+        ISecretResolver? secretResolver = null)
     {
         ArgumentNullException.ThrowIfNull(registry);
-        registry.Register(DriverTypeName, (id, json) => CreateInstance(id, json, loggerFactory));
+        var resolver = secretResolver ?? NullSecretResolver.Instance;
+        registry.Register(DriverTypeName, (id, json) => CreateInstance(id, json, loggerFactory, resolver));
     }
 
     /// <summary>Public for the Server-side bootstrapper + test consumers.</summary>
     /// <param name="driverInstanceId">The unique identifier for the driver instance.</param>
     /// <param name="driverConfigJson">The JSON configuration string for the driver.</param>
     /// <param name="loggerFactory">Optional logger factory for the per-instance logger.</param>
+    /// <param name="secretResolver">
+    ///     Optional shared secret resolver for the driver's <c>secret:</c> credential arm; defaults
+    ///     to the <see cref="NullSecretResolver"/> null-object (fail-closed on a <c>secret:</c> ref).
+    /// </param>
     /// <returns>A configured <see cref="OpcUaClientDriver"/>.</returns>
     public static OpcUaClientDriver CreateInstance(
-        string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory = null)
+        string driverInstanceId, string driverConfigJson, ILoggerFactory? loggerFactory = null,
+        ISecretResolver? secretResolver = null)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(driverInstanceId);
         ArgumentException.ThrowIfNullOrWhiteSpace(driverConfigJson);
@@ -55,6 +71,8 @@ public static class OpcUaClientDriverFactoryExtensions
             ?? throw new InvalidOperationException(
                 $"OpcUaClient driver config for '{driverInstanceId}' deserialised to null");
 
-        return new OpcUaClientDriver(options, driverInstanceId, loggerFactory?.CreateLogger<OpcUaClientDriver>());
+        return new OpcUaClientDriver(
+            options, driverInstanceId, loggerFactory?.CreateLogger<OpcUaClientDriver>(),
+            secretResolver ?? NullSecretResolver.Instance);
     }
 }

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientDriverProbe.cs

@@ -34,6 +34,12 @@ public sealed class OpcUaClientDriverProbe : IDriverProbe
     /// <inheritdoc />
     public async Task<DriverProbeResult> ProbeAsync(string configJson, TimeSpan timeout, CancellationToken ct)
     {
+        // G-2b note: the probe does an UNAUTHENTICATED GetEndpoints discovery preflight
+        // (BuildMinimalAppConfig sets no user identity) and never reads opts.Password /
+        // opts.UserCertificatePassword. Those credentials — including any secret: refs — are
+        // therefore intentionally NOT resolved here; resolving them would be dead code. Secret
+        // resolution happens lazily in OpcUaClientDriver's async session-open path, where the
+        // credentials are actually consumed.
         OpcUaClientDriverOptions? opts;
         try { opts = JsonSerializer.Deserialize<OpcUaClientDriverOptions>(configJson, _opts); }
         catch (Exception ex) { return new(false, $"Config JSON is invalid: {ex.Message}", null); }

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/OpcUaClientSecretResolution.cs

@@ -0,0 +1,90 @@
+using ZB.MOM.WW.Secrets.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
+
+/// <summary>
+///     Layer-B (G-2b) secret resolution for the OPC UA Client driver's credential fields. Resolves
+///     <c>secret:</c>-prefixed <see cref="OpcUaClientDriverOptions.Password"/> and
+///     <see cref="OpcUaClientDriverOptions.UserCertificatePassword"/> through the shared
+///     <see cref="ISecretResolver"/> (the encrypted-at-rest store) just before the async
+///     session-open path consumes them — retiring the cleartext password-in-DB model for
+///     production.
+/// </summary>
+/// <remarks>
+///     Resolution is lazy (called from the connect flow, not at config deserialization) so a
+///     full reconnect via <c>InitializeAsync</c> re-resolves and picks up secret rotations,
+///     mirroring the Galaxy driver's re-resolve-on-reconnect behaviour. Only <c>secret:</c>-prefixed
+///     values are resolved; a null/empty or non-<c>secret:</c> value passes through verbatim so the
+///     literal-password back-compat path is preserved. The <c>secret:</c> arm is <b>fail-closed</b>:
+///     an absent/tombstoned secret throws rather than leaving the <c>secret:</c> literal in place,
+///     which would otherwise be sent verbatim to the remote server as the password.
+/// </remarks>
+internal static class OpcUaClientSecretResolution
+{
+    private const string SecretPrefix = "secret:";
+
+    /// <summary>
+    ///     Return a copy of <paramref name="options"/> with any <c>secret:</c>-prefixed
+    ///     <see cref="OpcUaClientDriverOptions.Password"/> /
+    ///     <see cref="OpcUaClientDriverOptions.UserCertificatePassword"/> resolved to their
+    ///     plaintext via <paramref name="resolver"/>. Non-secret / null / empty fields are
+    ///     returned unchanged.
+    /// </summary>
+    /// <param name="options">The raw driver options (credential fields may carry <c>secret:</c> refs).</param>
+    /// <param name="resolver">The shared secret resolver used by the <c>secret:</c> arm.</param>
+    /// <param name="ct">Cancellation token for the async secret resolution.</param>
+    /// <returns>An options copy whose credential fields carry resolved plaintext.</returns>
+    /// <exception cref="InvalidOperationException">
+    ///     A <c>secret:</c> ref names a secret that is absent/tombstoned in the store (fail-closed).
+    /// </exception>
+    internal static async Task<OpcUaClientDriverOptions> ResolveSecretRefsAsync(
+        OpcUaClientDriverOptions options, ISecretResolver resolver, CancellationToken ct)
+    {
+        ArgumentNullException.ThrowIfNull(options);
+        ArgumentNullException.ThrowIfNull(resolver);
+
+        var password = await ResolveFieldAsync(options.Password, nameof(options.Password), resolver, ct)
+            .ConfigureAwait(false);
+        var certPassword = await ResolveFieldAsync(
+            options.UserCertificatePassword, nameof(options.UserCertificatePassword), resolver, ct)
+            .ConfigureAwait(false);
+
+        // Only re-materialize when something actually changed — a `with` on the reference-equal
+        // strings is harmless, but skipping it keeps the common (no-secret) case allocation-free.
+        if (ReferenceEquals(password, options.Password)
+            && ReferenceEquals(certPassword, options.UserCertificatePassword))
+        {
+            return options;
+        }
+
+        return options with { Password = password, UserCertificatePassword = certPassword };
+    }
+
+    /// <summary>
+    ///     Resolve a single credential field. Null/empty or non-<c>secret:</c> values pass through
+    ///     unchanged (the reference-equal original is returned). A <c>secret:NAME</c> value is
+    ///     resolved through <paramref name="resolver"/> and is fail-closed when the secret is absent.
+    /// </summary>
+    /// <param name="value">The raw field value (may be a <c>secret:</c> ref).</param>
+    /// <param name="fieldName">The field name, used in the fail-closed exception message.</param>
+    /// <param name="resolver">The shared secret resolver.</param>
+    /// <param name="ct">Cancellation token for the async resolution.</param>
+    /// <returns>The resolved plaintext, or the original value when it is not a <c>secret:</c> ref.</returns>
+    private static async Task<string?> ResolveFieldAsync(
+        string? value, string fieldName, ISecretResolver resolver, CancellationToken ct)
+    {
+        if (string.IsNullOrEmpty(value)
+            || !value.StartsWith(SecretPrefix, StringComparison.OrdinalIgnoreCase))
+        {
+            return value;
+        }
+
+        var name = value[SecretPrefix.Length..];
+        var resolved = await resolver.GetAsync(new SecretName(name), ct).ConfigureAwait(false);
+        return !string.IsNullOrEmpty(resolved)
+            ? resolved
+            : throw new InvalidOperationException(
+                $"OpcUaClientDriverOptions.{fieldName}='{value}' resolves secret '{name}', but it is " +
+                "absent from the store (fail-closed).");
+    }
+}

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.csproj

@@ -21,6 +21,7 @@
     <ItemGroup>
         <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua.Client"/>
         <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua.Configuration"/>
+        <PackageReference Include="ZB.MOM.WW.Secrets.Abstractions"/>
     </ItemGroup>
 
     <ItemGroup>

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/App.razor

@@ -19,7 +19,7 @@
     <HeadOutlet/>
 </head>
 <body>
-    <Routes/>
+    <Routes AdditionalAssemblies="@(new[] { typeof(ZB.MOM.WW.Secrets.Ui.SecretsPage).Assembly })" />
     <script src="_content/ZB.MOM.WW.OtOpcUa.AdminUI/lib/bootstrap/js/bootstrap.bundle.min.js"></script>
     <ThemeScripts />
     <script src="_content/ZB.MOM.WW.OtOpcUa.AdminUI/js/monaco-init.js"></script>

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Layout/MainLayout.razor

@@ -20,6 +20,7 @@
             <NavRailItem Href="/reservations" Text="Reservations" />
             <NavRailItem Href="/certificates" Text="Certificates" />
             <NavRailItem Href="/role-grants" Text="Role grants" />
+            <NavRailItem Href="/admin/secrets" Text="Secrets" />
         </NavRailSection>
         <NavRailSection Title="Scripting" Key="scripting">
             <NavRailItem Href="/scripts" Text="Scripts" />

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Alerts.razor

@@ -64,7 +64,22 @@ else
                         <tr>
                             <td><span class="mono small">@e.TimestampUtc.ToString("HH:mm:ss.fff")</span></td>
                             <td><span class="mono">@e.AlarmId</span><div class="text-muted small">@e.AlarmName</div></td>
-                            <td><span class="mono small">@e.EquipmentPath</span></td>
+                            <td>
+                                <span class="mono small">@e.EquipmentPath</span>
+                                @* v3 Batch 4 (multi-notifier native alarms): one condition row carries the list
+                                   of referencing equipment (Area/Line/Equipment) as display metadata. Shown only
+                                   when the producer populated it (native alarms whose raw tag ≥1 equipment
+                                   references); scripted alarms + unreferenced native alarms leave it empty. *@
+                                @if (e.ReferencingEquipmentPaths is { Count: > 0 } refs)
+                                {
+                                    <div class="text-muted small" title="Referencing equipment">
+                                        @foreach (var p in refs)
+                                        {
+                                            <span class="chip chip-idle" style="font-size:0.72rem; margin:1px">@p</span>
+                                        }
+                                    </div>
+                                }
+                            </td>
                             <td><span class="chip @KindChipClass(e.TransitionKind)">@e.TransitionKind</span></td>
                             <td class="num">@e.Severity</td>
                             <td>@e.User</td>

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/EndpointRouteBuilderExtensions.cs

@@ -1,3 +1,4 @@
+using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Web;
@@ -10,6 +11,7 @@ using ZB.MOM.WW.OtOpcUa.Commons.Browsing;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser;
 using ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser;
+using ZB.MOM.WW.Secrets.Ui;
 
 namespace ZB.MOM.WW.OtOpcUa.AdminUI;
 
@@ -28,8 +30,13 @@ public static class EndpointRouteBuilderExtensions
         // Razor class library static assets (_content/ZB.MOM.WW.OtOpcUa.AdminUI/**) are
         // served via the Host's app.UseStaticFiles() middleware which must run BEFORE
         // UseAuthentication() — see Program.cs.
+        // The /admin/secrets management page lives in the external ZB.MOM.WW.Secrets.Ui RCL, so its
+        // routable component must be discovered at the endpoint layer (AddAdditionalAssemblies) —
+        // the interactive Router's AdditionalAssemblies (App.razor) alone is not enough for SSR
+        // endpoint discovery. Both registrations are required or /admin/secrets 404s.
         app.MapRazorComponents<TApp>()
-            .AddInteractiveServerRenderMode();
+            .AddInteractiveServerRenderMode()
+            .AddAdditionalAssemblies(typeof(ZB.MOM.WW.Secrets.Ui.SecretsPage).Assembly);
         return app;
     }
 
@@ -43,6 +50,15 @@ public static class EndpointRouteBuilderExtensions
         services.AddRazorComponents().AddInteractiveServerComponents();
         services.AddOtOpcUaDriverStatusServices();
 
+        // Secrets-management UI (ZB.MOM.WW.Secrets.Ui RCL, mounted at /admin/secrets). Register its
+        // "secrets:manage"/"secrets:reveal" authorization policies additively onto the AuthorizationOptions
+        // that AddOtOpcUaAuth (called just before AddAdminUI on admin nodes) sets up — Configure<T> stacks,
+        // so this ADDS the two policies without disturbing FleetAdmin/DriverOperator/ConfigEditor. The
+        // policies' AdminRole = "Administrator" reads the same ClaimTypes.Role claim as FleetAdmin, so an
+        // existing Administrator satisfies them with no new group→role mapping. Registered here (the AdminUI
+        // composition layer that already references the RCL) rather than in the core Security lib.
+        services.Configure<AuthorizationOptions>(o => o.AddSecretsAuthorization());
+
         // Browse pipeline — see docs/plans/2026-05-28-driver-browsers-design.md
         services.AddSingleton<Browsing.BrowseSessionRegistry>();
         services.AddHostedService<Browsing.BrowseSessionReaper>();

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

@@ -10,6 +10,7 @@
         <FrameworkReference Include="Microsoft.AspNetCore.App"/>
         <PackageReference Include="Microsoft.AspNetCore.SignalR.Client"/>
         <PackageReference Include="ZB.MOM.WW.Theme"/>
+        <PackageReference Include="ZB.MOM.WW.Secrets.Ui"/>
     </ItemGroup>
 
     <ItemGroup>

src/Server/ZB.MOM.WW.OtOpcUa.Host/Drivers/DriverFactoryBootstrap.cs

@@ -4,6 +4,7 @@ using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.Core.Hosting;
 using ZB.MOM.WW.OtOpcUa.Core.Resilience;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Host.Drivers;
 
@@ -48,7 +49,10 @@ public static class DriverFactoryBootstrap
             // The calc driver needs the root script logger so a script failure fans out onto the
             // script-logs topic; resolve it here (null on nodes without the script pipeline wired).
             var scriptRoot = sp.GetService<ZB.MOM.WW.OtOpcUa.Core.Scripting.ScriptRootLogger>();
-            Register(registry, loggerFactory, scriptRoot);
+            // The Galaxy driver resolves its Gateway.ApiKeySecretRef secret: arm through the
+            // shared ISecretResolver (registered unconditionally by AddZbSecrets on every node).
+            var secretResolver = sp.GetRequiredService<ISecretResolver>();
+            Register(registry, loggerFactory, secretResolver, scriptRoot);
             return registry;
         });
         services.AddSingleton<IDriverFactory>(sp =>
@@ -131,15 +135,16 @@ public static class DriverFactoryBootstrap
     private static void Register(
         DriverFactoryRegistry registry,
         ILoggerFactory? loggerFactory,
+        ISecretResolver secretResolver,
         ZB.MOM.WW.OtOpcUa.Core.Scripting.ScriptRootLogger? scriptRoot = null)
     {
         Driver.AbCip.AbCipDriverFactoryExtensions.Register(registry);
         Driver.AbLegacy.AbLegacyDriverFactoryExtensions.Register(registry, loggerFactory);
         Driver.Calculation.CalculationDriverFactoryExtensions.Register(registry, loggerFactory, scriptRoot);
         Driver.FOCAS.FocasDriverFactoryExtensions.Register(registry);
-        Driver.Galaxy.GalaxyDriverFactoryExtensions.Register(registry, loggerFactory);
+        Driver.Galaxy.GalaxyDriverFactoryExtensions.Register(registry, secretResolver, loggerFactory);
         Driver.Modbus.ModbusDriverFactoryExtensions.Register(registry, loggerFactory);
-        Driver.OpcUaClient.OpcUaClientDriverFactoryExtensions.Register(registry, loggerFactory);
+        Driver.OpcUaClient.OpcUaClientDriverFactoryExtensions.Register(registry, loggerFactory, secretResolver);
         Driver.S7.S7DriverFactoryExtensions.Register(registry);
         Driver.TwinCAT.TwinCATDriverFactoryExtensions.Register(registry);
     }

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

@@ -37,6 +37,11 @@ using ZB.MOM.WW.OtOpcUa.Security.Ldap;
 using ZB.MOM.WW.Configuration;
 using ZB.MOM.WW.Telemetry.Serilog;
 using ZB.MOM.WW.OtOpcUa.AdminUI.Api;
+using Microsoft.Extensions.DependencyInjection;
+using ZB.MOM.WW.Secrets.Abstractions;
+using ZB.MOM.WW.Secrets.Configuration;
+using ZB.MOM.WW.Secrets.DependencyInjection;
+using ZB.MOM.WW.Secrets.Sqlite;
 
 // Roles drive the entire conditional wiring below — see ZB.MOM.WW.OtOpcUa.Cluster.RoleParser.
 var roles = RoleParser.Parse(Environment.GetEnvironmentVariable("OTOPCUA_ROLES"));
@@ -72,6 +77,27 @@ if (roleSuffix is not null)
     builder.Configuration.AddCommandLine(args);
 }
 
+// Pre-host ${secret:} expansion: rewrites ${secret:name} tokens in the assembled configuration
+// BEFORE the host is built, so every downstream binder/validator sees resolved plaintext.
+// Placement matters: this runs AFTER all config providers are assembled (base appsettings, the
+// role overlay, and the env-vars + command-line re-append above) but BEFORE anything READS a
+// config value (AddZbSerilog's ReadFrom.Configuration, AddOtOpcUaConfigDb, and the first
+// ValidateOnStart bind all follow). With no ${secret:} tokens present this is a no-op pass;
+// it also migrates the secrets SQLite store on startup.
+// ASP0000: DELIBERATE throwaway container — expansion must run before builder.Build(), so it
+// cannot use the app's DI. Fully disposed here; shares no singletons with the host container.
+#pragma warning disable ASP0000
+await using (var secretsProvider = new ServiceCollection()
+    .AddZbSecrets(builder.Configuration, "Secrets")
+    .BuildServiceProvider())
+#pragma warning restore ASP0000
+{
+    await secretsProvider.GetRequiredService<SqliteSecretsStoreMigrator>().MigrateAsync(default);
+    var resolver = secretsProvider.GetRequiredService<ISecretResolver>();
+    await new SecretReferenceExpander(resolver)
+        .ExpandConfigurationAsync((IConfigurationRoot)builder.Configuration, default);
+}
+
 // Anchor the process working directory to the install directory (AppContext.BaseDirectory) so every
 // relative runtime path resolves under the install dir rather than the service's startup CWD. A Windows
 // service starts with CWD=C:\Windows\System32, which otherwise scattered the Serilog rolling-file sink
@@ -323,6 +349,9 @@ if (hasAdmin)
     builder.Services.AddOtOpcUaAdminClients();
 }
 
+// Registered unconditionally: driver-role nodes resolve Layer-B DriverConfig secrets and have no auth/DP/AdminUI.
+builder.Services.AddZbSecrets(builder.Configuration, "Secrets");
+
 builder.Services.AddOtOpcUaHealth();
 builder.Services.AddOtOpcUaObservability(builder.Configuration);
 

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

@@ -33,6 +33,8 @@
         <PackageReference Include="ZB.MOM.WW.Telemetry" />
         <PackageReference Include="ZB.MOM.WW.Telemetry.Serilog" />
         <PackageReference Include="ZB.MOM.WW.Configuration" />
+        <PackageReference Include="ZB.MOM.WW.Secrets" />
+        <PackageReference Include="ZB.MOM.WW.Secrets.Abstractions" />
     </ItemGroup>
 
     <ItemGroup>

src/Server/ZB.MOM.WW.OtOpcUa.Host/appsettings.json

@@ -11,12 +11,21 @@
       "DisableLogin": false
     }
   },
+  "Secrets": {
+    "SqlitePath": "otopcua-secrets.db",
+    "MasterKey": {
+      "Source": "Environment",
+      "EnvVarName": "ZB_SECRETS_MASTER_KEY"
+    },
+    "RunMigrationsOnStartup": true,
+    "ResolveCacheTtl": "00:00:30"
+  },
   "ServerHistorian": {
     "_comment": "Server-side HistoryRead backend (the ZB.MOM.WW.HistorianGateway gRPC client). Disabled => NullHistorianDataSource (historized nodes return GoodNoData). The gateway must run RuntimeDb:EventReadsEnabled=true for alarm-history ReadEvents, and the API key must carry historian:read + historian:write + historian:tags:write scopes.",
     "Enabled": false,
     "Endpoint": "",
     "ApiKey": "",
-    "_ApiKeyComment": "NEVER commit a real key. Supply via the environment variable ServerHistorian__ApiKey.",
+    "_ApiKeyComment": "NEVER commit a real key. Supply via env var ServerHistorian__ApiKey, either as a literal or as a ${secret:otopcua/historian/api-key} token resolved fail-closed by the pre-host secrets expander.",
     "UseTls": true,
     "AllowUntrustedServerCertificate": false,
     "CaCertificatePath": null,

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceApplier.cs

@@ -1,5 +1,6 @@
 using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.OpcUaServer;
@@ -96,29 +97,33 @@ public sealed class AddressSpaceApplier
         var failedNodes = 0;
         foreach (var eq in plan.RemovedEquipment)
         {
-            if (!SafeWriteAlarmCondition(eq.EquipmentId, RemovedConditionState, ts)) failedNodes++;
+            if (!SafeWriteAlarmCondition(eq.EquipmentId, RemovedConditionState, ts, AddressSpaceRealm.Uns)) failedNodes++;
             removedCount++;
         }
         foreach (var alarm in plan.RemovedAlarms)
         {
-            if (!SafeWriteAlarmCondition(alarm.ScriptedAlarmId, RemovedConditionState, ts)) failedNodes++;
+            if (!SafeWriteAlarmCondition(alarm.ScriptedAlarmId, RemovedConditionState, ts, AddressSpaceRealm.Uns)) failedNodes++;
             removedCount++;
         }
         // Removed equipment tags / VirtualTags are plain variable nodes (no Part 9 condition to write
         // before tear-down), but they ARE real removals — count them so AddressSpaceApplyOutcome.RemovedNodes
-        // is accurate on a removed-tag-only deploy, which now reaches the rebuild path below.
+        // is accurate on a removed-tag-only deploy, which now reaches the rebuild path below. v3 Batch 4:
-        removedCount += plan.RemovedEquipmentTags.Count + plan.RemovedEquipmentVirtualTags.Count;
+        // removed raw containers/tags + UNS reference variables are likewise real removals.
+        removedCount += plan.RemovedEquipmentTags.Count + plan.RemovedEquipmentVirtualTags.Count +
+            plan.RemovedRawContainers.Count + plan.RemovedRawTags.Count + plan.RemovedUnsReferenceVariables.Count;
 
         var changedCount =
             plan.ChangedEquipment.Count + plan.ChangedDrivers.Count + plan.ChangedAlarms.Count +
             plan.ChangedEquipmentTags.Count +
             plan.ChangedEquipmentVirtualTags.Count +
+            plan.ChangedRawContainers.Count + plan.ChangedRawTags.Count + plan.ChangedUnsReferenceVariables.Count +
             // A UNS Area/Line rename is an in-place change to an existing folder node.
             plan.RenamedFolders.Count;
         var addedCount =
             plan.AddedEquipment.Count + plan.AddedDrivers.Count + plan.AddedAlarms.Count +
             plan.AddedEquipmentTags.Count +
-            plan.AddedEquipmentVirtualTags.Count;
+            plan.AddedEquipmentVirtualTags.Count +
+            plan.AddedRawContainers.Count + plan.AddedRawTags.Count + plan.AddedUnsReferenceVariables.Count;
 
         // R2-07 03/P1 — classify the plan and route each delta class to its MINIMAL mutation instead of
         // rebuilding the world for any topology change. AddressSpaceChangeClassifier is a pure policy over
@@ -172,7 +177,7 @@ public sealed class AddressSpaceApplier
                 foreach (var rename in renamedFolders)
                 {
                     bool ok;
-                    try { ok = surgical.UpdateFolderDisplayName(rename.FolderNodeId, rename.NewDisplayName); }
+                    try { ok = surgical.UpdateFolderDisplayName(rename.FolderNodeId, rename.NewDisplayName, AddressSpaceRealm.Uns); }
                     catch (Exception ex)
                     {
                         _logger.LogError(ex, "AddressSpaceApplier: surgical UpdateFolderDisplayName threw for {Node}", rename.FolderNodeId);
@@ -185,13 +190,13 @@ public sealed class AddressSpaceApplier
                     // Compute the node id + writable + historian + shape EXACTLY as MaterialiseEquipmentTags
                     // would so the in-place update matches what a rebuild would have produced. Array tags are
                     // forced read-only (same as EnsureVariable: the driver write path doesn't handle arrays).
-                    var nodeId = EquipmentNodeIds.Variable(d.Current.EquipmentId, d.Current.FolderPath, d.Current.Name);
+                    var nodeId = UnsEquipmentVar(d.Current.EquipmentId, d.Current.FolderPath, d.Current.Name);
                     var writable = d.Current.Writable && !d.Current.IsArray;
                     var historian = d.Current.IsHistorized
                         ? (string.IsNullOrWhiteSpace(d.Current.HistorianTagname) ? d.Current.FullName : d.Current.HistorianTagname)
                         : null;
                     bool ok;
-                    try { ok = surgical.UpdateTagAttributes(nodeId, writable, historian, d.Current.DataType, d.Current.IsArray, d.Current.ArrayLength); }
+                    try { ok = surgical.UpdateTagAttributes(nodeId, writable, historian, d.Current.DataType, d.Current.IsArray, d.Current.ArrayLength, AddressSpaceRealm.Uns); }
                     catch (Exception ex)
                     {
                         _logger.LogError(ex, "AddressSpaceApplier: surgical UpdateTagAttributes threw for {Node}", nodeId);
@@ -263,77 +268,108 @@ public sealed class AddressSpaceApplier
         // Removed equipment tags — value variables OR alarm-bearing conditions — for SURVIVING equipment.
         foreach (var tag in plan.RemovedEquipmentTags.Where(t => NotSubsumed(t.EquipmentId)))
         {
-            var nodeId = EquipmentNodeIds.Variable(tag.EquipmentId, tag.FolderPath, tag.Name);
+            var nodeId = UnsEquipmentVar(tag.EquipmentId, tag.FolderPath, tag.Name);
             if (tag.Alarm is not null)
             {
                 // Alarm-bearing tag → a Part 9 condition node. Terminal RemovedConditionState (today-gap
                 // closed), then remove the condition in place.
-                if (!SafeWriteAlarmCondition(nodeId, RemovedConditionState, ts)) failedNodes++;
+                if (!SafeWriteAlarmCondition(nodeId, RemovedConditionState, ts, AddressSpaceRealm.Uns)) failedNodes++;
-                if (!SafeRemoveAlarmCondition(surgical, nodeId)) return false;
+                if (!SafeRemoveAlarmCondition(surgical, nodeId, AddressSpaceRealm.Uns)) return false;
             }
             else
             {
                 // Plain value variable → terminal Bad so an in-flight MonitoredItem sees the removal.
-                SafeWriteValue(nodeId, null, OpcUaQuality.Bad, ts);
+                SafeWriteValue(nodeId, null, OpcUaQuality.Bad, ts, AddressSpaceRealm.Uns);
-                if (!SafeRemoveVariable(surgical, nodeId)) return false;
+                if (!SafeRemoveVariable(surgical, nodeId, AddressSpaceRealm.Uns)) return false;
             }
         }
 
         // Removed VirtualTags (always plain value variables) for surviving equipment.
         foreach (var v in plan.RemovedEquipmentVirtualTags.Where(t => NotSubsumed(t.EquipmentId)))
         {
-            var nodeId = EquipmentNodeIds.Variable(v.EquipmentId, v.FolderPath, v.Name);
+            var nodeId = UnsEquipmentVar(v.EquipmentId, v.FolderPath, v.Name);
-            SafeWriteValue(nodeId, null, OpcUaQuality.Bad, ts);
+            SafeWriteValue(nodeId, null, OpcUaQuality.Bad, ts, AddressSpaceRealm.Uns);
-            if (!SafeRemoveVariable(surgical, nodeId)) return false;
+            if (!SafeRemoveVariable(surgical, nodeId, AddressSpaceRealm.Uns)) return false;
         }
 
         // Removed scripted alarms for surviving equipment — the terminal RemovedConditionState was already
         // written by the top-of-Apply removal block; here we tear the condition node down in place.
         foreach (var alarm in plan.RemovedAlarms.Where(a => NotSubsumed(a.EquipmentId)))
         {
-            if (!SafeRemoveAlarmCondition(surgical, alarm.ScriptedAlarmId)) return false;
+            if (!SafeRemoveAlarmCondition(surgical, alarm.ScriptedAlarmId, AddressSpaceRealm.Uns)) return false;
         }
 
         // Removed equipment — one subtree teardown each (subsumes their child tags/vtags/alarms). The
         // top-of-Apply block already wrote the equipment id's terminal condition state.
         foreach (var eq in plan.RemovedEquipment)
         {
-            if (!SafeRemoveEquipmentSubtree(surgical, eq.EquipmentId)) return false;
+            if (!SafeRemoveEquipmentSubtree(surgical, eq.EquipmentId, AddressSpaceRealm.Uns)) return false;
         }
 
+        // v3 Batch 4 — removed UNS reference variables (Uns realm, plain value nodes): terminal Bad then
+        // in-place remove. A backing-raw rename is a re-point (Changed, → rebuild), NOT a removal, so a UNS
+        // ref only reaches here on a genuine dereference (the equipment dropped the reference).
+        foreach (var v in plan.RemovedUnsReferenceVariables)
+        {
+            SafeWriteValue(v.NodeId, null, OpcUaQuality.Bad, ts, AddressSpaceRealm.Uns);
+            if (!SafeRemoveVariable(surgical, v.NodeId, AddressSpaceRealm.Uns)) return false;
+        }
+
+        // v3 Batch 4 — removed RAW tags (Raw realm): an alarm-bearing raw tag is a condition node (terminal
+        // RemovedConditionState + RemoveAlarmConditionNode); a plain raw value tag is a variable (terminal Bad
+        // + RemoveVariableNode).
+        foreach (var t in plan.RemovedRawTags)
+        {
+            if (t.Alarm is not null)
+            {
+                if (!SafeWriteAlarmCondition(t.NodeId, RemovedConditionState, ts, AddressSpaceRealm.Raw)) failedNodes++;
+                if (!SafeRemoveAlarmCondition(surgical, t.NodeId, AddressSpaceRealm.Raw)) return false;
+            }
+            else
+            {
+                SafeWriteValue(t.NodeId, null, OpcUaQuality.Bad, ts, AddressSpaceRealm.Raw);
+                if (!SafeRemoveVariable(surgical, t.NodeId, AddressSpaceRealm.Raw)) return false;
+            }
+        }
+
+        // Removed raw CONTAINER nodes (Folder/Driver/Device/TagGroup) have no surgical folder-remove on the
+        // sink surface, so any container removal falls back to a full rebuild (the ratchet). Evaluated LAST so
+        // the cheap variable/condition removals above still run in place when only tags were removed.
+        if (plan.RemovedRawContainers.Count > 0) return false;
+
         return true;
     }
 
     /// <summary>Remove a value-variable node in place, treating a throw as a false (⇒ rebuild fallback).</summary>
     /// <returns><c>true</c> when the node was removed; <c>false</c> when unknown or the sink threw.</returns>
-    private bool SafeRemoveVariable(ISurgicalAddressSpaceSink surgical, string nodeId)
+    private bool SafeRemoveVariable(ISurgicalAddressSpaceSink surgical, string nodeId, AddressSpaceRealm realm)
     {
-        try { return surgical.RemoveVariableNode(nodeId); }
+        try { return surgical.RemoveVariableNode(nodeId, realm); }
         catch (Exception ex) { _logger.LogError(ex, "AddressSpaceApplier: surgical RemoveVariableNode threw for {Node}", nodeId); return false; }
     }
 
     /// <summary>Remove an alarm-condition node in place, treating a throw as a false (⇒ rebuild fallback).</summary>
     /// <returns><c>true</c> when the node was removed; <c>false</c> when unknown or the sink threw.</returns>
-    private bool SafeRemoveAlarmCondition(ISurgicalAddressSpaceSink surgical, string nodeId)
+    private bool SafeRemoveAlarmCondition(ISurgicalAddressSpaceSink surgical, string nodeId, AddressSpaceRealm realm)
     {
-        try { return surgical.RemoveAlarmConditionNode(nodeId); }
+        try { return surgical.RemoveAlarmConditionNode(nodeId, realm); }
         catch (Exception ex) { _logger.LogError(ex, "AddressSpaceApplier: surgical RemoveAlarmConditionNode threw for {Node}", nodeId); return false; }
     }
 
     /// <summary>Remove an equipment subtree in place, treating a throw as a false (⇒ rebuild fallback).</summary>
     /// <returns><c>true</c> when the subtree was removed; <c>false</c> when unknown or the sink threw.</returns>
-    private bool SafeRemoveEquipmentSubtree(ISurgicalAddressSpaceSink surgical, string nodeId)
+    private bool SafeRemoveEquipmentSubtree(ISurgicalAddressSpaceSink surgical, string nodeId, AddressSpaceRealm realm)
     {
-        try { return surgical.RemoveEquipmentSubtree(nodeId); }
+        try { return surgical.RemoveEquipmentSubtree(nodeId, realm); }
         catch (Exception ex) { _logger.LogError(ex, "AddressSpaceApplier: surgical RemoveEquipmentSubtree threw for {Node}", nodeId); return false; }
     }
 
     /// <summary>Write a value, swallowing (and Warning-logging) any sink fault — used for the terminal Bad
     /// on a removed variable so an in-flight MonitoredItem observes the removal.</summary>
     /// <returns><c>true</c> when the write landed; <c>false</c> when the sink threw.</returns>
-    private bool SafeWriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime ts)
+    private bool SafeWriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime ts, AddressSpaceRealm realm)
     {
-        try { _sink.WriteValue(nodeId, value, quality, ts); return true; }
+        try { _sink.WriteValue(nodeId, value, quality, ts, realm); return true; }
         catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: WriteValue threw for {Node}", nodeId); return false; }
     }
 
@@ -373,7 +409,22 @@ public sealed class AddressSpaceApplier
     /// <param name="folderPath">The tag/vtag FolderPath, or null/empty for "directly under the equipment".</param>
     /// <returns>The materialise-parent node id.</returns>
     private static string MaterialiseParent(string equipmentId, string? folderPath) =>
-        string.IsNullOrWhiteSpace(folderPath) ? equipmentId : EquipmentNodeIds.SubFolder(equipmentId, folderPath);
+        string.IsNullOrWhiteSpace(folderPath) ? equipmentId : UnsSubFolder(equipmentId, folderPath);
+
+    // ----- v3 UNS-equipment NodeId helpers (replace the retired EquipmentNodeIds) -----
+    // Equipment-owned UNS nodes (per-equipment VirtualTags, the vestigial equipment-tag path, and the
+    // discovered-node graft) keep their EquipmentId-anchored slash-path NodeId ({equipmentId}/{folderPath}/{name}),
+    // now expressed through the v3 identity authority V3NodeIds.Uns so the retired EquipmentNodeIds type can go.
+    // These live in the UNS realm. FolderPath may be multi-segment ("a/b") — each segment is validated
+    // by V3NodeIds.Uns like a RawPath. (UnsTagReference variables use the composer's Area/Line/Equipment/Name
+    // NodeId directly and are NOT built here.)
+    private static string UnsSubFolder(string equipmentId, string folderPath) =>
+        V3NodeIds.Uns(new[] { equipmentId }.Concat(folderPath.Split(RawPaths.Separator)));
+
+    private static string UnsEquipmentVar(string equipmentId, string? folderPath, string name) =>
+        string.IsNullOrWhiteSpace(folderPath)
+            ? V3NodeIds.Uns(equipmentId, name)
+            : V3NodeIds.Uns(new[] { equipmentId }.Concat(folderPath.Split(RawPaths.Separator)).Append(name));
 
     /// <summary>
     ///     Announce a Part 3 <c>GeneralModelChangeEvent(NodeAdded)</c> per distinct affected parent from
@@ -389,7 +440,7 @@ public sealed class AddressSpaceApplier
     {
         foreach (var id in ComputeAddAnnouncements(plan))
         {
-            try { _sink.RaiseNodesAddedModelChange(id); }
+            try { _sink.RaiseNodesAddedModelChange(id, AddressSpaceRealm.Uns); }
             catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: RaiseNodesAddedModelChange threw for {Node}", id); }
         }
     }
@@ -407,11 +458,11 @@ public sealed class AddressSpaceApplier
         try
         {
             List<HistorianTagProvisionRequest>? requests = null;
-            foreach (var tag in plan.AddedEquipmentTags)
+            // v3 Batch 4: historized value tags are RAW tags (added-raw-tag delta). Native-alarm tags
+            // materialise as Part 9 conditions (never historized value variables), so mirror the materialiser
+            // and skip them.
+            foreach (var tag in plan.AddedRawTags)
             {
-                // Only historized value variables are provisioned. Native-alarm tags materialise as
-                // Part 9 condition nodes (never historized value variables) — the materialiser resolves
-                // a historian tagname only for the non-alarm branch, so mirror that and skip them.
                 if (!tag.IsHistorized || tag.Alarm is not null) continue;
 
                 // Parse the driver-agnostic data type from the tag's DataType string. An unparseable
@@ -424,9 +475,9 @@ public sealed class AddressSpaceApplier
                     continue;
                 }
 
-                // Resolve the historian name EXACTLY as MaterialiseEquipmentTags does: a null/blank
+                // Resolve the historian name EXACTLY as MaterialiseRawSubtree does: a null/blank override
-                // override falls back to the driver-side FullName.
+                // falls back to the RawPath (== NodeId).
-                var historianName = string.IsNullOrWhiteSpace(tag.HistorianTagname) ? tag.FullName : tag.HistorianTagname;
+                var historianName = string.IsNullOrWhiteSpace(tag.HistorianTagname) ? tag.NodeId : tag.HistorianTagname;
                 (requests ??= new List<HistorianTagProvisionRequest>()).Add(
                     new HistorianTagProvisionRequest(historianName, dataType, EngineeringUnit: null, Description: tag.Name));
             }
@@ -493,22 +544,26 @@ public sealed class AddressSpaceApplier
             List<HistorizedTagRef>? added = null;
             List<HistorizedTagRef>? removed = null;
 
-            // Added historized value variables → new interest.
+            // v3 Batch 4: historized value tags are RAW tags (keyed by RawPath). The mux HistorizedTagRef
-            foreach (var tag in plan.AddedEquipmentTags)
+            // stays SINGLE, keyed by RawPath — a UNS reference node registers the same historian tagname in the
+            // node manager but does NOT add a second mux ref (no double historization). So this feed emits raw
+            // refs only.
+            // Added historized raw value tags → new interest.
+            foreach (var tag in plan.AddedRawTags)
             {
                 if (HistorizedRef(tag) is { } r) (added ??= new List<HistorizedTagRef>()).Add(r);
             }
 
-            // Removed historized value variables → drop interest.
+            // Removed historized raw value tags → drop interest.
-            foreach (var tag in plan.RemovedEquipmentTags)
+            foreach (var tag in plan.RemovedRawTags)
             {
                 if (HistorizedRef(tag) is { } r) (removed ??= new List<HistorizedTagRef>()).Add(r);
             }
 
-            // Changed tags: the historized ref may have flipped on/off or been renamed (override/FullName
+            // Changed raw tags: the historized ref may have flipped on/off or the historian override changed
-            // change). Compare previous-vs-current resolved ref PAIRS (record equality compares both the
+            // (a rename is remove+add, handled above). Compare previous-vs-current resolved ref PAIRS — an
-            // mux ref and the historian name) — an unchanged pair is a no-op.
+            // unchanged pair is a no-op.
-            foreach (var d in plan.ChangedEquipmentTags)
+            foreach (var d in plan.ChangedRawTags)
             {
                 var prev = HistorizedRef(d.Previous);
                 var cur = HistorizedRef(d.Current);
@@ -540,13 +595,15 @@ public sealed class AddressSpaceApplier
     ///     two diverge ONLY when an override is set. Returns <c>null</c> when the tag is not a historized
     ///     value variable (not historized, or a native-alarm condition node).
     /// </summary>
-    /// <param name="tag">The equipment tag to resolve a historized ref for.</param>
+    /// <param name="tag">The raw tag to resolve a historized ref for.</param>
     /// <returns>The resolved historized ref pair, or <c>null</c> when the tag is not a historized value variable.</returns>
-    private static HistorizedTagRef? HistorizedRef(EquipmentTagPlan tag) =>
+    private static HistorizedTagRef? HistorizedRef(RawTagPlan tag) =>
         tag.IsHistorized && tag.Alarm is null
+            // v3: the RawPath (== NodeId) is BOTH the mux ref (the driver fans values by RawPath) and the
+            // default historian tagname; an override diverges only the historian name.
             ? new HistorizedTagRef(
-                tag.FullName,
+                tag.NodeId,
-                string.IsNullOrWhiteSpace(tag.HistorianTagname) ? tag.FullName : tag.HistorianTagname)
+                string.IsNullOrWhiteSpace(tag.HistorianTagname) ? tag.NodeId : tag.HistorianTagname)
             : null;
 
     /// <summary>Rebuild the sink's address space, swallowing (and Error-logging) any fault.
@@ -585,17 +642,17 @@ public sealed class AddressSpaceApplier
         var failed = 0;
         foreach (var area in composition.UnsAreas)
         {
-            if (!SafeEnsureFolder(area.UnsAreaId, parentNodeId: null, displayName: area.DisplayName)) failed++;
+            if (!SafeEnsureFolder(area.UnsAreaId, parentNodeId: null, displayName: area.DisplayName, realm: AddressSpaceRealm.Uns)) failed++;
         }
         foreach (var line in composition.UnsLines)
         {
-            if (!SafeEnsureFolder(line.UnsLineId, parentNodeId: line.UnsAreaId, displayName: line.DisplayName)) failed++;
+            if (!SafeEnsureFolder(line.UnsLineId, parentNodeId: line.UnsAreaId, displayName: line.DisplayName, realm: AddressSpaceRealm.Uns)) failed++;
         }
         foreach (var equipment in composition.EquipmentNodes)
         {
             // Equipment with no UnsLineId (legacy / dev rows) hang under the root.
             var parent = string.IsNullOrWhiteSpace(equipment.UnsLineId) ? null : equipment.UnsLineId;
-            if (!SafeEnsureFolder(equipment.EquipmentId, parentNodeId: parent, displayName: equipment.DisplayName)) failed++;
+            if (!SafeEnsureFolder(equipment.EquipmentId, parentNodeId: parent, displayName: equipment.DisplayName, realm: AddressSpaceRealm.Uns)) failed++;
         }
 
         _logger.LogInformation(
@@ -604,6 +661,153 @@ public sealed class AddressSpaceApplier
         return failed;
     }
 
+    /// <summary>
+    ///     v3 Batch 4 — materialise the <b>Raw</b> device-oriented subtree (<c>ns=Raw</c>): the container
+    ///     nodes (Folder→Driver→Device→TagGroup, each an <c>Object</c>/<c>Folder</c>) parents-before-children,
+    ///     then the tag Variable nodes keyed <c>s=&lt;RawPath&gt;</c>. A native-alarm tag (<see cref="RawTagPlan.Alarm"/>
+    ///     non-null) materialises as a Part 9 condition node at its RawPath (ConditionId = RawPath, parent = its
+    ///     device/group folder) instead of a value variable — the single condition instance; WP4 wires the extra
+    ///     per-equipment notifiers. A historized value tag resolves its effective historian tagname HERE
+    ///     (override else the RawPath). Array tags are forced read-only (the driver write path can't handle
+    ///     arrays). Every sink call passes <see cref="AddressSpaceRealm.Raw"/> EXPLICITLY — the driver binds
+    ///     values to these raw NodeIds, and every referencing UNS node fans out from them. Idempotent.
+    /// </summary>
+    /// <param name="composition">The composition carrying the Raw subtree.</param>
+    /// <returns>The count of swallowed sink failures in this pass.</returns>
+    public int MaterialiseRawSubtree(AddressSpaceComposition composition)
+    {
+        ArgumentNullException.ThrowIfNull(composition);
+        if (composition.RawContainers.Count == 0 && composition.RawTags.Count == 0) return 0;
+
+        var failed = 0;
+        // Containers first — the composer sorts them by NodeId (ordinal) so a parent's RawPath precedes each
+        // child's; EnsureFolder is idempotent, so a re-apply is cheap.
+        foreach (var c in composition.RawContainers)
+        {
+            if (!SafeEnsureFolder(c.NodeId, c.ParentNodeId, c.DisplayName, AddressSpaceRealm.Raw)) failed++;
+        }
+
+        // v3 Batch 4 WP4 — reverse map (equipment UNS folder PATH → EquipmentId) so a native alarm's
+        // ReferencingEquipmentPaths (Area/Line/Equipment name paths, from the composer) resolve to the
+        // EquipmentId the equipment folders were materialised under by MaterialiseHierarchy. Built lazily only
+        // when at least one raw tag carries an alarm (the common no-alarm deploy pays nothing).
+        IReadOnlyDictionary<string, string>? equipIdByFolderPath = null;
+
+        foreach (var t in composition.RawTags)
+        {
+            if (t.Alarm is not null)
+            {
+                // Native alarm tag → a single Part 9 condition node at the RawPath (ConditionId = RawPath).
+                // Parent is its device/group folder. The single condition instance is materialised ONCE here.
+                if (!SafeMaterialiseAlarmCondition(t.NodeId, t.ParentNodeId ?? string.Empty, t.Name, t.Alarm.AlarmType, t.Alarm.Severity, isNative: true, AddressSpaceRealm.Raw))
+                {
+                    failed++;
+                }
+                else if (t.ReferencingEquipmentPaths.Count > 0)
+                {
+                    // WP4 multi-notifier fan-out: wire the SINGLE condition as an event notifier of each
+                    // referencing equipment's UNS folder, so one ReportEvent reaches every referencing equipment
+                    // (never re-reported per root). Resolve the folder PATHS to their EquipmentId folder NodeIds
+                    // (the id scheme MaterialiseHierarchy created the equipment folders under).
+                    equipIdByFolderPath ??= BuildEquipmentIdByFolderPath(composition);
+                    var equipFolderNodeIds = t.ReferencingEquipmentPaths
+                        .Select(p => equipIdByFolderPath!.GetValueOrDefault(p))
+                        .Where(id => !string.IsNullOrEmpty(id))
+                        .Select(id => id!)
+                        .Distinct(StringComparer.Ordinal)
+                        .ToList();
+                    if (equipFolderNodeIds.Count == 0)
+                    {
+                        // Wave C review M2: the alarm HAS referencing equipment but NONE of its paths resolved
+                        // to an EquipmentId folder — the native fan-out to those equipment is silently absent.
+                        // Surface it (Warning + a failed-node tally so the degraded-apply meter fires) instead
+                        // of swallowing zero operator signal. Today this only happens on a broken UNS ancestry /
+                        // an invalid segment (the composer would have dropped the equipment too); the latent
+                        // risk is a future editable Area/Line display-name feature breaking the path↔id coupling
+                        // (see BuildEquipmentIdByFolderPath + AddressSpaceComposerPathParityTests).
+                        _logger.LogWarning(
+                            "AddressSpaceApplier: native alarm {Node} has {Count} referencing equipment path(s) but NONE resolved to an equipment folder — the alarm's multi-notifier fan-out to those equipment is absent (paths={Paths})",
+                            t.NodeId, t.ReferencingEquipmentPaths.Count, string.Join(", ", t.ReferencingEquipmentPaths));
+                        failed++;
+                    }
+                    else if (!SafeWireAlarmNotifiers(t.NodeId, AddressSpaceRealm.Raw, equipFolderNodeIds, AddressSpaceRealm.Uns))
+                    {
+                        failed++;
+                    }
+                }
+            }
+            else
+            {
+                // A historized tag materialises Historizing + HistoryRead; the effective historian tagname is
+                // the override else the RawPath (== NodeId). Array writes are out of scope → force read-only.
+                string? historianTagname = t.IsHistorized
+                    ? (string.IsNullOrWhiteSpace(t.HistorianTagname) ? t.NodeId : t.HistorianTagname)
+                    : null;
+                var writable = t.Writable && !t.IsArray;
+                if (!SafeEnsureVariable(t.NodeId, t.ParentNodeId, t.Name, t.DataType, writable, AddressSpaceRealm.Raw, historianTagname, t.IsArray, t.ArrayLength)) failed++;
+            }
+        }
+
+        _logger.LogInformation(
+            "AddressSpaceApplier: raw subtree materialised (containers={Containers}, tags={Tags}, failed={Failed})",
+            composition.RawContainers.Count, composition.RawTags.Count, failed);
+        return failed;
+    }
+
+    /// <summary>
+    ///     v3 Batch 4 — materialise the <b>UNS</b> reference Variable nodes (<c>ns=UNS</c>): one per
+    ///     <see cref="UnsReferenceVariable"/>, keyed <c>s=&lt;Area&gt;/&lt;Line&gt;/&lt;Equipment&gt;/&lt;EffectiveName&gt;</c>,
+    ///     parented under its equipment folder (the logical <see cref="UnsReferenceVariable.EquipmentId"/> node
+    ///     <see cref="MaterialiseHierarchy"/> already created), THEN an <c>Organizes</c> reference
+    ///     UNS→Raw to its backing raw node. The UNS node inherits DataType / writable / array shape / historian
+    ///     tagname from its backing RAW tag (looked up by <see cref="UnsReferenceVariable.BackingRawPath"/>), so a
+    ///     historized raw tag's UNS reference registers the SAME tagname (both NodeIds → one tagname → HistoryRead
+    ///     works against either). The UNS node binds NO driver — the driver publish path fans values to it (WP3
+    ///     runtime binding). Every sink call passes <see cref="AddressSpaceRealm.Uns"/> / the Organizes edge
+    ///     passes both realms EXPLICITLY. Idempotent.
+    /// </summary>
+    /// <param name="composition">The composition carrying the UNS reference variables + Raw tags (for inherited shape).</param>
+    /// <returns>The count of swallowed sink failures in this pass.</returns>
+    public int MaterialiseUnsReferences(AddressSpaceComposition composition)
+    {
+        ArgumentNullException.ThrowIfNull(composition);
+        if (composition.UnsReferenceVariables.Count == 0) return 0;
+
+        // Backing raw tag shape/historian by RawPath — a UNS reference inherits these so its node matches the
+        // raw node it mirrors (a historized raw tag registers the SAME tagname on the UNS node for HistoryRead).
+        var rawByPath = new Dictionary<string, RawTagPlan>(StringComparer.Ordinal);
+        foreach (var t in composition.RawTags) rawByPath[t.NodeId] = t;
+
+        var failed = 0;
+        foreach (var v in composition.UnsReferenceVariables)
+        {
+            var backing = rawByPath.GetValueOrDefault(v.BackingRawPath);
+            var isArray = backing?.IsArray ?? false;
+            uint? arrayLength = backing?.ArrayLength;
+            // A UNS reference to a historized raw tag registers the SAME effective historian tagname (override
+            // else the backing RawPath) so HistoryRead resolves against the UNS NodeId too. The mux ref stays
+            // single (keyed by RawPath) — FeedHistorizedRefs emits raw refs only.
+            string? historianTagname = backing is { IsHistorized: true }
+                ? (string.IsNullOrWhiteSpace(backing.HistorianTagname) ? backing.NodeId : backing.HistorianTagname)
+                : null;
+            var writable = v.Writable && !isArray;
+            if (!SafeEnsureVariable(v.NodeId, v.EquipmentId, v.EffectiveName, v.DataType, writable, AddressSpaceRealm.Uns, historianTagname, isArray, arrayLength))
+            {
+                failed++;
+                continue; // node not created — skip the Organizes edge (a missing endpoint would no-op anyway)
+            }
+            // Organizes UNS→Raw so the linkage is browsable. Both endpoints are realm-qualified; a missing
+            // endpoint is a logged no-op in the sink (never throws), so this can't fault a deploy.
+            try { _sink.AddReference(v.NodeId, AddressSpaceRealm.Uns, v.BackingRawPath, AddressSpaceRealm.Raw); }
+            catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: AddReference (Organizes UNS->Raw) threw for {Node}", v.NodeId); failed++; }
+        }
+
+        _logger.LogInformation(
+            "AddressSpaceApplier: UNS reference variables materialised (refs={Refs}, failed={Failed})",
+            composition.UnsReferenceVariables.Count, failed);
+        return failed;
+    }
+
     /// <summary>
     ///     Materialise Equipment-namespace tags from a composition snapshot.
     ///     For each <see cref="EquipmentTagPlan"/>,
@@ -635,9 +839,9 @@ public sealed class AddressSpaceApplier
         foreach (var tag in composition.EquipmentTags)
         {
             if (string.IsNullOrWhiteSpace(tag.FolderPath)) continue;
-            var folderNodeId = EquipmentNodeIds.SubFolder(tag.EquipmentId, tag.FolderPath);
+            var folderNodeId = UnsSubFolder(tag.EquipmentId, tag.FolderPath);
             if (!foldersCreated.Add(folderNodeId)) continue;
-            if (!SafeEnsureFolder(folderNodeId, parentNodeId: tag.EquipmentId, displayName: tag.FolderPath)) failed++;
+            if (!SafeEnsureFolder(folderNodeId, parentNodeId: tag.EquipmentId, displayName: tag.FolderPath, realm: AddressSpaceRealm.Uns)) failed++;
         }
 
         // Variables: NodeId is FOLDER-SCOPED ("<parent>/<Name>"), NOT the raw FullName — a driver
@@ -650,13 +854,13 @@ public sealed class AddressSpaceApplier
         {
             var parent = string.IsNullOrWhiteSpace(tag.FolderPath)
                 ? tag.EquipmentId
-                : EquipmentNodeIds.SubFolder(tag.EquipmentId, tag.FolderPath);
+                : UnsSubFolder(tag.EquipmentId, tag.FolderPath);
-            var nodeId = EquipmentNodeIds.Variable(tag.EquipmentId, tag.FolderPath, tag.Name);
+            var nodeId = UnsEquipmentVar(tag.EquipmentId, tag.FolderPath, tag.Name);
             if (tag.Alarm is not null)
             {
                 // Native alarm tag → a real Part 9 condition node (reuses the scripted-alarm path),
                 // NOT a value variable. Parent is the sub-folder when set, else the equipment folder.
-                if (!SafeMaterialiseAlarmCondition(nodeId, parent, tag.Name, tag.Alarm.AlarmType, tag.Alarm.Severity, isNative: true)) failed++;
+                if (!SafeMaterialiseAlarmCondition(nodeId, parent, tag.Name, tag.Alarm.AlarmType, tag.Alarm.Severity, isNative: true, realm: AddressSpaceRealm.Uns)) failed++;
             }
             else
             {
@@ -670,7 +874,7 @@ public sealed class AddressSpaceApplier
                 // even if authored ReadWrite, so a client write cannot reach the driver write path which
                 // does not handle arrays (e.g. S7 BoxValueForWrite would crash).
                 var writable = tag.Writable && !tag.IsArray;
-                if (!SafeEnsureVariable(nodeId, parent, tag.Name, tag.DataType, writable, historianTagname, tag.IsArray, tag.ArrayLength)) failed++;
+                if (!SafeEnsureVariable(nodeId, parent, tag.Name, tag.DataType, writable, AddressSpaceRealm.Uns, historianTagname, tag.IsArray, tag.ArrayLength)) failed++;
             }
         }
 
@@ -708,17 +912,17 @@ public sealed class AddressSpaceApplier
         var failed = 0;
         // Parent-first: a child folder's parent must exist before it. Ordering by '/' count == depth.
         foreach (var f in folders.OrderBy(f => f.NodeId.Count(c => c == '/')))
-            if (!SafeEnsureFolder(f.NodeId, f.ParentNodeId, f.DisplayName)) failed++;
+            if (!SafeEnsureFolder(f.NodeId, f.ParentNodeId, f.DisplayName, AddressSpaceRealm.Raw)) failed++;
 
         foreach (var v in variables)
         {
             // Mirror MaterialiseEquipmentTags: arrays forced read-only (the driver write path can't handle arrays).
             var writable = v.Writable && !v.IsArray;
             if (!SafeEnsureVariable(v.NodeId, v.ParentNodeId, v.DisplayName, v.DataType, writable,
-                historianTagname: null, isArray: v.IsArray, arrayLength: v.ArrayLength)) failed++;
+                AddressSpaceRealm.Raw, historianTagname: null, isArray: v.IsArray, arrayLength: v.ArrayLength)) failed++;
         }
 
-        _sink.RaiseNodesAddedModelChange(equipmentRootNodeId);
+        _sink.RaiseNodesAddedModelChange(equipmentRootNodeId, AddressSpaceRealm.Raw);
 
         _logger.LogInformation(
             "AddressSpaceApplier: discovered nodes materialised under {Equipment} (folders={Folders}, vars={Vars}, failed={Failed})",
@@ -754,9 +958,9 @@ public sealed class AddressSpaceApplier
         foreach (var v in composition.EquipmentVirtualTags)
         {
             if (string.IsNullOrWhiteSpace(v.FolderPath)) continue;
-            var folderNodeId = EquipmentNodeIds.SubFolder(v.EquipmentId, v.FolderPath);
+            var folderNodeId = UnsSubFolder(v.EquipmentId, v.FolderPath);
             if (!foldersCreated.Add(folderNodeId)) continue;
-            if (!SafeEnsureFolder(folderNodeId, parentNodeId: v.EquipmentId, displayName: v.FolderPath)) failed++;
+            if (!SafeEnsureFolder(folderNodeId, parentNodeId: v.EquipmentId, displayName: v.FolderPath, realm: AddressSpaceRealm.Uns)) failed++;
         }
 
         // Variables: NodeId is FOLDER-SCOPED ("<parent>/<Name>"), mirroring the equipment-tag pass.
@@ -769,10 +973,10 @@ public sealed class AddressSpaceApplier
         {
             var parent = string.IsNullOrWhiteSpace(v.FolderPath)
                 ? v.EquipmentId
-                : EquipmentNodeIds.SubFolder(v.EquipmentId, v.FolderPath);
+                : UnsSubFolder(v.EquipmentId, v.FolderPath);
-            var nodeId = EquipmentNodeIds.Variable(v.EquipmentId, v.FolderPath, v.Name);
+            var nodeId = UnsEquipmentVar(v.EquipmentId, v.FolderPath, v.Name);
             // VirtualTags are computed outputs — read-only nodes (no inbound write).
-            if (!SafeEnsureVariable(nodeId, parent, v.Name, v.DataType, writable: false)) failed++;
+            if (!SafeEnsureVariable(nodeId, parent, v.Name, v.DataType, writable: false, realm: AddressSpaceRealm.Uns)) failed++;
         }
 
         _logger.LogInformation(
@@ -805,7 +1009,7 @@ public sealed class AddressSpaceApplier
         foreach (var alarm in composition.EquipmentScriptedAlarms)
         {
             if (!alarm.Enabled) continue;
-            if (!SafeMaterialiseAlarmCondition(alarm.ScriptedAlarmId, alarm.EquipmentId, alarm.Name, alarm.AlarmType, alarm.Severity, isNative: false)) failed++;
+            if (!SafeMaterialiseAlarmCondition(alarm.ScriptedAlarmId, alarm.EquipmentId, alarm.Name, alarm.AlarmType, alarm.Severity, isNative: false, realm: AddressSpaceRealm.Uns)) failed++;
             materialised++;
         }
 
@@ -822,9 +1026,9 @@ public sealed class AddressSpaceApplier
     /// on success, <c>false</c> when the sink threw — callers tally the false into their pass's failed-node
     /// count so a swallowed materialise failure is operator-visible (archreview 01/S-1).</summary>
     /// <returns><c>true</c> when the folder was ensured; <c>false</c> when the sink threw.</returns>
-    private bool SafeEnsureFolder(string nodeId, string? parentNodeId, string displayName)
+    private bool SafeEnsureFolder(string nodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm)
     {
-        try { _sink.EnsureFolder(nodeId, parentNodeId, displayName); return true; }
+        try { _sink.EnsureFolder(nodeId, parentNodeId, displayName, realm); return true; }
         catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: EnsureFolder threw for {Node}", nodeId); return false; }
     }
 
@@ -832,9 +1036,9 @@ public sealed class AddressSpaceApplier
     /// on success, <c>false</c> when the sink threw — callers tally the false into their pass's failed-node
     /// count (archreview 01/S-1).</summary>
     /// <returns><c>true</c> when the variable was ensured; <c>false</c> when the sink threw.</returns>
-    private bool SafeEnsureVariable(string nodeId, string? parentNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+    private bool SafeEnsureVariable(string nodeId, string? parentNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
     {
-        try { _sink.EnsureVariable(nodeId, parentNodeId, displayName, dataType, writable, historianTagname, isArray, arrayLength); return true; }
+        try { _sink.EnsureVariable(nodeId, parentNodeId, displayName, dataType, writable, realm, historianTagname, isArray, arrayLength); return true; }
         catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: EnsureVariable threw for {Node}", nodeId); return false; }
     }
 
@@ -859,9 +1063,9 @@ public sealed class AddressSpaceApplier
     /// Returns <c>true</c> on success, <c>false</c> when the sink threw — the removal pass tallies the
     /// false into <see cref="AddressSpaceApplyOutcome.FailedNodes"/> (archreview 01/S-1).</summary>
     /// <returns><c>true</c> when the write landed; <c>false</c> when the sink threw.</returns>
-    private bool SafeWriteAlarmCondition(string nodeId, AlarmConditionSnapshot state, DateTime ts)
+    private bool SafeWriteAlarmCondition(string nodeId, AlarmConditionSnapshot state, DateTime ts, AddressSpaceRealm realm)
     {
-        try { _sink.WriteAlarmCondition(nodeId, state, ts); return true; }
+        try { _sink.WriteAlarmCondition(nodeId, state, ts, realm); return true; }
         catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: WriteAlarmCondition threw for {Node}", nodeId); return false; }
     }
 
@@ -869,11 +1073,70 @@ public sealed class AddressSpaceApplier
     /// Returns <c>true</c> on success, <c>false</c> when the sink threw — callers tally the false into
     /// their pass's failed-node count (archreview 01/S-1).</summary>
     /// <returns><c>true</c> when the condition was materialised; <c>false</c> when the sink threw.</returns>
-    private bool SafeMaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative)
+    private bool SafeMaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative, AddressSpaceRealm realm)
     {
-        try { _sink.MaterialiseAlarmCondition(alarmNodeId, equipmentNodeId, displayName, alarmType, severity, isNative); return true; }
+        try { _sink.MaterialiseAlarmCondition(alarmNodeId, equipmentNodeId, displayName, alarmType, severity, realm, isNative); return true; }
         catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: MaterialiseAlarmCondition threw for {Node}", alarmNodeId); return false; }
     }
+
+    /// <summary>Wire a native alarm condition's extra equipment-folder notifiers (WP4 multi-notifier),
+    /// swallowing (and Warning-logging) any sink fault. Returns <c>true</c> on success, <c>false</c> when the
+    /// sink threw — callers tally the false into their pass's failed-node count (archreview 01/S-1).</summary>
+    /// <returns><c>true</c> when the notifiers were wired; <c>false</c> when the sink threw.</returns>
+    private bool SafeWireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm)
+    {
+        try { _sink.WireAlarmNotifiers(alarmNodeId, alarmRealm, notifierFolderNodeIds, notifierFolderRealm); return true; }
+        catch (Exception ex) { _logger.LogWarning(ex, "AddressSpaceApplier: WireAlarmNotifiers threw for {Node}", alarmNodeId); return false; }
+    }
+
+    /// <summary>
+    ///     v3 Batch 4 WP4 — build the reverse map <c>equipment UNS folder PATH (Area/Line/Equipment) →
+    ///     EquipmentId</c>. The composer emits a native alarm's <see cref="RawTagPlan.ReferencingEquipmentPaths"/>
+    ///     as name paths (<c>V3NodeIds.Uns(areaName, lineName, equipName)</c>), but the equipment folders were
+    ///     materialised under their logical <c>EquipmentId</c> by <see cref="MaterialiseHierarchy"/>, so the
+    ///     multi-notifier wiring must translate path → id. This inverts the composer's own equipment-folder-path
+    ///     construction EXACTLY — <b>path↔id coupling invariant:</b> the composer builds the path from the
+    ///     Area/Line/Equipment <c>Name</c>; this inverts it via the projected <c>DisplayName</c>, which the
+    ///     composer sets to that same <c>Name</c> at every level (verified by
+    ///     <c>AddressSpaceComposerPathParityTests</c>). A future editable Area/Line display-name feature that
+    ///     lets <c>DisplayName != Name</c> would silently break this inversion — that test is the tripwire.
+    ///     An invalid segment throws in <see cref="V3NodeIds.Uns"/> and is skipped (the same drop the composer
+    ///     applies), so an entry the composer produced always resolves here.
+    /// </summary>
+    /// <param name="composition">The composition carrying the UNS topology + equipment nodes.</param>
+    /// <returns>A map from each resolvable equipment folder path to its EquipmentId.</returns>
+    private IReadOnlyDictionary<string, string> BuildEquipmentIdByFolderPath(AddressSpaceComposition composition)
+    {
+        var areaName = composition.UnsAreas
+            .GroupBy(a => a.UnsAreaId, StringComparer.Ordinal)
+            .ToDictionary(g => g.Key, g => g.First().DisplayName, StringComparer.Ordinal);
+        var lineByid = composition.UnsLines
+            .GroupBy(l => l.UnsLineId, StringComparer.Ordinal)
+            .ToDictionary(g => g.Key, g => (g.First().UnsAreaId, g.First().DisplayName), StringComparer.Ordinal);
+
+        var map = new Dictionary<string, string>(StringComparer.Ordinal);
+        foreach (var e in composition.EquipmentNodes)
+        {
+            if (string.IsNullOrWhiteSpace(e.UnsLineId)) continue;
+            if (!lineByid.TryGetValue(e.UnsLineId, out var line)) continue;
+            if (!areaName.TryGetValue(line.UnsAreaId, out var aName)) continue;
+            string path;
+            try { path = V3NodeIds.Uns(aName, line.DisplayName, e.DisplayName); }
+            catch (ArgumentException) { continue; /* invalid segment — dropped, mirroring the composer */ }
+            // Wave C review L3: two equipment sharing an identical Area/Line/Name collapse to one id
+            // (last-write-wins). UNS uniqueness prevents this, so it is defense-in-depth: warn (mirroring the
+            // composer's own last-write-wins spot) rather than silently pick one — a collision here would send
+            // the alarm's notifier to the wrong equipment folder.
+            if (map.TryGetValue(path, out var existing) && !string.Equals(existing, e.EquipmentId, StringComparison.Ordinal))
+            {
+                _logger.LogWarning(
+                    "AddressSpaceApplier: two equipment share the UNS folder path {Path} ({Existing} vs {New}) — the native-alarm notifier map collapses them (last-write-wins); UNS uniqueness should prevent this",
+                    path, existing, e.EquipmentId);
+            }
+            map[path] = e.EquipmentId;
+        }
+        return map;
+    }
 }
 
 /// <summary>Summary of one apply pass. Useful for tests + audit-log entries on the deploy path.

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceChangeClassifier.cs

@@ -53,10 +53,24 @@ public static class AddressSpaceChangeClassifier
 
         // 2 — any node-affecting CHANGE forces a full rebuild (default-closed). ChangedEquipment /
         // ChangedAlarms are always node-affecting; a changed tag is node-affecting UNLESS it is
-        // surgical-eligible, and a changed vtag is node-affecting UNLESS it is node-irrelevant. Evaluated
+        // surgical-eligible, and a changed vtag is node-affecting UNLESS it is node-irrelevant. The v3
-        // BEFORE the add/remove split so a non-surgical change alongside pure adds still rebuilds.
+        // Batch-4 Raw/UNS Changed sets (container re-shape, raw-tag attribute/alarm edit, UNS re-point /
+        // display-name-override) route to Rebuild as the safe default — WP3's applier owns any surgical
+        // in-place refinement for them. Evaluated BEFORE the add/remove split so a non-surgical change
+        // alongside pure adds still rebuilds.
+        //
+        // WP4 BINDING GUARD (Wave C review M3): ChangedRawTags → Rebuild is what keeps native-alarm notifier
+        // wiring correct today. A native alarm's set of referencing equipment lives in
+        // RawTagPlan.ReferencingEquipmentPaths (part of its record equality), so ADDING/DROPPING a reference
+        // makes the raw tag a ChangedRawTag → full rebuild → OtOpcUaNodeManager clears + re-wires the notifiers
+        // cleanly. ANY future surgical (non-rebuild) ChangedRawTags path MUST also re-wire/unwire the alarm
+        // notifiers (WireAlarmNotifiers is a reconcile — pass the tag's COMPLETE current referencing set — plus
+        // an explicit unwire on removal), else a de-referenced equipment keeps receiving the alarm's events.
         if (plan.ChangedEquipment.Count > 0 ||
             plan.ChangedAlarms.Count > 0 ||
+            plan.ChangedRawContainers.Count > 0 ||
+            plan.ChangedRawTags.Count > 0 ||
+            plan.ChangedUnsReferenceVariables.Count > 0 ||
             plan.ChangedEquipmentTags.Any(d => !TagDeltaIsSurgicalEligible(d)) ||
             plan.ChangedEquipmentVirtualTags.Any(d => !VtagDeltaIsNodeIrrelevant(d)))
         {
@@ -68,10 +82,14 @@ public static class AddressSpaceChangeClassifier
         // add/remove split below and leave a driver-only plan classified AttributeOnly.
         var hasAdds =
             plan.AddedEquipment.Count + plan.AddedAlarms.Count +
-            plan.AddedEquipmentTags.Count + plan.AddedEquipmentVirtualTags.Count > 0;
+            plan.AddedEquipmentTags.Count + plan.AddedEquipmentVirtualTags.Count +
+            plan.AddedRawContainers.Count + plan.AddedRawTags.Count +
+            plan.AddedUnsReferenceVariables.Count > 0;
         var hasRemoves =
             plan.RemovedEquipment.Count + plan.RemovedAlarms.Count +
-            plan.RemovedEquipmentTags.Count + plan.RemovedEquipmentVirtualTags.Count > 0;
+            plan.RemovedEquipmentTags.Count + plan.RemovedEquipmentVirtualTags.Count +
+            plan.RemovedRawContainers.Count + plan.RemovedRawTags.Count +
+            plan.RemovedUnsReferenceVariables.Count > 0;
 
         // 3 — additions AND removals.
         if (hasAdds && hasRemoves) return AddressSpaceChangeKind.AddRemoveMix;

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpaceComposer.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using ZB.MOM.WW.OtOpcUa.Commons.Types;
 using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
@@ -53,8 +54,163 @@ public sealed record AddressSpaceComposition(
     ///     constructor + call site keeps compiling unchanged.
     /// </summary>
     public IReadOnlyList<EquipmentScriptedAlarmPlan> EquipmentScriptedAlarms { get; init; } = Array.Empty<EquipmentScriptedAlarmPlan>();
+
+    // ----- v3 Batch 4 dual-namespace address space (un-darkened) -----
+
+    /// <summary>
+    ///     The Raw subtree's <b>container</b> nodes (Folder → Driver → Device → TagGroup) as
+    ///     <c>Object</c>/<c>Folder</c> nodes in the <see cref="AddressSpaceRealm.Raw"/> namespace. Each
+    ///     carries its <c>s=&lt;RawPath&gt;</c> NodeId and its parent NodeId (<see langword="null"/> = cluster
+    ///     root) so <c>AddressSpaceApplier</c> can materialise parents-before-children. Sorted by NodeId
+    ///     (ordinal, so a parent precedes each child). Init-only, defaults empty so every existing constructor
+    ///     + call site keeps compiling unchanged.
+    /// </summary>
+    public IReadOnlyList<RawContainerNode> RawContainers { get; init; } = Array.Empty<RawContainerNode>();
+
+    /// <summary>
+    ///     The Raw subtree's <b>tag</b> Variable nodes — one per raw <see cref="Tag"/> — keyed
+    ///     <c>(realm=Raw, s=&lt;RawPath&gt;)</c>. The RawPath IS the node identity + the single value source
+    ///     the driver binds; every referencing UNS variable fans out from it. Carries DataType / writable /
+    ///     historize + array shape, the optional native-alarm intent (attached at the RAW tag —
+    ///     ConditionId = RawPath), and the list of referencing equipment UNS folder paths (so WP4 wires the
+    ///     multi-notifier alarm). Init-only, defaults empty.
+    /// </summary>
+    public IReadOnlyList<RawTagPlan> RawTags { get; init; } = Array.Empty<RawTagPlan>();
+
+    /// <summary>
+    ///     The UNS subtree's reference Variable nodes — one per <see cref="UnsTagReference"/> — keyed
+    ///     <c>(realm=Uns, s=&lt;Area&gt;/&lt;Line&gt;/&lt;Equipment&gt;/&lt;EffectiveName&gt;)</c>. Each carries
+    ///     its backing raw tag's RawPath (the <c>Organizes</c> UNS→Raw target + the fan-out source) plus the
+    ///     inherited DataType / writable from that raw tag. UNS nodes never bind a driver directly — they fan
+    ///     out from the raw node. Init-only, defaults empty.
+    /// </summary>
+    public IReadOnlyList<UnsReferenceVariable> UnsReferenceVariables { get; init; } = Array.Empty<UnsReferenceVariable>();
 }
 
+/// <summary>Which Raw-tree container a <see cref="RawContainerNode"/> is (all are <c>Object</c>/<c>Folder</c>
+/// nodes; the kind lets the applier pick the OPC UA type + reference).</summary>
+public enum RawNodeKind
+{
+    /// <summary>A driver-organizing <see cref="RawFolder"/>.</summary>
+    Folder,
+
+    /// <summary>A <see cref="DriverInstance"/>.</summary>
+    Driver,
+
+    /// <summary>A <see cref="Device"/>.</summary>
+    Device,
+
+    /// <summary>A tag-organizing <see cref="TagGroup"/>.</summary>
+    TagGroup,
+}
+
+/// <summary>
+///     One Raw-subtree container node (Folder / Driver / Device / TagGroup). <see cref="NodeId"/> is its
+///     <c>RawPath</c> (== the <c>ns=Raw</c> <c>s=</c> id); <see cref="ParentNodeId"/> is the parent container's
+///     RawPath (<see langword="null"/> = directly under the cluster root). <see cref="Realm"/> is always
+///     <see cref="AddressSpaceRealm.Raw"/> — carried explicitly so the applier chooses the namespace at the
+///     call site rather than inferring it.
+/// </summary>
+/// <param name="NodeId">The container's RawPath (its <c>ns=Raw</c> <c>s=</c> identifier).</param>
+/// <param name="ParentNodeId">The parent container's RawPath, or <see langword="null"/> for a cluster-root node.</param>
+/// <param name="DisplayName">The friendly browse name (the container's leaf <c>Name</c>).</param>
+/// <param name="Kind">Which container this is.</param>
+/// <param name="Realm">The address-space realm (always <see cref="AddressSpaceRealm.Raw"/>).</param>
+public sealed record RawContainerNode(
+    string NodeId,
+    string? ParentNodeId,
+    string DisplayName,
+    RawNodeKind Kind,
+    AddressSpaceRealm Realm = AddressSpaceRealm.Raw);
+
+/// <summary>
+///     One Raw-subtree tag Variable node. <see cref="NodeId"/> is the tag's <c>RawPath</c> — the single
+///     identity string at every seam (the <c>ns=Raw</c> <c>s=</c> id, the driver fan-out/write key, the
+///     historian default tagname, the native-alarm <c>ConditionId</c>). <see cref="ParentNodeId"/> is the
+///     owning TagGroup's RawPath (or the Device's when the tag sits directly under the device).
+///     <see cref="Writable"/> mirrors <c>Tag.AccessLevel == ReadWrite</c>. <see cref="Alarm"/> /
+///     <see cref="IsHistorized"/> / <see cref="HistorianTagname"/> / <see cref="IsArray"/> /
+///     <see cref="ArrayLength"/> are parsed from <c>Tag.TagConfig</c> via
+///     <see cref="TagConfigIntent"/> (the single byte-parity authority). <see cref="ReferencingEquipmentPaths"/>
+///     is the (possibly empty) set of UNS equipment-folder paths (<c>Area/Line/Equipment</c>) that reference
+///     this tag — WP4 wires one notifier per path so the raw tag's single alarm condition fans to every
+///     referencing equipment. <see cref="Realm"/> is always <see cref="AddressSpaceRealm.Raw"/>.
+///     A null <see cref="HistorianTagname"/> means the historian tagname defaults to the RawPath (resolved
+///     later, not here).
+/// </summary>
+public sealed record RawTagPlan(
+    string TagId,
+    string NodeId,
+    string? ParentNodeId,
+    string DriverInstanceId,
+    string Name,
+    string DataType,
+    bool Writable,
+    EquipmentTagAlarmInfo? Alarm,
+    IReadOnlyList<string> ReferencingEquipmentPaths,
+    bool IsHistorized = false,
+    string? HistorianTagname = null,
+    bool IsArray = false,
+    uint? ArrayLength = null,
+    AddressSpaceRealm Realm = AddressSpaceRealm.Raw)
+{
+    /// <inheritdoc />
+    // Structural equality: the auto-generated record equality compares ReferencingEquipmentPaths (an
+    // interface-typed list) BY REFERENCE, which would flag every raw tag as "changed" on every parse
+    // (fresh list instances). Compare it element-wise so a no-op redeploy diffs empty (mirrors
+    // EquipmentVirtualTagPlan).
+    public bool Equals(RawTagPlan? other) =>
+        other is not null &&
+        TagId == other.TagId &&
+        NodeId == other.NodeId &&
+        ParentNodeId == other.ParentNodeId &&
+        DriverInstanceId == other.DriverInstanceId &&
+        Name == other.Name &&
+        DataType == other.DataType &&
+        Writable == other.Writable &&
+        EqualityComparer<EquipmentTagAlarmInfo?>.Default.Equals(Alarm, other.Alarm) &&
+        IsHistorized == other.IsHistorized &&
+        HistorianTagname == other.HistorianTagname &&
+        IsArray == other.IsArray &&
+        ArrayLength == other.ArrayLength &&
+        Realm == other.Realm &&
+        ReferencingEquipmentPaths.SequenceEqual(other.ReferencingEquipmentPaths, StringComparer.Ordinal);
+
+    /// <inheritdoc />
+    public override int GetHashCode()
+    {
+        var hash = new HashCode();
+        hash.Add(TagId); hash.Add(NodeId); hash.Add(ParentNodeId); hash.Add(DriverInstanceId);
+        hash.Add(Name); hash.Add(DataType); hash.Add(Writable); hash.Add(Alarm);
+        hash.Add(IsHistorized); hash.Add(HistorianTagname); hash.Add(IsArray); hash.Add(ArrayLength);
+        hash.Add(Realm);
+        foreach (var p in ReferencingEquipmentPaths) hash.Add(p, StringComparer.Ordinal);
+        return hash.ToHashCode();
+    }
+}
+
+/// <summary>
+///     One UNS-subtree reference Variable node projected from a <see cref="UnsTagReference"/>.
+///     <see cref="NodeId"/> is the slash-joined UNS path <c>Area/Line/Equipment/EffectiveName</c> (the
+///     <c>ns=UNS</c> <c>s=</c> id); <see cref="EffectiveName"/> is <c>DisplayNameOverride</c> else the backing
+///     raw tag's <c>Name</c>. <see cref="BackingRawPath"/> is the backing raw tag's RawPath — the
+///     <c>Organizes</c> UNS→Raw reference target AND the fan-out value source (the UNS node binds no driver;
+///     it mirrors the raw node). <see cref="DataType"/> / <see cref="Writable"/> are inherited from the
+///     backing raw tag. <see cref="UnsTagReferenceId"/> is the stable diff identity (a display-name-override
+///     edit keeps the same id while the NodeId/effective-name changes; a backing-tag rename keeps the same id
+///     + NodeId while <see cref="BackingRawPath"/> re-points). <see cref="Realm"/> is always
+///     <see cref="AddressSpaceRealm.Uns"/>.
+/// </summary>
+public sealed record UnsReferenceVariable(
+    string UnsTagReferenceId,
+    string EquipmentId,
+    string NodeId,
+    string EffectiveName,
+    string BackingRawPath,
+    string DataType,
+    bool Writable,
+    AddressSpaceRealm Realm = AddressSpaceRealm.Uns);
+
 public sealed record UnsAreaProjection(string UnsAreaId, string DisplayName);
 public sealed record UnsLineProjection(string UnsLineId, string UnsAreaId, string DisplayName);
 
@@ -301,12 +457,17 @@ public static class AddressSpaceComposer
 
     /// <summary>
     ///     Composes the address space build plan from the v3 configuration entities.
-    ///     <para><b>v3 DARK address space (Batch 1):</b> equipment-tag variable nodes do NOT materialize —
+    ///     <para><b>v3 dual namespace (Batch 4):</b> the composer emits BOTH subtrees. The
-    ///     <c>EquipmentTags</c> is deliberately empty (the raw + UNS variable nodes are lit up in Batch 4's
+    ///     <see cref="AddressSpaceComposition.RawContainers"/> + <see cref="AddressSpaceComposition.RawTags"/>
-    ///     dual namespace). The composer carries the UNS folder hierarchy (Area/Line/Equipment) +
+    ///     light up the device-oriented <c>ns=Raw</c> tree (Folder→Driver→Device→TagGroup→Tag, each tag keyed
-    ///     per-equipment VirtualTags + ScriptedAlarms only. Equipment no longer binds a driver/device, so
+    ///     <c>s=&lt;RawPath&gt;</c>); the <see cref="AddressSpaceComposition.UnsReferenceVariables"/> light up
-    ///     <see cref="EquipmentNode"/>'s driver/device hooks are always null. This is the pure reference
+    ///     the equipment-oriented <c>ns=UNS</c> tree (one Variable per <see cref="UnsTagReference"/>, keyed
-    ///     mirror of <c>DeploymentArtifact.ParseComposition</c> (byte-parity target for the corpus tests).</para>
+    ///     <c>s=&lt;Area&gt;/&lt;Line&gt;/&lt;Equipment&gt;/&lt;EffectiveName&gt;</c>, carrying its backing RawPath
+    ///     for the <c>Organizes</c> reference + fan-out). Native-alarm intents attach at the RAW tag
+    ///     (ConditionId = RawPath) with the list of referencing equipment paths. The legacy
+    ///     <see cref="AddressSpaceComposition.EquipmentTags"/> set stays EMPTY (the retired
+    ///     equipment-namespace tag path); UNS folders + per-equipment VirtualTags + ScriptedAlarms are
+    ///     unchanged.</para>
     /// </summary>
     /// <param name="unsAreas">The UNS areas.</param>
     /// <param name="unsLines">The UNS lines.</param>
@@ -366,15 +527,19 @@ public static class AddressSpaceComposer
             .Select(a => new ScriptedAlarmPlan(a.ScriptedAlarmId, a.EquipmentId, a.PredicateScriptId, a.MessageTemplate))
             .ToList();
 
-        // v3 DARK: no equipment-tag variable plans this batch (Batch 4 owns UNS↔Raw fan-out).
+        // v3: the retired equipment-namespace tag path stays empty — raw + UNS variable nodes now carry
+        // every value (see RawTags / UnsReferenceVariables below).
         var equipmentTags = Array.Empty<EquipmentTagPlan>();
 
-        // Per-equipment {{equip}}/<RefName> reference map (effectiveName → backing-tag RawPath), built
+        // The shared raw topology (RawPathResolver over the folder/driver/device/group ancestry + the
-        // from the equipment's UnsTagReferences + the raw tags + the raw topology via the shared
+        // container RawPath maps). One authority for the Raw subtree emit, the UNS backing RawPaths, and the
-        // RawPathResolver — the same identity authority the artifact-decode mirror + the draft validator
+        // {{equip}} reference map — so the three agree byte-for-byte on every RawPath.
-        // use, so the three agree byte-for-byte on the resolved RawPath.
+        var topology = RawTopology.Build(rawFolders, driverInstances, devices, tagGroups);
-        var referenceMapByEquip = BuildEquipmentReferenceMap(
+
-            unsTagReferences, tags, rawFolders, driverInstances, devices, tagGroups);
+        // Per-equipment {{equip}}/<RefName> reference map (effectiveName → backing-tag RawPath), built via
+        // the shared EquipmentReferenceMap over the SAME resolver — the same identity authority the
+        // artifact-decode mirror + the draft validator use.
+        var referenceMapByEquip = BuildEquipmentReferenceMap(unsTagReferences, tags, topology.Resolver);
         var emptyRefMap = (IReadOnlyDictionary<string, string>)
             new Dictionary<string, string>(StringComparer.Ordinal);
 
@@ -451,45 +616,38 @@ public static class AddressSpaceComposer
                 Enabled: a.Enabled));
         }
 
+        // Raw subtree (device-oriented) + UNS subtree (equipment-oriented) — the Batch-4 dual namespace.
+        var (rawContainers, rawTags) = BuildRawSubtree(
+            rawFolders, driverInstances, devices, tagGroups, tags, unsTagReferences,
+            unsAreas, unsLines, equipment, topology);
+        var unsReferenceVariables = BuildUnsReferenceVariables(
+            unsTagReferences, tags, unsAreas, unsLines, equipment, topology);
+
         return new AddressSpaceComposition(areas, lines, nodes, plans, alarms)
         {
             EquipmentTags = equipmentTags,
             EquipmentVirtualTags = equipmentVirtualTags,
             EquipmentScriptedAlarms = equipmentScriptedAlarms,
+            RawContainers = rawContainers,
+            RawTags = rawTags,
+            UnsReferenceVariables = unsReferenceVariables,
         };
     }
 
     /// <summary>Build the per-equipment <c>{{equip}}/&lt;RefName&gt;</c> reference map from the v3 entities
-    /// via the shared <see cref="EquipmentReferenceMap"/> + <see cref="RawPathResolver"/> — the entity-side
+    /// via the shared <see cref="EquipmentReferenceMap"/> over the SHARED <paramref name="resolver"/> — the
-    /// mirror of <c>DeploymentArtifact.BuildEquipmentReferenceMap</c> (JSON side). Empty when no references
+    /// entity-side mirror of <c>DeploymentArtifact.BuildEquipmentReferenceMap</c> (JSON side). Empty when no
-    /// are supplied (every test / earlier caller that omits the reference data).</summary>
+    /// references are supplied (every test / earlier caller that omits the reference data).</summary>
     private static IReadOnlyDictionary<string, IReadOnlyDictionary<string, string>> BuildEquipmentReferenceMap(
         IReadOnlyList<UnsTagReference>? unsTagReferences,
         IReadOnlyList<Tag>? tags,
-        IReadOnlyList<RawFolder>? rawFolders,
+        RawPathResolver resolver)
-        IReadOnlyList<DriverInstance> driverInstances,
-        IReadOnlyList<Device>? devices,
-        IReadOnlyList<TagGroup>? tagGroups)
     {
         var refs = unsTagReferences ?? Array.Empty<UnsTagReference>();
         var tagRows = tags ?? Array.Empty<Tag>();
         if (refs.Count == 0 || tagRows.Count == 0)
             return new Dictionary<string, IReadOnlyDictionary<string, string>>(StringComparer.Ordinal);
 
-        var folders = (rawFolders ?? Array.Empty<RawFolder>())
-            .GroupBy(f => f.RawFolderId, StringComparer.Ordinal)
-            .ToDictionary(g => g.Key, g => ((string?)g.First().ParentRawFolderId, g.First().Name), StringComparer.Ordinal);
-        var drivers = driverInstances
-            .GroupBy(d => d.DriverInstanceId, StringComparer.Ordinal)
-            .ToDictionary(g => g.Key, g => ((string?)g.First().RawFolderId, g.First().Name), StringComparer.Ordinal);
-        var deviceMap = (devices ?? Array.Empty<Device>())
-            .GroupBy(d => d.DeviceId, StringComparer.Ordinal)
-            .ToDictionary(g => g.Key, g => (g.First().DriverInstanceId, g.First().Name), StringComparer.Ordinal);
-        var groups = (tagGroups ?? Array.Empty<TagGroup>())
-            .GroupBy(t => t.TagGroupId, StringComparer.Ordinal)
-            .ToDictionary(g => g.Key, g => ((string?)g.First().ParentTagGroupId, g.First().Name), StringComparer.Ordinal);
-        var resolver = new RawPathResolver(folders, drivers, deviceMap, groups);
-
         var tagsById = tagRows
             .GroupBy(t => t.TagId, StringComparer.Ordinal)
             .ToDictionary(
@@ -503,4 +661,363 @@ public static class AddressSpaceComposer
             tagsById,
             resolver);
     }
+
+    /// <summary>
+    ///     Emit the Raw subtree: the container nodes (Folder→Driver→Device→TagGroup) as
+    ///     <c>Object</c>/<c>Folder</c> nodes, and the tag Variable nodes keyed <c>(realm=Raw, s=RawPath)</c>.
+    ///     A node whose RawPath cannot be resolved (broken/unknown ancestry, or an invalid segment) is
+    ///     SKIPPED rather than faulting the whole compose (mirrors <see cref="RawPathResolver"/>'s
+    ///     null-not-throw policy). Both lists are sorted by NodeId ordinal so a parent precedes each child.
+    /// </summary>
+    private static (IReadOnlyList<RawContainerNode> Containers, IReadOnlyList<RawTagPlan> Tags) BuildRawSubtree(
+        IReadOnlyList<RawFolder>? rawFolders,
+        IReadOnlyList<DriverInstance> driverInstances,
+        IReadOnlyList<Device>? devices,
+        IReadOnlyList<TagGroup>? tagGroups,
+        IReadOnlyList<Tag>? tags,
+        IReadOnlyList<UnsTagReference>? unsTagReferences,
+        IReadOnlyList<UnsArea> unsAreas,
+        IReadOnlyList<UnsLine> unsLines,
+        IReadOnlyList<Equipment> equipment,
+        RawTopology topology)
+    {
+        var containers = new List<RawContainerNode>();
+
+        foreach (var f in rawFolders ?? Array.Empty<RawFolder>())
+        {
+            if (!topology.FolderPaths.TryGetValue(f.RawFolderId, out var path)) continue;
+            var parent = f.ParentRawFolderId is not null
+                ? topology.FolderPaths.GetValueOrDefault(f.ParentRawFolderId)
+                : null;
+            containers.Add(new RawContainerNode(path, parent, f.Name, RawNodeKind.Folder));
+        }
+
+        foreach (var d in driverInstances)
+        {
+            if (!topology.DriverPaths.TryGetValue(d.DriverInstanceId, out var path)) continue;
+            var parent = d.RawFolderId is not null
+                ? topology.FolderPaths.GetValueOrDefault(d.RawFolderId)
+                : null;
+            containers.Add(new RawContainerNode(path, parent, d.Name, RawNodeKind.Driver));
+        }
+
+        foreach (var dev in devices ?? Array.Empty<Device>())
+        {
+            if (!topology.DevicePaths.TryGetValue(dev.DeviceId, out var path)) continue;
+            var parent = topology.DriverPaths.GetValueOrDefault(dev.DriverInstanceId);
+            containers.Add(new RawContainerNode(path, parent, dev.Name, RawNodeKind.Device));
+        }
+
+        foreach (var g in tagGroups ?? Array.Empty<TagGroup>())
+        {
+            if (!topology.GroupPaths.TryGetValue(g.TagGroupId, out var path)) continue;
+            var parent = g.ParentTagGroupId is not null
+                ? topology.GroupPaths.GetValueOrDefault(g.ParentTagGroupId)
+                : topology.DevicePaths.GetValueOrDefault(g.DeviceId);
+            containers.Add(new RawContainerNode(path, parent, g.Name, RawNodeKind.TagGroup));
+        }
+
+        // TagId → the set of referencing equipment UNS folder paths (Area/Line/Equipment), for the
+        // native-alarm multi-notifier. Distinct + ordinal-sorted for determinism.
+        var equipPathByTag = BuildReferencingEquipmentPathsByTag(unsTagReferences, unsAreas, unsLines, equipment);
+
+        var rawTags = new List<RawTagPlan>();
+        foreach (var t in tags ?? Array.Empty<Tag>())
+        {
+            var nodeId = topology.Resolver.TryBuildTagPath(t.DeviceId, t.TagGroupId, t.Name);
+            if (nodeId is null) continue;
+            var parent = t.TagGroupId is not null
+                ? topology.GroupPaths.GetValueOrDefault(t.TagGroupId)
+                : topology.DevicePaths.GetValueOrDefault(t.DeviceId);
+            var driverInstanceId = topology.DriverIdByDevice.GetValueOrDefault(t.DeviceId, string.Empty);
+            var intent = TagConfigIntent.Parse(t.TagConfig);
+            var alarm = intent.Alarm is { } a
+                ? new EquipmentTagAlarmInfo(a.AlarmType, a.Severity, a.HistorizeToAveva)
+                : null;
+            var refEquipPaths = equipPathByTag.GetValueOrDefault(t.TagId, Array.Empty<string>());
+
+            rawTags.Add(new RawTagPlan(
+                TagId: t.TagId,
+                NodeId: nodeId,
+                ParentNodeId: parent,
+                DriverInstanceId: driverInstanceId,
+                Name: t.Name,
+                DataType: t.DataType,
+                Writable: t.AccessLevel == TagAccessLevel.ReadWrite,
+                Alarm: alarm,
+                ReferencingEquipmentPaths: refEquipPaths,
+                IsHistorized: intent.IsHistorized,
+                HistorianTagname: intent.HistorianTagname,
+                IsArray: intent.IsArray,
+                ArrayLength: intent.ArrayLength));
+        }
+
+        containers.Sort((x, y) => string.CompareOrdinal(x.NodeId, y.NodeId));
+        rawTags.Sort((x, y) => string.CompareOrdinal(x.NodeId, y.NodeId));
+        return (containers, rawTags);
+    }
+
+    /// <summary>
+    ///     Emit the UNS reference Variables: one per <see cref="UnsTagReference"/> whose backing raw tag +
+    ///     equipment path resolve, keyed <c>(realm=Uns, s=Area/Line/Equipment/EffectiveName)</c> and carrying
+    ///     the backing RawPath (Organizes target + fan-out) plus the inherited DataType / writable. A
+    ///     reference whose backing tag is unknown, whose RawPath is unresolvable, or whose UNS path segments
+    ///     are invalid is SKIPPED. Sorted by NodeId ordinal.
+    /// </summary>
+    private static IReadOnlyList<UnsReferenceVariable> BuildUnsReferenceVariables(
+        IReadOnlyList<UnsTagReference>? unsTagReferences,
+        IReadOnlyList<Tag>? tags,
+        IReadOnlyList<UnsArea> unsAreas,
+        IReadOnlyList<UnsLine> unsLines,
+        IReadOnlyList<Equipment> equipment,
+        RawTopology topology)
+    {
+        var refs = unsTagReferences ?? Array.Empty<UnsTagReference>();
+        if (refs.Count == 0) return Array.Empty<UnsReferenceVariable>();
+
+        var tagsById = (tags ?? Array.Empty<Tag>())
+            .GroupBy(t => t.TagId, StringComparer.Ordinal)
+            .ToDictionary(g => g.Key, g => g.First(), StringComparer.Ordinal);
+        var equipFolderPath = BuildEquipmentFolderPaths(unsAreas, unsLines, equipment);
+
+        var vars = new List<UnsReferenceVariable>();
+        foreach (var r in refs.OrderBy(x => x.UnsTagReferenceId, StringComparer.Ordinal))
+        {
+            if (!tagsById.TryGetValue(r.TagId, out var tag)) continue;
+            if (!equipFolderPath.TryGetValue(r.EquipmentId, out var equipPath)) continue;
+            var rawPath = topology.Resolver.TryBuildTagPath(tag.DeviceId, tag.TagGroupId, tag.Name);
+            if (rawPath is null) continue;
+            var effectiveName = string.IsNullOrEmpty(r.DisplayNameOverride) ? tag.Name : r.DisplayNameOverride!;
+
+            string nodeId;
+            try
+            {
+                nodeId = V3NodeIds.UnsChild(equipPath, effectiveName);
+            }
+            catch (ArgumentException)
+            {
+                continue; // invalid effective-name segment — dropped (deploy gate rejects invalid names)
+            }
+
+            vars.Add(new UnsReferenceVariable(
+                UnsTagReferenceId: r.UnsTagReferenceId,
+                EquipmentId: r.EquipmentId,
+                NodeId: nodeId,
+                EffectiveName: effectiveName,
+                BackingRawPath: rawPath,
+                DataType: tag.DataType,
+                Writable: tag.AccessLevel == TagAccessLevel.ReadWrite));
+        }
+
+        vars.Sort((x, y) => string.CompareOrdinal(x.NodeId, y.NodeId));
+        return vars;
+    }
+
+    /// <summary>
+    ///     <c>EquipmentId → UNS folder path</c> (<c>Area/Line/Equipment</c>, slash-joined via
+    ///     <see cref="V3NodeIds"/>) for every equipment whose Area/Line ancestry resolves + whose three
+    ///     segments are valid. Equipment with a broken ancestry or an invalid segment is absent.
+    /// </summary>
+    private static IReadOnlyDictionary<string, string> BuildEquipmentFolderPaths(
+        IReadOnlyList<UnsArea> unsAreas,
+        IReadOnlyList<UnsLine> unsLines,
+        IReadOnlyList<Equipment> equipment)
+    {
+        var areaName = unsAreas
+            .GroupBy(a => a.UnsAreaId, StringComparer.Ordinal)
+            .ToDictionary(g => g.Key, g => g.First().Name, StringComparer.Ordinal);
+        var line = unsLines
+            .GroupBy(l => l.UnsLineId, StringComparer.Ordinal)
+            .ToDictionary(g => g.Key, g => (g.First().UnsAreaId, g.First().Name), StringComparer.Ordinal);
+
+        var byEquip = new Dictionary<string, string>(StringComparer.Ordinal);
+        foreach (var e in equipment)
+        {
+            if (!line.TryGetValue(e.UnsLineId, out var ln)) continue;
+            if (!areaName.TryGetValue(ln.UnsAreaId, out var aName)) continue;
+            try
+            {
+                byEquip[e.EquipmentId] = V3NodeIds.Uns(aName, ln.Name, e.Name);
+            }
+            catch (ArgumentException)
+            {
+                // invalid Area/Line/Equipment segment — dropped (deploy gate rejects invalid names).
+            }
+        }
+        return byEquip;
+    }
+
+    /// <summary>
+    ///     <c>TagId → distinct, ordinal-sorted list of referencing equipment UNS folder paths</c>
+    ///     (<c>Area/Line/Equipment</c>). Drives the native-alarm multi-notifier (WP4): the raw tag's single
+    ///     alarm condition fans one event to each referencing equipment's UNS folder. A tag with no
+    ///     resolvable reference is absent (⇒ an empty list at the call site).
+    /// </summary>
+    private static IReadOnlyDictionary<string, IReadOnlyList<string>> BuildReferencingEquipmentPathsByTag(
+        IReadOnlyList<UnsTagReference>? unsTagReferences,
+        IReadOnlyList<UnsArea> unsAreas,
+        IReadOnlyList<UnsLine> unsLines,
+        IReadOnlyList<Equipment> equipment)
+    {
+        var refs = unsTagReferences ?? Array.Empty<UnsTagReference>();
+        if (refs.Count == 0) return new Dictionary<string, IReadOnlyList<string>>(StringComparer.Ordinal);
+
+        var equipFolderPath = BuildEquipmentFolderPaths(unsAreas, unsLines, equipment);
+        var byTag = new Dictionary<string, SortedSet<string>>(StringComparer.Ordinal);
+        foreach (var r in refs)
+        {
+            if (!equipFolderPath.TryGetValue(r.EquipmentId, out var equipPath)) continue;
+            if (!byTag.TryGetValue(r.TagId, out var set))
+                byTag[r.TagId] = set = new SortedSet<string>(StringComparer.Ordinal);
+            set.Add(equipPath);
+        }
+        return byTag.ToDictionary(
+            kv => kv.Key,
+            kv => (IReadOnlyList<string>)kv.Value.ToList(),
+            StringComparer.Ordinal);
+    }
+
+    /// <summary>
+    ///     The shared Raw-tree topology: a <see cref="RawPathResolver"/> over the folder/driver/device/group
+    ///     ancestry plus the resolved container RawPath maps (memoised) + the device→driver id map. Built
+    ///     once per compose and reused for the Raw subtree, the UNS backing RawPaths, and the <c>{{equip}}</c>
+    ///     reference map so every RawPath is produced by the single authority.
+    /// </summary>
+    private sealed class RawTopology
+    {
+        public required RawPathResolver Resolver { get; init; }
+
+        /// <summary><c>RawFolderId → RawPath</c> (absent when the ancestry is broken).</summary>
+        public required IReadOnlyDictionary<string, string> FolderPaths { get; init; }
+
+        /// <summary><c>DriverInstanceId → RawPath</c> (absent when the ancestry is broken).</summary>
+        public required IReadOnlyDictionary<string, string> DriverPaths { get; init; }
+
+        /// <summary><c>DeviceId → RawPath</c> (absent when the ancestry is broken).</summary>
+        public required IReadOnlyDictionary<string, string> DevicePaths { get; init; }
+
+        /// <summary><c>TagGroupId → RawPath</c> (absent when the ancestry is broken).</summary>
+        public required IReadOnlyDictionary<string, string> GroupPaths { get; init; }
+
+        /// <summary><c>DeviceId → DriverInstanceId</c> — the raw tag's owning driver (for RawTagPlan).</summary>
+        public required IReadOnlyDictionary<string, string> DriverIdByDevice { get; init; }
+
+        public static RawTopology Build(
+            IReadOnlyList<RawFolder>? rawFolders,
+            IReadOnlyList<DriverInstance> driverInstances,
+            IReadOnlyList<Device>? devices,
+            IReadOnlyList<TagGroup>? tagGroups)
+        {
+            var folderRows = (rawFolders ?? Array.Empty<RawFolder>())
+                .GroupBy(f => f.RawFolderId, StringComparer.Ordinal)
+                .ToDictionary(g => g.Key, g => ((string?)g.First().ParentRawFolderId, g.First().Name), StringComparer.Ordinal);
+            var driverRows = driverInstances
+                .GroupBy(d => d.DriverInstanceId, StringComparer.Ordinal)
+                .ToDictionary(g => g.Key, g => ((string?)g.First().RawFolderId, g.First().Name), StringComparer.Ordinal);
+            var deviceRows = (devices ?? Array.Empty<Device>())
+                .GroupBy(d => d.DeviceId, StringComparer.Ordinal)
+                .ToDictionary(g => g.Key, g => (g.First().DriverInstanceId, g.First().Name), StringComparer.Ordinal);
+            var groupRows = (tagGroups ?? Array.Empty<TagGroup>())
+                .GroupBy(t => t.TagGroupId, StringComparer.Ordinal)
+                .ToDictionary(g => g.Key, g => ((string?)g.First().ParentTagGroupId, g.First().Name), StringComparer.Ordinal);
+
+            var resolver = new RawPathResolver(folderRows, driverRows, deviceRows, groupRows);
+
+            // Container RawPaths — reuse the resolver for driver prefix + memoise folder/device/group chains.
+            var folderPaths = new Dictionary<string, string>(StringComparer.Ordinal);
+            foreach (var id in folderRows.Keys)
+                ResolveFolder(id, folderRows, folderPaths, 0);
+
+            var driverPaths = new Dictionary<string, string>(StringComparer.Ordinal);
+            foreach (var id in driverRows.Keys)
+            {
+                var p = resolver.TryBuildDriverPrefix(id);
+                if (p is not null) driverPaths[id] = p;
+            }
+
+            var devicePaths = new Dictionary<string, string>(StringComparer.Ordinal);
+            foreach (var (id, dev) in deviceRows)
+            {
+                if (!driverPaths.TryGetValue(dev.DriverInstanceId, out var driverPrefix)) continue;
+                try { devicePaths[id] = RawPaths.Combine(driverPrefix, dev.Name); }
+                catch (ArgumentException) { /* invalid device name — dropped */ }
+            }
+
+            var groupPaths = new Dictionary<string, string>(StringComparer.Ordinal);
+            var groupDeviceById = (tagGroups ?? Array.Empty<TagGroup>())
+                .GroupBy(t => t.TagGroupId, StringComparer.Ordinal)
+                .ToDictionary(g => g.Key, g => g.First().DeviceId, StringComparer.Ordinal);
+            foreach (var id in groupRows.Keys)
+                ResolveGroup(id, groupRows, groupDeviceById, devicePaths, groupPaths, 0);
+
+            var driverIdByDevice = deviceRows.ToDictionary(kv => kv.Key, kv => kv.Value.DriverInstanceId, StringComparer.Ordinal);
+
+            return new RawTopology
+            {
+                Resolver = resolver,
+                FolderPaths = folderPaths,
+                DriverPaths = driverPaths,
+                DevicePaths = devicePaths,
+                GroupPaths = groupPaths,
+                DriverIdByDevice = driverIdByDevice,
+            };
+        }
+
+        private const int MaxDepth = 256;
+
+        private static string? ResolveFolder(
+            string id,
+            IReadOnlyDictionary<string, (string? ParentId, string Name)> rows,
+            Dictionary<string, string> memo,
+            int depth)
+        {
+            if (depth > MaxDepth) return null;
+            if (memo.TryGetValue(id, out var cached)) return cached;
+            if (!rows.TryGetValue(id, out var row)) return null;
+            var parentPath = row.ParentId is null ? null : ResolveFolder(row.ParentId, rows, memo, depth + 1);
+            if (row.ParentId is not null && parentPath is null) return null; // broken parent chain
+            try
+            {
+                var path = RawPaths.Combine(parentPath, row.Name);
+                memo[id] = path;
+                return path;
+            }
+            catch (ArgumentException) { return null; }
+        }
+
+        private static string? ResolveGroup(
+            string id,
+            IReadOnlyDictionary<string, (string? ParentId, string Name)> rows,
+            IReadOnlyDictionary<string, string> groupDeviceById,
+            IReadOnlyDictionary<string, string> devicePaths,
+            Dictionary<string, string> memo,
+            int depth)
+        {
+            if (depth > MaxDepth) return null;
+            if (memo.TryGetValue(id, out var cached)) return cached;
+            if (!rows.TryGetValue(id, out var row)) return null;
+
+            string? parentPath;
+            if (row.ParentId is not null)
+            {
+                parentPath = ResolveGroup(row.ParentId, rows, groupDeviceById, devicePaths, memo, depth + 1);
+                if (parentPath is null) return null; // broken parent chain
+            }
+            else
+            {
+                // Root group: parent is the owning device's RawPath.
+                if (!groupDeviceById.TryGetValue(id, out var deviceId)
+                    || !devicePaths.TryGetValue(deviceId, out parentPath))
+                    return null;
+            }
+
+            try
+            {
+                var path = RawPaths.Combine(parentPath, row.Name);
+                memo[id] = path;
+                return path;
+            }
+            catch (ArgumentException) { return null; }
+        }
+    }
 }

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/AddressSpacePlan.cs

@@ -69,6 +69,46 @@ public sealed record AddressSpacePlan(
     /// </summary>
     public IReadOnlyList<FolderRename> RenamedFolders { get; init; } = Array.Empty<FolderRename>();
 
+    /// <summary>
+    ///     v3 Batch 4 — the Raw subtree's <b>container</b> diff (Folder/Driver/Device/TagGroup nodes),
+    ///     keyed by <see cref="RawContainerNode.NodeId"/> (the RawPath). A rename of any container changes
+    ///     its RawPath (and every descendant's), so it manifests as remove(old)+add(new) — an OPC UA NodeId
+    ///     is immutable identity. Init-only, defaulting empty, so existing construction sites compile
+    ///     unchanged (consistent with the EquipmentTag diff sets above).
+    /// </summary>
+    public IReadOnlyList<RawContainerNode> AddedRawContainers { get; init; } = Array.Empty<RawContainerNode>();
+    /// <inheritdoc cref="AddedRawContainers"/>
+    public IReadOnlyList<RawContainerNode> RemovedRawContainers { get; init; } = Array.Empty<RawContainerNode>();
+    /// <inheritdoc cref="AddedRawContainers"/>
+    public IReadOnlyList<RawContainerDelta> ChangedRawContainers { get; init; } = Array.Empty<RawContainerDelta>();
+
+    /// <summary>
+    ///     v3 Batch 4 — the Raw subtree's <b>tag</b> diff, keyed by <see cref="RawTagPlan.NodeId"/> (the
+    ///     RawPath). A raw tag <b>rename</b> changes its RawPath ⇒ remove(old NodeId)+add(new NodeId) here
+    ///     (the immutable-NodeId rule); an attribute-only edit (historize / writable / array / alarm) keeps
+    ///     the same NodeId ⇒ a <see cref="RawTagDelta"/>. Init-only, defaulting empty.
+    /// </summary>
+    public IReadOnlyList<RawTagPlan> AddedRawTags { get; init; } = Array.Empty<RawTagPlan>();
+    /// <inheritdoc cref="AddedRawTags"/>
+    public IReadOnlyList<RawTagPlan> RemovedRawTags { get; init; } = Array.Empty<RawTagPlan>();
+    /// <inheritdoc cref="AddedRawTags"/>
+    public IReadOnlyList<RawTagDelta> ChangedRawTags { get; init; } = Array.Empty<RawTagDelta>();
+
+    /// <summary>
+    ///     v3 Batch 4 — the UNS subtree's reference-Variable diff, keyed by
+    ///     <see cref="UnsReferenceVariable.UnsTagReferenceId"/> (the stable row id, NOT the NodeId). Keying on
+    ///     the row id is what makes a backing-raw-tag rename a <b>re-point</b> (same reference row, same
+    ///     effective name ⇒ same UNS NodeId, but <see cref="UnsReferenceVariable.BackingRawPath"/> — the
+    ///     <c>Organizes</c> target + fan-out source — moves) rather than a remove+add; and a
+    ///     display-name-override edit a <see cref="UnsReferenceDelta"/> (same row id, NodeId + effective name
+    ///     change) with NO raw-side change. Init-only, defaulting empty.
+    /// </summary>
+    public IReadOnlyList<UnsReferenceVariable> AddedUnsReferenceVariables { get; init; } = Array.Empty<UnsReferenceVariable>();
+    /// <inheritdoc cref="AddedUnsReferenceVariables"/>
+    public IReadOnlyList<UnsReferenceVariable> RemovedUnsReferenceVariables { get; init; } = Array.Empty<UnsReferenceVariable>();
+    /// <inheritdoc cref="AddedUnsReferenceVariables"/>
+    public IReadOnlyList<UnsReferenceDelta> ChangedUnsReferenceVariables { get; init; } = Array.Empty<UnsReferenceDelta>();
+
     /// <summary>Gets a value indicating whether the composition plan contains no changes.</summary>
     public bool IsEmpty =>
         AddedEquipment.Count == 0 && RemovedEquipment.Count == 0 && ChangedEquipment.Count == 0 &&
@@ -76,6 +116,9 @@ public sealed record AddressSpacePlan(
         AddedAlarms.Count == 0 && RemovedAlarms.Count == 0 && ChangedAlarms.Count == 0 &&
         AddedEquipmentTags.Count == 0 && RemovedEquipmentTags.Count == 0 && ChangedEquipmentTags.Count == 0 &&
         AddedEquipmentVirtualTags.Count == 0 && RemovedEquipmentVirtualTags.Count == 0 && ChangedEquipmentVirtualTags.Count == 0 &&
+        AddedRawContainers.Count == 0 && RemovedRawContainers.Count == 0 && ChangedRawContainers.Count == 0 &&
+        AddedRawTags.Count == 0 && RemovedRawTags.Count == 0 && ChangedRawTags.Count == 0 &&
+        AddedUnsReferenceVariables.Count == 0 && RemovedUnsReferenceVariables.Count == 0 && ChangedUnsReferenceVariables.Count == 0 &&
         RenamedFolders.Count == 0;
 
     public sealed record EquipmentDelta(EquipmentNode Previous, EquipmentNode Current);
@@ -84,6 +127,16 @@ public sealed record AddressSpacePlan(
     public sealed record EquipmentTagDelta(EquipmentTagPlan Previous, EquipmentTagPlan Current);
     public sealed record EquipmentVirtualTagDelta(EquipmentVirtualTagPlan Previous, EquipmentVirtualTagPlan Current);
 
+    /// <summary>A Raw container node present in both snapshots (same RawPath) with ≥1 differing field.</summary>
+    public sealed record RawContainerDelta(RawContainerNode Previous, RawContainerNode Current);
+    /// <summary>A Raw tag present in both snapshots (same RawPath) with ≥1 differing attribute (historize /
+    /// writable / array / alarm / referencing-equipment set). A rename is NOT a delta — it is remove+add.</summary>
+    public sealed record RawTagDelta(RawTagPlan Previous, RawTagPlan Current);
+    /// <summary>A UNS reference variable present in both snapshots (same UnsTagReferenceId) with ≥1 differing
+    /// field — a backing-tag re-point (<c>BackingRawPath</c> moved) or a display-name-override edit (NodeId +
+    /// effective name changed).</summary>
+    public sealed record UnsReferenceDelta(UnsReferenceVariable Previous, UnsReferenceVariable Current);
+
     /// <summary>One renamed UNS Area / Line folder: the stable folder
     /// <paramref name="FolderNodeId"/> (the area's <c>UnsAreaId</c> or line's <c>UnsLineId</c>, the exact
     /// NodeId <c>MaterialiseHierarchy</c> placed the folder at) and the <paramref name="NewDisplayName"/>
@@ -139,6 +192,32 @@ public static class AddressSpacePlanner
             t => t.VirtualTagId,
             (a, b) => new AddressSpacePlan.EquipmentVirtualTagDelta(a, b));
 
+        // Raw subtree — containers keyed by RawPath (NodeId). A rename changes the RawPath, so it surfaces
+        // as remove(old)+add(new) here (an OPC UA NodeId is immutable identity). Attribute-only container
+        // changes (none today — a container carries only DisplayName == leaf name, which lives in the
+        // RawPath) fall to Changed, kept for completeness / future fields.
+        var (addedRawContainers, removedRawContainers, changedRawContainers) = DiffById(
+            previous.RawContainers, next.RawContainers,
+            c => c.NodeId,
+            (a, b) => new AddressSpacePlan.RawContainerDelta(a, b));
+
+        // Raw subtree — tags keyed by RawPath (NodeId). A rename ⇒ remove(old NodeId)+add(new NodeId); an
+        // attribute-only edit (historize / writable / array / alarm) ⇒ Changed. RawTagPlan overrides record
+        // equality to compare ReferencingEquipmentPaths element-wise so a no-op redeploy diffs empty.
+        var (addedRawTags, removedRawTags, changedRawTags) = DiffById(
+            previous.RawTags, next.RawTags,
+            t => t.NodeId,
+            (a, b) => new AddressSpacePlan.RawTagDelta(a, b));
+
+        // UNS subtree — reference variables keyed by the STABLE UnsTagReferenceId (NOT the NodeId). Keying on
+        // the row id is what makes a backing-raw-tag rename a re-point (same row + effective name ⇒ same UNS
+        // NodeId, but BackingRawPath moves) rather than a remove+add, and a display-name-override edit a
+        // Changed delta (same row id, NodeId + effective name changed) with no raw-side entry.
+        var (addedUnsRefs, removedUnsRefs, changedUnsRefs) = DiffById(
+            previous.UnsReferenceVariables, next.UnsReferenceVariables,
+            v => v.UnsTagReferenceId,
+            (a, b) => new AddressSpacePlan.UnsReferenceDelta(a, b));
+
         // UNS Area / Line renames: a folder whose stable id is unchanged but whose
         // DisplayName differs. Diffed by stable id (UnsAreaId / UnsLineId) so an Area/Line whose ONLY
         // change is its friendly name is no longer a silent no-op at the IsEmpty gate. The folder NodeId
@@ -159,6 +238,15 @@ public static class AddressSpacePlanner
             AddedEquipmentVirtualTags = addedVTags,
             RemovedEquipmentVirtualTags = removedVTags,
             ChangedEquipmentVirtualTags = changedVTags,
+            AddedRawContainers = addedRawContainers,
+            RemovedRawContainers = removedRawContainers,
+            ChangedRawContainers = changedRawContainers,
+            AddedRawTags = addedRawTags,
+            RemovedRawTags = removedRawTags,
+            ChangedRawTags = changedRawTags,
+            AddedUnsReferenceVariables = addedUnsRefs,
+            RemovedUnsReferenceVariables = removedUnsRefs,
+            ChangedUnsReferenceVariables = changedUnsRefs,
             RenamedFolders = renamedFolders,
         };
     }

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/SdkAddressSpaceSink.cs

@@ -21,48 +21,56 @@ public sealed class SdkAddressSpaceSink : IOpcUaAddressSpaceSink, ISurgicalAddre
     }
 
     /// <inheritdoc />
-    public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc)
+    public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm)
-        => _nodeManager.WriteValue(nodeId, value, quality, sourceTimestampUtc);
+        => _nodeManager.WriteValue(nodeId, value, quality, sourceTimestampUtc, realm);
 
     /// <inheritdoc />
-    public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
+    public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm)
-        => _nodeManager.WriteAlarmCondition(alarmNodeId, state, sourceTimestampUtc);
+        => _nodeManager.WriteAlarmCondition(alarmNodeId, state, sourceTimestampUtc, realm);
 
     /// <inheritdoc />
-    public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false)
+    public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false)
-        => _nodeManager.MaterialiseAlarmCondition(alarmNodeId, equipmentNodeId, displayName, alarmType, severity, isNative);
+        => _nodeManager.MaterialiseAlarmCondition(alarmNodeId, equipmentNodeId, displayName, alarmType, severity, realm, isNative);
 
     /// <inheritdoc />
-    public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
+    public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm)
-        => _nodeManager.EnsureFolder(folderNodeId, parentNodeId, displayName);
+        => _nodeManager.WireAlarmNotifiers(alarmNodeId, alarmRealm, notifierFolderNodeIds, notifierFolderRealm);
 
     /// <inheritdoc />
-    public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+    public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm)
-        => _nodeManager.EnsureVariable(variableNodeId, parentFolderNodeId, displayName, dataType, writable, historianTagname, isArray, arrayLength);
+        => _nodeManager.EnsureFolder(folderNodeId, parentNodeId, displayName, realm);
 
     /// <inheritdoc />
-    public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
+    public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
-        => _nodeManager.UpdateTagAttributes(variableNodeId, writable, historianTagname, dataType, isArray, arrayLength);
+        => _nodeManager.EnsureVariable(variableNodeId, parentFolderNodeId, displayName, dataType, writable, realm, historianTagname, isArray, arrayLength);
 
     /// <inheritdoc />
-    public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+    public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength, AddressSpaceRealm realm)
-        => _nodeManager.UpdateFolderDisplayName(folderNodeId, displayName);
+        => _nodeManager.UpdateTagAttributes(variableNodeId, writable, historianTagname, dataType, isArray, arrayLength, realm);
 
     /// <inheritdoc />
-    public bool RemoveVariableNode(string variableNodeId)
+    public bool UpdateFolderDisplayName(string folderNodeId, string displayName, AddressSpaceRealm realm)
-        => _nodeManager.RemoveVariableNode(variableNodeId);
+        => _nodeManager.UpdateFolderDisplayName(folderNodeId, displayName, realm);
 
     /// <inheritdoc />
-    public bool RemoveAlarmConditionNode(string alarmNodeId)
+    public bool RemoveVariableNode(string variableNodeId, AddressSpaceRealm realm)
-        => _nodeManager.RemoveAlarmConditionNode(alarmNodeId);
+        => _nodeManager.RemoveVariableNode(variableNodeId, realm);
 
     /// <inheritdoc />
-    public bool RemoveEquipmentSubtree(string equipmentNodeId)
+    public bool RemoveAlarmConditionNode(string alarmNodeId, AddressSpaceRealm realm)
-        => _nodeManager.RemoveEquipmentSubtree(equipmentNodeId);
+        => _nodeManager.RemoveAlarmConditionNode(alarmNodeId, realm);
+
+    /// <inheritdoc />
+    public bool RemoveEquipmentSubtree(string equipmentNodeId, AddressSpaceRealm realm)
+        => _nodeManager.RemoveEquipmentSubtree(equipmentNodeId, realm);
 
     /// <inheritdoc />
     public void RebuildAddressSpace() => _nodeManager.RebuildAddressSpace();
 
     /// <inheritdoc />
-    public void RaiseNodesAddedModelChange(string affectedNodeId) => _nodeManager.RaiseNodesAddedModelChange(affectedNodeId);
+    public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm) => _nodeManager.RaiseNodesAddedModelChange(affectedNodeId, realm);
+
+    /// <inheritdoc />
+    public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes")
+        => _nodeManager.AddReference(sourceNodeId, sourceRealm, targetNodeId, targetRealm, referenceType);
 }

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/ActorNodeWriteGateway.cs

@@ -43,7 +43,7 @@ public sealed class ActorNodeWriteGateway : IOpcUaNodeWriteGateway
     }
 
     /// <inheritdoc />
-    public async Task<NodeWriteOutcome> WriteAsync(string nodeId, object? value, CancellationToken ct)
+    public async Task<NodeWriteOutcome> WriteAsync(string nodeId, object? value, AddressSpaceRealm realm, CancellationToken ct)
     {
         var driverHost = _resolveDriverHost();
         if (driverHost is null)
@@ -55,7 +55,7 @@ public sealed class ActorNodeWriteGateway : IOpcUaNodeWriteGateway
         try
         {
             var result = await driverHost.Ask<DriverHostActor.NodeWriteResult>(
-                new DriverHostActor.RouteNodeWrite(nodeId, value), _askTimeout, ct).ConfigureAwait(false);
+                new DriverHostActor.RouteNodeWrite(nodeId, value, realm), _askTimeout, ct).ConfigureAwait(false);
             if (!result.Success)
                 _logger.LogWarning("Operator write to {NodeId} rejected: {Reason}", nodeId, result.Reason);
             return new NodeWriteOutcome(result.Success, result.Reason);

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DeploymentArtifact.cs

@@ -1,6 +1,7 @@
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using ZB.MOM.WW.OtOpcUa.Commons.Types;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.OpcUaServer;
@@ -253,6 +254,142 @@ public static class DeploymentArtifact
         return EquipmentReferenceMap.Build(references, tagsById, resolver);
     }
 
+    /// <summary>
+    ///     v3 Batch 4 — reconstruct the raw/UNS <b>entities</b> from the artifact JSON and drive the pure
+    ///     <see cref="AddressSpaceComposer.Compose"/>, returning ONLY the three dual-namespace lists
+    ///     (<see cref="AddressSpaceComposition.RawContainers"/> / <see cref="AddressSpaceComposition.RawTags"/> /
+    ///     <see cref="AddressSpaceComposition.UnsReferenceVariables"/>). Reusing the composer verbatim is what
+    ///     guarantees BYTE-PARITY between the live-edit compose seam and this artifact-decode seam — the same
+    ///     <c>RawPathResolver</c> / <c>RawPaths</c> / <c>TagConfigIntent</c> / <c>V3NodeIds</c> authorities
+    ///     produce every RawPath, UNS NodeId, and Organizes backing path. Enums serialize numerically in the
+    ///     artifact (no <c>JsonStringEnumConverter</c>), so <c>AccessLevel</c> is read as an int.
+    /// </summary>
+    /// <param name="root">The artifact root element.</param>
+    /// <returns>The Raw containers, Raw tags, and UNS reference variables.</returns>
+    private static (IReadOnlyList<RawContainerNode> Containers, IReadOnlyList<RawTagPlan> Tags, IReadOnlyList<UnsReferenceVariable> UnsRefs)
+        BuildRawAndUnsSubtrees(JsonElement root)
+    {
+        var rawFolders = new List<RawFolder>();
+        foreach (var el in EnumerateArray(root, "RawFolders"))
+        {
+            var id = ReadString(el, "RawFolderId");
+            if (string.IsNullOrWhiteSpace(id)) continue;
+            rawFolders.Add(new RawFolder
+            {
+                RawFolderId = id!, ParentRawFolderId = ReadNullableString(el, "ParentRawFolderId"),
+                Name = ReadString(el, "Name") ?? id!, ClusterId = ReadString(el, "ClusterId") ?? string.Empty,
+            });
+        }
+
+        var driverInstances = new List<DriverInstance>();
+        foreach (var el in EnumerateArray(root, "DriverInstances"))
+        {
+            var id = ReadString(el, "DriverInstanceId");
+            if (string.IsNullOrWhiteSpace(id)) continue;
+            driverInstances.Add(new DriverInstance
+            {
+                DriverInstanceId = id!, RawFolderId = ReadNullableString(el, "RawFolderId"),
+                Name = ReadString(el, "Name") ?? id!, DriverType = ReadString(el, "DriverType") ?? string.Empty,
+                DriverConfig = ReadString(el, "DriverConfig") ?? "{}", ClusterId = ReadString(el, "ClusterId") ?? string.Empty,
+            });
+        }
+
+        var devices = new List<Device>();
+        foreach (var el in EnumerateArray(root, "Devices"))
+        {
+            var id = ReadString(el, "DeviceId");
+            var di = ReadString(el, "DriverInstanceId");
+            if (string.IsNullOrWhiteSpace(id) || string.IsNullOrWhiteSpace(di)) continue;
+            devices.Add(new Device
+            {
+                DeviceId = id!, DriverInstanceId = di!, Name = ReadString(el, "Name") ?? id!,
+                DeviceConfig = ReadString(el, "DeviceConfig") ?? "{}",
+            });
+        }
+
+        var tagGroups = new List<TagGroup>();
+        foreach (var el in EnumerateArray(root, "TagGroups"))
+        {
+            var id = ReadString(el, "TagGroupId");
+            if (string.IsNullOrWhiteSpace(id)) continue;
+            tagGroups.Add(new TagGroup
+            {
+                TagGroupId = id!, ParentTagGroupId = ReadNullableString(el, "ParentTagGroupId"),
+                DeviceId = ReadString(el, "DeviceId") ?? string.Empty, Name = ReadString(el, "Name") ?? id!,
+            });
+        }
+
+        var tags = new List<Tag>();
+        foreach (var el in EnumerateArray(root, "Tags"))
+        {
+            var id = ReadString(el, "TagId");
+            var deviceId = ReadString(el, "DeviceId");
+            var name = ReadString(el, "Name");
+            if (string.IsNullOrWhiteSpace(id) || string.IsNullOrWhiteSpace(deviceId) || string.IsNullOrWhiteSpace(name)) continue;
+            var accessLevel = el.TryGetProperty("AccessLevel", out var alEl) && alEl.ValueKind == JsonValueKind.Number
+                ? (TagAccessLevel)alEl.GetInt32() : TagAccessLevel.Read;
+            var tagConfig = el.TryGetProperty("TagConfig", out var tcEl) && tcEl.ValueKind == JsonValueKind.String
+                ? tcEl.GetString() ?? "{}" : "{}";
+            tags.Add(new Tag
+            {
+                TagId = id!, DeviceId = deviceId!, TagGroupId = ReadNullableString(el, "TagGroupId"),
+                Name = name!, DataType = ReadString(el, "DataType") ?? "Float",
+                AccessLevel = accessLevel, TagConfig = tagConfig,
+            });
+        }
+
+        var unsTagReferences = new List<UnsTagReference>();
+        foreach (var el in EnumerateArray(root, "UnsTagReferences"))
+        {
+            var id = ReadString(el, "UnsTagReferenceId");
+            var equipmentId = ReadString(el, "EquipmentId");
+            var tagId = ReadString(el, "TagId");
+            if (string.IsNullOrWhiteSpace(id) || string.IsNullOrWhiteSpace(equipmentId) || string.IsNullOrWhiteSpace(tagId)) continue;
+            unsTagReferences.Add(new UnsTagReference
+            {
+                UnsTagReferenceId = id!, EquipmentId = equipmentId!, TagId = tagId!,
+                DisplayNameOverride = ReadNullableString(el, "DisplayNameOverride"),
+            });
+        }
+
+        var unsAreas = new List<UnsArea>();
+        foreach (var el in EnumerateArray(root, "UnsAreas"))
+        {
+            var id = ReadString(el, "UnsAreaId");
+            if (string.IsNullOrWhiteSpace(id)) continue;
+            unsAreas.Add(new UnsArea { UnsAreaId = id!, Name = ReadString(el, "Name") ?? id!, ClusterId = ReadString(el, "ClusterId") ?? string.Empty });
+        }
+
+        var unsLines = new List<UnsLine>();
+        foreach (var el in EnumerateArray(root, "UnsLines"))
+        {
+            var id = ReadString(el, "UnsLineId");
+            if (string.IsNullOrWhiteSpace(id)) continue;
+            unsLines.Add(new UnsLine { UnsLineId = id!, UnsAreaId = ReadString(el, "UnsAreaId") ?? string.Empty, Name = ReadString(el, "Name") ?? id! });
+        }
+
+        var equipment = new List<Equipment>();
+        foreach (var el in EnumerateArray(root, "Equipment"))
+        {
+            var id = ReadString(el, "EquipmentId");
+            if (string.IsNullOrWhiteSpace(id)) continue;
+            equipment.Add(new Equipment
+            {
+                EquipmentId = id!, UnsLineId = ReadString(el, "UnsLineId") ?? string.Empty,
+                Name = ReadString(el, "Name") ?? id!,
+                // MachineCode is a required member but is not used by the raw/UNS compose path (it drives no
+                // NodeId); read it when present, else a placeholder so the object initializer is satisfied.
+                MachineCode = ReadString(el, "MachineCode") ?? id!,
+            });
+        }
+
+        var composition = AddressSpaceComposer.Compose(
+            unsAreas, unsLines, equipment, driverInstances, Array.Empty<ScriptedAlarm>(),
+            unsTagReferences: unsTagReferences, tags: tags,
+            rawFolders: rawFolders, devices: devices, tagGroups: tagGroups);
+        return (composition.RawContainers, composition.RawTags, composition.UnsReferenceVariables);
+    }
+
     /// <summary>Build the <c>scriptId → SourceCode</c> map from the artifact's <c>Scripts</c> array (mirrors
     /// the VirtualTag plan builder's join). Empty when the artifact carries no Scripts.</summary>
     private static Dictionary<string, string> BuildScriptSourceMap(JsonElement root)
@@ -482,11 +619,21 @@ public static class DeploymentArtifact
             var equipmentVirtualTags = BuildEquipmentVirtualTagPlans(root, referenceMapByEquip);
             var equipmentScriptedAlarms = BuildEquipmentScriptedAlarmPlans(root, referenceMapByEquip);
 
+            // v3 Batch 4 — the Raw device subtree + UNS reference variables. Built by reconstructing the raw/UNS
+            // entities from the artifact JSON and driving the SAME pure AddressSpaceComposer the live-edit side
+            // uses, so the artifact-decode seam is BYTE-PARITY with the composer (identical RawPaths, identical
+            // UNS NodeIds, identical Organizes backing paths). Only the three dual-namespace lists are taken from
+            // the composer result; the (already byte-parity) folder/vtag/alarm plans above are kept as-is.
+            var (rawContainers, rawTags, unsReferenceVariables) = BuildRawAndUnsSubtrees(root);
+
             return new AddressSpaceComposition(areas, lines, equipment, drivers, alarms)
             {
                 EquipmentTags = equipmentTags,
                 EquipmentVirtualTags = equipmentVirtualTags,
                 EquipmentScriptedAlarms = equipmentScriptedAlarms,
+                RawContainers = rawContainers,
+                RawTags = rawTags,
+                UnsReferenceVariables = unsReferenceVariables,
             };
         }
         catch (JsonException)
@@ -548,6 +695,13 @@ public static class DeploymentArtifact
             EquipmentTags = full.EquipmentTags.Where(t => sets.DriverIds.Contains(t.DriverInstanceId)).ToArray(),
             EquipmentVirtualTags = full.EquipmentVirtualTags.Where(v => sets.EquipmentIds.Contains(v.EquipmentId)).ToArray(),
             EquipmentScriptedAlarms = full.EquipmentScriptedAlarms.Where(a => sets.EquipmentIds.Contains(a.EquipmentId)).ToArray(),
+            // v3 Batch 4: raw tags scope by their owning driver's cluster; UNS references by their equipment's
+            // cluster. Raw CONTAINER nodes carry no driver id, so they are kept in full — an out-of-cluster
+            // folder/driver/device/group node materialises only as an empty browse folder (harmless), while every
+            // raw VALUE + UNS reference node is correctly cluster-scoped.
+            RawContainers = full.RawContainers,
+            RawTags = full.RawTags.Where(t => sets.DriverIds.Contains(t.DriverInstanceId)).ToArray(),
+            UnsReferenceVariables = full.UnsReferenceVariables.Where(v => sets.EquipmentIds.Contains(v.EquipmentId)).ToArray(),
         };
     }
 

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DiscoveredNodeMapper.cs

@@ -1,4 +1,5 @@
 using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.OpcUaServer;
 
@@ -36,8 +37,12 @@ public static class DiscoveredNodeMapper
     /// </param>
     /// <returns>The folders, variables, and routing map to apply against the OPC UA address space.</returns>
     public static DiscoveredInjectionPlan Map(
-        string equipmentId, IReadOnlyList<DiscoveredNode> nodes, IReadOnlySet<string> authoredRefs)
+        string rootNodeId, IReadOnlyList<DiscoveredNode> nodes, IReadOnlySet<string> authoredRefs)
     {
+        // v3 Batch 4: discovered nodes graft onto the RAW device subtree — a discovered node's NodeId is
+        // <rootDevicePath>/<folder…>/<name> (slash-joined RawPath), NOT the retired equipment-scoped
+        // {equipmentId}/{folderPath}/{name}. Root-relative combine (the root is an already-built RawPath).
+        static string Combine(string root, string tail) => root + RawPaths.SeparatorString + tail;
         var kept = nodes.Where(n => !authoredRefs.Contains(n.FullReference)).ToList();
 
         // Device-folder collapse: when every kept node shares one identical index-1 segment (the single
@@ -64,20 +69,20 @@ public static class DiscoveredNodeMapper
             for (var i = 0; i < segs.Count; i++)
             {
                 var folderPath = string.Join('/', segs.Take(i + 1));
-                var nodeId = EquipmentNodeIds.SubFolder(equipmentId, folderPath);
+                var nodeId = Combine(rootNodeId, folderPath);
                 if (folders.ContainsKey(nodeId)) continue;
-                var parent = i == 0 ? equipmentId : EquipmentNodeIds.SubFolder(equipmentId, string.Join('/', segs.Take(i)));
+                var parent = i == 0 ? rootNodeId : Combine(rootNodeId, string.Join('/', segs.Take(i)));
                 folders[nodeId] = new DiscoveredFolder(nodeId, parent, segs[i]);
             }
 
             var varFolderPath = string.Join('/', segs);
-            var varNodeId = EquipmentNodeIds.Variable(equipmentId, varFolderPath, n.BrowseName);
+            var varNodeId = string.IsNullOrEmpty(varFolderPath)
-            // Mirror AddressSpaceApplier.MaterialiseEquipmentTags: a folder-less variable parents directly
+                ? Combine(rootNodeId, n.BrowseName)
-            // at the equipment (SubFolder("", ...) would yield a trailing-slash "EQ-1/" that mismatches the
+                : Combine(rootNodeId, varFolderPath + RawPaths.SeparatorString + n.BrowseName);
-            // EquipmentNodeIds.Variable NodeId, which guards IsNullOrWhiteSpace).
+            // A folder-less variable parents directly at the root device node.
             var varParent = string.IsNullOrEmpty(varFolderPath)
-                ? equipmentId
+                ? rootNodeId
-                : EquipmentNodeIds.SubFolder(equipmentId, varFolderPath);
+                : Combine(rootNodeId, varFolderPath);
             variables.Add(new DiscoveredVariable(
                 varNodeId, varParent, n.DisplayName, ToBuiltinTypeString(n.DataType), n.Writable, n.IsArray, n.ArrayDim));
             routing[n.FullReference] = varNodeId;

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Drivers/DriverHostActor.cs

@@ -111,34 +111,46 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     // spawn so a restart's respawn never collides with the still-terminating old child.
     private long _childSpawnGeneration;
 
-    /// <summary>
+    /// <summary>A materialised NodeId together with the v3 <see cref="AddressSpaceRealm"/> it lives in, so the
-    ///     Driver live-value routing map: <c>(DriverInstanceId, FullName) → folder-scoped equipment
+    /// driver value fan-out posts each update to the sink with the right namespace. The same driver ref fans
-    ///     NodeId(s)</c>. Rebuilt every apply by <see cref="PushDesiredSubscriptions"/> from the
+    /// to its raw node (<see cref="AddressSpaceRealm.Raw"/>) and to every referencing UNS node
-    ///     composition's <c>EquipmentTags</c> (mirroring <c>VirtualTagHostActor._nodeIdByVtag</c>), and
+    /// (<see cref="AddressSpaceRealm.Uns"/>).</summary>
-    ///     resolved in <see cref="ForwardToMux"/> so a driver value published by wire-ref FullName lands
+    private readonly record struct NodeRealmRef(string NodeId, AddressSpaceRealm Realm);
-    ///     on the variable's actual folder-scoped NodeId. A set because the same driver ref can back
-    ///     several equipment variables (e.g. identical machines sharing a register), and the per-apply
-    ///     rebuild dedups by NodeId.
-    /// </summary>
-    private readonly Dictionary<(string DriverInstanceId, string RawPath), HashSet<string>> _nodeIdByDriverRef = new();
 
     /// <summary>
-    ///     Inverse of <see cref="_nodeIdByDriverRef"/>: <c>folder-scoped equipment NodeId →
+    ///     Driver live-value routing map: <c>(DriverInstanceId, RawPath) → materialised NodeId(s) (realm-tagged)</c>.
-    ///     (DriverInstanceId, FullName)</c>. Rebuilt every apply by <see cref="PushDesiredSubscriptions"/>
+    ///     Rebuilt every apply by <see cref="PushDesiredSubscriptions"/> from the composition's <c>RawTags</c>
-    ///     from the same <c>EquipmentTags</c> pass, and resolved by <see cref="HandleRouteNodeWrite"/> so an
+    ///     ∪ <c>UnsReferenceVariables</c>, and resolved in <see cref="ForwardToMux"/> so a driver value
-    ///     inbound operator write targeting an equipment variable's NodeId is forwarded to the owning
+    ///     published by wire-ref RawPath fans to its raw node AND every referencing UNS node with identical
-    ///     driver child as a write of its wire-ref <c>FullName</c>. Each NodeId maps to exactly one driver
+    ///     value/quality/timestamp — the single-source-fan-out (no independent buffer, so no drift). A set
-    ///     ref (a variable is backed by a single driver attribute), so this is a flat 1:1 map (the forward
+    ///     because one driver ref can back the raw node plus N UNS references; the per-apply rebuild dedups.
-    ///     map fans out 1:N because one ref can back several variables).
     /// </summary>
-    private readonly Dictionary<string, (string DriverInstanceId, string RawPath)> _driverRefByNodeId =
+    private readonly Dictionary<(string DriverInstanceId, string RawPath), HashSet<NodeRealmRef>> _nodeIdByDriverRef = new();
-        new(StringComparer.Ordinal);
 
-    /// <summary>(DriverInstanceId, FullName = alarm ConditionId / AlarmFullReference) → folder-scoped condition NodeId(s).
+    /// <summary>
-    /// Built from EquipmentTags whose plan carries Alarm, alongside the value maps; resolves a native
+    ///     Inverse of <see cref="_nodeIdByDriverRef"/>: <c>(Realm, BARE <c>s=</c> id) → (DriverInstanceId,
-    /// alarm transition to the materialised Part 9 condition node(s). Alarm tags are conditions, not
+    ///     RawPath)</c>. v3 Batch 4: keyed by BOTH the raw NodeId (<see cref="AddressSpaceRealm.Raw"/>) AND every
-    /// value variables, so they are kept OUT of the value maps + value-subscription set.</summary>
+    ///     referencing UNS NodeId (<see cref="AddressSpaceRealm.Uns"/>) — all mapping to the same driver ref
-    private readonly Dictionary<(string DriverInstanceId, string RawPath), HashSet<string>> _alarmNodeIdByDriverRef = new();
+    ///     (the single value source). Rebuilt every apply by <see cref="PushDesiredSubscriptions"/> from the
+    ///     composition's <c>RawTags</c> ∪ <c>UnsReferenceVariables</c>, and resolved by
+    ///     <see cref="HandleRouteNodeWrite"/> so an inbound operator write to EITHER NodeId is forwarded to the
+    ///     owning driver child as a write of its wire-ref RawPath.
+    ///     <para><b>The realm is part of the key</b> (Wave B review H1): a raw <c>s=&lt;RawPath&gt;</c> and a UNS
+    ///     <c>s=&lt;Area/Line/Equip/Eff&gt;</c> can collide as bare strings (folder/driver/device names and
+    ///     Area/Line/Equip names are independent), so a bare-only key would let a colliding raw + UNS pair route
+    ///     to the WRONG driver ref (last-writer-wins). The node manager's write hook passes the full
+    ///     ns-qualified id PLUS the realm it resolved (<c>RealmOf</c>); <see cref="HandleRouteNodeWrite"/>
+    ///     normalises the id to the bare form and looks up <c>(realm, bareId)</c>, preserving exactly the
+    ///     namespace disambiguation the ns-qualified id carries.</para>
+    /// </summary>
+    private readonly Dictionary<(AddressSpaceRealm Realm, string NodeId), (string DriverInstanceId, string RawPath)> _driverRefByNodeId = new();
+
+    /// <summary>(DriverInstanceId, RawPath = alarm ConditionId) → materialised condition NodeId(s) (realm-tagged).
+    /// v3 Batch 4: a native alarm is a single condition at the RawPath (Raw realm); WP4 adds the referencing
+    /// equipment notifier NodeIds. Resolves a native alarm transition to the materialised Part 9 condition
+    /// node(s). Alarm tags are conditions, not value variables, so they are kept OUT of the value maps +
+    /// value-subscription set.</summary>
+    private readonly Dictionary<(string DriverInstanceId, string RawPath), HashSet<NodeRealmRef>> _alarmNodeIdByDriverRef = new();
 
     /// <summary>
     ///     Inverse of <see cref="_alarmNodeIdByDriverRef"/>: <c>folder-scoped condition NodeId →
@@ -159,7 +171,7 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// <c>TagConfig.alarm.historizeToAveva</c>; it is threaded onto the transition so the
     /// HistorianAdapterActor's <c>is not false</c> gate suppresses the durable AVEVA row only on an
     /// explicit false (mirroring the scripted-alarm opt-out).</summary>
-    private readonly Dictionary<string, (string EquipmentId, string Name, string AlarmType, bool? HistorizeToAveva)> _alarmMetaByNodeId =
+    private readonly Dictionary<string, (string EquipmentId, string Name, string AlarmType, bool? HistorizeToAveva, IReadOnlyList<string> ReferencingEquipmentPaths)> _alarmMetaByNodeId =
         new(StringComparer.Ordinal);
 
     /// <summary>Derives a full Part 9 condition snapshot from each native alarm transition delta,
@@ -232,7 +244,7 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// </summary>
     /// <param name="NodeId">The folder-scoped equipment-variable NodeId the operator wrote to.</param>
     /// <param name="Value">The value to write (the driver coerces it to the attribute's data type).</param>
-    public sealed record RouteNodeWrite(string NodeId, object? Value);
+    public sealed record RouteNodeWrite(string NodeId, object? Value, AddressSpaceRealm Realm);
 
     /// <summary>Reply to <see cref="RouteNodeWrite"/>: the outcome of forwarding the write to the driver
     /// (or a gate/lookup failure that never reached the driver).</summary>
@@ -620,13 +632,15 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
         // equipment variables (identical machines sharing a register), hence the fan-out.
         if (_nodeIdByDriverRef.TryGetValue((msg.DriverInstanceId, msg.FullReference), out var nodeIds))
         {
-            foreach (var nodeId in nodeIds)
+            // v3 Batch 4 single-source fan-out: one driver publish for a RawPath lands on the raw NodeId AND
+            // every referencing UNS NodeId, each with its realm, carrying IDENTICAL value/quality/timestamp.
+            foreach (var n in nodeIds)
                 _opcUaPublishActor.Tell(new ZB.MOM.WW.OtOpcUa.Runtime.OpcUa.OpcUaPublishActor.AttributeValueUpdate(
-                    nodeId, msg.Value, msg.Quality, msg.TimestampUtc));
+                    n.NodeId, msg.Value, msg.Quality, msg.TimestampUtc, n.Realm));
         }
         else
         {
-            _log.Debug("DriverHost {Node}: no equipment-tag NodeId for ({Driver},{Ref}) — value dropped",
+            _log.Debug("DriverHost {Node}: no bound NodeId for ({Driver},{Ref}) — value dropped",
                 _localNode, msg.DriverInstanceId, msg.FullReference);
         }
     }
@@ -643,6 +657,21 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
     /// </summary>
     private void HandleDiscoveredNodes(DriverInstanceActor.DiscoveredNodesReady msg)
     {
+        // v3 Batch 4 (review M1): discovered-node INJECTION is DORMANT in v3 and hard-guarded here. In v2 a
+        // driver-connected FixedTree was grafted under an equipment folder (equipment bound a driver); v3
+        // retired that binding — equipment references raw tags via UnsTagReference, and discovered raw tags are
+        // authored explicitly through the Batch-2 /raw browse-commit flow, NOT injected at runtime. The
+        // downstream mapper/materialiser were half-migrated to the Raw tree but are still rooted at an
+        // equipment id, so letting this fire would materialise incoherent nodes. Short-circuit BEFORE any
+        // caching/routing so _discoveredByDriver stays empty (the redeploy re-inject tail is therefore inert
+        // too) and there is exactly one enforcement point. Re-migrating injection onto the raw device subtree
+        // is a separate follow-up.
+        _log.Debug(
+            "DriverHost {Node}: discovered-node injection is dormant in v3 (DiscoveredNodesReady from {Driver} ignored; discovered raw tags are authored via /raw browse-commit)",
+            _localNode, msg.DriverInstanceId);
+        return;
+
+#pragma warning disable CS0162 // Unreachable code — retained for the raw-subtree re-migration follow-up.
         if (_lastComposition is null)
         {
             _log.Debug("DriverHost {Node}: DiscoveredNodesReady from {Driver} before any composition applied — ignored",
@@ -717,6 +746,7 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
 
         _discoveredByDriver[msg.DriverInstanceId] = newPlans;
         ApplyDiscoveredPlansForDriver(msg.DriverInstanceId, newPlans);
+#pragma warning restore CS0162
     }
 
     /// <summary>
@@ -918,9 +948,11 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
             {
                 var key = (driverId, driverRef);
                 if (!_nodeIdByDriverRef.TryGetValue(key, out var set))
-                    _nodeIdByDriverRef[key] = set = new HashSet<string>(StringComparer.Ordinal);
+                    _nodeIdByDriverRef[key] = set = new HashSet<NodeRealmRef>();
-                set.Add(nodeId);
+                // v3 Batch 4: discovered (FixedTree) nodes graft onto the RAW device subtree, so they route
-                _driverRefByNodeId[nodeId] = key;
+                // through the Raw realm.
+                set.Add(new NodeRealmRef(nodeId, AddressSpaceRealm.Raw));
+                _driverRefByNodeId[(AddressSpaceRealm.Raw, nodeId)] = key;
             }
             _opcUaPublishActor?.Tell(new ZB.MOM.WW.OtOpcUa.Runtime.OpcUa.OpcUaPublishActor.MaterialiseDiscoveredNodes(
                 equipmentId, plan.Folders, plan.Variables));
@@ -1005,17 +1037,19 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
                 _localNode, msg.DriverInstanceId, msg.Args.ConditionId);
         }
 
-        foreach (var nodeId in nodeIds)
+        foreach (var n in nodeIds)
         {
+            var nodeId = n.NodeId;
             var snapshot = _nativeAlarmProjector.Project(nodeId, msg.Args);
             _opcUaPublishActor.Tell(new ZB.MOM.WW.OtOpcUa.Runtime.OpcUa.OpcUaPublishActor.AlarmStateUpdate(
-                nodeId, snapshot, msg.Args.SourceTimestampUtc));
+                nodeId, snapshot, msg.Args.SourceTimestampUtc, n.Realm));
 
             // Only the Primary publishes the cluster-wide alerts transition (see the gate above).
             if (!serviceAlertsAsPrimary) continue;
 
             var meta = _alarmMetaByNodeId.TryGetValue(nodeId, out var m)
-                ? m : (EquipmentId: nodeId, Name: nodeId, AlarmType: "AlarmCondition", HistorizeToAveva: (bool?)null);
+                ? m : (EquipmentId: nodeId, Name: nodeId, AlarmType: "AlarmCondition", HistorizeToAveva: (bool?)null,
+                    ReferencingEquipmentPaths: (IReadOnlyList<string>)Array.Empty<string>());
             _mediator.Tell(new Publish(ScriptedAlarmHostActor.AlertsTopic, new AlarmTransitionEvent(
                 AlarmId: nodeId,
                 EquipmentPath: meta.EquipmentId,
@@ -1035,7 +1069,10 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
                 // historize). The HistorianAdapterActor gate (historizeToAveva is not false) historizes null +
                 // true and suppresses the durable AVEVA row only on an explicit false — the same posture as the
                 // scripted-alarm opt-out. null here rides through unchanged (the gate treats it as default-on).
-                HistorizeToAveva: meta.HistorizeToAveva)));
+                HistorizeToAveva: meta.HistorizeToAveva,
+                // WP4: the Area/Line/Equipment UNS paths that reference this raw condition — the /alerts row
+                // renders them as the equipment list (empty for a raw condition no equipment references yet).
+                ReferencingEquipmentPaths: meta.ReferencingEquipmentPaths)));
         }
     }
 
@@ -1087,9 +1124,15 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
             return;
         }
 
-        if (!_driverRefByNodeId.TryGetValue(msg.NodeId, out var target))
+        // v3 Batch 4 (review H1): the node manager's write hook passes the FULL ns-qualified NodeId string
+        // (node.NodeId.ToString(), e.g. "ns=3;s=<id>") PLUS the realm it resolved from the namespace index.
+        // The routing map is keyed by (realm, BARE s= identifier). Normalise the id to its bare form and look
+        // up (realm, bareId) — the realm disambiguates a raw RawPath from a UNS path that happen to share a
+        // bare string, so a write always routes to its OWN driver ref (never a colliding sibling's).
+        var bareNodeId = BareNodeId(msg.NodeId);
+        if (!_driverRefByNodeId.TryGetValue((msg.Realm, bareNodeId), out var target))
         {
-            Sender.Tell(new NodeWriteResult(false, $"no driver mapping for node {msg.NodeId}"));
+            Sender.Tell(new NodeWriteResult(false, $"no driver mapping for node {msg.NodeId} ({msg.Realm})"));
             return;
         }
 
@@ -1115,6 +1158,25 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
             .PipeTo(replyTo);
     }
 
+    /// <summary>
+    ///     Normalise an OPC UA NodeId string to its BARE <c>s=</c> identifier. The node manager's inbound-write
+    ///     hook passes the full ns-qualified form (<c>NodeId.ToString()</c> == <c>"ns=&lt;N&gt;;s=&lt;id&gt;"</c>);
+    ///     the routing maps are keyed by the bare id (the RawPath / UNS path). The SDK format always prefixes
+    ///     <c>"ns=N;s="</c> for a string identifier in a non-zero namespace, so the first <c>";s="</c> is the
+    ///     delimiter (an id may itself contain <c>";s="</c> later — <c>IndexOf</c> takes the FIRST, which is the
+    ///     namespace delimiter). A bare id (no prefix) passes through unchanged.
+    /// </summary>
+    /// <param name="nodeId">The (possibly ns-qualified) NodeId string.</param>
+    /// <returns>The bare <c>s=</c> identifier.</returns>
+    internal static string BareNodeId(string nodeId)
+    {
+        if (string.IsNullOrEmpty(nodeId)) return nodeId;
+        var i = nodeId.IndexOf(";s=", StringComparison.Ordinal);
+        if (i >= 0) return nodeId[(i + 3)..];
+        if (nodeId.StartsWith("s=", StringComparison.Ordinal)) return nodeId[2..];
+        return nodeId;
+    }
+
     /// <summary>
     ///     Routes an inbound native-condition acknowledge (the host Tells this from the OPC UA node-manager
     ///     side when a client Acknowledges a NATIVE Part 9 condition) to the owning driver child. Mirrors
@@ -1456,89 +1518,89 @@ public sealed class DriverHostActor : ReceiveActor, IWithTimers
             return;
         }
 
-        // Value-subscription set: alarm-bearing tags are Part 9 conditions, not value variables, so they
+        // v3 Batch 4: the driver subscribes + publishes by RawPath (the wire-ref == RawPath == RawTagPlan.NodeId
-        // are excluded — the driver must not value-subscribe an alarm attribute (it is fed via the native
+        // per the v3 identity contract). Value-subscription set = the non-alarm raw tags' RawPaths; alarm-bearing
-        // alarm event stream, routed by ForwardNativeAlarm).
+        // raw tags are Part 9 conditions, fed via the native alarm event stream (ForwardNativeAlarm), so they are
-        var refsByDriver = composition.EquipmentTags
+        // excluded from the value set.
+        var refsByDriver = composition.RawTags
             .Where(t => t.Alarm is null)
             .GroupBy(t => t.DriverInstanceId, StringComparer.Ordinal)
             .ToDictionary(
                 g => g.Key,
-                g => (IReadOnlyList<string>)g.Select(t => t.FullName)
+                g => (IReadOnlyList<string>)g.Select(t => t.NodeId)
                     .Distinct(StringComparer.Ordinal)
                     .ToArray(),
                 StringComparer.Ordinal);
 
-        // Native-alarm subscription set: the alarm-bearing tags' FullNames (= the driver's
+        // Native-alarm subscription set: the alarm-bearing raw tags' RawPaths (= the driver's ConditionId).
-        // ConditionId/AlarmFullReference). An IAlarmSource driver suppresses OnAlarmEvent until at least one
+        // An IAlarmSource driver suppresses OnAlarmEvent until at least one alarm subscription exists, so the
-        // alarm subscription exists (e.g. GalaxyDriver gates its central feed on _alarmSubscriptions), so the
+        // instance actor must SubscribeAlarmsAsync these refs to un-gate the feed. Routing stays by ConditionId
-        // instance actor must SubscribeAlarmsAsync these refs to un-gate the feed. Routing stays by
+        // in ForwardNativeAlarm; this set just opens (and scopes) the subscription.
-        // ConditionId in ForwardNativeAlarm; this set just opens (and scopes) the subscription.
+        var alarmRefsByDriver = composition.RawTags
-        var alarmRefsByDriver = composition.EquipmentTags
             .Where(t => t.Alarm is not null)
             .GroupBy(t => t.DriverInstanceId, StringComparer.Ordinal)
             .ToDictionary(
                 g => g.Key,
-                g => (IReadOnlyList<string>)g.Select(t => t.FullName)
+                g => (IReadOnlyList<string>)g.Select(t => t.NodeId)
                     .Distinct(StringComparer.Ordinal)
                     .ToArray(),
                 StringComparer.Ordinal);
 
-        // Rebuild the driver live-value routing map from the SAME EquipmentTags pass (mirrors
+        // Referencing UNS nodes by backing RawPath — each raw value tag fans out to its own raw NodeId PLUS
-        // VirtualTagHostActor._nodeIdByVtag): map each tag's (DriverInstanceId, FullName) wire-ref to
+        // every UNS reference that projects it (dual-NodeId registration against the SAME driver ref).
-        // the folder-scoped equipment NodeId the materialiser placed its variable at, so ForwardToMux
+        var unsRefsByRawPath = new Dictionary<string, List<UnsReferenceVariable>>(StringComparer.Ordinal);
-        // can land driver values on the right node. Clear-and-repopulate every apply so renames
+        foreach (var v in composition.UnsReferenceVariables)
-        // (Name/FolderPath/EquipmentId changes) and removals are reflected.
+        {
+            if (!unsRefsByRawPath.TryGetValue(v.BackingRawPath, out var list))
+                unsRefsByRawPath[v.BackingRawPath] = list = new List<UnsReferenceVariable>();
+            list.Add(v);
+        }
+
+        // Rebuild the driver live-value + write routing maps from the RawTags ∪ UnsReferenceVariables pass.
+        // Clear-and-repopulate every apply so renames/removals/re-points are reflected.
         _nodeIdByDriverRef.Clear();
-        // Inverse map for the inbound operator-write path (NodeId → (DriverInstanceId, FullName)): an
-        // operator writes to the variable's folder-scoped NodeId, but the driver writes by its wire-ref
-        // FullName. Cleared + repopulated from the SAME EquipmentTags pass so renames/removals are
-        // reflected. Each NodeId maps to exactly one driver ref (a variable is backed by a single driver
-        // attribute), so last-writer-wins on the rare duplicate is harmless.
         _driverRefByNodeId.Clear();
-        // Alarm condition routing map: (DriverInstanceId, FullName = alarm ConditionId/AlarmFullReference) → folder-scoped
-        // condition NodeId(s). Built from the SAME EquipmentTags pass (alarm-bearing tags only) so
-        // ForwardNativeAlarm can land a native transition on the right condition node. Clear-and-rebuild
-        // every apply; the projector is Clear()'d too so stale per-condition state never leaks across
-        // redeploys (renames/removals/address-space rebuilds).
         _alarmNodeIdByDriverRef.Clear();
-        // Inverse alarm map for the inbound native-condition ack path (condition NodeId → (DriverInstanceId,
-        // FullName)): an OPC UA client acknowledges the condition's folder-scoped NodeId, but the driver
-        // acknowledges by its wire-ref FullName (= ConditionId). Cleared + repopulated from the SAME
-        // alarm-bearing EquipmentTags pass so renames/removals are reflected. Each condition NodeId maps to
-        // exactly one driver ref (a condition is backed by a single driver alarm), so last-writer-wins on the
-        // rare duplicate is harmless.
         _driverRefByAlarmNodeId.Clear();
-        // Per-condition metadata (EquipmentId / Name / OPC UA alarm type) for the alerts fan-out, built in
-        // the SAME alarm branch as the node map so a redeploy can't leave it out of sync. Cleared alongside it.
         _alarmMetaByNodeId.Clear();
         _nativeAlarmProjector.Clear();
-        foreach (var t in composition.EquipmentTags)
+        foreach (var t in composition.RawTags)
         {
-            var key = (t.DriverInstanceId, t.FullName);
+            var key = (t.DriverInstanceId, t.NodeId); // (DriverInstanceId, RawPath) — RawPath IS the wire-ref
-            var nodeId = EquipmentNodeIds.Variable(t.EquipmentId, t.FolderPath, t.Name);
             if (t.Alarm is not null)
             {
-                // Alarm tags are conditions, not value variables: route them ONLY into the alarm map and
+                // Native alarm → a single Part 9 condition at the RawPath (Raw realm). WP4 adds the referencing
-                // keep them OUT of the value maps + value-subscription set (so they don't get both a value
+                // equipment notifier NodeIds; WP3 wires the single raw condition.
-                // variable AND a condition).
                 if (!_alarmNodeIdByDriverRef.TryGetValue(key, out var aset))
-                    _alarmNodeIdByDriverRef[key] = aset = new HashSet<string>(StringComparer.Ordinal);
+                    _alarmNodeIdByDriverRef[key] = aset = new HashSet<NodeRealmRef>();
-                aset.Add(nodeId);
+                aset.Add(new NodeRealmRef(t.NodeId, AddressSpaceRealm.Raw));
-                // Inverse 1:1 map for the inbound native-condition ack path: the materialised condition
+                // Inverse 1:1 map for the inbound native-condition ack path (keyed by BARE condition NodeId).
-                // NodeId routes back to the owning (DriverInstanceId, FullName=ConditionId) so an OPC UA
+                _driverRefByAlarmNodeId[t.NodeId] = key;
-                // acknowledge of this condition reaches the right driver child.
+                // Per-condition metadata for the alerts fan-out. WP4 refines /alerts identity to the referencing
-                _driverRefByAlarmNodeId[nodeId] = key;
+                // equipment paths; WP3 keys the display off the RawPath. The referencing-equipment paths (the
-                // Capture the per-condition metadata the alerts fan-out (ForwardNativeAlarm) needs to build
+                // Area/Line/Equipment UNS folder paths carried on the RawTagPlan) ride onto every transition so
-                // the AlarmTransitionEvent: the equipment path, the operator-visible alarm name, and the
+                // the /alerts row lists which equipment reference this raw condition.
-                // OPC UA Part 9 subtype. Keyed by the condition NodeId (the projection's own key).
+                _alarmMetaByNodeId[t.NodeId] = (t.NodeId, t.Name, t.Alarm.AlarmType, t.Alarm.HistorizeToAveva, t.ReferencingEquipmentPaths);
-                _alarmMetaByNodeId[nodeId] = (t.EquipmentId, t.Name, t.Alarm.AlarmType, t.Alarm.HistorizeToAveva);
                 continue;
             }
+
+            // Value tag: register the RAW NodeId (Raw realm) AND every referencing UNS NodeId (Uns realm)
+            // against the SAME driver ref — the single value source fans to all of them.
             if (!_nodeIdByDriverRef.TryGetValue(key, out var set))
-                _nodeIdByDriverRef[key] = set = new HashSet<string>(StringComparer.Ordinal);
+                _nodeIdByDriverRef[key] = set = new HashSet<NodeRealmRef>();
-            set.Add(nodeId);
+            set.Add(new NodeRealmRef(t.NodeId, AddressSpaceRealm.Raw));
-            _driverRefByNodeId[nodeId] = key;
+            _driverRefByNodeId[(AddressSpaceRealm.Raw, t.NodeId)] = key;
+
+            if (unsRefsByRawPath.TryGetValue(t.NodeId, out var refs))
+            {
+                foreach (var v in refs)
+                {
+                    set.Add(new NodeRealmRef(v.NodeId, AddressSpaceRealm.Uns));
+                    // A UNS write resolves to the same driver ref — keyed under the Uns realm so it can never
+                    // collide with a raw NodeId that shares its bare string.
+                    _driverRefByNodeId[(AddressSpaceRealm.Uns, v.NodeId)] = key;
+                }
+            }
         }
 
         // Snapshot the cached (FixedTree-discovered) driver set BEFORE the bulk loop, while _discoveredByDriver

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/ServerHistorianOptions.cs

@@ -40,8 +40,10 @@ public sealed class ServerHistorianOptions
     /// <summary>
     ///     The peppered-HMAC API key (<c>histgw_&lt;id&gt;_&lt;secret&gt;</c>) the gateway validates
     ///     in the <c>Authorization: Bearer</c> header. Supply via the environment variable
-    ///     <c>ServerHistorian__ApiKey</c> — never commit it to config. Required when
+    ///     <c>ServerHistorian__ApiKey</c> — never commit it to config. The value may be a literal
-    ///     <see cref="Enabled"/> is <c>true</c>.
+    ///     key or a <c>${secret:otopcua/historian/api-key}</c> token, which the pre-host secrets
+    ///     expander resolves fail-closed (throwing if the secret is absent) before this options
+    ///     class binds. Required when <see cref="Enabled"/> is <c>true</c>.
     /// </summary>
     public string ApiKey { get; init; } = "";
 

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/OpcUa/OpcUaPublishActor.cs

@@ -39,16 +39,25 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     /// for its cached status. Private singleton — the actor pumps this for itself, no external sender.</summary>
     private sealed class HealthTick { public static readonly HealthTick Instance = new(); private HealthTick() { } }
 
-    public sealed record AttributeValueUpdate(string NodeId, object? Value, OpcUaQuality Quality, DateTime TimestampUtc);
+    /// <summary>A driver/vtag value update for a single materialised Variable node. v3 Batch 4: carries the
+    /// node's <see cref="AddressSpaceRealm"/> so the sink resolves the right namespace — the driver fan-out
+    /// posts one of these per registered NodeId (the raw node in <see cref="AddressSpaceRealm.Raw"/> and each
+    /// referencing UNS node in <see cref="AddressSpaceRealm.Uns"/>) with identical value/quality/timestamp.
+    /// <see cref="Realm"/> defaults to <see cref="AddressSpaceRealm.Uns"/> so pre-v3 callers (VirtualTag
+    /// equipment nodes) keep compiling; the driver fan-out passes it EXPLICITLY per node.</summary>
+    public sealed record AttributeValueUpdate(string NodeId, object? Value, OpcUaQuality Quality, DateTime TimestampUtc, AddressSpaceRealm Realm);
 
     /// <summary>Carries the full Part 9 condition state for a scripted alarm to the sink. The
     /// <paramref name="State"/> snapshot is the Commons projection the Runtime host maps from the engine's
     /// Core <c>AlarmConditionState</c> + severity/message — the actor stays decoupled from
     /// <c>Core.ScriptedAlarms</c>.</summary>
-    /// <param name="AlarmNodeId">The alarm node id (== ScriptedAlarmId for materialised conditions).</param>
+    /// <param name="AlarmNodeId">The alarm node id (== ScriptedAlarmId for scripted conditions; == RawPath for
+    /// v3 native raw conditions).</param>
     /// <param name="State">The full condition state to project onto the node.</param>
     /// <param name="TimestampUtc">The source timestamp of the transition in UTC.</param>
-    public sealed record AlarmStateUpdate(string AlarmNodeId, AlarmConditionSnapshot State, DateTime TimestampUtc);
+    /// <param name="Realm">The namespace realm the condition lives in — <see cref="AddressSpaceRealm.Uns"/> for
+    /// scripted alarms (default), <see cref="AddressSpaceRealm.Raw"/> for v3 native raw conditions.</param>
+    public sealed record AlarmStateUpdate(string AlarmNodeId, AlarmConditionSnapshot State, DateTime TimestampUtc, AddressSpaceRealm Realm);
     /// <summary>
     ///     Triggers an address-space rebuild. <paramref name="DeploymentId"/> is the deployment
     ///     just applied by the host; the rebuild loads THAT artifact so materialisation matches the
@@ -263,7 +272,7 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     {
         try
         {
-            _sink.WriteValue(msg.NodeId, msg.Value, msg.Quality, msg.TimestampUtc);
+            _sink.WriteValue(msg.NodeId, msg.Value, msg.Quality, msg.TimestampUtc, msg.Realm);
             Interlocked.Increment(ref _writes);
             OtOpcUaTelemetry.OpcUaSinkWrite.Add(1, new KeyValuePair<string, object?>("kind", "value"));
         }
@@ -277,7 +286,7 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
     {
         try
         {
-            _sink.WriteAlarmCondition(msg.AlarmNodeId, msg.State, msg.TimestampUtc);
+            _sink.WriteAlarmCondition(msg.AlarmNodeId, msg.State, msg.TimestampUtc, msg.Realm);
             Interlocked.Increment(ref _writes);
             OtOpcUaTelemetry.OpcUaSinkWrite.Add(1, new KeyValuePair<string, object?>("kind", "alarm"));
         }
@@ -340,6 +349,14 @@ public sealed class OpcUaPublishActor : ReceiveActor, IWithTimers
             // Warnings + an optimistic Info line; now it surfaces at Error + a dedicated meter.
             var failedNodes = outcome.FailedNodes;
             failedNodes += _applier.MaterialiseHierarchy(composition);
+            // v3 Batch 4 — the Raw device subtree (ns=Raw): containers (Folder→Driver→Device→TagGroup) then
+            // tag Variables keyed by RawPath. Materialised BEFORE the UNS references so each UNS Organizes→Raw
+            // edge finds its raw target. The driver binds live values to these raw NodeIds.
+            failedNodes += _applier.MaterialiseRawSubtree(composition);
+            // v3 Batch 4 — the UNS reference Variables (ns=UNS): each projects a raw tag under its equipment
+            // folder (created by MaterialiseHierarchy) with an Organizes→Raw edge; values fan out from the raw
+            // node. Runs AFTER both the equipment folders AND the raw subtree exist.
+            failedNodes += _applier.MaterialiseUnsReferences(composition);
             // T14 — scripted alarms get their own pass right after the hierarchy so the equipment
             // folders they parent under already exist. Materialises real Part 9 AlarmConditionState
             // nodes (keyed by ScriptedAlarmId so AlarmStateUpdate writes target them); disabled

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/ScriptedAlarms/ScriptedAlarmHostActor.cs

@@ -297,10 +297,12 @@ public sealed class ScriptedAlarmHostActor : ReceiveActor
         // Bridge to OPC UA: project the FULL Part 9 condition state (enabled/active/acked/confirmed/
         // shelving/severity/message) onto the materialised condition node via the Commons snapshot.
         // e.AlarmId is the materialised condition's NodeId (T14 aligned it to the ScriptedAlarmId).
+        // Scripted alarms are per-equipment condition nodes in the UNS realm.
         _publishActor.Tell(new OpcUaPublishActor.AlarmStateUpdate(
             AlarmNodeId: e.AlarmId,
             State: ToSnapshot(e),
-            TimestampUtc: e.TimestampUtc));
+            TimestampUtc: e.TimestampUtc,
+            Realm: AddressSpaceRealm.Uns));
 
         // Publish the transition to the cluster `alerts` topic — the single historization + live
         // fan-out path. The mediator was cached on the ACTOR thread in PreStart; we only Tell it here.

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/VirtualTags/VirtualTagActor.cs

@@ -31,12 +31,24 @@ public sealed class VirtualTagActor : ReceiveActor
 
     public sealed record DependencyValueChanged(string TagId, object? Value, DateTime TimestampUtc);
 
+    /// <summary>Re-assert the last emitted value/quality to the parent bridge, bypassing the value dedup.
+    /// Sent by <see cref="VirtualTagHostActor"/> on every apply (deploy) to a surviving child: a deploy
+    /// re-materialises the child's published UNS node to <c>BadWaitingForInitialData</c>, but an
+    /// unchanged-plan child keeps its dedup state, so a static-dependency recompute is suppressed and the
+    /// node would stay Bad forever. Re-asserting the last state recovers it. Singleton — carries no data.</summary>
+    public sealed class ReassertValue { public static readonly ReassertValue Instance = new(); private ReassertValue() { } }
+
     /// <summary>Result emitted to the parent (the host bridge). <paramref name="Quality"/> carries the
     /// OPC UA quality the node should read: <see cref="OpcUaQuality.Good"/> for a fresh computed value,
     /// <see cref="OpcUaQuality.Bad"/> when the script failed/timed out (02/S13) — in which case
     /// <paramref name="Value"/> is the last-known value (or null if none). Defaulting to Good keeps
     /// every existing construction site source-compatible.</summary>
-    public sealed record EvaluationResult(string VirtualTagId, object? Value, DateTime TimestampUtc, CorrelationId Correlation, OpcUaQuality Quality = OpcUaQuality.Good);
+    /// <param name="IsReassert"><c>true</c> when this result is a deploy-time re-assertion of the last
+    /// value/quality (see <see cref="ReassertValue"/>) rather than a fresh evaluation. The host still
+    /// publishes it (to repair the reset OPC UA node) but must NOT re-record it to the historian — it is a
+    /// stale value stamped with a fresh deploy-time timestamp, never a real evaluation sample. Defaults to
+    /// <c>false</c> so every existing construction site stays source-compatible.</param>
+    public sealed record EvaluationResult(string VirtualTagId, object? Value, DateTime TimestampUtc, CorrelationId Correlation, OpcUaQuality Quality = OpcUaQuality.Good, bool IsReassert = false);
 
     private readonly string _virtualTagId;
     private readonly string _scriptId;
@@ -105,6 +117,7 @@ public sealed class VirtualTagActor : ReceiveActor
         _mux = mux;
 
         Receive<DependencyValueChanged>(OnDependencyChanged);
+        Receive<ReassertValue>(_ => OnReassertValue());
     }
 
     /// <inheritdoc />
@@ -122,6 +135,32 @@ public sealed class VirtualTagActor : ReceiveActor
         _mux?.Tell(new DependencyMuxActor.UnregisterInterest(Self));
     }
 
+    /// <summary>Re-emit the last emitted value/quality to the parent bridge, bypassing the value dedup, so a
+    /// deploy that re-materialised our published UNS node to <c>BadWaitingForInitialData</c> recovers even when
+    /// the recomputed value is unchanged (permanent Bad otherwise, with a static dependency). No-op until the
+    /// child has emitted at least once — the first dependency arrival publishes the initial value normally.
+    /// <para>
+    ///     The result is flagged <see cref="EvaluationResult.IsReassert"/> so the host publishes it (repairing
+    ///     the reset node) but does NOT re-record it to the historian — it is a stale value stamped with a
+    ///     fresh deploy-time timestamp, not a real evaluation sample (M1).
+    /// </para>
+    /// <para>
+    ///     Ordering (why the re-publish lands on the freshly-materialised node, not the pre-reset one): the
+    ///     reset and this re-publish converge on the SAME single-threaded <c>OpcUaPublishActor</c>. On a deploy
+    ///     <c>DriverHostActor</c> enqueues <c>RebuildAddressSpace</c> (the reset) to that actor FIRST, then sends
+    ///     <c>ApplyVirtualTags</c> to the VirtualTag HOST; the host tells this child <c>ReassertValue</c>, and
+    ///     only then does this method Tell the host an <c>EvaluationResult</c> which the host bridges onward to
+    ///     the publish actor. That multi-hop chain guarantees the re-publish arrives AFTER <c>RebuildAddressSpace</c>
+    ///     in the publish actor's FIFO mailbox, so the materialise runs before the write.
+    /// </para></summary>
+    private void OnReassertValue()
+    {
+        if (!_hasLastValue && !_lastPublishedBad) return;
+        var quality = _lastPublishedBad ? OpcUaQuality.Bad : OpcUaQuality.Good;
+        Context.Parent.Tell(new EvaluationResult(
+            _virtualTagId, _lastValue, DateTime.UtcNow, CorrelationId.NewId(), quality, IsReassert: true));
+    }
+
     private void OnDependencyChanged(DependencyValueChanged msg)
     {
         _dependencies[msg.TagId] = msg.Value;

src/Server/ZB.MOM.WW.OtOpcUa.Runtime/VirtualTags/VirtualTagHostActor.cs

@@ -19,9 +19,10 @@ namespace ZB.MOM.WW.OtOpcUa.Runtime.VirtualTags;
 ///     already-materialised Variable node (currently BadWaitingForInitialData) reflects the value.
 ///
 ///     <para>
-///         The published NodeId is computed by the shared <see cref="EquipmentNodeIds.Variable"/> —
+///         The published NodeId is computed via <see cref="V3NodeIds.Uns(string[])"/> (the equipment-anchored
-///         the single source of truth <c>AddressSpaceApplier.MaterialiseEquipmentVirtualTags</c> also
+///         slash path <c>{EquipmentId}[/{FolderPath}]/{Name}</c>) — byte-identical to the NodeId
-///         materialises against — so the value always lands on a NodeId that exists.
+///         <c>AddressSpaceApplier.MaterialiseEquipmentVirtualTags</c> materialises against — so the value
+///         always lands on a NodeId that exists.
 ///     </para>
 /// </summary>
 public sealed class VirtualTagHostActor : ReceiveActor
@@ -149,6 +150,9 @@ public sealed class VirtualTagHostActor : ReceiveActor
         // recreated here from the new plan, adopting the edited Expression/DependencyRefs. Children
         // whose plan was unchanged still have a live entry and are skipped, keeping their mux
         // subscriptions and last-value dedup state.
+        // Track the just-spawned vtags so the re-assert pass below skips them: a fresh child has no last
+        // value to re-assert and publishes its initial value on the first dependency arrival anyway.
+        var newlySpawned = new HashSet<string>(StringComparer.Ordinal);
         foreach (var p in msg.Plans)
         {
             if (_children.ContainsKey(p.VirtualTagId)) continue;
@@ -165,6 +169,7 @@ public sealed class VirtualTagHostActor : ReceiveActor
                 mux: _mux));
             Context.Watch(child);
             _children[p.VirtualTagId] = child;
+            newlySpawned.Add(p.VirtualTagId);
             _log.Debug("VirtualTagHost: spawned child for vtag {VirtualTagId}", p.VirtualTagId);
         }
 
@@ -176,6 +181,24 @@ public sealed class VirtualTagHostActor : ReceiveActor
             _planByVtag[p.VirtualTagId] = p;
         }
 
+        // Re-assert last values on surviving (not just-spawned) children. Every apply coincides with a
+        // deploy, and on a deploy DriverHostActor enqueues RebuildAddressSpace — which re-materialises each
+        // VirtualTag's UNS node to BadWaitingForInitialData — to the single-threaded OpcUaPublishActor FIRST,
+        // then sends ApplyVirtualTags to THIS host. A surviving child keeps its value-dedup state, so an
+        // unchanged recompute is suppressed and its freshly-reset node would stay Bad forever (permanent with
+        // a static dependency). Telling each survivor to ReassertValue makes it re-publish its last state; that
+        // re-publish reaches the publish actor via a multi-hop chain (host → child ReassertValue → child →
+        // parent EvaluationResult → OnResult → publish actor), so its AttributeValueUpdate lands AFTER
+        // RebuildAddressSpace in the publish actor's FIFO mailbox — the materialise runs before the write, and
+        // the node recovers. (The ordering does NOT come from ApplyVirtualTags itself reaching the publish
+        // actor — it doesn't; it goes to this host.) Fresh children are skipped (nothing to re-assert; their
+        // first dependency arrival publishes normally).
+        foreach (var (vtagId, child) in _children)
+        {
+            if (newlySpawned.Contains(vtagId)) continue;
+            child.Tell(VirtualTagActor.ReassertValue.Instance);
+        }
+
         _log.Debug("VirtualTagHost: applied (desired={Desired}, children={Children})",
             desired.Count, _children.Count);
     }
@@ -192,15 +215,20 @@ public sealed class VirtualTagHostActor : ReceiveActor
         // 02/S13: the child now expresses quality — a Good fresh value or a Bad degradation (script
         // failure/timeout) carrying the last-known value. Bridge result.Quality through verbatim; the
         // sink maps it to StatusCodes.Good/Bad on the node so a broken script no longer freezes Good.
+        // VirtualTags materialise as equipment nodes in the UNS realm — publish there.
         _publishActor.Tell(new OpcUaPublishActor.AttributeValueUpdate(
-            nodeId, result.Value, result.Quality, result.TimestampUtc));
+            nodeId, result.Value, result.Quality, result.TimestampUtc, AddressSpaceRealm.Uns));
 
-        // Historize iff the plan opted in. Reuses _planByVtag (kept in lock-step with _children), so
+        // Historize iff the plan opted in — but NEVER for a re-assert (M1). A re-assert re-publishes a
-        // no parallel map. The historian path key is the SAME folder-scoped NodeId we just published
+        // stale last value stamped with a fresh deploy-time timestamp purely to repair the reset OPC UA
-        // to. For a computed value source == server, so both timestamps are the evaluation time. Bad
+        // node; recording it would append an artificial historian sample that never corresponded to a real
-        // results record BadInternalError (0x80020000u) — the dormant VirtualTagEngine's Bad-snapshot
+        // evaluation (and, if the last state was Bad, a fabricated BadInternalError point). Reuses
-        // status — so the historian trend can distinguish a degraded sample from a Good one.
+        // _planByVtag (kept in lock-step with _children), so no parallel map. The historian path key is the
-        if (_planByVtag.TryGetValue(result.VirtualTagId, out var plan) && plan.Historize)
+        // SAME folder-scoped NodeId we just published to. For a computed value source == server, so both
+        // timestamps are the evaluation time. Bad results record BadInternalError (0x80020000u) — the
+        // dormant VirtualTagEngine's Bad-snapshot status — so the historian trend can distinguish a degraded
+        // sample from a Good one.
+        if (!result.IsReassert && _planByVtag.TryGetValue(result.VirtualTagId, out var plan) && plan.Historize)
         {
             var status = result.Quality == OpcUaQuality.Good ? 0u : 0x80020000u /* BadInternalError — dormant-engine parity */;
             _history.Record(nodeId, new DataValueSnapshot(
@@ -223,9 +251,13 @@ public sealed class VirtualTagHostActor : ReceiveActor
         }
     }
 
-    /// <summary>Folder-scoped NodeId for a VirtualTag plan. The formula now lives in the shared
+    /// <summary>UNS-realm NodeId for a VirtualTag plan — the equipment-anchored slash path
-    /// <see cref="EquipmentNodeIds"/> (the single source of truth that <c>AddressSpaceApplier</c> also
+    /// <c>{EquipmentId}[/{FolderPath}]/{Name}</c>, expressed through the v3 identity authority
-    /// materialises against), so the published value always lands on the NodeId that was materialised.</summary>
+    /// <see cref="V3NodeIds.Uns(string[])"/>. Byte-identical to the applier's equipment-VirtualTag materialise
+    /// pass (its private <c>UnsEquipmentVar</c>), so the published value always lands on the materialised
+    /// NodeId. FolderPath is empty for VirtualTags today, but a multi-segment path is split into segments.</summary>
     private static string NodeIdFor(EquipmentVirtualTagPlan p) =>
-        EquipmentNodeIds.Variable(p.EquipmentId, p.FolderPath, p.Name);
+        string.IsNullOrWhiteSpace(p.FolderPath)
+            ? V3NodeIds.Uns(p.EquipmentId, p.Name)
+            : V3NodeIds.Uns(new[] { p.EquipmentId }.Concat(p.FolderPath.Split('/')).Append(p.Name));
 }

tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/OpcUa/DeferredAddressSpaceSinkTests.cs

@@ -19,7 +19,7 @@ public class DeferredAddressSpaceSinkTests
     {
         var sink = new DeferredAddressSpaceSink();
         // Must not throw.
-        sink.WriteValue("ns=2;s=x", 42, OpcUaQuality.Good, DateTime.UtcNow);
+        sink.WriteValue("ns=2;s=x", 42, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
     }
 
     [Fact]
@@ -34,7 +34,7 @@ public class DeferredAddressSpaceSinkTests
     {
         var sink = new DeferredAddressSpaceSink();
         sink.UpdateTagAttributes("ns=2;s=x", writable: true, historianTagname: null,
-            dataType: "Boolean", isArray: false, arrayLength: null).ShouldBeFalse();
+            dataType: "Boolean", isArray: false, arrayLength: null, AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     // ---------- after SetSink — operations are forwarded ----------
@@ -46,7 +46,7 @@ public class DeferredAddressSpaceSinkTests
         var sink = new DeferredAddressSpaceSink();
         sink.SetSink(inner);
 
-        sink.WriteValue("ns=2;s=x", 99, OpcUaQuality.Good, DateTime.UtcNow);
+        sink.WriteValue("ns=2;s=x", 99, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
         inner.WriteValueCalled.ShouldBeTrue();
     }
@@ -63,6 +63,25 @@ public class DeferredAddressSpaceSinkTests
         inner.RebuildCalled.ShouldBeTrue();
     }
 
+    [Fact]
+    public void After_SetSink_WireAlarmNotifiers_is_forwarded_with_all_args()
+    {
+        // v3 Batch 4 WP4: without this forward the native-alarm multi-notifier fan-out ships INERT on every
+        // driver-role host (actors inject THIS wrapper, not the inner sink) — the F10b / PR#423 trap class.
+        var inner = new SpySink();
+        var sink = new DeferredAddressSpaceSink();
+        sink.SetSink(inner);
+
+        sink.WireAlarmNotifiers("Plant/Modbus/dev1/temp_hi", AddressSpaceRealm.Raw,
+            new[] { "EQ-1", "EQ-2" }, AddressSpaceRealm.Uns);
+
+        inner.WireAlarmNotifiersArgs.ShouldNotBeNull();
+        inner.WireAlarmNotifiersArgs!.Value.AlarmNodeId.ShouldBe("Plant/Modbus/dev1/temp_hi");
+        inner.WireAlarmNotifiersArgs.Value.AlarmRealm.ShouldBe(AddressSpaceRealm.Raw);
+        inner.WireAlarmNotifiersArgs.Value.Folders.ShouldBe(new[] { "EQ-1", "EQ-2" });
+        inner.WireAlarmNotifiersArgs.Value.FolderRealm.ShouldBe(AddressSpaceRealm.Uns);
+    }
+
     // ---------- ISurgicalAddressSpaceSink forwarding ----------
 
     [Fact]
@@ -73,7 +92,7 @@ public class DeferredAddressSpaceSinkTests
         sink.SetSink(new SpySink());
 
         sink.UpdateTagAttributes("ns=2;s=x", writable: true, historianTagname: null,
-            dataType: "Int32", isArray: false, arrayLength: null).ShouldBeFalse();
+            dataType: "Int32", isArray: false, arrayLength: null, AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     [Fact]
@@ -84,7 +103,7 @@ public class DeferredAddressSpaceSinkTests
         sink.SetSink(surgical);
 
         var result = sink.UpdateTagAttributes("ns=2;s=x", writable: true, historianTagname: null,
-            dataType: "Float", isArray: false, arrayLength: null);
+            dataType: "Float", isArray: false, arrayLength: null, AddressSpaceRealm.Uns);
 
         result.ShouldBeTrue();
         surgical.UpdateCalled.ShouldBeTrue();
@@ -97,7 +116,7 @@ public class DeferredAddressSpaceSinkTests
         var sink = new DeferredAddressSpaceSink();
         sink.SetSink(new SpySink());
 
-        sink.UpdateFolderDisplayName("area-1", "Plant South").ShouldBeFalse();
+        sink.UpdateFolderDisplayName("area-1", "Plant South", AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     [Fact]
@@ -108,7 +127,7 @@ public class DeferredAddressSpaceSinkTests
         var sink = new DeferredAddressSpaceSink();
         sink.SetSink(surgical);
 
-        var result = sink.UpdateFolderDisplayName("area-1", "Plant South");
+        var result = sink.UpdateFolderDisplayName("area-1", "Plant South", AddressSpaceRealm.Uns);
 
         result.ShouldBeTrue();
         surgical.FolderRenameCalled.ShouldBeTrue();
@@ -122,9 +141,9 @@ public class DeferredAddressSpaceSinkTests
         var sink = new DeferredAddressSpaceSink();
         sink.SetSink(new SpySink());
 
-        sink.RemoveVariableNode("v-1").ShouldBeFalse();
+        sink.RemoveVariableNode("v-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        sink.RemoveAlarmConditionNode("a-1").ShouldBeFalse();
+        sink.RemoveAlarmConditionNode("a-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        sink.RemoveEquipmentSubtree("eq-1").ShouldBeFalse();
+        sink.RemoveEquipmentSubtree("eq-1", AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     [Fact]
@@ -134,9 +153,9 @@ public class DeferredAddressSpaceSinkTests
         var sink = new DeferredAddressSpaceSink();
         sink.SetSink(surgical);
 
-        sink.RemoveVariableNode("v-1").ShouldBeTrue();
+        sink.RemoveVariableNode("v-1", AddressSpaceRealm.Uns).ShouldBeTrue();
-        sink.RemoveAlarmConditionNode("a-1").ShouldBeTrue();
+        sink.RemoveAlarmConditionNode("a-1", AddressSpaceRealm.Uns).ShouldBeTrue();
-        sink.RemoveEquipmentSubtree("eq-1").ShouldBeTrue();
+        sink.RemoveEquipmentSubtree("eq-1", AddressSpaceRealm.Uns).ShouldBeTrue();
 
         surgical.RemoveVariableCalled.ShouldBeTrue();
         surgical.RemoveAlarmCalled.ShouldBeTrue();
@@ -147,9 +166,9 @@ public class DeferredAddressSpaceSinkTests
     public void Before_SetSink_remove_members_return_false()
     {
         var sink = new DeferredAddressSpaceSink();
-        sink.RemoveVariableNode("v-1").ShouldBeFalse();
+        sink.RemoveVariableNode("v-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        sink.RemoveAlarmConditionNode("a-1").ShouldBeFalse();
+        sink.RemoveAlarmConditionNode("a-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        sink.RemoveEquipmentSubtree("eq-1").ShouldBeFalse();
+        sink.RemoveEquipmentSubtree("eq-1", AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     // ---------- SetSink(null) reverts to null sink ----------
@@ -163,7 +182,7 @@ public class DeferredAddressSpaceSinkTests
         sink.SetSink(null); // revert
 
         sink.UpdateTagAttributes("ns=2;s=x", writable: false, historianTagname: null,
-            dataType: "Boolean", isArray: false, arrayLength: null).ShouldBeFalse();
+            dataType: "Boolean", isArray: false, arrayLength: null, AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     [Fact]
@@ -174,7 +193,7 @@ public class DeferredAddressSpaceSinkTests
         sink.SetSink(inner);
         sink.SetSink(null); // revert
 
-        sink.WriteValue("ns=2;s=x", 1, OpcUaQuality.Good, DateTime.UtcNow);
+        sink.WriteValue("ns=2;s=x", 1, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
         inner.WriteValueCalled.ShouldBeFalse("write should be no-op after reverting to null sink");
     }
@@ -185,16 +204,20 @@ public class DeferredAddressSpaceSinkTests
     {
         public bool WriteValueCalled { get; private set; }
         public bool RebuildCalled { get; private set; }
+        public (string AlarmNodeId, AddressSpaceRealm AlarmRealm, IReadOnlyList<string> Folders, AddressSpaceRealm FolderRealm)? WireAlarmNotifiersArgs { get; private set; }
 
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc)
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => WriteValueCalled = true;
 
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc) { }
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName) { }
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
         public void RebuildAddressSpace() => RebuildCalled = true;
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm)
+            => WireAlarmNotifiersArgs = (alarmNodeId, alarmRealm, notifierFolderNodeIds, notifierFolderRealm);
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 
     private sealed class SpySurgicalSink : IOpcUaAddressSpaceSink, ISurgicalAddressSpaceSink
@@ -202,21 +225,23 @@ public class DeferredAddressSpaceSinkTests
         public bool UpdateCalled { get; private set; }
         public bool FolderRenameCalled { get; private set; }
 
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc) { }
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName) { }
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
         public void RebuildAddressSpace() { }
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
 
-        public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
+        public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             UpdateCalled = true;
             return true;
         }
 
-        public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+        public bool UpdateFolderDisplayName(string folderNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             FolderRenameCalled = true;
             return true;
@@ -226,8 +251,8 @@ public class DeferredAddressSpaceSinkTests
         public bool RemoveAlarmCalled { get; private set; }
         public bool RemoveSubtreeCalled { get; private set; }
 
-        public bool RemoveVariableNode(string variableNodeId) { RemoveVariableCalled = true; return true; }
+        public bool RemoveVariableNode(string variableNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { RemoveVariableCalled = true; return true; }
-        public bool RemoveAlarmConditionNode(string alarmNodeId) { RemoveAlarmCalled = true; return true; }
+        public bool RemoveAlarmConditionNode(string alarmNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { RemoveAlarmCalled = true; return true; }
-        public bool RemoveEquipmentSubtree(string equipmentNodeId) { RemoveSubtreeCalled = true; return true; }
+        public bool RemoveEquipmentSubtree(string equipmentNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { RemoveSubtreeCalled = true; return true; }
     }
 }

tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/OpcUa/DeferredSinkForwardingReflectionTests.cs

@@ -74,6 +74,24 @@ public class DeferredSinkForwardingReflectionTests
         }
     }
 
+    [Fact]
+    public void Every_node_naming_sink_method_carries_a_realm_discriminator()
+    {
+        // v3 B4-WP2 dual-namespace invariant: a node id alone is no longer globally unique across the two
+        // namespaces (Raw vs UNS), so every sink method that NAMES a node must carry an AddressSpaceRealm
+        // discriminator — the sink resolves the namespace from the realm rather than parsing the id string.
+        // RebuildAddressSpace is the sole node-naming-free method (it clears BOTH realms). This guard locks in
+        // the realm surface so a future method can't be added that names a node without a realm.
+        foreach (var method in ForwardingInterfaces.SelectMany(i => i.GetMethods()))
+        {
+            if (method.Name == nameof(IOpcUaAddressSpaceSink.RebuildAddressSpace)) continue;
+
+            method.GetParameters().Any(p => p.ParameterType == typeof(AddressSpaceRealm)).ShouldBeTrue(
+                $"{method.DeclaringType!.Name}.{method.Name} names a node but has no AddressSpaceRealm parameter — " +
+                "a bare node id is ambiguous across the Raw and UNS namespaces (B4-WP2). Add the realm discriminator.");
+        }
+    }
+
     [Fact]
     public void Every_IServiceLevelPublisher_method_reaches_the_inner_publisher()
     {

tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/OpcUa/EquipmentNodeIdsTests.cs

@@ -1,28 +0,0 @@
-using Shouldly;
-using Xunit;
-using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
-
-namespace ZB.MOM.WW.OtOpcUa.Commons.Tests.OpcUa;
-
-public class EquipmentNodeIdsTests
-{
-    [Fact]
-    public void Variable_with_no_folder_is_equipment_slash_name()
-        => EquipmentNodeIds.Variable("eq-1", "", "speed").ShouldBe("eq-1/speed");
-
-    [Fact]
-    public void Variable_with_null_folder_is_equipment_slash_name()
-        => EquipmentNodeIds.Variable("eq-1", null, "speed").ShouldBe("eq-1/speed");
-
-    [Fact]
-    public void Variable_with_folder_is_equipment_slash_folder_slash_name()
-        => EquipmentNodeIds.Variable("eq-1", "registers", "speed").ShouldBe("eq-1/registers/speed");
-
-    [Fact]
-    public void Variable_with_whitespace_folder_is_equipment_slash_name()
-        => EquipmentNodeIds.Variable("eq-1", "   ", "speed").ShouldBe("eq-1/speed");
-
-    [Fact]
-    public void SubFolder_is_equipment_slash_folder()
-        => EquipmentNodeIds.SubFolder("eq-1", "registers").ShouldBe("eq-1/registers");
-}

tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/OpcUa/NullOpcUaNodeWriteGatewayTests.cs

@@ -9,7 +9,7 @@ public class NullOpcUaNodeWriteGatewayTests
     [Fact]
     public async Task NullGateway_returns_writes_unavailable()
     {
-        var outcome = await NullOpcUaNodeWriteGateway.Instance.WriteAsync("ns=2;s=x", 1, TestContext.Current.CancellationToken);
+        var outcome = await NullOpcUaNodeWriteGateway.Instance.WriteAsync("ns=2;s=x", 1, AddressSpaceRealm.Uns, TestContext.Current.CancellationToken);
         outcome.Success.ShouldBeFalse();
         outcome.Reason.ShouldBe("writes unavailable");
     }

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser.Tests/GalaxyDriverBrowserTests.cs

@@ -1,5 +1,6 @@
 using Shouldly;
 using Xunit;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser.Tests;
 
@@ -14,7 +15,17 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Browser.Tests;
 [Trait("Category", "Unit")]
 public sealed class GalaxyDriverBrowserTests
 {
-    private readonly GalaxyDriverBrowser _sut = new();
+    // These unit tests exercise only the pre-connect validation paths (empty endpoint,
+    // blank client name) that throw BEFORE the API-key secret: arm is resolved, so a
+    // null-returning stub resolver suffices — it is never consulted.
+    private readonly GalaxyDriverBrowser _sut = new(new StubSecretResolver());
+
+    /// <summary>A no-op resolver: every name resolves to null. Never consulted by these tests.</summary>
+    private sealed class StubSecretResolver : ISecretResolver
+    {
+        /// <inheritdoc />
+        public Task<string?> GetAsync(SecretName name, CancellationToken ct) => Task.FromResult<string?>(null);
+    }
 
     /// <summary>The DriverType key must match the AdminUI's persisted "GalaxyMxGateway" value
     /// so the factory wire-up picks the right browser implementation.</summary>

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverApiKeyResolverTests.cs

@@ -2,35 +2,48 @@ using Microsoft.Extensions.Logging;
 using Shouldly;
 using Xunit;
 using ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Config;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests;
 
 /// <summary>
-///     Follow-up #2 — pins the three resolution forms supported by
+///     Follow-up #2 + G-2a — pins the five resolution forms supported by
-///     <see cref="GalaxySecretRef.ResolveApiKey"/>: <c>env:NAME</c>, <c>file:PATH</c>,
+///     <see cref="GalaxySecretRef.ResolveApiKeyAsync"/>: <c>env:NAME</c>, <c>file:PATH</c>,
-///     and the literal-string fallback. A future DPAPI arm slots in here without
+///     <c>dev:KEY</c>, <c>secret:NAME</c> (via the shared <see cref="ISecretResolver"/>), and
-///     touching the call site. (The resolver was extracted from <c>GalaxyDriver</c> to
+///     the literal-string fallback. The <c>secret:</c> arm is fail-closed — an absent secret
-///     the shared <c>GalaxySecretRef</c> in Driver.Galaxy.Contracts so the runtime
+///     throws rather than leaking the ref string as the key. (The resolver was extracted from
-///     driver and the AdminUI browser share one copy.)
+///     <c>GalaxyDriver</c> to the shared <c>GalaxySecretRef</c> in Driver.Galaxy.Contracts so the
+///     runtime driver and the AdminUI browser share one copy.)
 /// </summary>
 public sealed class GalaxyDriverApiKeyResolverTests
 {
+    /// <summary>Name the fake resolver knows; matches the SecretName-normalized form.</summary>
+    private const string KnownSecretName = "galaxy/inst1/apikey";
+
+    /// <summary>The value the fake resolver returns for <see cref="KnownSecretName"/>.</summary>
+    private const string KnownSecretValue = "key-from-secret-store";
+
+    /// <summary>A fake resolver: returns a known value for one known name, null otherwise.</summary>
+    private static ISecretResolver FakeResolver() => new StubSecretResolver();
+
     /// <summary>Verifies that a literal string is returned unchanged.</summary>
     [Fact]
-    public void Literal_string_is_returned_unchanged()
+    public async Task Literal_string_is_returned_unchanged()
     {
-        GalaxySecretRef.ResolveApiKey("plain-text-key").ShouldBe("plain-text-key");
+        (await GalaxySecretRef.ResolveApiKeyAsync("plain-text-key", FakeResolver()))
+            .ShouldBe("plain-text-key");
     }
 
     /// <summary>Verifies that env: prefix resolves to an environment variable.</summary>
     [Fact]
-    public void Env_prefix_resolves_to_environment_variable()
+    public async Task Env_prefix_resolves_to_environment_variable()
     {
         const string name = "OTOPCUA_TEST_GALAXY_API_KEY";
         Environment.SetEnvironmentVariable(name, "key-from-env");
         try
         {
-            GalaxySecretRef.ResolveApiKey($"env:{name}").ShouldBe("key-from-env");
+            (await GalaxySecretRef.ResolveApiKeyAsync($"env:{name}", FakeResolver()))
+                .ShouldBe("key-from-env");
         }
         finally
         {
@@ -40,26 +53,27 @@ public sealed class GalaxyDriverApiKeyResolverTests
 
     /// <summary>Verifies that unset environment variables throw with a descriptive message.</summary>
     [Fact]
-    public void Env_prefix_unset_variable_throws_with_descriptive_message()
+    public async Task Env_prefix_unset_variable_throws_with_descriptive_message()
     {
         const string name = "OTOPCUA_TEST_GALAXY_API_KEY_UNSET";
         Environment.SetEnvironmentVariable(name, null);
 
-        var ex = Should.Throw<InvalidOperationException>(() =>
+        var ex = await Should.ThrowAsync<InvalidOperationException>(() =>
-            GalaxySecretRef.ResolveApiKey($"env:{name}"));
+            GalaxySecretRef.ResolveApiKeyAsync($"env:{name}", FakeResolver()));
         ex.Message.ShouldContain(name);
         ex.Message.ShouldContain("unset");
     }
 
     /// <summary>Verifies that file: prefix resolves to trimmed file contents.</summary>
     [Fact]
-    public void File_prefix_resolves_to_trimmed_file_contents()
+    public async Task File_prefix_resolves_to_trimmed_file_contents()
     {
         var path = Path.Combine(Path.GetTempPath(), $"galaxy-key-{Guid.NewGuid():N}.txt");
         File.WriteAllText(path, "  key-from-file  \n");
         try
         {
-            GalaxySecretRef.ResolveApiKey($"file:{path}").ShouldBe("key-from-file");
+            (await GalaxySecretRef.ResolveApiKeyAsync($"file:{path}", FakeResolver()))
+                .ShouldBe("key-from-file");
         }
         finally
         {
@@ -69,26 +83,60 @@ public sealed class GalaxyDriverApiKeyResolverTests
 
     /// <summary>Verifies that file: prefix with missing path throws.</summary>
     [Fact]
-    public void File_prefix_missing_path_throws()
+    public async Task File_prefix_missing_path_throws()
     {
         var path = Path.Combine(Path.GetTempPath(), $"does-not-exist-{Guid.NewGuid():N}.txt");
-        var ex = Should.Throw<InvalidOperationException>(() =>
+        var ex = await Should.ThrowAsync<InvalidOperationException>(() =>
-            GalaxySecretRef.ResolveApiKey($"file:{path}"));
+            GalaxySecretRef.ResolveApiKeyAsync($"file:{path}", FakeResolver()));
         ex.Message.ShouldContain(path);
         ex.Message.ShouldContain("doesn't exist");
     }
 
+    // ===== G-2a: secret: arm — resolves through the shared ISecretResolver, fail-closed =====
+
+    /// <summary>Verifies that secret: prefix resolves through the ISecretResolver.</summary>
+    [Fact]
+    public async Task Secret_prefix_resolves_through_secret_resolver()
+    {
+        (await GalaxySecretRef.ResolveApiKeyAsync($"secret:{KnownSecretName}", FakeResolver()))
+            .ShouldBe(KnownSecretValue);
+    }
+
+    /// <summary>Verifies that an absent secret throws (fail-closed) and does NOT leak the ref string.</summary>
+    [Fact]
+    public async Task Secret_prefix_absent_secret_throws_fail_closed()
+    {
+        const string missingRef = "secret:galaxy/missing/apikey";
+
+        var ex = await Should.ThrowAsync<InvalidOperationException>(() =>
+            GalaxySecretRef.ResolveApiKeyAsync(missingRef, FakeResolver()));
+
+        // Fail-closed: must throw, must reference the secret + "absent"/"fail-closed", and
+        // must NOT return the ref string as the key.
+        ex.Message.ShouldContain("galaxy/missing/apikey");
+        ex.Message.ShouldContain("absent");
+    }
+
+    /// <summary>Verifies that the secret: arm does not consult the logger's literal warning.</summary>
+    [Fact]
+    public async Task Secret_prefix_does_not_emit_literal_warning()
+    {
+        var logger = new CaptureLogger();
+        await GalaxySecretRef.ResolveApiKeyAsync($"secret:{KnownSecretName}", FakeResolver(), logger);
+        logger.Entries.ShouldNotContain(e => e.Level == LogLevel.Warning);
+    }
+
     // ===== Driver.Galaxy-010 regression: literal arm warns + dev: prefix path =====
 
     /// <summary>Verifies that literal strings emit a warning when a logger is supplied.</summary>
     [Fact]
-    public void Literal_string_emits_warning_when_logger_supplied()
+    public async Task Literal_string_emits_warning_when_logger_supplied()
     {
         // A literal API key on a production deployment means the cleartext key sits
         // in the DriverConfig JSON. The resolver must surface a warning so an
         // operator who committed one by accident sees it at startup.
         var logger = new CaptureLogger();
-        var key = GalaxySecretRef.ResolveApiKey("plain-text-key", logger);
+        var key = await GalaxySecretRef.ResolveApiKeyAsync("plain-text-key", FakeResolver(), logger);
 
         key.ShouldBe("plain-text-key");
         logger.Entries.ShouldContain(e =>
@@ -97,13 +145,13 @@ public sealed class GalaxyDriverApiKeyResolverTests
 
     /// <summary>Verifies that dev: prefix returns literal text without emitting warnings.</summary>
     [Fact]
-    public void Dev_prefix_returns_literal_without_warning()
+    public async Task Dev_prefix_returns_literal_without_warning()
     {
         // An explicit dev: prefix signals the operator knowingly opted into a literal
         // key (dev / parity rig). The resolver must accept it AND suppress the
         // warning so production logs aren't polluted on a deliberate dev choice.
         var logger = new CaptureLogger();
-        var key = GalaxySecretRef.ResolveApiKey("dev:plain-text-key", logger);
+        var key = await GalaxySecretRef.ResolveApiKeyAsync("dev:plain-text-key", FakeResolver(), logger);
 
         key.ShouldBe("plain-text-key");
         logger.Entries.ShouldNotContain(e => e.Level == LogLevel.Warning);
@@ -111,14 +159,14 @@ public sealed class GalaxyDriverApiKeyResolverTests
 
     /// <summary>Verifies that env: prefix does not emit literal string warnings.</summary>
     [Fact]
-    public void Env_prefix_does_not_emit_literal_warning()
+    public async Task Env_prefix_does_not_emit_literal_warning()
     {
         const string name = "OTOPCUA_TEST_GALAXY_API_KEY_NOWARN";
         Environment.SetEnvironmentVariable(name, "v");
         try
         {
             var logger = new CaptureLogger();
-            GalaxySecretRef.ResolveApiKey($"env:{name}", logger);
+            await GalaxySecretRef.ResolveApiKeyAsync($"env:{name}", FakeResolver(), logger);
             logger.Entries.ShouldNotContain(e => e.Level == LogLevel.Warning);
         }
         finally
@@ -127,6 +175,14 @@ public sealed class GalaxyDriverApiKeyResolverTests
         }
     }
 
+    /// <summary>Verifies that a null resolver is rejected (ArgumentNullException).</summary>
+    [Fact]
+    public async Task Null_resolver_throws()
+    {
+        await Should.ThrowAsync<ArgumentNullException>(() =>
+            GalaxySecretRef.ResolveApiKeyAsync("plain-text-key", resolver: null!));
+    }
+
     /// <summary>A test logger that captures log entries for verification.</summary>
     private sealed class CaptureLogger : ILogger
     {
@@ -144,16 +200,27 @@ public sealed class GalaxyDriverApiKeyResolverTests
             => Entries.Add((logLevel, formatter(state, exception)));
     }
 
+    /// <summary>A fake ISecretResolver returning one known value; null for every other name.</summary>
+    private sealed class StubSecretResolver : ISecretResolver
+    {
+        /// <inheritdoc />
+        public Task<string?> GetAsync(SecretName name, CancellationToken ct) =>
+            Task.FromResult<string?>(
+                string.Equals(name.Value, KnownSecretName, StringComparison.Ordinal)
+                    ? KnownSecretValue
+                    : null);
+    }
+
     /// <summary>Verifies that file: prefix with empty file throws.</summary>
     [Fact]
-    public void File_prefix_empty_file_throws()
+    public async Task File_prefix_empty_file_throws()
     {
         var path = Path.Combine(Path.GetTempPath(), $"galaxy-key-empty-{Guid.NewGuid():N}.txt");
         File.WriteAllText(path, "   \n  ");
         try
         {
-            var ex = Should.Throw<InvalidOperationException>(() =>
+            var ex = await Should.ThrowAsync<InvalidOperationException>(() =>
-                GalaxySecretRef.ResolveApiKey($"file:{path}"));
+                GalaxySecretRef.ResolveApiKeyAsync($"file:{path}", FakeResolver()));
             ex.Message.ShouldContain("empty");
         }
         finally

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/GalaxyDriverFactoryTests.cs

@@ -143,7 +143,7 @@ public sealed class GalaxyDriverFactoryTests
     public void Register_AddsFactoryToRegistry()
     {
         var registry = new DriverFactoryRegistry();
-        GalaxyDriverFactoryExtensions.Register(registry);
+        GalaxyDriverFactoryExtensions.Register(registry, NullSecretResolver.Instance);
 
         registry.RegisteredTypes.ShouldContain(GalaxyDriverFactoryExtensions.DriverTypeName);
 

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GalaxyDriverReadTests.cs

@@ -78,7 +78,7 @@ public sealed class GalaxyDriverReadTests
         // _dataReader and _subscriber are both null. The follow-up read path can't
         // synthesise a Read without one, so it surfaces a NotSupportedException
         // pointing at the misuse rather than NullRef'ing inside the pump path.
-        var driver = new GalaxyDriver("g", Opts());
+        var driver = new GalaxyDriver("g", Opts(), hierarchySource: null);
 
         var ex = await Should.ThrowAsync<NotSupportedException>(() =>
             driver.ReadAsync(["x"], CancellationToken.None));

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GalaxyDriverSubscribeTests.cs

@@ -242,7 +242,7 @@ public sealed class GalaxyDriverSubscribeTests
     [Fact]
     public async Task SubscribeAsync_NoSubscriber_Throws()
     {
-        using var driver = new GalaxyDriver("g", Opts());
+        using var driver = new GalaxyDriver("g", Opts(), hierarchySource: null);
         var ex = await Should.ThrowAsync<NotSupportedException>(() =>
             driver.SubscribeAsync(["x"], TimeSpan.FromSeconds(1), CancellationToken.None));
         ex.Message.ShouldContain("GalaxyDriver.SubscribeAsync requires");

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests/Runtime/GalaxyDriverWriteTests.cs

@@ -192,7 +192,7 @@ public sealed class GalaxyDriverWriteTests
     [Fact]
     public async Task WriteAsync_NoWriter_Throws()
     {
-        var driver = new GalaxyDriver("g", Opts());
+        var driver = new GalaxyDriver("g", Opts(), hierarchySource: null);
 
         var ex = await Should.ThrowAsync<NotSupportedException>(() =>
             driver.WriteAsync([new WriteRequest("x", 1)], CancellationToken.None));

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests/OpcUaClientSecretResolutionTests.cs

@@ -0,0 +1,95 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient;
+using ZB.MOM.WW.Secrets.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Tests;
+
+/// <summary>
+///     G-2b — pins <see cref="OpcUaClientSecretResolution.ResolveSecretRefsAsync"/>, the Layer-B
+///     arm that resolves <c>secret:</c>-prefixed <see cref="OpcUaClientDriverOptions.Password"/>
+///     and <see cref="OpcUaClientDriverOptions.UserCertificatePassword"/> through the shared
+///     <see cref="ISecretResolver"/> just before the async session-open consumes them. The
+///     <c>secret:</c> arm is fail-closed — an absent secret throws rather than leaving the
+///     <c>secret:</c> literal in place (which would be sent verbatim as the password).
+///     Non-secret literals and null/empty pass through unchanged.
+/// </summary>
+public sealed class OpcUaClientSecretResolutionTests
+{
+    private const string KnownPwName = "opcua/inst/password";
+    private const string KnownPwValue = "resolved-password-plaintext";
+    private const string KnownCertPwName = "opcua/inst/cert-pw";
+    private const string KnownCertPwValue = "resolved-cert-pw-plaintext";
+
+    /// <summary>A fake resolver: returns known values for two known names, null otherwise.</summary>
+    private static ISecretResolver FakeResolver() => new StubSecretResolver();
+
+    /// <summary>(a) A <c>secret:</c> Password resolves to the store's plaintext.</summary>
+    [Fact]
+    public async Task Secret_password_resolves_to_store_plaintext()
+    {
+        var options = new OpcUaClientDriverOptions { Password = $"secret:{KnownPwName}" };
+
+        var resolved = await OpcUaClientSecretResolution.ResolveSecretRefsAsync(
+            options, FakeResolver(), CancellationToken.None);
+
+        resolved.Password.ShouldBe(KnownPwValue);
+    }
+
+    /// <summary>(b) A <c>secret:</c> UserCertificatePassword resolves to the store's plaintext.</summary>
+    [Fact]
+    public async Task Secret_cert_password_resolves_to_store_plaintext()
+    {
+        var options = new OpcUaClientDriverOptions { UserCertificatePassword = $"secret:{KnownCertPwName}" };
+
+        var resolved = await OpcUaClientSecretResolution.ResolveSecretRefsAsync(
+            options, FakeResolver(), CancellationToken.None);
+
+        resolved.UserCertificatePassword.ShouldBe(KnownCertPwValue);
+    }
+
+    /// <summary>(c) A non-secret literal Password and a null field pass through unchanged.</summary>
+    [Fact]
+    public async Task Literal_and_null_pass_through_unchanged()
+    {
+        var options = new OpcUaClientDriverOptions
+        {
+            Password = "plainpw",
+            UserCertificatePassword = null,
+        };
+
+        var resolved = await OpcUaClientSecretResolution.ResolveSecretRefsAsync(
+            options, FakeResolver(), CancellationToken.None);
+
+        resolved.Password.ShouldBe("plainpw");
+        resolved.UserCertificatePassword.ShouldBeNull();
+    }
+
+    /// <summary>(d) An unknown <c>secret:</c> ref (resolver returns null) is fail-closed — it throws
+    ///     and never leaves the <c>secret:</c> literal in place.</summary>
+    [Fact]
+    public async Task Unknown_secret_ref_is_fail_closed()
+    {
+        var options = new OpcUaClientDriverOptions { Password = "secret:opcua/inst/absent" };
+
+        var ex = await Should.ThrowAsync<InvalidOperationException>(() =>
+            OpcUaClientSecretResolution.ResolveSecretRefsAsync(
+                options, FakeResolver(), CancellationToken.None));
+
+        ex.Message.ShouldContain("Password");
+        ex.Message.ShouldContain("opcua/inst/absent");
+    }
+
+    /// <summary>A fake resolver: returns known values for two known names, null otherwise.</summary>
+    private sealed class StubSecretResolver : ISecretResolver
+    {
+        /// <inheritdoc />
+        public Task<string?> GetAsync(SecretName name, CancellationToken ct) =>
+            Task.FromResult<string?>(name.Value switch
+            {
+                KnownPwName => KnownPwValue,
+                KnownCertPwName => KnownCertPwValue,
+                _ => null,
+            });
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.AdminUI.Tests/Uns/RawTreeServiceSecretRefRoundTripTests.cs

@@ -0,0 +1,110 @@
+using Microsoft.EntityFrameworkCore;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.AdminUI.Uns;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+
+namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Uns;
+
+/// <summary>
+/// Secrets-adoption (G-2c) regression guard: the AdminUI driver-config editor persists <c>DriverConfig</c>
+/// as an OPAQUE JSON string through <see cref="RawTreeService"/> (see <c>UpdateDriverAsync</c> /
+/// <c>CreateDriverAsync</c> — <c>entity.DriverConfig = driverConfigJson</c> verbatim, and
+/// <c>LoadDriverForEditAsync</c> reads it back verbatim). A <c>secret:</c>/<c>env:</c>/<c>file:</c>
+/// reference stored in a driver secret field (OpcUaClient <c>Password</c>/<c>UserCertificatePassword</c>,
+/// Galaxy <c>Gateway.ApiKeySecretRef</c>) MUST survive save→reload as the literal ref string — the save
+/// path must never resolve-then-resave cleartext (which would re-leak the secret into the config store and
+/// defeat G-2). Secret resolution belongs ONLY at driver-instantiation / Test-connect time (Tasks 7-8),
+/// never on the AdminUI persistence path — and indeed <see cref="RawTreeService"/> takes no secret resolver
+/// (its only dependency is the DbContext factory), so resolution is structurally impossible here.
+/// <para>
+/// Reuses the shared <see cref="RawTreeTestDb"/> InMemory fixture, matching the WP3 driver-config tests.
+/// </para>
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class RawTreeServiceSecretRefRoundTripTests
+{
+    private static (RawTreeService Service, string DbName) Seeded()
+    {
+        var name = RawTreeTestDb.SeedFresh();
+        return (new RawTreeService(RawTreeTestDb.Factory(name)), name);
+    }
+
+    private static byte[] RowVersionOf(string dbName, string driverId)
+    {
+        using var db = RawTreeTestDb.CreateNamed(dbName);
+        return db.DriverInstances.Single(d => d.DriverInstanceId == driverId).RowVersion;
+    }
+
+    [Fact]
+    public async Task UpdateDriver_preserves_OpcUaClient_secret_refs_verbatim_on_save_and_reload()
+    {
+        var (service, dbName) = Seeded();
+        var rv = RowVersionOf(dbName, RawTreeTestDb.FolderedDriverId);
+
+        // The editor emits the raw ref strings the user typed — they must NOT be resolved on save.
+        const string config =
+            "{\"Password\":\"secret:opcua/x/pw\",\"UserCertificatePassword\":\"secret:opcua/x/certpw\"}";
+
+        var result = await service.UpdateDriverAsync(
+            RawTreeTestDb.FolderedDriverId, "modbus-1", config, null, rv);
+        result.Ok.ShouldBeTrue();
+
+        // Reload through the same seam the modal uses.
+        var reloaded = await service.LoadDriverForEditAsync(RawTreeTestDb.FolderedDriverId);
+        reloaded.ShouldNotBeNull();
+
+        // Byte-identical: nothing on the save path rewrote the string.
+        reloaded!.DriverConfig.ShouldBe(config);
+        // The literal refs survived (not resolved to cleartext, not stripped).
+        reloaded.DriverConfig.ShouldContain("secret:opcua/x/pw");
+        reloaded.DriverConfig.ShouldContain("secret:opcua/x/certpw");
+
+        // And the raw column agrees with the projection.
+        using var db = RawTreeTestDb.CreateNamed(dbName);
+        db.DriverInstances.Single(d => d.DriverInstanceId == RawTreeTestDb.FolderedDriverId)
+            .DriverConfig.ShouldBe(config);
+    }
+
+    [Fact]
+    public async Task CreateDriver_preserves_Galaxy_ApiKeySecretRef_verbatim_on_save_and_reload()
+    {
+        var (service, dbName) = Seeded();
+
+        const string config = "{\"Gateway\":{\"ApiKeySecretRef\":\"secret:galaxy/x/apikey\"}}";
+
+        var created = await service.CreateDriverAsync(
+            RawTreeTestDb.ClusterId, RawTreeTestDb.RootFolderId, "galaxy-1", "Galaxy", config);
+        created.Ok.ShouldBeTrue();
+        created.CreatedId.ShouldNotBeNull();
+
+        var reloaded = await service.LoadDriverForEditAsync(created.CreatedId!);
+        reloaded.ShouldNotBeNull();
+
+        reloaded!.DriverConfig.ShouldBe(config);
+        reloaded.DriverConfig.ShouldContain("secret:galaxy/x/apikey");
+
+        using var db = RawTreeTestDb.CreateNamed(dbName);
+        db.DriverInstances.Single(d => d.DriverInstanceId == created.CreatedId)
+            .DriverConfig.ShouldBe(config);
+    }
+
+    [Fact]
+    public async Task UpdateDriver_preserves_env_and_file_ref_forms_verbatim()
+    {
+        var (service, dbName) = Seeded();
+        var rv = RowVersionOf(dbName, RawTreeTestDb.FolderedDriverId);
+
+        const string config =
+            "{\"Password\":\"env:OPCUA_PW\",\"UserCertificatePassword\":\"file:/run/secrets/certpw\"}";
+
+        var result = await service.UpdateDriverAsync(
+            RawTreeTestDb.FolderedDriverId, "modbus-1", config, null, rv);
+        result.Ok.ShouldBeTrue();
+
+        var reloaded = await service.LoadDriverForEditAsync(RawTreeTestDb.FolderedDriverId);
+        reloaded!.DriverConfig.ShouldBe(config);
+        reloaded.DriverConfig.ShouldContain("env:OPCUA_PW");
+        reloaded.DriverConfig.ShouldContain("file:/run/secrets/certpw");
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/DriverProbeRegistrationTests.cs

@@ -17,8 +17,10 @@ namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
 public sealed class DriverProbeRegistrationTests
 {
     // The canonical "all drivers" set — one entry per AdminUI typed driver page's DriverTypeKey.
-    // Keep in sync with the DriverTypeKey constants in
+    // Keep in sync with the IDriverProbe registrations in
-    // src/Server/.../Components/Pages/Clusters/Drivers/*DriverPage.razor.
+    // src/Server/.../Host/Drivers/DriverFactoryBootstrap.AddOtOpcUaDriverProbes (the routed
+    // *DriverPage.razor flow was retired in v3 Batch 2 — the driver-type keys now live in the /raw
+    // modals, but the probe set is the authority for what the AdminUI can Test-connect).
     private static readonly string[] AdminUiDriverTypeKeys =
     [
         "Modbus",
@@ -29,6 +31,7 @@ public sealed class DriverProbeRegistrationTests
         "Focas",                 // page key; probe reports "FOCAS"  — must resolve case-insensitively
         "OpcUaClient",
         "GalaxyMxGateway",
+        "Calculation",           // v3 Batch 2 pseudo-driver; CalculationProbe registered in DriverFactoryBootstrap
     ];
 
     [Fact]

tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/EquipmentNamespaceMaterializationTests.cs

@@ -4,10 +4,12 @@ using Shouldly;
 using Xunit;
 using ZB.MOM.WW.OtOpcUa.Commons.Interfaces;
 using ZB.MOM.WW.OtOpcUa.Commons.Messages.Admin;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using ZB.MOM.WW.OtOpcUa.Configuration;
 using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
 using ZB.MOM.WW.OtOpcUa.Configuration.Validation;
+using ZB.MOM.WW.OtOpcUa.OpcUaServer;
 using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
 
 namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
@@ -15,15 +17,23 @@ namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
 /// <summary>
 /// End-to-end deploy of a UNS folder hierarchy through the <b>real</b> <c>ConfigComposer</c>: seed a
 /// 1-area / 1-line / 1-equipment UNS plus a v3 raw-tag chain (RawFolder → DriverInstance → Device →
-/// Tag), <c>StartDeployment</c>, then assert the deployment's persisted artifact decodes (via
+/// Tag) + a <see cref="UnsTagReference"/> projecting the raw tag into the equipment, <c>StartDeployment</c>,
+/// then assert the deployment's persisted artifact decodes (via
 /// <see cref="DeploymentArtifact.ParseComposition"/>).
 /// <para>
-/// <b>v3 DARK address space (Batch 1):</b> the composer + artifact deliberately emit an EMPTY
+/// <b>v3 dual namespace (Batch 4):</b> the <c>AddressSpaceComposer</c> un-darkens BOTH subtrees. The
-/// equipment-tag plan set — raw-tag variable nodes are lit up in Batch 4's dual-namespace UNS↔Raw
+/// <see cref="Deploying_a_uns_hierarchy_carries_folder_nodes_and_leaves_equipment_tags_dark"/> case pins the
-/// fan-out. So the live assertion here is the DARK contract: the Area/Line/Equipment folder nodes
+/// artifact-decode invariant that the retired equipment-namespace <c>EquipmentTags</c> set stays EMPTY
-/// decode with their friendly UNS names, and <c>EquipmentTags</c> is empty EVEN THOUGH a raw tag was
+/// (values now flow through the raw + UNS variable nodes). The
-/// seeded. The full equipment-signal materialization (raw tag → EquipmentTag with FullName) is
+/// <see cref="Composing_the_seeded_config_emits_the_raw_tag_and_uns_reference_variables"/> case drives the
-/// preserved as a Batch-4-pending Skipped test below (the plan explicitly says keep it, don't delete).
+/// real <c>AddressSpaceComposer</c> over the SAME seeded config (loaded back from the deploy DB) and pins
+/// the Batch-4 dual-tree: the seeded raw tag surfaces as a Raw-realm Variable keyed by its RawPath, and the
+/// UnsTagReference surfaces as a UNS-realm Variable carrying that RawPath (the Organizes target + fan-out).
+/// <para><i>Note:</i> the composer is what WP1 lights up. WP3 migrated the artifact-decode seam
+/// (<c>DeploymentArtifact.ParseComposition</c>) to carry both realms too, so
+/// <see cref="Deployed_artifact_round_trips_both_namespaces_and_seals_on_the_cluster"/> (added in WP5) pins
+/// the dual tree through the FULL deploy → persisted-artifact → decode round-trip a driver node applies, and
+/// additionally asserts the dual-namespace deploy seals across the redundant 2-node cluster.</para>
 /// </para>
 /// <para>
 /// The OPC UA address-space browse is exercised separately against a real SDK node manager in
@@ -33,12 +43,6 @@ namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
 /// </summary>
 public sealed class EquipmentNamespaceMaterializationTests
 {
-    private const string Batch4Pending =
-        "v3 dark address space: equipment-tag variable plans (raw tag → EquipmentTag with FullName) do " +
-        "not materialize until Batch 4 (dual-namespace UNS↔Raw fan-out). The composer + artifact emit an " +
-        "empty equipment-tag plan set this batch; re-enable this full-materialization assertion (re-authored " +
-        "against the UnsTagReference fan-out) when Batch 4 lights the raw/UNS variable nodes.";
-
     private static CancellationToken Ct => TestContext.Current.CancellationToken;
 
     // Equipment.EquipmentId must equal DraftValidator.DeriveEquipmentId(EquipmentUuid) — the
@@ -95,12 +99,62 @@ public sealed class EquipmentNamespaceMaterializationTests
         composition.EquipmentTags.ShouldBeEmpty();
     }
 
-    /// <summary>BATCH-4-PENDING: the full equipment-signal materialization — the seeded raw tag decodes
+    /// <summary>BATCH-4 dual namespace: the real <see cref="AddressSpaceComposer"/> over the seeded config
-    /// (via the real ConfigComposer → ParseComposition) into an EquipmentTag carrying its FullName. Dark
+    /// (loaded back from the deploy DB) emits BOTH subtrees — the seeded raw tag as a Raw-realm Variable
-    /// until Batch 4's UNS↔Raw fan-out; preserved (not deleted) so re-enabling is a one-line change once
+    /// keyed by its RawPath, and the UnsTagReference as a UNS-realm Variable carrying that RawPath (the
-    /// the equipment-tag plan set is lit up.</summary>
+    /// Organizes UNS→Raw target + fan-out source) and inheriting the raw tag's DataType. Drives the composer
-    [Fact(Skip = Batch4Pending)]
+    /// directly (not the artifact-decode round-trip, which WP3 migrates).</summary>
-    public async Task Deploying_an_equipment_namespace_carries_the_signal_into_the_artifact()
+    [Fact]
+    public async Task Composing_the_seeded_config_emits_the_raw_tag_and_uns_reference_variables()
+    {
+        await using var harness = await TwoNodeClusterHarness.StartAsync();
+        await harness.SeedDefaultClusterAsync("c1");
+        await SeedUnsHierarchyAsync(harness);
+
+        await using var db = await CreateDbAsync(harness);
+        var composition = AddressSpaceComposer.Compose(
+            await db.UnsAreas.AsNoTracking().ToListAsync(Ct),
+            await db.UnsLines.AsNoTracking().ToListAsync(Ct),
+            await db.Equipment.AsNoTracking().ToListAsync(Ct),
+            await db.DriverInstances.AsNoTracking().ToListAsync(Ct),
+            await db.ScriptedAlarms.AsNoTracking().ToListAsync(Ct),
+            unsTagReferences: await db.UnsTagReferences.AsNoTracking().ToListAsync(Ct),
+            tags: await db.Tags.AsNoTracking().ToListAsync(Ct),
+            rawFolders: await db.RawFolders.AsNoTracking().ToListAsync(Ct),
+            devices: await db.Devices.AsNoTracking().ToListAsync(Ct),
+            tagGroups: await db.TagGroups.AsNoTracking().ToListAsync(Ct));
+
+        // Raw subtree: the seeded raw tag is a Raw-realm Variable keyed by its RawPath (Plant/Modbus/dev-1/Speed).
+        var rawTag = composition.RawTags.ShouldHaveSingleItem();
+        rawTag.TagId.ShouldBe("tag-speed");
+        rawTag.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        rawTag.NodeId.ShouldBe("Plant/Modbus/dev-1/Speed");
+        rawTag.DataType.ShouldBe("Float");
+
+        // UNS subtree: the UnsTagReference is a UNS-realm Variable carrying the backing RawPath + inherited type.
+        var unsVar = composition.UnsReferenceVariables.ShouldHaveSingleItem();
+        unsVar.Realm.ShouldBe(AddressSpaceRealm.Uns);
+        unsVar.EquipmentId.ShouldBe(EquipmentId);
+        unsVar.NodeId.ShouldBe("filling/line-1/station-1/Speed");
+        unsVar.EffectiveName.ShouldBe("Speed");
+        unsVar.BackingRawPath.ShouldBe("Plant/Modbus/dev-1/Speed"); // Organizes UNS→Raw + fan-out
+        unsVar.DataType.ShouldBe("Float");
+
+        // The retired equipment-namespace tag path stays empty (values flow through raw + UNS now).
+        composition.EquipmentTags.ShouldBeEmpty();
+    }
+
+    /// <summary>BATCH-4 harness round-trip + redundancy: deploying the seeded dual-namespace config through the
+    /// REAL deploy pipeline (AdminOperations → ConfigPublishCoordinator → BOTH DriverHostActors) seals on the
+    /// 2-node cluster, AND the persisted artifact round-trips BOTH realms via
+    /// <see cref="DeploymentArtifact.ParseComposition(System.ReadOnlySpan{byte})"/> — the raw tag as a Raw-realm
+    /// Variable keyed by its RawPath, and the UnsTagReference as a UNS-realm Variable carrying that RawPath (the
+    /// Organizes/fan-out backing path). This is the harness-level dual-namespace materialization proof: the
+    /// second namespace neither breaks redundant sealing nor is lost across artifact serialization. (WP3 migrated
+    /// the artifact-decode seam to carry both realms, so — unlike the composer-direct test above — this exercises
+    /// the full deploy → persisted-artifact → decode path a driver node actually applies.)</summary>
+    [Fact]
+    public async Task Deployed_artifact_round_trips_both_namespaces_and_seals_on_the_cluster()
     {
         await using var harness = await TwoNodeClusterHarness.StartAsync();
         await harness.SeedDefaultClusterAsync("c1");
@@ -113,29 +167,51 @@ public sealed class EquipmentNamespaceMaterializationTests
         result.Outcome.ShouldBe(StartDeploymentOutcome.Accepted, $"Deploy not accepted: {result.Message}");
         var deploymentId = result.DeploymentId!.Value.Value;
 
+        // Redundancy non-interference: the dual-namespace deploy seals after BOTH DriverHostActors apply — the
+        // second namespace does not break the redundant seal path (the ServiceLevel / primary-gate machinery
+        // is orthogonal to the address-space namespace count; see FailoverDuringDeploy / PrimaryGateFailover).
         var artifact = Array.Empty<byte>();
         await WaitForAsync(async () =>
         {
             await using var db = await CreateDbAsync(harness);
             var d = await db.Deployments.AsNoTracking()
                 .FirstOrDefaultAsync(x => x.DeploymentId == deploymentId, Ct);
-            if (d is { ArtifactBlob.Length: > 0 })
+            if (d is { Status: DeploymentStatus.Sealed, ArtifactBlob.Length: > 0 })
             {
                 artifact = d.ArtifactBlob;
                 return true;
             }
             return false;
-        }, TimeSpan.FromSeconds(15));
+        }, TimeSpan.FromSeconds(20));
 
+        await using (var db = await CreateDbAsync(harness))
+        {
+            var nodeStates = await db.NodeDeploymentStates.AsNoTracking()
+                .Where(s => s.DeploymentId == deploymentId)
+                .ToListAsync(Ct);
+            nodeStates.Count.ShouldBe(2, "both cluster nodes record a per-node deployment state");
+            nodeStates.ShouldAllBe(s => s.Status == NodeDeploymentStatus.Applied);
+        }
+
+        // Round-trip the PERSISTED artifact through the artifact-decode seam and pin the dual tree.
         var composition = DeploymentArtifact.ParseComposition(artifact);
 
-        // Batch 4: the raw tag surfaces as an EquipmentTag with FullName pulled from TagConfig.
+        // Raw subtree: the seeded raw tag survives as a Raw-realm Variable keyed by its RawPath.
-        var tag = composition.EquipmentTags.ShouldHaveSingleItem();
+        var rawTag = composition.RawTags.ShouldHaveSingleItem();
-        tag.TagId.ShouldBe("tag-speed");
+        rawTag.TagId.ShouldBe("tag-speed");
-        tag.EquipmentId.ShouldBe(EquipmentId);
+        rawTag.Realm.ShouldBe(AddressSpaceRealm.Raw);
-        tag.Name.ShouldBe("Speed");
+        rawTag.NodeId.ShouldBe("Plant/Modbus/dev-1/Speed");
-        tag.DataType.ShouldBe("Float");
+
-        tag.FullName.ShouldBe("40001");
+        // UNS subtree: the UnsTagReference survives as a UNS-realm Variable carrying the backing RawPath (the
+        // Organizes UNS→Raw target + the fan-out source).
+        var unsVar = composition.UnsReferenceVariables.ShouldHaveSingleItem();
+        unsVar.Realm.ShouldBe(AddressSpaceRealm.Uns);
+        unsVar.EquipmentId.ShouldBe(EquipmentId);
+        unsVar.NodeId.ShouldBe("filling/line-1/station-1/Speed");
+        unsVar.BackingRawPath.ShouldBe("Plant/Modbus/dev-1/Speed");
+
+        // The retired equipment-namespace tag path stays empty (values flow through raw + UNS now).
+        composition.EquipmentTags.ShouldBeEmpty();
     }
 
     private static async Task SeedUnsHierarchyAsync(TwoNodeClusterHarness harness)
@@ -170,6 +246,11 @@ public sealed class EquipmentNamespaceMaterializationTests
             Name = "Speed", DataType = "Float", AccessLevel = TagAccessLevel.Read,
             TagConfig = "{\"FullName\":\"40001\"}",
         });
+        // v3 Batch 4: the equipment projects the raw tag by reference (reference-only UNS).
+        db.UnsTagReferences.Add(new UnsTagReference
+        {
+            UnsTagReferenceId = "ref-speed", EquipmentId = EquipmentId, TagId = "tag-speed",
+        });
 
         await db.SaveChangesAsync(Ct);
     }

tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/PrimaryGateFailoverTests.cs

@@ -2,6 +2,7 @@ using Akka.Actor;
 using Akka.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 using Shouldly;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Xunit;
 using ZB.MOM.WW.OtOpcUa.Runtime;
 using ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
@@ -68,7 +69,7 @@ public sealed class PrimaryGateFailoverTests
 
     private static async Task<DriverHostActor.NodeWriteResult> RouteProbeWriteAsync(IActorRef driverHost)
         => await driverHost.Ask<DriverHostActor.NodeWriteResult>(
-            new DriverHostActor.RouteNodeWrite(UnmappedProbeNode, 0.0), TimeSpan.FromSeconds(10));
+            new DriverHostActor.RouteNodeWrite(UnmappedProbeNode, 0.0, AddressSpaceRealm.Uns), TimeSpan.FromSeconds(10));
 
     private static bool IsGateReject(DriverHostActor.NodeWriteResult r)
         => !r.Success && r.Reason is not null && r.Reason.StartsWith("not primary", StringComparison.Ordinal);

tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ResilienceInvokerFactoryRegistrationTests.cs

@@ -4,6 +4,7 @@ using Xunit;
 using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
 using ZB.MOM.WW.OtOpcUa.Core.Resilience;
 using ZB.MOM.WW.OtOpcUa.Host.Drivers;
+using ZB.MOM.WW.Secrets.Abstractions;
 
 namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
 
@@ -24,6 +25,9 @@ public sealed class ResilienceInvokerFactoryRegistrationTests
     {
         var services = new ServiceCollection();
         services.AddLogging();
+        // The driver-factory registration resolves ISecretResolver (Galaxy/OpcUaClient secret: refs);
+        // the real host always has it via AddZbSecrets (registered unconditionally). Mirror that here.
+        services.AddSingleton<ISecretResolver>(new StubSecretResolver());
         services.AddOtOpcUaDriverFactories();
 
         using var sp = services.BuildServiceProvider();
@@ -38,6 +42,9 @@ public sealed class ResilienceInvokerFactoryRegistrationTests
     {
         var services = new ServiceCollection();
         services.AddLogging();
+        // The driver-factory registration resolves ISecretResolver (Galaxy/OpcUaClient secret: refs);
+        // the real host always has it via AddZbSecrets (registered unconditionally). Mirror that here.
+        services.AddSingleton<ISecretResolver>(new StubSecretResolver());
         services.AddOtOpcUaDriverFactories();
 
         using var sp = services.BuildServiceProvider();
@@ -54,6 +61,9 @@ public sealed class ResilienceInvokerFactoryRegistrationTests
     {
         var services = new ServiceCollection();
         services.AddLogging();
+        // The driver-factory registration resolves ISecretResolver (Galaxy/OpcUaClient secret: refs);
+        // the real host always has it via AddZbSecrets (registered unconditionally). Mirror that here.
+        services.AddSingleton<ISecretResolver>(new StubSecretResolver());
         services.AddOtOpcUaDriverFactories();
 
         using var sp = services.BuildServiceProvider();
@@ -65,4 +75,12 @@ public sealed class ResilienceInvokerFactoryRegistrationTests
         sp.GetRequiredService<DriverResiliencePipelineBuilder>()
             .ShouldBeSameAs(sp.GetRequiredService<DriverResiliencePipelineBuilder>(), "builder must be a singleton");
     }
+
+    // Minimal ISecretResolver so AddOtOpcUaDriverFactories' registration (which resolves it for
+    // Galaxy/OpcUaClient secret: refs) can be built. These tests exercise no secret: refs, so
+    // returning null for every name is sufficient — the real resolver comes from AddZbSecrets.
+    private sealed class StubSecretResolver : ISecretResolver
+    {
+        public Task<string?> GetAsync(SecretName name, CancellationToken ct) => Task.FromResult<string?>(null);
+    }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests/DualNamespaceAddressSpaceTests.cs

@@ -0,0 +1,326 @@
+using System.Net;
+using System.Net.Sockets;
+using Microsoft.Extensions.Logging.Abstractions;
+using Opc.Ua;
+using Opc.Ua.Client;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP5) — the over-the-wire proof of the dual-namespace address space. Boots the real
+///     <see cref="OtOpcUaSdkServer"/> (exactly as <c>SubscriptionSurvivalTests</c> / the multi-notifier
+///     alarm test do), materialises a raw device folder + a raw tag Variable (<c>ns=Raw, s=&lt;RawPath&gt;</c>)
+///     and an equipment folder + a UNS reference Variable (<c>ns=UNS, s=&lt;Area/Line/Equip/Eff&gt;</c>) through
+///     the PRODUCTION <see cref="SdkAddressSpaceSink"/>, wires the <c>Organizes</c> UNS→Raw edge, then drives a
+///     real OPC UA client to assert:
+///     <list type="number">
+///       <item>BOTH namespace URIs (<see cref="V3NodeIds.RawNamespaceUri"/> +
+///         <see cref="V3NodeIds.UnsNamespaceUri"/>) are registered + distinct (they replaced the single
+///         <c>.../ns</c>).</item>
+///       <item>Both subtrees browse + read: the raw Variable at its RawPath NodeId and the UNS Variable at its
+///         equipment-path NodeId.</item>
+///       <item>The UNS Variable <c>Organizes</c>-references its backing raw node.</item>
+///       <item>Single-source fan-out parity: one driver publish (modelled as a
+///         <see cref="SdkAddressSpaceSink.WriteValue"/> to each NodeId with identical value/quality/timestamp)
+///         is read back IDENTICALLY on both NodeIds.</item>
+///       <item>HistoryRead via EITHER NodeId returns <c>GoodNoData</c> under the shared historian tagname (the
+///         <c>NullHistorianDataSource</c> default — the offline parity path).</item>
+///       <item>The <c>WriteOperate</c> gate is symmetric across both NodeIds: an anonymous client write is
+///         rejected identically on the raw and the UNS NodeId (fail-closed at the role gate — the POSITIVE
+///         realm-qualified routing path is unit-covered in <c>DriverHostActorWriteRoutingTests</c> /
+///         <c>NodeManagerWriteRevertTests</c>, which drive a role-carrying identity the node manager
+///         directly).</item>
+///     </list>
+///     Heavy in-process server+client integration — runs in the serial integration pass, and is fully
+///     offline-safe (no Docker / SQL / gateway; the historian read defaults to the Null source).
+/// </summary>
+public sealed class DualNamespaceAddressSpaceTests
+{
+    private const string ServerUri = "urn:OtOpcUa.DualNamespaceAddressSpace";
+
+    // Raw device tree (ns=Raw): Folder → tag Variable, both keyed by RawPath.
+    private const string RawDeviceFolder = "Plant/Modbus/dev1";
+    private const string RawTagPath = "Plant/Modbus/dev1/Speed";
+    // UNS equipment tree (ns=UNS): equipment Folder → reference Variable keyed by the equipment path.
+    private const string EquipFolder = "filling/line1/station1";
+    private const string UnsVarPath = "filling/line1/station1/Speed";
+    // Both NodeIds register the SAME historian tagname (the raw tag's RawPath).
+    private const string HistorianTagname = RawTagPath;
+
+    [Fact]
+    public async Task Both_namespaces_registered_and_both_subtrees_browse_read_and_organize()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-dualns-browse-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri, ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            MaterialiseDualTree(sink);
+            // One driver publish per NodeId (the fan-out the DriverHostActor performs) — identical payload.
+            var ts = DateTime.UtcNow;
+            sink.WriteValue(RawTagPath, 42.5f, OpcUaQuality.Good, ts, AddressSpaceRealm.Raw);
+            sink.WriteValue(UnsVarPath, 42.5f, OpcUaQuality.Good, ts, AddressSpaceRealm.Uns);
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+
+            // (1) both namespaces registered + distinct.
+            var rawNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.RawNamespaceUri);
+            var unsNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.UnsNamespaceUri);
+            rawNs.ShouldBeGreaterThan((ushort)0, "the Raw namespace must be registered");
+            unsNs.ShouldBeGreaterThan((ushort)0, "the UNS namespace must be registered");
+            rawNs.ShouldNotBe(unsNs, "the two namespaces must have distinct indices");
+
+            var rawNodeId = new NodeId(RawTagPath, rawNs);
+            var unsNodeId = new NodeId(UnsVarPath, unsNs);
+
+            // (2) both subtrees browse + read.
+            var rawValue = await session.ReadValueAsync(rawNodeId, ct);
+            var unsValue = await session.ReadValueAsync(unsNodeId, ct);
+            StatusCode.IsGood(rawValue.StatusCode).ShouldBeTrue("raw node reads Good");
+            StatusCode.IsGood(unsValue.StatusCode).ShouldBeTrue("uns node reads Good");
+            Convert.ToSingle(rawValue.Value).ShouldBe(42.5f);
+            Convert.ToSingle(unsValue.Value).ShouldBe(42.5f);
+
+            // (3) the UNS Variable Organizes-references its backing raw node.
+            var (_, refs) = await BrowseForwardAsync(session, unsNodeId, ReferenceTypeIds.Organizes);
+            var organizesRaw = refs.Any(r =>
+                r.ReferenceTypeId == ReferenceTypeIds.Organizes &&
+                r.NodeId.NamespaceIndex == rawNs &&
+                r.NodeId.ToString().Contains(RawTagPath, StringComparison.Ordinal));
+            organizesRaw.ShouldBeTrue(
+                $"the UNS variable ({UnsVarPath}) must Organizes-reference its raw node ({RawTagPath}); " +
+                $"forward Organizes refs = [{string.Join(", ", refs.Select(r => r.NodeId))}]");
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    [Fact]
+    public async Task Single_source_fans_to_both_nodeids_with_identical_value_quality_and_timestamp()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-dualns-fanout-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri + ".Fanout", ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            MaterialiseDualTree(sink);
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+            var rawNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.RawNamespaceUri);
+            var unsNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.UnsNamespaceUri);
+
+            // The single source (one RawPath) fans to the raw NodeId AND every referencing UNS NodeId with
+            // identical value/quality/timestamp — the fan-out drift invariant.
+            var ts = new DateTime(2026, 7, 16, 8, 30, 0, DateTimeKind.Utc);
+            sink.WriteValue(RawTagPath, 123.75f, OpcUaQuality.Good, ts, AddressSpaceRealm.Raw);
+            sink.WriteValue(UnsVarPath, 123.75f, OpcUaQuality.Good, ts, AddressSpaceRealm.Uns);
+
+            var rawValue = await session.ReadValueAsync(new NodeId(RawTagPath, rawNs), ct);
+            var unsValue = await session.ReadValueAsync(new NodeId(UnsVarPath, unsNs), ct);
+
+            Convert.ToSingle(unsValue.Value).ShouldBe(Convert.ToSingle(rawValue.Value));
+            unsValue.StatusCode.ShouldBe(rawValue.StatusCode);
+            unsValue.SourceTimestamp.ShouldBe(rawValue.SourceTimestamp);
+            unsValue.SourceTimestamp.ShouldBe(ts);
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    [Fact]
+    public async Task HistoryRead_via_either_nodeid_returns_GoodNoData_under_the_shared_tagname()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-dualns-hist-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri + ".History", ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            MaterialiseDualTree(sink); // both variables historized under the SAME tagname (HistorianTagname)
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+            var rawNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.RawNamespaceUri);
+            var unsNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.UnsNamespaceUri);
+
+            var rawStatus = await HistoryReadRawStatusAsync(session, new NodeId(RawTagPath, rawNs), ct);
+            var unsStatus = await HistoryReadRawStatusAsync(session, new NodeId(UnsVarPath, unsNs), ct);
+
+            // NullHistorianDataSource default: a historized node's HistoryRead surfaces GoodNoData (never an
+            // error) — identical for the raw and the UNS NodeId under the one registered historian tagname.
+            rawStatus.ShouldBe((StatusCode)StatusCodes.GoodNoData, "raw NodeId HistoryRead");
+            unsStatus.ShouldBe((StatusCode)StatusCodes.GoodNoData, "uns NodeId HistoryRead");
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    [Fact]
+    public async Task WriteOperate_gate_is_symmetric_across_both_nodeids()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-dualns-write-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri + ".Write", ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            MaterialiseDualTree(sink); // both variables writable
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+            var rawNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.RawNamespaceUri);
+            var unsNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.UnsNamespaceUri);
+
+            var rawWrite = await WriteValueStatusAsync(session, new NodeId(RawTagPath, rawNs), 7.0f, ct);
+            var unsWrite = await WriteValueStatusAsync(session, new NodeId(UnsVarPath, unsNs), 7.0f, ct);
+
+            // The anonymous session carries no WriteOperate role, so the node manager's fail-closed write gate
+            // rejects BOTH writes identically — the gate applies uniformly to the raw and the UNS NodeId (a
+            // UNS write is neither more nor less privileged than the raw write it fans from).
+            rawWrite.ShouldBe((StatusCode)StatusCodes.BadUserAccessDenied, "raw NodeId write (no WriteOperate role)");
+            unsWrite.ShouldBe(rawWrite, "uns NodeId write rejected identically to the raw NodeId");
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    /// <summary>Materialise the raw device folder + raw tag Variable, the equipment folder + UNS reference
+    /// Variable (both historized under the SAME tagname, both writable), and the Organizes UNS→Raw edge.</summary>
+    private static void MaterialiseDualTree(SdkAddressSpaceSink sink)
+    {
+        sink.EnsureFolder(RawDeviceFolder, parentNodeId: null, displayName: "dev1", realm: AddressSpaceRealm.Raw);
+        sink.EnsureVariable(RawTagPath, RawDeviceFolder, "Speed", "Float", writable: true,
+            realm: AddressSpaceRealm.Raw, historianTagname: HistorianTagname);
+
+        sink.EnsureFolder(EquipFolder, parentNodeId: null, displayName: "station1", realm: AddressSpaceRealm.Uns);
+        sink.EnsureVariable(UnsVarPath, EquipFolder, "Speed", "Float", writable: true,
+            realm: AddressSpaceRealm.Uns, historianTagname: HistorianTagname);
+
+        // Organizes UNS→Raw: the UNS variable references its backing raw node (the fan-out source).
+        sink.AddReference(UnsVarPath, AddressSpaceRealm.Uns, RawTagPath, AddressSpaceRealm.Raw, "Organizes");
+    }
+
+    private static async Task<(byte[]? ContinuationPoint, ReferenceDescriptionCollection References)>
+        BrowseForwardAsync(ISession session, NodeId node, NodeId referenceType)
+    {
+        // Match the SDK overload the codebase uses (DefaultSessionAdapter.BrowseAsync) — no trailing ct.
+        var (_, cp, refs) = await session.BrowseAsync(
+            null, null, node, 0u, BrowseDirection.Forward, referenceType,
+            includeSubtypes: true, nodeClassMask: 0u);
+        return (cp, refs ?? new ReferenceDescriptionCollection());
+    }
+
+    private static async Task<StatusCode> HistoryReadRawStatusAsync(ISession session, NodeId node, CancellationToken ct)
+    {
+        var details = new ReadRawModifiedDetails
+        {
+            StartTime = DateTime.UtcNow.AddHours(-1),
+            EndTime = DateTime.UtcNow,
+            NumValuesPerNode = 10,
+            IsReadModified = false,
+            ReturnBounds = false,
+        };
+        var nodesToRead = new HistoryReadValueIdCollection { new HistoryReadValueId { NodeId = node } };
+        var response = await session.HistoryReadAsync(
+            null, new ExtensionObject(details), TimestampsToReturn.Source, false, nodesToRead, ct);
+        response.Results.ShouldNotBeNull();
+        response.Results.Count.ShouldBe(1);
+        return response.Results[0].StatusCode;
+    }
+
+    private static async Task<StatusCode> WriteValueStatusAsync(ISession session, NodeId node, object value, CancellationToken ct)
+    {
+        var writeCollection = new WriteValueCollection
+        {
+            new WriteValue { NodeId = node, AttributeId = Attributes.Value, Value = new DataValue(new Variant(value)) },
+        };
+        var response = await session.WriteAsync(null, writeCollection, ct);
+        response.Results.ShouldNotBeNull();
+        response.Results.Count.ShouldBe(1);
+        return response.Results[0];
+    }
+
+    private static async Task<(OtOpcUaSdkServer Server, OpcUaApplicationHost Host)> BootServerAsync(
+        int port, string pkiRoot, string appUri, CancellationToken ct)
+    {
+        var options = new OpcUaApplicationHostOptions
+        {
+            ApplicationName = appUri,
+            ApplicationUri = appUri,
+            OpcUaPort = port,
+            PublicHostname = "127.0.0.1",
+            PkiStoreRoot = pkiRoot,
+            EnabledSecurityProfiles = new List<OpcUaSecurityProfile> { OpcUaSecurityProfile.None },
+            AutoAcceptUntrustedClientCertificates = true,
+        };
+        var server = new OtOpcUaSdkServer();
+        var host = new OpcUaApplicationHost(options, NullLogger<OpcUaApplicationHost>.Instance);
+        await host.StartAsync(server, ct);
+        return (server, host);
+    }
+
+    private static async Task<ISession> OpenSessionAsync(string endpointUrl, CancellationToken ct)
+    {
+        var appConfig = new ApplicationConfiguration
+        {
+            ApplicationName = "OtOpcUa.DualNamespaceClient",
+            ApplicationUri = $"urn:OtOpcUa.DualNamespaceClient.{Guid.NewGuid():N}",
+            ApplicationType = ApplicationType.Client,
+            SecurityConfiguration = TestClientSecurity.Build(TestClientSecurity.AllocatePkiRoot()),
+            ClientConfiguration = new ClientConfiguration { DefaultSessionTimeout = 60_000 },
+        };
+        await appConfig.ValidateAsync(ApplicationType.Client, ct);
+        appConfig.CertificateValidator.CertificateValidation += (_, e) => e.Accept = true;
+
+        var endpoint = await CoreClientUtils.SelectEndpointAsync(
+            appConfig, endpointUrl, false, DefaultTelemetry.Create(_ => { }), ct);
+        var endpointConfiguration = EndpointConfiguration.Create(appConfig);
+        var configuredEndpoint = new ConfiguredEndpoint(null, endpoint, endpointConfiguration);
+
+        return await new DefaultSessionFactory(DefaultTelemetry.Create(_ => { })).CreateAsync(
+            appConfig, configuredEndpoint, updateBeforeConnect: false, checkDomain: false,
+            sessionName: "DualNamespaceAddressSpaceTests", sessionTimeout: 60_000,
+            identity: new UserIdentity(new AnonymousIdentityToken()), preferredLocales: null, ct: ct);
+    }
+
+    private static int AllocateFreePort()
+    {
+        var listener = new TcpListener(IPAddress.Loopback, 0);
+        listener.Start();
+        var port = ((IPEndPoint)listener.LocalEndpoint).Port;
+        listener.Stop();
+        return port;
+    }
+
+    private static void SafeDelete(string dir)
+    {
+        if (Directory.Exists(dir))
+        {
+            try { Directory.Delete(dir, recursive: true); }
+            catch { /* best-effort */ }
+        }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests/NativeAlarmEventIdentityFieldDeliveryTests.cs

@@ -0,0 +1,257 @@
+using System.Net;
+using System.Net.Sockets;
+using Microsoft.Extensions.Logging.Abstractions;
+using Opc.Ua;
+using Opc.Ua.Client;
+using Shouldly;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests;
+
+/// <summary>
+///     Issue #473 — the over-the-wire proof that a live condition event carries the mandatory
+///     <c>BaseEventType</c> identity fields <c>EventType</c> / <c>SourceNode</c> / <c>SourceName</c>. All three
+///     previously arrived <b>null</b> on every condition event: <c>MaterialiseAlarmCondition</c> never assigned
+///     them, and nothing downstream synthesises them (<c>ReportEvent</c> / <c>InstanceStateSnapshot</c> copy the
+///     condition's children verbatim), so a conforming client could not attribute an alarm to its source.
+///
+///     <para>This is the WIRE-level guard the node-level
+///     <c>NodeManagerAlarmSourceFieldsTests</c> cannot give: it proves the values survive the snapshot +
+///     serialization all the way into a real client's <c>EventFieldList</c>. The select clause is deliberately
+///     the exact one a real consumer uses — ScadaBridge's Data Connection Layer selects
+///     <c>[EventType, SourceNode, SourceName, Time, Message, Severity]</c> — so this test fails the way that
+///     client failed.</para>
+///
+///     <para>Boots the real <see cref="OtOpcUaSdkServer"/> and drives the production
+///     <see cref="SdkAddressSpaceSink"/>, mirroring <c>NativeAlarmMultiNotifierEventDeliveryTests</c>. Heavy
+///     in-process server+client integration — runs in the serial integration pass.</para>
+/// </summary>
+public sealed class NativeAlarmEventIdentityFieldDeliveryTests
+{
+    private const string ServerUri = "urn:OtOpcUa.AlarmEventIdentityFields";
+
+    private const string RawDeviceFolder = "pymodbus/plc";
+    private const string RawAlarmPath = "pymodbus/plc/HR200";
+    private const string LeafName = "HR200";
+    private const string Equip1 = "EQ-filling-line1-station1";
+    private const string AlarmMessage = "HR200 over limit (identity-field test)";
+
+    // Field indices in the select clause built by BuildEventFilter — ScadaBridge's exact clause.
+    private const int EventTypeIndex = 0;
+    private const int SourceNodeIndex = 1;
+    private const int SourceNameIndex = 2;
+    private const int TimeIndex = 3;
+    private const int MessageIndex = 4;
+    private const int SeverityIndex = 5;
+
+    /// <summary>A live native condition event delivers a populated EventType / SourceNode / SourceName to a
+    /// Server-object subscriber using the standard BaseEventType select clause.</summary>
+    [Fact]
+    public async Task Condition_event_carries_populated_EventType_SourceNode_and_SourceName_on_the_wire()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-alarm-identity-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri, ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            WireCondition(sink);
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+            // Resolve the RAW namespace index CLIENT-side (from the server's advertised NamespaceArray) so the
+            // expected SourceNode is built exactly as a real client would resolve it.
+            var rawNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.RawNamespaceUri);
+            rawNs.ShouldBeGreaterThan((ushort)0);
+
+            var collector = new EventCollector();
+            var subscription = new Subscription(session.DefaultSubscription) { PublishingInterval = 100 };
+            subscription.FastEventCallback = collector.OnEvents;
+            session.AddSubscription(subscription);
+            await subscription.CreateAsync(ct);
+
+            // The collector filters by our unique Message, so the item's ClientHandle is not needed here
+            // (unlike the sibling multi-notifier test, which tallies delivery per monitored item).
+            AddEventItem(subscription, ObjectIds.Server);
+            await subscription.ApplyChangesAsync(ct);
+
+            sink.WriteAlarmCondition(RawAlarmPath, ActiveSnapshot(), DateTime.UtcNow, AddressSpaceRealm.Raw);
+
+            await WaitUntilAsync(() => collector.Fields.Count >= 1, TimeSpan.FromSeconds(5));
+            var fields = collector.Fields.ShouldHaveSingleItem();
+
+            // --- the three fields this issue is about ---
+            // EventType: the concrete condition type, readable as a FIELD (not just via an OfType where-clause).
+            fields[EventTypeIndex].Value.ShouldBe(ObjectTypeIds.OffNormalAlarmType,
+                "EventType must carry the concrete condition type, not null");
+
+            // SourceNode: the condition's own NodeId in the RAW namespace == ConditionId.
+            fields[SourceNodeIndex].Value.ShouldBe(new NodeId(RawAlarmPath, rawNs),
+                "SourceNode must identify the source condition node, not null");
+
+            // SourceName: the full RawPath — unique across devices, matching SourceNode/ConditionId. The leaf
+            // name (HR200) is deliberately NOT used here: it collides across PLCs and is carried by ConditionName.
+            fields[SourceNameIndex].Value.ShouldBe(RawAlarmPath,
+                "SourceName must carry the unique RawPath, not null");
+            fields[SourceNameIndex].Value.ShouldNotBe(LeafName,
+                "SourceName is deliberately the unique RawPath, not the ambiguous leaf name");
+
+            // The rest of the standard envelope still arrives intact (guards against a regression that
+            // populated identity at the cost of the existing fields).
+            fields[TimeIndex].Value.ShouldBeOfType<DateTime>();
+            ((LocalizedText)fields[MessageIndex].Value).Text.ShouldBe(AlarmMessage);
+            fields[SeverityIndex].Value.ShouldBe((ushort)700);
+
+            await subscription.DeleteAsync(true, ct);
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    /// <summary>Materialise the raw device folder + the native condition at its RawPath, plus one referencing
+    /// equipment folder wired as a notifier (the production topology).</summary>
+    private static void WireCondition(SdkAddressSpaceSink sink)
+    {
+        sink.EnsureFolder(RawDeviceFolder, parentNodeId: null, displayName: "plc", realm: AddressSpaceRealm.Raw);
+        sink.MaterialiseAlarmCondition(RawAlarmPath, RawDeviceFolder, LeafName, "OffNormalAlarm", 700, AddressSpaceRealm.Raw, isNative: true);
+        sink.EnsureFolder(Equip1, parentNodeId: null, displayName: "station1", realm: AddressSpaceRealm.Uns);
+        sink.WireAlarmNotifiers(RawAlarmPath, AddressSpaceRealm.Raw, new[] { Equip1 }, AddressSpaceRealm.Uns);
+    }
+
+    private static AlarmConditionSnapshot ActiveSnapshot() =>
+        new(Active: true, Acknowledged: false, Confirmed: true, Enabled: true,
+            Shelving: AlarmShelvingKind.Unshelved, Severity: 700, Message: AlarmMessage);
+
+    private static MonitoredItem AddEventItem(Subscription subscription, NodeId source)
+    {
+        var item = new MonitoredItem(subscription.DefaultItem)
+        {
+            StartNodeId = source,
+            AttributeId = Attributes.EventNotifier,
+            Filter = BuildEventFilter(),
+            QueueSize = 100,
+            SamplingInterval = 0,
+        };
+        subscription.AddItem(item);
+        return item;
+    }
+
+    /// <summary>ScadaBridge's exact select clause: [EventType, SourceNode, SourceName, Time, Message, Severity].</summary>
+    private static EventFilter BuildEventFilter()
+    {
+        var filter = new EventFilter();
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.EventType);
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.SourceNode);
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.SourceName);
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.Time);
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.Message);
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.Severity);
+        return filter;
+    }
+
+    /// <summary>Captures the delivered event field lists, filtered to our unique alarm Message so unrelated
+    /// server events / refresh brackets never count.</summary>
+    private sealed class EventCollector
+    {
+        private readonly object _gate = new();
+        private readonly List<VariantCollection> _fields = new();
+
+        public IReadOnlyList<VariantCollection> Fields
+        {
+            get { lock (_gate) return _fields.ToList(); }
+        }
+
+        public void OnEvents(Subscription subscription, EventNotificationList notification, IList<string> stringTable)
+        {
+            lock (_gate)
+            {
+                foreach (var e in notification.Events)
+                {
+                    if (e.EventFields.Count > MessageIndex &&
+                        e.EventFields[MessageIndex].Value is LocalizedText lt &&
+                        lt.Text == AlarmMessage)
+                    {
+                        _fields.Add(e.EventFields);
+                    }
+                }
+            }
+        }
+    }
+
+    private static async Task<(OtOpcUaSdkServer Server, OpcUaApplicationHost Host)> BootServerAsync(
+        int port, string pkiRoot, string appUri, CancellationToken ct)
+    {
+        var options = new OpcUaApplicationHostOptions
+        {
+            ApplicationName = appUri,
+            ApplicationUri = appUri,
+            OpcUaPort = port,
+            PublicHostname = "127.0.0.1",
+            PkiStoreRoot = pkiRoot,
+            EnabledSecurityProfiles = new List<OpcUaSecurityProfile> { OpcUaSecurityProfile.None },
+            AutoAcceptUntrustedClientCertificates = true,
+        };
+        var server = new OtOpcUaSdkServer();
+        var host = new OpcUaApplicationHost(options, NullLogger<OpcUaApplicationHost>.Instance);
+        await host.StartAsync(server, ct);
+        return (server, host);
+    }
+
+    private static async Task<ISession> OpenSessionAsync(string endpointUrl, CancellationToken ct)
+    {
+        var appConfig = new ApplicationConfiguration
+        {
+            ApplicationName = "OtOpcUa.AlarmEventIdentityFieldsClient",
+            ApplicationUri = $"urn:OtOpcUa.AlarmEventIdentityFieldsClient.{Guid.NewGuid():N}",
+            ApplicationType = ApplicationType.Client,
+            SecurityConfiguration = TestClientSecurity.Build(TestClientSecurity.AllocatePkiRoot()),
+            ClientConfiguration = new ClientConfiguration { DefaultSessionTimeout = 60_000 },
+        };
+        await appConfig.ValidateAsync(ApplicationType.Client, ct);
+        appConfig.CertificateValidator.CertificateValidation += (_, e) => e.Accept = true;
+
+        var endpoint = await CoreClientUtils.SelectEndpointAsync(
+            appConfig, endpointUrl, false, DefaultTelemetry.Create(_ => { }), ct);
+        var endpointConfiguration = EndpointConfiguration.Create(appConfig);
+        var configuredEndpoint = new ConfiguredEndpoint(null, endpoint, endpointConfiguration);
+
+        return await new DefaultSessionFactory(DefaultTelemetry.Create(_ => { })).CreateAsync(
+            appConfig, configuredEndpoint, updateBeforeConnect: false, checkDomain: false,
+            sessionName: "AlarmEventIdentityFieldDeliveryTests", sessionTimeout: 60_000,
+            identity: new UserIdentity(new AnonymousIdentityToken()), preferredLocales: null, ct: ct);
+    }
+
+    private static async Task WaitUntilAsync(Func<bool> condition, TimeSpan timeout)
+    {
+        var deadline = DateTime.UtcNow + timeout;
+        while (DateTime.UtcNow < deadline)
+        {
+            if (condition()) return;
+            await Task.Delay(50);
+        }
+        condition().ShouldBeTrue("condition not met within timeout");
+    }
+
+    private static int AllocateFreePort()
+    {
+        var listener = new TcpListener(IPAddress.Loopback, 0);
+        listener.Start();
+        var port = ((IPEndPoint)listener.LocalEndpoint).Port;
+        listener.Stop();
+        return port;
+    }
+
+    private static void SafeDelete(string dir)
+    {
+        if (Directory.Exists(dir))
+        {
+            try { Directory.Delete(dir, recursive: true); }
+            catch { /* best-effort */ }
+        }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests/NativeAlarmMultiNotifierEventDeliveryTests.cs

@@ -0,0 +1,282 @@
+using System.Net;
+using System.Net.Sockets;
+using Microsoft.Extensions.Logging.Abstractions;
+using Opc.Ua;
+using Opc.Ua.Client;
+using Shouldly;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP4) — the HEADLINE over-the-wire proof for the multi-notifier native alarm (Wave C
+///     review M1): a SINGLE native transition on a condition wired to MULTIPLE notifier roots (its raw
+///     device-folder parent + N referencing equipment folders) delivers <b>exactly one</b> event copy to a
+///     Server-object event subscriber — the Part 9 shared-<c>InstanceStateSnapshot</c> dedup
+///     (<c>MonitoredItem.QueueEvent</c> → <c>IsEventContainedInQueue</c>), NOT one copy per root. This is the
+///     regression guard the design's "duplicate-report fallback rejected" decision rests on, and it is exactly
+///     the multi-root topology (2 equipment folders → 2 notifier paths up to Server) where a per-root
+///     re-report would surface as double delivery.
+///
+///     <para>Boots the real <see cref="OtOpcUaSdkServer"/> exactly as <c>SubscriptionSurvivalTests</c> does,
+///     materialises the raw condition + two referencing equipment folders + the notifier wiring through the
+///     production <see cref="SdkAddressSpaceSink"/>, opens a real client subscription with event monitored
+///     items (captured via the subscription <see cref="Subscription.FastEventCallback"/>, keyed by
+///     <c>ClientHandle</c>), fires ONE transition via <see cref="SdkAddressSpaceSink.WriteAlarmCondition"/>,
+///     and counts the delivered events. Heavy in-process server+client integration — runs in the serial
+///     integration pass, not the lightweight unit sweep.</para>
+/// </summary>
+public sealed class NativeAlarmMultiNotifierEventDeliveryTests
+{
+    private const string ServerUri = "urn:OtOpcUa.MultiNotifierEventDelivery";
+
+    // The raw device-oriented topology (ns=Raw) + two referencing equipment folders (ns=UNS).
+    private const string RawDeviceFolder = "Plant/Modbus/dev1";
+    private const string RawAlarmPath = "Plant/Modbus/dev1/temp_hi";
+    private const string Equip1 = "EQ-filling-line1-station1";
+    private const string Equip2 = "EQ-filling-line2-station2";
+    private const string AlarmMessage = "over-temperature (multi-notifier test)";
+
+    // Index of the Message select clause in the event filter (see BuildEventFilter): [0]=EventId, [1]=Message.
+    private const int MessageFieldIndex = 1;
+
+    /// <summary>One native transition on a condition wired to two equipment folders delivers EXACTLY ONE event
+    /// to a Server-object subscriber (not one per notifier root) — the shared-snapshot queue dedup.</summary>
+    [Fact]
+    public async Task Single_transition_delivers_exactly_one_event_at_the_Server_object()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-multinotif-evt-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri, ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            WireSingleConditionToTwoEquipment(sink);
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+            var collector = new EventCollector();
+            var subscription = new Subscription(session.DefaultSubscription) { PublishingInterval = 100 };
+            subscription.FastEventCallback = collector.OnEvents;
+            session.AddSubscription(subscription);
+            await subscription.CreateAsync(ct);
+
+            var serverItem = AddEventItem(subscription, ObjectIds.Server);
+            await subscription.ApplyChangesAsync(ct);
+
+            // Fire ONE genuine transition (inactive+acked → active+unacked). No ConditionRefresh is issued, so
+            // the ONLY event is this transition — a per-root re-report would show up as a second copy.
+            sink.WriteAlarmCondition(RawAlarmPath, ActiveSnapshot(), DateTime.UtcNow, AddressSpaceRealm.Raw);
+
+            await WaitUntilAsync(() => collector.CountFor(serverItem.ClientHandle) >= 1, TimeSpan.FromSeconds(5));
+            // Settle past the publishing interval so any (erroneous) duplicate would have arrived.
+            await Task.Delay(TimeSpan.FromMilliseconds(700), ct);
+
+            collector.CountFor(serverItem.ClientHandle).ShouldBe(1,
+                "the single condition must deliver exactly ONE event to the Server object despite two notifier " +
+                "roots (2 equipment folders) — a per-root re-report would deliver 2.");
+
+            await subscription.DeleteAsync(true, ct);
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    /// <summary>Overlapping subscriptions: event monitored items at the Server object AND an equipment folder
+    /// each receive EXACTLY ONE copy of the one transition — the multi-root topology does not multiply delivery
+    /// to any single subscriber, and the equipment-folder subscriber (ns=UNS) sees the native alarm without
+    /// touching ns=Raw.</summary>
+    [Fact]
+    public async Task Overlapping_folder_and_server_subscriptions_each_receive_exactly_one_copy()
+    {
+        var pkiRoot = Path.Combine(Path.GetTempPath(), $"otopcua-multinotif-ovl-{Guid.NewGuid():N}");
+        var port = AllocateFreePort();
+        var ct = TestContext.Current.CancellationToken;
+        try
+        {
+            var (server, host) = await BootServerAsync(port, pkiRoot + "-srv", ServerUri + ".Overlap", ct);
+            await using var _ = host;
+
+            var sink = new SdkAddressSpaceSink(server.NodeManager!);
+            WireSingleConditionToTwoEquipment(sink);
+
+            using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
+            var unsNs = (ushort)session.NamespaceUris.GetIndex(V3NodeIds.UnsNamespaceUri);
+            unsNs.ShouldBeGreaterThan((ushort)0);
+
+            var collector = new EventCollector();
+            var subscription = new Subscription(session.DefaultSubscription) { PublishingInterval = 100 };
+            subscription.FastEventCallback = collector.OnEvents;
+            session.AddSubscription(subscription);
+            await subscription.CreateAsync(ct);
+
+            var serverItem = AddEventItem(subscription, ObjectIds.Server);
+            var equipItem = AddEventItem(subscription, new NodeId(Equip1, unsNs));
+            await subscription.ApplyChangesAsync(ct);
+
+            sink.WriteAlarmCondition(RawAlarmPath, ActiveSnapshot(), DateTime.UtcNow, AddressSpaceRealm.Raw);
+
+            await WaitUntilAsync(() =>
+                    collector.CountFor(serverItem.ClientHandle) >= 1 &&
+                    collector.CountFor(equipItem.ClientHandle) >= 1,
+                TimeSpan.FromSeconds(5));
+            await Task.Delay(TimeSpan.FromMilliseconds(700), ct);
+
+            // Each subscriber gets exactly one copy — the shared snapshot is deduped per monitored item; the
+            // multi-root topology never multiplies delivery.
+            collector.CountFor(serverItem.ClientHandle).ShouldBe(1, "Server-object subscriber");
+            collector.CountFor(equipItem.ClientHandle).ShouldBe(1, "equipment-folder subscriber (ns=UNS) sees the native alarm");
+
+            await subscription.DeleteAsync(true, ct);
+        }
+        finally
+        {
+            SafeDelete(pkiRoot + "-srv");
+        }
+    }
+
+    /// <summary>Materialise the raw device folder + the single native condition at its RawPath + two referencing
+    /// equipment folders (UNS), then wire the condition as an event notifier of both equipment folders.</summary>
+    private static void WireSingleConditionToTwoEquipment(SdkAddressSpaceSink sink)
+    {
+        sink.EnsureFolder(RawDeviceFolder, parentNodeId: null, displayName: "dev1", realm: AddressSpaceRealm.Raw);
+        sink.MaterialiseAlarmCondition(RawAlarmPath, RawDeviceFolder, "temp_hi", "OffNormalAlarm", 700, AddressSpaceRealm.Raw, isNative: true);
+        sink.EnsureFolder(Equip1, parentNodeId: null, displayName: "station1", realm: AddressSpaceRealm.Uns);
+        sink.EnsureFolder(Equip2, parentNodeId: null, displayName: "station2", realm: AddressSpaceRealm.Uns);
+        sink.WireAlarmNotifiers(RawAlarmPath, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+    }
+
+    private static AlarmConditionSnapshot ActiveSnapshot() =>
+        new(Active: true, Acknowledged: false, Confirmed: true, Enabled: true,
+            Shelving: AlarmShelvingKind.Unshelved, Severity: 700, Message: AlarmMessage);
+
+    private static MonitoredItem AddEventItem(Subscription subscription, NodeId source)
+    {
+        var item = new MonitoredItem(subscription.DefaultItem)
+        {
+            StartNodeId = source,
+            AttributeId = Attributes.EventNotifier,
+            Filter = BuildEventFilter(),
+            QueueSize = 100,
+            SamplingInterval = 0,
+        };
+        subscription.AddItem(item);
+        return item;
+    }
+
+    /// <summary>An EventFilter selecting [0]=EventId (dedup identity) and [1]=Message (our discriminator).</summary>
+    private static EventFilter BuildEventFilter()
+    {
+        var filter = new EventFilter();
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.EventId);
+        filter.AddSelectClause(ObjectTypes.BaseEventType, BrowseNames.Message);
+        return filter;
+    }
+
+    /// <summary>Collects events delivered to a subscription's <see cref="Subscription.FastEventCallback"/>,
+    /// tallying per monitored-item ClientHandle and filtering to our unique alarm Message (so unrelated server
+    /// events / refresh brackets never count).</summary>
+    private sealed class EventCollector
+    {
+        private readonly object _gate = new();
+        private readonly Dictionary<uint, int> _byHandle = new();
+
+        public void OnEvents(Subscription subscription, EventNotificationList notification, IList<string> stringTable)
+        {
+            lock (_gate)
+            {
+                foreach (var e in notification.Events)
+                {
+                    if (e.EventFields.Count > MessageFieldIndex &&
+                        e.EventFields[MessageFieldIndex].Value is LocalizedText lt &&
+                        lt.Text == AlarmMessage)
+                    {
+                        _byHandle[e.ClientHandle] = _byHandle.GetValueOrDefault(e.ClientHandle) + 1;
+                    }
+                }
+            }
+        }
+
+        public int CountFor(uint clientHandle)
+        {
+            lock (_gate) return _byHandle.GetValueOrDefault(clientHandle);
+        }
+    }
+
+    private static async Task<(OtOpcUaSdkServer Server, OpcUaApplicationHost Host)> BootServerAsync(
+        int port, string pkiRoot, string appUri, CancellationToken ct)
+    {
+        var options = new OpcUaApplicationHostOptions
+        {
+            ApplicationName = appUri,
+            ApplicationUri = appUri,
+            OpcUaPort = port,
+            PublicHostname = "127.0.0.1",
+            PkiStoreRoot = pkiRoot,
+            EnabledSecurityProfiles = new List<OpcUaSecurityProfile> { OpcUaSecurityProfile.None },
+            AutoAcceptUntrustedClientCertificates = true,
+        };
+        var server = new OtOpcUaSdkServer();
+        var host = new OpcUaApplicationHost(options, NullLogger<OpcUaApplicationHost>.Instance);
+        await host.StartAsync(server, ct);
+        return (server, host);
+    }
+
+    private static async Task<ISession> OpenSessionAsync(string endpointUrl, CancellationToken ct)
+    {
+        var appConfig = new ApplicationConfiguration
+        {
+            ApplicationName = "OtOpcUa.MultiNotifierEventDeliveryClient",
+            ApplicationUri = $"urn:OtOpcUa.MultiNotifierEventDeliveryClient.{Guid.NewGuid():N}",
+            ApplicationType = ApplicationType.Client,
+            SecurityConfiguration = TestClientSecurity.Build(TestClientSecurity.AllocatePkiRoot()),
+            ClientConfiguration = new ClientConfiguration { DefaultSessionTimeout = 60_000 },
+        };
+        await appConfig.ValidateAsync(ApplicationType.Client, ct);
+        appConfig.CertificateValidator.CertificateValidation += (_, e) => e.Accept = true;
+
+        var endpoint = await CoreClientUtils.SelectEndpointAsync(
+            appConfig, endpointUrl, false, DefaultTelemetry.Create(_ => { }), ct);
+        var endpointConfiguration = EndpointConfiguration.Create(appConfig);
+        var configuredEndpoint = new ConfiguredEndpoint(null, endpoint, endpointConfiguration);
+
+        return await new DefaultSessionFactory(DefaultTelemetry.Create(_ => { })).CreateAsync(
+            appConfig, configuredEndpoint, updateBeforeConnect: false, checkDomain: false,
+            sessionName: "MultiNotifierEventDeliveryTests", sessionTimeout: 60_000,
+            identity: new UserIdentity(new AnonymousIdentityToken()), preferredLocales: null, ct: ct);
+    }
+
+    private static async Task WaitUntilAsync(Func<bool> condition, TimeSpan timeout)
+    {
+        var deadline = DateTime.UtcNow + timeout;
+        while (DateTime.UtcNow < deadline)
+        {
+            if (condition()) return;
+            await Task.Delay(50);
+        }
+        condition().ShouldBeTrue("condition not met within timeout");
+    }
+
+    private static int AllocateFreePort()
+    {
+        var listener = new TcpListener(IPAddress.Loopback, 0);
+        listener.Start();
+        var port = ((IPEndPoint)listener.LocalEndpoint).Port;
+        listener.Stop();
+        return port;
+    }
+
+    private static void SafeDelete(string dir)
+    {
+        if (Directory.Exists(dir))
+        {
+            try { Directory.Delete(dir, recursive: true); }
+            catch { /* best-effort */ }
+        }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests/SubscriptionSurvivalTests.cs

@@ -4,6 +4,7 @@ using Microsoft.Extensions.Logging.Abstractions;
 using Opc.Ua;
 using Opc.Ua.Client;
 using Shouldly;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Xunit;
 
 namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.IntegrationTests;
@@ -65,8 +66,8 @@ public sealed class SubscriptionSurvivalTests
                 new EquipmentTagPlan("tag-a", "eq-1", "drv", FolderPath: "", Name: "A", DataType: "Int32", FullName: "1", Writable: false, Alarm: null));
             applier.MaterialiseHierarchy(withA);
             applier.MaterialiseEquipmentTags(withA);
-            var nodeIdAString = Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "A");
+            var nodeIdAString = V3NodeIds.Uns("eq-1", "A");
-            sink.WriteValue(nodeIdAString, 41, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdAString, 41, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
             // --- Open a client session + subscription + monitored item on A. ---
             using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
@@ -115,7 +116,7 @@ public sealed class SubscriptionSurvivalTests
 
             // --- A's monitored item must still be alive: a new write to A is delivered. ---
             lock (gate) received.Clear();
-            sink.WriteValue(nodeIdAString, 42, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdAString, 42, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
             await WaitUntilAsync(() => { lock (gate) return received.Any(v => Equals(v.Value, 42)); }, TimeSpan.FromSeconds(5));
             lock (gate)
@@ -125,8 +126,8 @@ public sealed class SubscriptionSurvivalTests
             }
 
             // --- B is browsable + readable (the add landed). ---
-            var nodeIdB = new NodeId(Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "B"), ns);
+            var nodeIdB = new NodeId(V3NodeIds.Uns("eq-1", "B"), ns);
-            sink.WriteValue(nodeIdB.Identifier.ToString()!, 7, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdB.Identifier.ToString()!, 7, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
             var bValue = await session.ReadValueAsync(nodeIdB, ct);
             bValue.StatusCode.ShouldNotBe(StatusCodes.BadNodeIdUnknown);
             bValue.Value.ShouldBe(7);
@@ -173,10 +174,10 @@ public sealed class SubscriptionSurvivalTests
                 new EquipmentTagPlan("tag-b", "eq-1", "drv", FolderPath: "", Name: "B", DataType: "Int32", FullName: "2", Writable: false, Alarm: null));
             applier.MaterialiseHierarchy(withAB);
             applier.MaterialiseEquipmentTags(withAB);
-            var nodeIdAString = Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "A");
+            var nodeIdAString = V3NodeIds.Uns("eq-1", "A");
-            var nodeIdBString = Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "B");
+            var nodeIdBString = V3NodeIds.Uns("eq-1", "B");
-            sink.WriteValue(nodeIdAString, 10, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdAString, 10, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
-            sink.WriteValue(nodeIdBString, 20, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdBString, 20, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
             using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
             var ns = (ushort)session.NamespaceUris.GetIndex(OtOpcUaNodeManager.DefaultNamespaceUri);
@@ -212,7 +213,7 @@ public sealed class SubscriptionSurvivalTests
             await WaitUntilAsync(() => { lock (gate) return receivedB.Any(v => StatusCode.IsBad(v.StatusCode)); }, TimeSpan.FromSeconds(5));
 
             // A stays alive: a fresh write to A is delivered.
-            sink.WriteValue(nodeIdAString, 11, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdAString, 11, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
             await WaitUntilAsync(() => { lock (gate) return receivedA.Any(v => Equals(v.Value, 11)); }, TimeSpan.FromSeconds(5));
 
             // B is gone: a re-read surfaces BadNodeIdUnknown. The 1.5.378 node-cache read path
@@ -261,8 +262,8 @@ public sealed class SubscriptionSurvivalTests
                 new EquipmentTagPlan("tag-b", "eq-1", "drv", FolderPath: "", Name: "B", DataType: "Int32", FullName: "2", Writable: false, Alarm: null));
             applier.MaterialiseHierarchy(withAB);
             applier.MaterialiseEquipmentTags(withAB);
-            var nodeIdAString = Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "A");
+            var nodeIdAString = V3NodeIds.Uns("eq-1", "A");
-            sink.WriteValue(nodeIdAString, 10, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdAString, 10, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
             using var session = await OpenSessionAsync($"opc.tcp://127.0.0.1:{port}/OtOpcUa", ct);
             var ns = (ushort)session.NamespaceUris.GetIndex(OtOpcUaNodeManager.DefaultNamespaceUri);
@@ -295,18 +296,18 @@ public sealed class SubscriptionSurvivalTests
             applier.AnnounceAddedNodes(plan);
 
             // A stays alive.
-            sink.WriteValue(nodeIdAString, 11, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdAString, 11, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
             await WaitUntilAsync(() => { lock (gate) return receivedA.Any(v => Equals(v.Value, 11)); }, TimeSpan.FromSeconds(5));
 
             // B is gone. (1.5.378 node-cache read throws for an unknown node — see above.)
-            var nodeIdB = new NodeId(Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "B"), ns);
+            var nodeIdB = new NodeId(V3NodeIds.Uns("eq-1", "B"), ns);
             var bReadEx = await Should.ThrowAsync<ServiceResultException>(
                 async () => await session.ReadValueAsync(nodeIdB, ct));
             bReadEx.StatusCode.ShouldBe(StatusCodes.BadNodeIdUnknown);
 
             // C is browsable + readable.
-            var nodeIdC = new NodeId(Commons.OpcUa.EquipmentNodeIds.Variable("eq-1", "", "C"), ns);
+            var nodeIdC = new NodeId(V3NodeIds.Uns("eq-1", "C"), ns);
-            sink.WriteValue(nodeIdC.Identifier.ToString()!, 9, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow);
+            sink.WriteValue(nodeIdC.Identifier.ToString()!, 9, Commons.OpcUa.OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
             var cRead = await session.ReadValueAsync(nodeIdC, ct);
             cRead.StatusCode.ShouldNotBe((StatusCode)StatusCodes.BadNodeIdUnknown);
             cRead.Value.ShouldBe(9);

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceApplierFailureSurfaceTests.cs

@@ -161,24 +161,24 @@ public sealed class AddressSpaceApplierFailureSurfaceTests
         public bool ThrowOnAlarmWrite { get; init; }
         public bool ThrowOnMaterialiseAlarm { get; init; }
 
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
 
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             if (ThrowOnAlarmWrite) throw new InvalidOperationException("simulated WriteAlarmCondition fault");
         }
 
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false)
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false)
         {
             if (ThrowOnMaterialiseAlarm) throw new InvalidOperationException("simulated MaterialiseAlarmCondition fault");
         }
 
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             if (ThrowOnEnsureFolder) throw new InvalidOperationException("simulated EnsureFolder fault");
         }
 
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
         {
             if (ThrowOnEnsureVariable) throw new InvalidOperationException("simulated EnsureVariable fault");
         }
@@ -188,6 +188,8 @@ public sealed class AddressSpaceApplierFailureSurfaceTests
             if (ThrowOnRebuild) throw new InvalidOperationException("simulated RebuildAddressSpace fault");
         }
 
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceApplierHierarchyTests.cs

@@ -307,24 +307,24 @@ public sealed class AddressSpaceApplierHierarchyTests : IDisposable
         /// <param name="value">The value to write.</param>
         /// <param name="quality">The OPC UA quality value.</param>
         /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>Records an alarm condition write (stub implementation for testing).</summary>
         /// <param name="alarmNodeId">The node ID of the alarm condition.</param>
         /// <param name="state">The full condition state snapshot.</param>
         /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc) { }
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>Materialises an alarm condition (stub implementation for testing).</summary>
         /// <param name="alarmNodeId">The alarm node ID (== ScriptedAlarmId).</param>
         /// <param name="equipmentNodeId">The equipment folder node ID.</param>
         /// <param name="displayName">The condition display name.</param>
         /// <param name="alarmType">The domain alarm type.</param>
         /// <param name="severity">The domain severity.</param>
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
         /// <summary>Records a folder creation request.</summary>
         /// <param name="folderNodeId">The node ID of the folder.</param>
         /// <param name="parentNodeId">The node ID of the parent folder, or null for root.</param>
         /// <param name="displayName">The display name of the folder.</param>
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => _calls.Enqueue((folderNodeId, parentNodeId, displayName));
         /// <summary>Ensures a variable exists (stub implementation for testing).</summary>
         /// <param name="variableNodeId">The node ID of the variable.</param>
@@ -333,10 +333,12 @@ public sealed class AddressSpaceApplierHierarchyTests : IDisposable
         /// <param name="dataType">The OPC UA built-in type name.</param>
         /// <param name="writable">Whether the node is created read/write.</param>
         /// <param name="historianTagname">The resolved historian tagname (null ⇒ not historized).</param>
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
         /// <summary>Rebuilds the address space (stub implementation for testing).</summary>
         public void RebuildAddressSpace() { }
         /// <summary>Announces a NodeAdded model-change (stub implementation for testing).</summary>
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceApplierProvisioningTests.cs

@@ -292,8 +292,8 @@ public sealed class AddressSpaceApplierProvisioningTests
             RemovedAlarms: Array.Empty<ScriptedAlarmPlan>(),
             ChangedAlarms: Array.Empty<AddressSpacePlan.AlarmDelta>())
         {
-            RemovedEquipmentTags = new[] { removedTag },
+            RemovedRawTags = new[] { removedTag },
-            ChangedEquipmentTags = new[] { new AddressSpacePlan.EquipmentTagDelta(prev, cur) },
+            ChangedRawTags = new[] { new AddressSpacePlan.RawTagDelta(prev, cur) },
         };
 
         applier.Apply(plan);
@@ -324,15 +324,20 @@ public sealed class AddressSpaceApplierProvisioningTests
         outcome.RebuildCalled.ShouldBeFalse(); // PureAdd — no rebuild; Apply still completed + provisioned
     }
 
-    private static EquipmentTagPlan HistorizedTag(string displayName, string? historianName, string dataType, string fullName = "ref")
+    // v3 Batch 4: historized value tags are RAW tags — the mux ref + historian default are the RawPath
-        => new("tag-" + displayName, "eq-1", "drv", FolderPath: "", Name: displayName, DataType: dataType, FullName: fullName,
+    // (== NodeId). The `fullName` param plays the role of the RawPath here (kept as a param name so the
-            Writable: false, Alarm: null, IsHistorized: true, HistorianTagname: historianName);
+    // existing assertions — HistorizedTagRef("ref"/"40001", …) — read unchanged).
+    private static RawTagPlan HistorizedTag(string displayName, string? historianName, string dataType, string fullName = "ref")
+        => new("tag-" + displayName, NodeId: fullName, ParentNodeId: null, DriverInstanceId: "drv", Name: displayName,
+            DataType: dataType, Writable: false, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>(),
+            IsHistorized: true, HistorianTagname: historianName);
 
-    private static EquipmentTagPlan NonHistorizedTag(string displayName, string dataType)
+    private static RawTagPlan NonHistorizedTag(string displayName, string dataType)
-        => new("tag-" + displayName, "eq-1", "drv", FolderPath: "", Name: displayName, DataType: dataType, FullName: "ref",
+        => new("tag-" + displayName, NodeId: "ref", ParentNodeId: null, DriverInstanceId: "drv", Name: displayName,
-            Writable: false, Alarm: null, IsHistorized: false, HistorianTagname: null);
+            DataType: dataType, Writable: false, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>(),
+            IsHistorized: false, HistorianTagname: null);
 
-    private static AddressSpacePlan PlanWithAddedTags(params EquipmentTagPlan[] tags) => new(
+    private static AddressSpacePlan PlanWithAddedTags(params RawTagPlan[] tags) => new(
         AddedEquipment: Array.Empty<EquipmentNode>(),
         RemovedEquipment: Array.Empty<EquipmentNode>(),
         ChangedEquipment: Array.Empty<AddressSpacePlan.EquipmentDelta>(),
@@ -343,6 +348,6 @@ public sealed class AddressSpaceApplierProvisioningTests
         RemovedAlarms: Array.Empty<ScriptedAlarmPlan>(),
         ChangedAlarms: Array.Empty<AddressSpacePlan.AlarmDelta>())
     {
-        AddedEquipmentTags = tags,
+        AddedRawTags = tags,
     };
 }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceApplierRawUnsTests.cs

@@ -0,0 +1,308 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
+using ZB.MOM.WW.OtOpcUa.OpcUaServer;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP3) — the applier's dual-realm materialise passes.
+///     <see cref="AddressSpaceApplier.MaterialiseRawSubtree"/> lights up the <c>ns=Raw</c> device tree
+///     (containers as folders + tags as variables, each keyed by its RawPath, all in
+///     <see cref="AddressSpaceRealm.Raw"/>); <see cref="AddressSpaceApplier.MaterialiseUnsReferences"/> lights
+///     up the <c>ns=UNS</c> reference variables (each under its equipment folder in
+///     <see cref="AddressSpaceRealm.Uns"/>) and wires an <c>Organizes</c> reference UNS→Raw. A historized raw
+///     tag's UNS reference inherits the SAME historian tagname (both NodeIds → one tagname). Every call carries
+///     its realm EXPLICITLY.
+/// </summary>
+public sealed class AddressSpaceApplierRawUnsTests
+{
+    private static AddressSpaceApplier NewApplier(RealmRecordingSink sink) =>
+        new(sink, NullLogger<AddressSpaceApplier>.Instance);
+
+    [Fact]
+    public void MaterialiseRawSubtree_creates_raw_containers_and_tags_in_raw_realm()
+    {
+        var sink = new RealmRecordingSink();
+        var composition = new AddressSpaceComposition(
+            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>())
+        {
+            RawContainers = new[]
+            {
+                new RawContainerNode("Plant", null, "Plant", RawNodeKind.Folder),
+                new RawContainerNode("Plant/Modbus", "Plant", "Modbus", RawNodeKind.Driver),
+                new RawContainerNode("Plant/Modbus/dev1", "Plant/Modbus", "dev1", RawNodeKind.Device),
+            },
+            RawTags = new[]
+            {
+                new RawTagPlan("t1", "Plant/Modbus/dev1/speed", "Plant/Modbus/dev1", "drv-1", "speed",
+                    "Float", Writable: true, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>()),
+            },
+        };
+
+        NewApplier(sink).MaterialiseRawSubtree(composition);
+
+        // Containers are folders in the Raw realm, parents-before-children.
+        sink.Folders.Select(f => (f.NodeId, f.Realm)).ShouldBe(new[]
+        {
+            ("Plant", AddressSpaceRealm.Raw),
+            ("Plant/Modbus", AddressSpaceRealm.Raw),
+            ("Plant/Modbus/dev1", AddressSpaceRealm.Raw),
+        });
+        // The tag is a variable keyed by its RawPath, in the Raw realm, parented under its group/device.
+        var v = sink.Variables.ShouldHaveSingleItem();
+        v.NodeId.ShouldBe("Plant/Modbus/dev1/speed");
+        v.Parent.ShouldBe("Plant/Modbus/dev1");
+        v.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        v.Writable.ShouldBeTrue();
+        v.HistorianTagname.ShouldBeNull();
+    }
+
+    [Fact]
+    public void MaterialiseRawSubtree_resolves_historian_tagname_default_and_override()
+    {
+        var sink = new RealmRecordingSink();
+        var composition = new AddressSpaceComposition(
+            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>())
+        {
+            RawTags = new[]
+            {
+                // Historized, no override → historian tagname defaults to the RawPath.
+                new RawTagPlan("t1", "Plant/A/dev/def", "Plant/A/dev", "drv", "def", "Float",
+                    Writable: false, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>(), IsHistorized: true),
+                // Historized with override → the override wins.
+                new RawTagPlan("t2", "Plant/A/dev/ovr", "Plant/A/dev", "drv", "ovr", "Float",
+                    Writable: false, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>(), IsHistorized: true, HistorianTagname: "WW.Override"),
+            },
+        };
+
+        NewApplier(sink).MaterialiseRawSubtree(composition);
+
+        var byId = sink.Variables.ToDictionary(v => v.NodeId);
+        byId["Plant/A/dev/def"].HistorianTagname.ShouldBe("Plant/A/dev/def"); // default = RawPath
+        byId["Plant/A/dev/ovr"].HistorianTagname.ShouldBe("WW.Override");
+    }
+
+    [Fact]
+    public void MaterialiseRawSubtree_alarm_tag_materialises_a_raw_condition_not_a_variable()
+    {
+        var sink = new RealmRecordingSink();
+        var composition = new AddressSpaceComposition(
+            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>())
+        {
+            RawTags = new[]
+            {
+                new RawTagPlan("t1", "Plant/A/dev/OverTemp", "Plant/A/dev", "drv", "OverTemp", "Boolean",
+                    Writable: false, Alarm: new EquipmentTagAlarmInfo("OffNormalAlarm", 700),
+                    ReferencingEquipmentPaths: Array.Empty<string>()),
+            },
+        };
+
+        NewApplier(sink).MaterialiseRawSubtree(composition);
+
+        sink.Variables.ShouldBeEmpty(); // an alarm tag is a condition, not a value variable
+        var c = sink.Conditions.ShouldHaveSingleItem();
+        c.NodeId.ShouldBe("Plant/A/dev/OverTemp"); // ConditionId == RawPath
+        c.Parent.ShouldBe("Plant/A/dev");
+        c.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        c.IsNative.ShouldBeTrue();
+        // No referencing equipment ⇒ no multi-notifier wiring.
+        sink.NotifierWirings.ShouldBeEmpty();
+    }
+
+    [Fact]
+    public void MaterialiseRawSubtree_alarm_tag_wires_a_notifier_per_referencing_equipment_folder()
+    {
+        var sink = new RealmRecordingSink();
+        // UNS topology so the alarm's referencing-equipment PATHS (Area/Line/Equipment) resolve to the
+        // EquipmentId the equipment folders were materialised under. Two equipment reference the one alarm tag.
+        var composition = new AddressSpaceComposition(
+            new[] { new UnsAreaProjection("a1", "filling") },
+            new[] { new UnsLineProjection("l1", "a1", "line1"), new UnsLineProjection("l2", "a1", "line2") },
+            new[]
+            {
+                new EquipmentNode("EQ-1", "station1", "l1"),
+                new EquipmentNode("EQ-2", "station2", "l2"),
+            },
+            Array.Empty<DriverInstancePlan>(),
+            Array.Empty<ScriptedAlarmPlan>())
+        {
+            RawTags = new[]
+            {
+                new RawTagPlan("t1", "Plant/A/dev/OverTemp", "Plant/A/dev", "drv", "OverTemp", "Boolean",
+                    Writable: false, Alarm: new EquipmentTagAlarmInfo("OffNormalAlarm", 700),
+                    // The composer emits Area/Line/Equipment NAME paths here.
+                    ReferencingEquipmentPaths: new[] { "filling/line1/station1", "filling/line2/station2" }),
+            },
+        };
+
+        NewApplier(sink).MaterialiseRawSubtree(composition);
+
+        // The single condition is materialised ONCE at the RawPath (Raw realm)...
+        var c = sink.Conditions.ShouldHaveSingleItem();
+        c.NodeId.ShouldBe("Plant/A/dev/OverTemp");
+        c.Realm.ShouldBe(AddressSpaceRealm.Raw);
+        // ...and wired as a notifier of BOTH referencing equipment folders — resolved from the name paths to the
+        // logical EquipmentId folder NodeIds, in the Uns realm. ONE wiring call (single condition), not per-root.
+        var w = sink.NotifierWirings.ShouldHaveSingleItem();
+        w.AlarmNodeId.ShouldBe("Plant/A/dev/OverTemp");
+        w.AlarmRealm.ShouldBe(AddressSpaceRealm.Raw);
+        w.FolderRealm.ShouldBe(AddressSpaceRealm.Uns);
+        w.FolderNodeIds.ShouldBe(new[] { "EQ-1", "EQ-2" }, ignoreOrder: true);
+    }
+
+    /// <summary>
+    ///     Wave C review M2 — composer↔applier PATH-AGREEMENT (the tripwire for the latent DisplayName==Name
+    ///     coupling). The composer builds a native alarm's <c>ReferencingEquipmentPaths</c> from the
+    ///     Area/Line/Equipment <c>Name</c>s; the applier's <c>BuildEquipmentIdByFolderPath</c> inverts those
+    ///     paths back to the <c>EquipmentId</c> via the projected DisplayName. Feed a REAL composer output
+    ///     (not a hand-built plan) through <see cref="AddressSpaceApplier.MaterialiseRawSubtree"/> and assert
+    ///     the notifier wired to exactly the backing equipment's id — proving the two path constructions agree
+    ///     end-to-end. If a future editable Area/Line display-name feature made <c>DisplayName != Name</c>, this
+    ///     inversion (and thus the native-alarm fan-out) would break with no deploy error; this test trips first.
+    /// </summary>
+    [Fact]
+    public void Composer_referencing_equipment_paths_resolve_back_to_equipment_ids_in_the_applier()
+    {
+        // Real config: a raw alarm tag (Speed) referenced by one equipment (eq-1 under Area "filling" /
+        // Line "line-1" / Equipment "station-1").
+        var folder = new RawFolder { RawFolderId = "raw-plant", ClusterId = "c1", Name = "Plant" };
+        var driver = new DriverInstance
+        {
+            DriverInstanceId = "drv-modbus", ClusterId = "c1", RawFolderId = "raw-plant",
+            Name = "Modbus1", DriverType = "Modbus", DriverConfig = "{}",
+        };
+        var device = new Device { DeviceId = "dev-1", DriverInstanceId = "drv-modbus", Name = "PLC-A", DeviceConfig = "{}" };
+        var speed = new Tag
+        {
+            TagId = "t-speed", DeviceId = "dev-1", Name = "Speed", DataType = "Float",
+            AccessLevel = TagAccessLevel.Read,
+            TagConfig = "{\"alarm\":{\"alarmType\":\"OffNormalAlarm\",\"severity\":700}}",
+        };
+        var area = new UnsArea { UnsAreaId = "area-1", ClusterId = "c1", Name = "filling" };
+        var line = new UnsLine { UnsLineId = "line-1", UnsAreaId = "area-1", Name = "line-1" };
+        var equip = new Equipment { EquipmentId = "eq-1", UnsLineId = "line-1", Name = "station-1", MachineCode = "STATION_001" };
+        var refSpeed = new UnsTagReference { UnsTagReferenceId = "ref-speed", EquipmentId = "eq-1", TagId = "t-speed" };
+
+        var composition = AddressSpaceComposer.Compose(
+            new[] { area }, new[] { line }, new[] { equip },
+            new[] { driver }, Array.Empty<ScriptedAlarm>(),
+            unsTagReferences: new[] { refSpeed },
+            tags: new[] { speed },
+            rawFolders: new[] { folder },
+            devices: new[] { device },
+            tagGroups: Array.Empty<TagGroup>());
+
+        // The composer emitted the alarm tag's referencing-equipment path from the Area/Line/Equipment Names.
+        var alarmTag = composition.RawTags.Single(t => t.Alarm is not null);
+        alarmTag.ReferencingEquipmentPaths.ShouldBe(new[] { V3NodeIds.Uns("filling", "line-1", "station-1") });
+
+        // The applier inverts that path back to the EquipmentId folder and wires the notifier there.
+        var sink = new RealmRecordingSink();
+        NewApplier(sink).MaterialiseRawSubtree(composition);
+
+        var w = sink.NotifierWirings.ShouldHaveSingleItem();
+        w.AlarmNodeId.ShouldBe(alarmTag.NodeId);
+        w.FolderNodeIds.ShouldBe(new[] { "eq-1" }); // resolved path → EquipmentId
+    }
+
+    /// <summary>Wave C review M2 — when a native alarm HAS referencing equipment paths but NONE resolve to an
+    /// equipment folder (broken ancestry / the latent coupling breaking), the applier surfaces it as a failed
+    /// node (so the degraded-apply meter fires) instead of silently skipping — no notifier is wired, but the
+    /// condition itself is still materialised.</summary>
+    [Fact]
+    public void MaterialiseRawSubtree_alarm_with_unresolvable_referencing_equipment_counts_as_failed()
+    {
+        var sink = new RealmRecordingSink();
+        // No equipment nodes in the composition → the referencing path can't resolve to an EquipmentId folder.
+        var composition = new AddressSpaceComposition(
+            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>())
+        {
+            RawTags = new[]
+            {
+                new RawTagPlan("t1", "Plant/A/dev/OverTemp", "Plant/A/dev", "drv", "OverTemp", "Boolean",
+                    Writable: false, Alarm: new EquipmentTagAlarmInfo("OffNormalAlarm", 700),
+                    ReferencingEquipmentPaths: new[] { "filling/line1/ghost" }),
+            },
+        };
+
+        var failed = NewApplier(sink).MaterialiseRawSubtree(composition);
+
+        failed.ShouldBeGreaterThanOrEqualTo(1); // resolution failure surfaced (not a silent skip)
+        sink.NotifierWirings.ShouldBeEmpty();   // nothing wired
+        sink.Conditions.ShouldHaveSingleItem(); // the condition itself still materialised
+    }
+
+    [Fact]
+    public void MaterialiseUnsReferences_creates_uns_variable_and_organizes_edge_inheriting_historian()
+    {
+        var sink = new RealmRecordingSink();
+        var composition = new AddressSpaceComposition(
+            Array.Empty<EquipmentNode>(), Array.Empty<DriverInstancePlan>(), Array.Empty<ScriptedAlarmPlan>())
+        {
+            RawTags = new[]
+            {
+                // Backing raw tag: historized with an override → the UNS ref must register the SAME tagname.
+                new RawTagPlan("t1", "Plant/A/dev/speed", "Plant/A/dev", "drv", "speed", "Float",
+                    Writable: true, Alarm: null, ReferencingEquipmentPaths: new[] { "filling/line1/station1" },
+                    IsHistorized: true, HistorianTagname: "WW.Speed"),
+            },
+            UnsReferenceVariables = new[]
+            {
+                new UnsReferenceVariable("r1", "EQ-1", "filling/line1/station1/speed", "speed",
+                    "Plant/A/dev/speed", "Float", Writable: true),
+            },
+        };
+
+        NewApplier(sink).MaterialiseUnsReferences(composition);
+
+        // The UNS reference is a variable in the Uns realm, parented under its equipment folder (EquipmentId).
+        var v = sink.Variables.ShouldHaveSingleItem();
+        v.NodeId.ShouldBe("filling/line1/station1/speed");
+        v.Parent.ShouldBe("EQ-1");
+        v.Realm.ShouldBe(AddressSpaceRealm.Uns);
+        v.Writable.ShouldBeTrue();
+        v.HistorianTagname.ShouldBe("WW.Speed"); // inherited from the backing historized raw tag
+
+        // An Organizes reference UNS→Raw links the two.
+        var r = sink.References.ShouldHaveSingleItem();
+        r.Source.ShouldBe("filling/line1/station1/speed");
+        r.SourceRealm.ShouldBe(AddressSpaceRealm.Uns);
+        r.Target.ShouldBe("Plant/A/dev/speed");
+        r.TargetRealm.ShouldBe(AddressSpaceRealm.Raw);
+        r.ReferenceType.ShouldBe("Organizes");
+    }
+
+    /// <summary>A capturing sink that records (nodeId, realm) for every materialise + the Organizes edges.</summary>
+    private sealed class RealmRecordingSink : IOpcUaAddressSpaceSink
+    {
+        public List<(string NodeId, string? Parent, AddressSpaceRealm Realm)> Folders { get; } = new();
+        public List<(string NodeId, string? Parent, bool Writable, string? HistorianTagname, AddressSpaceRealm Realm)> Variables { get; } = new();
+        public List<(string NodeId, string? Parent, bool IsNative, AddressSpaceRealm Realm)> Conditions { get; } = new();
+        public List<(string Source, AddressSpaceRealm SourceRealm, string Target, AddressSpaceRealm TargetRealm, string ReferenceType)> References { get; } = new();
+        public List<(string AlarmNodeId, AddressSpaceRealm AlarmRealm, IReadOnlyList<string> FolderNodeIds, AddressSpaceRealm FolderRealm)> NotifierWirings { get; } = new();
+
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm)
+            => Folders.Add((folderNodeId, parentNodeId, realm));
+
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+            => Variables.Add((variableNodeId, parentFolderNodeId, writable, historianTagname, realm));
+
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false)
+            => Conditions.Add((alarmNodeId, equipmentNodeId, isNative, realm));
+
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm)
+            => NotifierWirings.Add((alarmNodeId, alarmRealm, notifierFolderNodeIds, notifierFolderRealm));
+
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes")
+            => References.Add((sourceNodeId, sourceRealm, targetNodeId, targetRealm, referenceType));
+
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm) { }
+        public void RebuildAddressSpace() { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm) { }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceApplierTests.cs

@@ -148,7 +148,7 @@ public sealed class AddressSpaceApplierTests
         // A ReadWrite plan threads Writable: true through the applier to the sink (the node is created CurrentReadWrite).
         sink.VariableCalls.ShouldHaveSingleItem().ShouldBe(("eq-1/Speed", "eq-1", "Speed", "Float", true));
         // Parity: the materialiser's NodeId is the shared EquipmentNodeIds formula (null/empty FolderPath).
-        sink.VariableCalls.Single().NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        sink.VariableCalls.Single().NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Speed"));
     }
 
     /// <summary>Verifies a FolderPath on an equipment tag becomes a sub-folder UNDER the equipment
@@ -175,7 +175,7 @@ public sealed class AddressSpaceApplierTests
         // A Read plan threads Writable: false (the node stays CurrentRead).
         sink.VariableCalls.ShouldHaveSingleItem().ShouldBe(("eq-1/Diagnostics/Temp", "eq-1/Diagnostics", "Temp", "Float", false));
         // Parity: the materialiser's NodeId is the shared EquipmentNodeIds formula (with FolderPath).
-        sink.VariableCalls.Single().NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "Diagnostics", "Temp"));
+        sink.VariableCalls.Single().NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Diagnostics", "Temp"));
     }
 
     /// <summary>Regression for the FullName-as-NodeId collision: two identical machines exposing the
@@ -228,13 +228,13 @@ public sealed class AddressSpaceApplierTests
         applier.MaterialiseEquipmentTags(composition);
 
         // The plain tag drove EnsureVariable at its folder-scoped NodeId, and NOT a condition.
-        var plainNodeId = EquipmentNodeIds.Variable("eq-1", "", "Speed");
+        var plainNodeId = V3NodeIds.Uns("eq-1", "Speed");
         sink.VariableCalls.ShouldHaveSingleItem().ShouldBe((plainNodeId, "eq-1", "Speed", "Float", true));
         sink.AlarmConditionCalls.ShouldNotContain(c => c.AlarmNodeId == plainNodeId);
 
         // The alarm tag drove MaterialiseAlarmCondition (folder-scoped NodeId, equipment parent,
         // matching display/type/severity) and did NOT drive EnsureVariable.
-        var alarmNodeId = EquipmentNodeIds.Variable("eq-1", "", "OverTemp");
+        var alarmNodeId = V3NodeIds.Uns("eq-1", "OverTemp");
         // A native equipment-tag alarm: the call-site threads isNative: true.
         sink.AlarmConditionCalls.ShouldHaveSingleItem()
             .ShouldBe((alarmNodeId, "eq-1", "OverTemp", "OffNormalAlarm", 700, true));
@@ -264,7 +264,7 @@ public sealed class AddressSpaceApplierTests
         // The sub-folder is still created for an alarm tag with a FolderPath.
         sink.FolderCalls.ShouldHaveSingleItem().ShouldBe(("eq-1/Diagnostics", "eq-1", "Diagnostics"));
         // Condition is parented to the sub-folder, with the folder-scoped NodeId. No value variable.
-        var alarmNodeId = EquipmentNodeIds.Variable("eq-1", "Diagnostics", "OverTemp");
+        var alarmNodeId = V3NodeIds.Uns("eq-1", "Diagnostics", "OverTemp");
         // A native equipment-tag alarm (with a FolderPath): the call-site still threads isNative: true.
         sink.AlarmConditionCalls.ShouldHaveSingleItem()
             .ShouldBe((alarmNodeId, "eq-1/Diagnostics", "OverTemp", "OffNormalAlarm", 500, true));
@@ -300,9 +300,9 @@ public sealed class AddressSpaceApplierTests
         applier.MaterialiseEquipmentTags(composition);
 
         var byNode = sink.HistorianCalls.ToDictionary(c => c.NodeId, c => c.HistorianTagname);
-        byNode[EquipmentNodeIds.Variable("eq-1", "", "ADefault")].ShouldBe("T.A");          // default ⇒ FullName
+        byNode[V3NodeIds.Uns("eq-1", "ADefault")].ShouldBe("T.A");          // default ⇒ FullName
-        byNode[EquipmentNodeIds.Variable("eq-1", "", "BOverride")].ShouldBe("WW.Override");  // override verbatim
+        byNode[V3NodeIds.Uns("eq-1", "BOverride")].ShouldBe("WW.Override");  // override verbatim
-        byNode[EquipmentNodeIds.Variable("eq-1", "", "CPlain")].ShouldBeNull();              // not historized ⇒ null
+        byNode[V3NodeIds.Uns("eq-1", "CPlain")].ShouldBeNull();              // not historized ⇒ null
     }
 
     /// <summary>Phase C Task 2 — a historized tag whose override is blank/whitespace still falls back to
@@ -326,7 +326,7 @@ public sealed class AddressSpaceApplierTests
         applier.MaterialiseEquipmentTags(composition);
 
         var call = sink.HistorianCalls.ShouldHaveSingleItem();
-        call.NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        call.NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Speed"));
         call.HistorianTagname.ShouldBe("40001");
     }
 
@@ -353,7 +353,7 @@ public sealed class AddressSpaceApplierTests
         applier.MaterialiseEquipmentTags(composition);
 
         var call = sink.ArrayCalls.ShouldHaveSingleItem();
-        call.NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Buffer"));
+        call.NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Buffer"));
         call.IsArray.ShouldBeTrue();
         call.ArrayLength.ShouldBe(16u);
     }
@@ -380,7 +380,7 @@ public sealed class AddressSpaceApplierTests
         applier.MaterialiseEquipmentTags(composition);
 
         var call = sink.ArrayCalls.ShouldHaveSingleItem();
-        call.NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        call.NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Speed"));
         call.IsArray.ShouldBeFalse();
         call.ArrayLength.ShouldBeNull();
     }
@@ -471,11 +471,11 @@ public sealed class AddressSpaceApplierTests
         // VirtualTags are computed outputs — always read-only (Writable: false).
         sink.VariableCalls.ShouldHaveSingleItem().ShouldBe(("eq-1/speed-rpm", "eq-1", "speed-rpm", "Float64", false));
         // Parity: the vtag materialiser's NodeId is the shared EquipmentNodeIds formula.
-        sink.VariableCalls.Single().NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "speed-rpm"));
+        sink.VariableCalls.Single().NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "speed-rpm"));
     }
 
     /// <summary>Golden/parity guard: the materialiser's Variable NodeId for BOTH the equipment-tag and
-    /// the equipment-VirtualTag pass is byte-identical to <see cref="EquipmentNodeIds.Variable"/> — the
+    /// the equipment-VirtualTag pass is byte-identical to <c>V3NodeIds.Uns</c> — the
     /// single source of truth AddressSpaceApplier + VirtualTagHostActor both point at. Covers null/empty
     /// FolderPath (directly under equipment) and a non-empty FolderPath (sub-folder scoped). This test
     /// LOCKS the formula against drift: any change to the materialiser NodeId that diverges from the
@@ -507,10 +507,10 @@ public sealed class AddressSpaceApplierTests
         applier.MaterialiseEquipmentVirtualTags(composition);
 
         var nodeIds = sink.VariableCalls.Select(v => v.NodeId).ToList();
-        nodeIds.ShouldContain(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        nodeIds.ShouldContain(V3NodeIds.Uns("eq-1", "Speed"));
-        nodeIds.ShouldContain(EquipmentNodeIds.Variable("eq-1", "Diagnostics", "Temp"));
+        nodeIds.ShouldContain(V3NodeIds.Uns("eq-1", "Diagnostics", "Temp"));
-        nodeIds.ShouldContain(EquipmentNodeIds.Variable("eq-2", "", "Efficiency"));
+        nodeIds.ShouldContain(V3NodeIds.Uns("eq-2", "Efficiency"));
-        nodeIds.ShouldContain(EquipmentNodeIds.Variable("eq-2", "Calc", "Avg"));
+        nodeIds.ShouldContain(V3NodeIds.Uns("eq-2", "Calc", "Avg"));
     }
 
     /// <summary>Two VirtualTags under the SAME equipment produce two distinct folder-scoped variables
@@ -760,7 +760,7 @@ public sealed class AddressSpaceApplierTests
         outcome.RebuildCalled.ShouldBeFalse();
         sink.RebuildCalls.ShouldBe(0);
         var call = sink.SurgicalCalls.ShouldHaveSingleItem();
-        call.NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        call.NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Speed"));
         call.Writable.ShouldBeTrue();
     }
 
@@ -815,7 +815,7 @@ public sealed class AddressSpaceApplierTests
 
         outcome.RebuildCalled.ShouldBeFalse();
         sink.RebuildCalls.ShouldBe(0);
-        var nodeId = EquipmentNodeIds.Variable("eq-1", "", "Speed");
+        var nodeId = V3NodeIds.Uns("eq-1", "Speed");
         // Terminal Bad written to the removed variable BEFORE the removal.
         sink.ValueWrites.ShouldContain((nodeId, OpcUaQuality.Bad));
         sink.RemoveCalls.ShouldHaveSingleItem().ShouldBe(("var", nodeId));
@@ -842,7 +842,7 @@ public sealed class AddressSpaceApplierTests
         var outcome = applier.Apply(plan);
 
         outcome.RebuildCalled.ShouldBeFalse();
-        var nodeId = EquipmentNodeIds.Variable("eq-1", "", "OverTemp");
+        var nodeId = V3NodeIds.Uns("eq-1", "OverTemp");
         // Terminal RemovedConditionState (inactive/acked/confirmed) written to the condition node.
         var write = sink.AlarmWrites.ShouldHaveSingleItem();
         write.NodeId.ShouldBe(nodeId);
@@ -953,7 +953,7 @@ public sealed class AddressSpaceApplierTests
         outcome.RebuildCalled.ShouldBeFalse();
         sink.RebuildCalls.ShouldBe(0);
         // The removed node is torn down in place; the add is left to the publish actor's materialise passes.
-        sink.RemoveCalls.ShouldHaveSingleItem().ShouldBe(("var", EquipmentNodeIds.Variable("eq-1", "", "Old")));
+        sink.RemoveCalls.ShouldHaveSingleItem().ShouldBe(("var", V3NodeIds.Uns("eq-1", "Old")));
         outcome.AddedNodes.ShouldBe(1);
         outcome.RemovedNodes.ShouldBe(1);
     }
@@ -967,7 +967,7 @@ public sealed class AddressSpaceApplierTests
         var sink = new RecordingSink();
         var applier = new AddressSpaceApplier(sink, NullLogger<AddressSpaceApplier>.Instance);
 
-        var nodeId = EquipmentNodeIds.Variable("eq-1", "", "Slot");
+        var nodeId = V3NodeIds.Uns("eq-1", "Slot");
         var plan = EmptyPlan with
         {
             // Different TagId, but both resolve to the SAME folder-scoped NodeId (eq-1/Slot).
@@ -1457,8 +1457,8 @@ public sealed class AddressSpaceApplierTests
         sink.RebuildCalls.ShouldBe(0);
         outcome.RemovedNodes.ShouldBe(2); // both removals counted
         sink.RemoveCalls.Count.ShouldBe(2);
-        sink.RemoveCalls.ShouldContain(("var", EquipmentNodeIds.Variable("eq-1", "", "Speed")));
+        sink.RemoveCalls.ShouldContain(("var", V3NodeIds.Uns("eq-1", "Speed")));
-        sink.RemoveCalls.ShouldContain(("var", EquipmentNodeIds.Variable("eq-1", "", "Efficiency")));
+        sink.RemoveCalls.ShouldContain(("var", V3NodeIds.Uns("eq-1", "Efficiency")));
     }
 
     // ----- F10b: surgical in-place tag-attribute writes (Writable / IsHistorized / HistorianTagname) -----
@@ -1490,7 +1490,7 @@ public sealed class AddressSpaceApplierTests
         outcome.RebuildCalled.ShouldBeFalse();
         sink.RebuildCalls.ShouldBe(0);                 // NO RebuildAddressSpace — subscriptions preserved
         var call = sink.SurgicalCalls.ShouldHaveSingleItem();
-        call.NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        call.NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Speed"));
         call.Writable.ShouldBeTrue();                  // the NEW Writable value
         call.Historian.ShouldBeNull();                 // not historized
         outcome.ChangedNodes.ShouldBe(1);
@@ -1584,7 +1584,7 @@ public sealed class AddressSpaceApplierTests
         outcome.RebuildCalled.ShouldBeFalse();
         sink.RebuildCalls.ShouldBe(0);                 // NO rebuild — subscriptions preserved
         var call = sink.SurgicalCalls.ShouldHaveSingleItem();
-        call.NodeId.ShouldBe(EquipmentNodeIds.Variable("eq-1", "", "Speed"));
+        call.NodeId.ShouldBe(V3NodeIds.Uns("eq-1", "Speed"));
         call.DataType.ShouldBe("Int32");               // the NEW DataType
         call.Writable.ShouldBeTrue();                  // the NEW Writable, applied in the same call
         call.IsArray.ShouldBeFalse();
@@ -1781,8 +1781,8 @@ public sealed class AddressSpaceApplierTests
         sink.SurgicalCalls.Count.ShouldBe(2);
 
         // Both expected node ids must appear (order is not guaranteed).
-        var nodeId1 = EquipmentNodeIds.Variable("eq-1", "", "Speed");
+        var nodeId1 = V3NodeIds.Uns("eq-1", "Speed");
-        var nodeId2 = EquipmentNodeIds.Variable("eq-1", "", "Pressure");
+        var nodeId2 = V3NodeIds.Uns("eq-1", "Pressure");
         sink.SurgicalCalls.ShouldContain(c => c.NodeId == nodeId1 && c.Writable);
         sink.SurgicalCalls.ShouldContain(c => c.NodeId == nodeId2 && c.Writable);
 
@@ -2040,7 +2040,7 @@ public sealed class AddressSpaceApplierTests
             },
         };
 
-        applier.ComputeAddAnnouncements(plan).ShouldBe(new[] { EquipmentNodeIds.SubFolder("eq-1", "Diag") });
+        applier.ComputeAddAnnouncements(plan).ShouldBe(new[] { V3NodeIds.Uns("eq-1", "Diag") });
     }
 
     /// <summary>An added scripted alarm announces its equipment folder (where its condition node parents).</summary>
@@ -2101,7 +2101,7 @@ public sealed class AddressSpaceApplierTests
         applier.AnnounceAddedNodes(plan);
 
         sink.ModelChangeCalls.OrderBy(x => x).ShouldBe(
-            new[] { "eq-1", EquipmentNodeIds.SubFolder("eq-1", "Diag"), "line-7" }.OrderBy(x => x));
+            new[] { "eq-1", V3NodeIds.Uns("eq-1", "Diag"), "line-7" }.OrderBy(x => x));
     }
 
     private static AddressSpaceComposition CompositionWithAreas(params UnsAreaProjection[] areas) =>
@@ -2170,7 +2170,7 @@ public sealed class AddressSpaceApplierTests
         /// <param name="dataType">The new OPC UA data type name to apply in place.</param>
         /// <param name="isArray">The new array-ness of the node.</param>
         /// <param name="arrayLength">The new 1-D array length when <paramref name="isArray"/> is true.</param>
-        public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
+        public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             SurgicalQueue.Enqueue((variableNodeId, writable, historianTagname, dataType, isArray, arrayLength));
             return SurgicalReturns;
@@ -2187,7 +2187,7 @@ public sealed class AddressSpaceApplierTests
         /// <summary>Records a surgical in-place folder display-name update; returns <see cref="FolderRenameReturns"/>.</summary>
         /// <param name="folderNodeId">The folder node ID to update in place.</param>
         /// <param name="displayName">The new display name to apply.</param>
-        public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+        public bool UpdateFolderDisplayName(string folderNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             FolderRenameQueue.Enqueue((folderNodeId, displayName));
             return FolderRenameReturns;
@@ -2202,21 +2202,21 @@ public sealed class AddressSpaceApplierTests
         public bool RemoveReturns { get; init; } = true;
 
         /// <summary>Records a surgical variable-node removal; returns <see cref="RemoveReturns"/>.</summary>
-        public bool RemoveVariableNode(string variableNodeId)
+        public bool RemoveVariableNode(string variableNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             RemoveQueue.Enqueue(("var", variableNodeId));
             return RemoveReturns;
         }
 
         /// <summary>Records a surgical alarm-condition-node removal; returns <see cref="RemoveReturns"/>.</summary>
-        public bool RemoveAlarmConditionNode(string alarmNodeId)
+        public bool RemoveAlarmConditionNode(string alarmNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             RemoveQueue.Enqueue(("alarm", alarmNodeId));
             return RemoveReturns;
         }
 
         /// <summary>Records a surgical equipment-subtree removal; returns <see cref="RemoveReturns"/>.</summary>
-        public bool RemoveEquipmentSubtree(string equipmentNodeId)
+        public bool RemoveEquipmentSubtree(string equipmentNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             RemoveQueue.Enqueue(("equipment", equipmentNodeId));
             return RemoveReturns;
@@ -2262,13 +2262,13 @@ public sealed class AddressSpaceApplierTests
         /// <param name="value">The value to write.</param>
         /// <param name="quality">The OPC UA quality.</param>
         /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc)
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => ValueWriteQueue.Enqueue((nodeId, quality));
         /// <summary>Records an alarm condition write call.</summary>
         /// <param name="alarmNodeId">The alarm node ID.</param>
         /// <param name="state">The full condition state snapshot.</param>
         /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => AlarmQueue.Enqueue((alarmNodeId, state));
         /// <summary>Records an alarm-condition materialise call.</summary>
         /// <param name="alarmNodeId">The alarm node ID (== ScriptedAlarmId).</param>
@@ -2276,13 +2276,13 @@ public sealed class AddressSpaceApplierTests
         /// <param name="displayName">The condition display name.</param>
         /// <param name="alarmType">The domain alarm type.</param>
         /// <param name="severity">The domain severity.</param>
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false)
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false)
             => AlarmConditionQueue.Enqueue((alarmNodeId, equipmentNodeId, displayName, alarmType, severity, isNative));
         /// <summary>Records a folder creation call.</summary>
         /// <param name="folderNodeId">The folder node ID.</param>
         /// <param name="parentNodeId">The parent folder node ID, if any.</param>
         /// <param name="displayName">The display name for the folder.</param>
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => FolderQueue.Enqueue((folderNodeId, parentNodeId, displayName));
         /// <summary>Records a variable creation call.</summary>
         /// <param name="variableNodeId">The variable node ID.</param>
@@ -2291,7 +2291,7 @@ public sealed class AddressSpaceApplierTests
         /// <param name="dataType">The OPC UA built-in type name.</param>
         /// <param name="writable">Whether the node is created read/write.</param>
         /// <param name="historianTagname">The resolved historian tagname (null ⇒ not historized).</param>
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
         {
             VariableQueue.Enqueue((variableNodeId, parentFolderNodeId, displayName, dataType, writable));
             HistorianQueue.Enqueue((variableNodeId, historianTagname));
@@ -2306,7 +2306,9 @@ public sealed class AddressSpaceApplierTests
         public List<string> ModelChangeCalls => ModelChangeQueue.ToList();
         /// <summary>Records a NodeAdded model-change announcement.</summary>
         /// <param name="affectedNodeId">The node under which discovered nodes were added.</param>
-        public void RaiseNodesAddedModelChange(string affectedNodeId) => ModelChangeQueue.Enqueue(affectedNodeId);
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) => ModelChangeQueue.Enqueue(affectedNodeId);
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 
     /// <summary>A recording sink that does NOT implement <see cref="ISurgicalAddressSpaceSink"/> — used to
@@ -2318,19 +2320,21 @@ public sealed class AddressSpaceApplierTests
         public int RebuildCalls;
 
         /// <summary>Records a value write (no-op in this sink).</summary>
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>No-op alarm condition write call.</summary>
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc) { }
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>No-op alarm-condition materialise call.</summary>
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
         /// <summary>No-op folder creation call.</summary>
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName) { }
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>No-op variable creation call.</summary>
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
         /// <summary>Records a rebuild address space call.</summary>
         public void RebuildAddressSpace() => Interlocked.Increment(ref RebuildCalls);
         /// <summary>No-op NodeAdded model-change announcement.</summary>
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 
     private sealed class ThrowingSink : IOpcUaAddressSpaceSink
@@ -2345,13 +2349,13 @@ public sealed class AddressSpaceApplierTests
         /// <param name="value">The value to write.</param>
         /// <param name="quality">The OPC UA quality.</param>
         /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>Throws an exception if configured to do so.</summary>
         /// <param name="alarmNodeId">The alarm node ID.</param>
         /// <param name="state">The full condition state snapshot.</param>
         /// <param name="sourceTimestampUtc">The source timestamp in UTC.</param>
         /// <exception cref="InvalidOperationException">Thrown when configured to throw on alarm write.</exception>
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             if (_throwOnAlarmWrite) throw new InvalidOperationException("simulated sink fault");
         }
@@ -2361,12 +2365,12 @@ public sealed class AddressSpaceApplierTests
         /// <param name="displayName">The condition display name.</param>
         /// <param name="alarmType">The domain alarm type.</param>
         /// <param name="severity">The domain severity.</param>
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
         /// <summary>No-op folder creation call.</summary>
         /// <param name="folderNodeId">The folder node ID.</param>
         /// <param name="parentNodeId">The parent folder node ID, if any.</param>
         /// <param name="displayName">The display name for the folder.</param>
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName) { }
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <summary>No-op variable creation call.</summary>
         /// <param name="variableNodeId">The variable node ID.</param>
         /// <param name="parentFolderNodeId">The parent folder node ID, if any.</param>
@@ -2374,10 +2378,12 @@ public sealed class AddressSpaceApplierTests
         /// <param name="dataType">The OPC UA built-in type name.</param>
         /// <param name="writable">Whether the node is created read/write.</param>
         /// <param name="historianTagname">The resolved historian tagname (null ⇒ not historized).</param>
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
         /// <summary>No-op rebuild address space call.</summary>
         public void RebuildAddressSpace() { }
         /// <summary>No-op NodeAdded model-change announcement.</summary>
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceChangeClassifierDualNamespaceTests.cs

@@ -0,0 +1,103 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP1) — the classifier folds the Raw + UNS subtree diff sets into its routing policy:
+///     raw/uns adds count as adds (PureAdd), removes as removes (PureRemove), and any Changed raw/uns delta
+///     routes to Rebuild (the safe default — WP3's applier owns surgical refinement).
+/// </summary>
+public sealed class AddressSpaceChangeClassifierDualNamespaceTests
+{
+    private static readonly RawContainerNode Folder = new("Plant", null, "Plant", RawNodeKind.Folder);
+
+    private static RawTagPlan RawTag(string nodeId) =>
+        new("t-1", nodeId, "Plant/Modbus1/PLC-A", "drv-1", "Speed", "Float",
+            Writable: false, Alarm: null, ReferencingEquipmentPaths: Array.Empty<string>());
+
+    private static UnsReferenceVariable UnsRef(string nodeId) =>
+        new("ref-1", "eq-1", nodeId, "Speed", "Plant/Modbus1/PLC-A/Speed", "Float", Writable: false);
+
+    private static AddressSpacePlan Empty() => new(
+        Array.Empty<EquipmentNode>(), Array.Empty<EquipmentNode>(), Array.Empty<AddressSpacePlan.EquipmentDelta>(),
+        Array.Empty<DriverInstancePlan>(), Array.Empty<DriverInstancePlan>(), Array.Empty<AddressSpacePlan.DriverDelta>(),
+        Array.Empty<ScriptedAlarmPlan>(), Array.Empty<ScriptedAlarmPlan>(), Array.Empty<AddressSpacePlan.AlarmDelta>());
+
+    [Fact]
+    public void Added_raw_tag_only_is_PureAdd()
+    {
+        var plan = Empty() with { AddedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Speed") } };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
+    }
+
+    [Fact]
+    public void Added_raw_container_only_is_PureAdd()
+    {
+        var plan = Empty() with { AddedRawContainers = new[] { Folder } };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
+    }
+
+    [Fact]
+    public void Added_uns_reference_only_is_PureAdd()
+    {
+        var plan = Empty() with { AddedUnsReferenceVariables = new[] { UnsRef("filling/line-1/station-1/Speed") } };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureAdd);
+    }
+
+    [Fact]
+    public void Removed_raw_tag_only_is_PureRemove()
+    {
+        var plan = Empty() with { RemovedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Speed") } };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureRemove);
+    }
+
+    [Fact]
+    public void Removed_uns_reference_only_is_PureRemove()
+    {
+        var plan = Empty() with { RemovedUnsReferenceVariables = new[] { UnsRef("filling/line-1/station-1/Speed") } };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.PureRemove);
+    }
+
+    [Fact]
+    public void Raw_rename_add_and_remove_is_AddRemoveMix()
+    {
+        var plan = Empty() with
+        {
+            RemovedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Speed") },
+            AddedRawTags = new[] { RawTag("Plant/Modbus1/PLC-A/Velocity") },
+        };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.AddRemoveMix);
+    }
+
+    [Fact]
+    public void Changed_raw_tag_is_Rebuild()
+    {
+        var plan = Empty() with
+        {
+            ChangedRawTags = new[]
+            {
+                new AddressSpacePlan.RawTagDelta(
+                    RawTag("Plant/Modbus1/PLC-A/Speed"),
+                    RawTag("Plant/Modbus1/PLC-A/Speed") with { IsHistorized = true }),
+            },
+        };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.Rebuild);
+    }
+
+    [Fact]
+    public void Uns_reference_repoint_is_Rebuild()
+    {
+        var plan = Empty() with
+        {
+            ChangedUnsReferenceVariables = new[]
+            {
+                new AddressSpacePlan.UnsReferenceDelta(
+                    UnsRef("filling/line-1/station-1/Speed"),
+                    UnsRef("filling/line-1/station-1/Speed") with { BackingRawPath = "Plant/Modbus1/PLC-A/Velocity" }),
+            },
+        };
+        AddressSpaceChangeClassifier.Classify(plan).ShouldBe(AddressSpaceChangeKind.Rebuild);
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpaceComposerDualNamespaceTests.cs

@@ -0,0 +1,208 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP1) — the composer un-darkens BOTH subtrees. Verifies the Raw subtree
+///     (Folder→Driver→Device→TagGroup container nodes + raw-tag Variables keyed <c>s=&lt;RawPath&gt;</c>,
+///     realm <see cref="AddressSpaceRealm.Raw"/>) and the UNS subtree (one Variable per
+///     <see cref="UnsTagReference"/> keyed <c>s=&lt;Area&gt;/&lt;Line&gt;/&lt;Equipment&gt;/&lt;EffectiveName&gt;</c>,
+///     realm <see cref="AddressSpaceRealm.Uns"/>, carrying its backing RawPath for the Organizes ref +
+///     fan-out). Native-alarm intents attach at the RAW tag and carry the referencing equipment paths.
+/// </summary>
+public sealed class AddressSpaceComposerDualNamespaceTests
+{
+    // A raw chain: RawFolder "Plant" → Driver "Modbus1" → Device "PLC-A" → Group "Motors" → tags.
+    // Speed sits under the group; Status directly under the device; Levels is an array tag.
+    private static AddressSpaceComposition ComposeFullFixture()
+    {
+        var folder = new RawFolder { RawFolderId = "raw-plant", ClusterId = "c1", Name = "Plant" };
+        var driver = new DriverInstance
+        {
+            DriverInstanceId = "drv-modbus", ClusterId = "c1", RawFolderId = "raw-plant",
+            Name = "Modbus1", DriverType = "Modbus", DriverConfig = "{}",
+        };
+        var device = new Device { DeviceId = "dev-1", DriverInstanceId = "drv-modbus", Name = "PLC-A", DeviceConfig = "{}" };
+        var group = new TagGroup { TagGroupId = "g1", DeviceId = "dev-1", Name = "Motors" };
+
+        var speed = new Tag
+        {
+            TagId = "t-speed", DeviceId = "dev-1", TagGroupId = "g1", Name = "Speed",
+            DataType = "Float", AccessLevel = TagAccessLevel.ReadWrite,
+            TagConfig = "{\"isHistorized\":true,\"historianTagname\":\"speed_hist\"," +
+                        "\"alarm\":{\"alarmType\":\"LimitAlarm\",\"severity\":700}}",
+        };
+        var status = new Tag
+        {
+            TagId = "t-status", DeviceId = "dev-1", Name = "Status",
+            DataType = "Boolean", AccessLevel = TagAccessLevel.Read, TagConfig = "{}",
+        };
+        var levels = new Tag
+        {
+            TagId = "t-levels", DeviceId = "dev-1", Name = "Levels",
+            DataType = "Int32", AccessLevel = TagAccessLevel.Read,
+            TagConfig = "{\"isArray\":true,\"arrayLength\":8}",
+        };
+
+        var area = new UnsArea { UnsAreaId = "area-1", ClusterId = "c1", Name = "filling" };
+        var line = new UnsLine { UnsLineId = "line-1", UnsAreaId = "area-1", Name = "line-1" };
+        var equip = new Equipment { EquipmentId = "eq-1", UnsLineId = "line-1", Name = "station-1", MachineCode = "STATION_001" };
+
+        var refSpeed = new UnsTagReference { UnsTagReferenceId = "ref-speed", EquipmentId = "eq-1", TagId = "t-speed" };
+        var refStatus = new UnsTagReference
+        {
+            UnsTagReferenceId = "ref-status", EquipmentId = "eq-1", TagId = "t-status",
+            DisplayNameOverride = "MachineStatus",
+        };
+
+        return AddressSpaceComposer.Compose(
+            new[] { area }, new[] { line }, new[] { equip },
+            new[] { driver }, Array.Empty<ScriptedAlarm>(),
+            unsTagReferences: new[] { refSpeed, refStatus },
+            tags: new[] { speed, status, levels },
+            rawFolders: new[] { folder },
+            devices: new[] { device },
+            tagGroups: new[] { group });
+    }
+
+    /// <summary>The Raw subtree emits Folder/Driver/Device/TagGroup container nodes keyed by RawPath, each
+    /// realm=Raw, with parents-before-children ordering + correct parent NodeIds.</summary>
+    [Fact]
+    public void Raw_container_nodes_materialise_with_rawpath_nodeids_and_parents()
+    {
+        var c = ComposeFullFixture();
+
+        c.RawContainers.ShouldAllBe(n => n.Realm == AddressSpaceRealm.Raw);
+
+        var folder = c.RawContainers.Single(n => n.Kind == RawNodeKind.Folder);
+        folder.NodeId.ShouldBe("Plant");
+        folder.ParentNodeId.ShouldBeNull(); // cluster root
+        folder.DisplayName.ShouldBe("Plant");
+
+        var driver = c.RawContainers.Single(n => n.Kind == RawNodeKind.Driver);
+        driver.NodeId.ShouldBe("Plant/Modbus1");
+        driver.ParentNodeId.ShouldBe("Plant");
+
+        var device = c.RawContainers.Single(n => n.Kind == RawNodeKind.Device);
+        device.NodeId.ShouldBe("Plant/Modbus1/PLC-A");
+        device.ParentNodeId.ShouldBe("Plant/Modbus1");
+
+        var group = c.RawContainers.Single(n => n.Kind == RawNodeKind.TagGroup);
+        group.NodeId.ShouldBe("Plant/Modbus1/PLC-A/Motors");
+        group.ParentNodeId.ShouldBe("Plant/Modbus1/PLC-A");
+
+        // Sorted by NodeId ordinal ⇒ a parent always precedes each of its children.
+        c.RawContainers.Select(n => n.NodeId)
+            .ShouldBe(new[] { "Plant", "Plant/Modbus1", "Plant/Modbus1/PLC-A", "Plant/Modbus1/PLC-A/Motors" });
+    }
+
+    /// <summary>Raw tags are Variables keyed <c>s=&lt;RawPath&gt;</c> (realm=Raw), carrying DataType /
+    /// writable / historize + historian tagname / array shape, and hang under their group (or device).</summary>
+    [Fact]
+    public void Raw_tags_materialise_as_variables_keyed_by_rawpath_with_carried_attributes()
+    {
+        var c = ComposeFullFixture();
+
+        c.RawTags.ShouldAllBe(t => t.Realm == AddressSpaceRealm.Raw);
+
+        var speed = c.RawTags.Single(t => t.TagId == "t-speed");
+        speed.NodeId.ShouldBe("Plant/Modbus1/PLC-A/Motors/Speed");
+        speed.ParentNodeId.ShouldBe("Plant/Modbus1/PLC-A/Motors");
+        speed.DriverInstanceId.ShouldBe("drv-modbus");
+        speed.DataType.ShouldBe("Float");
+        speed.Writable.ShouldBeTrue();
+        speed.IsHistorized.ShouldBeTrue();
+        speed.HistorianTagname.ShouldBe("speed_hist");
+
+        var status = c.RawTags.Single(t => t.TagId == "t-status");
+        status.NodeId.ShouldBe("Plant/Modbus1/PLC-A/Status"); // no group ⇒ under the device
+        status.ParentNodeId.ShouldBe("Plant/Modbus1/PLC-A");
+        status.Writable.ShouldBeFalse();
+        status.IsHistorized.ShouldBeFalse();
+
+        var levels = c.RawTags.Single(t => t.TagId == "t-levels");
+        levels.IsArray.ShouldBeTrue();
+        levels.ArrayLength.ShouldBe(8u);
+    }
+
+    /// <summary>A native-alarm intent attaches at the RAW tag (ConditionId = RawPath) and carries the list
+    /// of referencing equipment UNS folder paths — one alarm at the raw tag, not one per equipment.</summary>
+    [Fact]
+    public void Native_alarm_attaches_at_raw_tag_with_referencing_equipment_paths()
+    {
+        var c = ComposeFullFixture();
+
+        var speed = c.RawTags.Single(t => t.TagId == "t-speed");
+        speed.Alarm.ShouldNotBeNull();
+        speed.Alarm!.AlarmType.ShouldBe("LimitAlarm");
+        speed.Alarm.Severity.ShouldBe(700);
+        speed.ReferencingEquipmentPaths.ShouldBe(new[] { "filling/line-1/station-1" });
+
+        // A non-alarm tag carries no condition + its own referencing-equipment list.
+        var status = c.RawTags.Single(t => t.TagId == "t-status");
+        status.Alarm.ShouldBeNull();
+        status.ReferencingEquipmentPaths.ShouldBe(new[] { "filling/line-1/station-1" });
+
+        // An unreferenced tag has an empty referencing-equipment set.
+        var levels = c.RawTags.Single(t => t.TagId == "t-levels");
+        levels.ReferencingEquipmentPaths.ShouldBeEmpty();
+    }
+
+    /// <summary>Each UnsTagReference emits a UNS Variable keyed
+    /// <c>s=&lt;Area&gt;/&lt;Line&gt;/&lt;Equipment&gt;/&lt;EffectiveName&gt;</c> (realm=Uns), carrying its backing
+    /// RawPath (the Organizes target + fan-out) and inheriting DataType + writable from the raw tag. Effective
+    /// name = DisplayNameOverride else the backing raw tag's Name.</summary>
+    [Fact]
+    public void Uns_reference_variables_carry_backing_rawpath_and_inherit_type_and_access()
+    {
+        var c = ComposeFullFixture();
+
+        c.UnsReferenceVariables.ShouldAllBe(v => v.Realm == AddressSpaceRealm.Uns);
+
+        var speedRef = c.UnsReferenceVariables.Single(v => v.UnsTagReferenceId == "ref-speed");
+        speedRef.EffectiveName.ShouldBe("Speed"); // no override ⇒ backing raw tag Name
+        speedRef.NodeId.ShouldBe("filling/line-1/station-1/Speed");
+        speedRef.BackingRawPath.ShouldBe("Plant/Modbus1/PLC-A/Motors/Speed"); // Organizes UNS→Raw + fan-out
+        speedRef.DataType.ShouldBe("Float");
+        speedRef.Writable.ShouldBeTrue(); // inherited from the ReadWrite raw tag
+
+        var statusRef = c.UnsReferenceVariables.Single(v => v.UnsTagReferenceId == "ref-status");
+        statusRef.EffectiveName.ShouldBe("MachineStatus"); // display-name override wins
+        statusRef.NodeId.ShouldBe("filling/line-1/station-1/MachineStatus");
+        statusRef.BackingRawPath.ShouldBe("Plant/Modbus1/PLC-A/Status");
+        statusRef.DataType.ShouldBe("Boolean");
+        statusRef.Writable.ShouldBeFalse(); // inherited from the Read raw tag
+    }
+
+    /// <summary>A composition with no raw/UNS inputs leaves all three new subtree sets empty (the legacy
+    /// convenience overloads + earlier callers keep working).</summary>
+    [Fact]
+    public void No_raw_or_uns_inputs_leaves_both_subtrees_empty()
+    {
+        var c = AddressSpaceComposer.Compose(
+            equipment: Array.Empty<Equipment>(),
+            driverInstances: Array.Empty<DriverInstance>(),
+            scriptedAlarms: Array.Empty<ScriptedAlarm>());
+
+        c.RawContainers.ShouldBeEmpty();
+        c.RawTags.ShouldBeEmpty();
+        c.UnsReferenceVariables.ShouldBeEmpty();
+    }
+
+    /// <summary>The Raw + UNS emit is deterministic — repeated calls produce element-identical output
+    /// (RawTagPlan/UnsReferenceVariable compare by value, so ShouldBe is a content comparison).</summary>
+    [Fact]
+    public void Dual_subtree_emit_is_deterministic()
+    {
+        var a = ComposeFullFixture();
+        var b = ComposeFullFixture();
+
+        a.RawContainers.ShouldBe(b.RawContainers);
+        a.RawTags.ShouldBe(b.RawTags);
+        a.UnsReferenceVariables.ShouldBe(b.UnsReferenceVariables);
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AddressSpacePlannerDualNamespaceTests.cs

@@ -0,0 +1,234 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP1) — the planner diffs per realm. Raw containers + raw tags diff by RawPath
+///     (NodeId), so a rename is remove(old)+add(new); UNS reference variables diff by the stable
+///     <c>UnsTagReferenceId</c>, so a backing-tag rename is a re-point (BackingRawPath moves, NodeId stable)
+///     and a display-name-override edit is a UNS-only change with no raw delta.
+///     <para><b>The pinned invariant:</b> a raw-tag rename = remove+add in Raw AND re-point in UNS.</para>
+/// </summary>
+public sealed class AddressSpacePlannerDualNamespaceTests
+{
+    private const string RawFolderName = "Plant";
+    private const string DriverName = "Modbus1";
+    private const string DeviceName = "PLC-A";
+
+    // Compose a fixture with one raw tag (given name) under Plant/Modbus1/PLC-A and one UNS reference to it
+    // (with an optional display-name override so the effective name can be held stable across a raw rename).
+    private static AddressSpaceComposition Compose(string tagName, string? displayOverride)
+    {
+        var folder = new RawFolder { RawFolderId = "raw-plant", ClusterId = "c1", Name = RawFolderName };
+        var driver = new DriverInstance
+        {
+            DriverInstanceId = "drv-modbus", ClusterId = "c1", RawFolderId = "raw-plant",
+            Name = DriverName, DriverType = "Modbus", DriverConfig = "{}",
+        };
+        var device = new Device { DeviceId = "dev-1", DriverInstanceId = "drv-modbus", Name = DeviceName, DeviceConfig = "{}" };
+        var tag = new Tag
+        {
+            TagId = "t-speed", DeviceId = "dev-1", Name = tagName,
+            DataType = "Float", AccessLevel = TagAccessLevel.ReadWrite, TagConfig = "{}",
+        };
+        var area = new UnsArea { UnsAreaId = "area-1", ClusterId = "c1", Name = "filling" };
+        var line = new UnsLine { UnsLineId = "line-1", UnsAreaId = "area-1", Name = "line-1" };
+        var equip = new Equipment { EquipmentId = "eq-1", UnsLineId = "line-1", Name = "station-1", MachineCode = "STATION_001" };
+        var reference = new UnsTagReference
+        {
+            UnsTagReferenceId = "ref-1", EquipmentId = "eq-1", TagId = "t-speed",
+            DisplayNameOverride = displayOverride,
+        };
+
+        return AddressSpaceComposer.Compose(
+            new[] { area }, new[] { line }, new[] { equip },
+            new[] { driver }, Array.Empty<ScriptedAlarm>(),
+            unsTagReferences: new[] { reference },
+            tags: new[] { tag },
+            rawFolders: new[] { folder },
+            devices: new[] { device });
+    }
+
+    /// <summary>A newly-added raw tag surfaces in AddedRawTags (keyed by RawPath); the plan is non-empty.</summary>
+    [Fact]
+    public void Added_raw_tag_goes_to_AddedRawTags()
+    {
+        var prev = Compose("Speed", displayOverride: null);
+        var next = Compose("Speed", displayOverride: null);
+        // prev without the tag: strip RawTags/UNS by composing an empty raw side.
+        var empty = AddressSpaceComposer.Compose(
+            Array.Empty<UnsArea>(), Array.Empty<UnsLine>(), Array.Empty<Equipment>(),
+            Array.Empty<DriverInstance>(), Array.Empty<ScriptedAlarm>());
+
+        var plan = AddressSpacePlanner.Compute(empty, next);
+
+        plan.IsEmpty.ShouldBeFalse();
+        plan.AddedRawTags.Select(t => t.NodeId).ShouldContain("Plant/Modbus1/PLC-A/Speed");
+        plan.RemovedRawTags.ShouldBeEmpty();
+        _ = prev;
+    }
+
+    /// <summary>A disappeared raw tag surfaces in RemovedRawTags.</summary>
+    [Fact]
+    public void Removed_raw_tag_goes_to_RemovedRawTags()
+    {
+        var prev = Compose("Speed", displayOverride: null);
+        var empty = AddressSpaceComposer.Compose(
+            Array.Empty<UnsArea>(), Array.Empty<UnsLine>(), Array.Empty<Equipment>(),
+            Array.Empty<DriverInstance>(), Array.Empty<ScriptedAlarm>());
+
+        var plan = AddressSpacePlanner.Compute(prev, empty);
+
+        plan.RemovedRawTags.Select(t => t.NodeId).ShouldContain("Plant/Modbus1/PLC-A/Speed");
+        plan.AddedRawTags.ShouldBeEmpty();
+    }
+
+    /// <summary>A newly-added UNS reference surfaces in AddedUnsReferenceVariables.</summary>
+    [Fact]
+    public void Added_uns_reference_goes_to_AddedUnsReferenceVariables()
+    {
+        var empty = AddressSpaceComposer.Compose(
+            Array.Empty<UnsArea>(), Array.Empty<UnsLine>(), Array.Empty<Equipment>(),
+            Array.Empty<DriverInstance>(), Array.Empty<ScriptedAlarm>());
+        var next = Compose("Speed", displayOverride: null);
+
+        var plan = AddressSpacePlanner.Compute(empty, next);
+
+        plan.AddedUnsReferenceVariables.Single().UnsTagReferenceId.ShouldBe("ref-1");
+        plan.RemovedUnsReferenceVariables.ShouldBeEmpty();
+    }
+
+    /// <summary>A disappeared UNS reference surfaces in RemovedUnsReferenceVariables.</summary>
+    [Fact]
+    public void Removed_uns_reference_goes_to_RemovedUnsReferenceVariables()
+    {
+        var prev = Compose("Speed", displayOverride: null);
+        var empty = AddressSpaceComposer.Compose(
+            Array.Empty<UnsArea>(), Array.Empty<UnsLine>(), Array.Empty<Equipment>(),
+            Array.Empty<DriverInstance>(), Array.Empty<ScriptedAlarm>());
+
+        var plan = AddressSpacePlanner.Compute(prev, empty);
+
+        plan.RemovedUnsReferenceVariables.Single().UnsTagReferenceId.ShouldBe("ref-1");
+        plan.AddedUnsReferenceVariables.ShouldBeEmpty();
+    }
+
+    /// <summary><b>THE PIN:</b> a raw-tag rename = remove+add in Raw AND re-point in UNS. With a display-name
+    /// override holding the effective name stable, the reference row is unchanged (same UnsTagReferenceId,
+    /// same UNS NodeId) but its backing NodeId moved ⇒ the UNS variable's Organizes target (BackingRawPath)
+    /// re-points via a ChangedUnsReferenceVariables delta.</summary>
+    [Fact]
+    public void Raw_rename_is_remove_add_in_raw_and_repoint_in_uns()
+    {
+        var prev = Compose("Speed", displayOverride: "Spd");
+        var next = Compose("Velocity", displayOverride: "Spd"); // raw tag renamed; effective name held stable
+
+        var plan = AddressSpacePlanner.Compute(prev, next);
+
+        // Raw realm: remove the old RawPath, add the new one (immutable NodeId ⇒ not a Changed delta).
+        plan.RemovedRawTags.Select(t => t.NodeId).ShouldBe(new[] { "Plant/Modbus1/PLC-A/Speed" });
+        plan.AddedRawTags.Select(t => t.NodeId).ShouldBe(new[] { "Plant/Modbus1/PLC-A/Velocity" });
+        plan.ChangedRawTags.ShouldBeEmpty();
+
+        // UNS realm: the reference row is unchanged in identity + NodeId, but re-points to the new RawPath.
+        plan.AddedUnsReferenceVariables.ShouldBeEmpty();
+        plan.RemovedUnsReferenceVariables.ShouldBeEmpty();
+        var repoint = plan.ChangedUnsReferenceVariables.ShouldHaveSingleItem();
+        repoint.Previous.UnsTagReferenceId.ShouldBe("ref-1");
+        repoint.Current.UnsTagReferenceId.ShouldBe("ref-1");
+        repoint.Previous.NodeId.ShouldBe(repoint.Current.NodeId); // effective name stable ⇒ NodeId stable
+        repoint.Previous.BackingRawPath.ShouldBe("Plant/Modbus1/PLC-A/Speed");
+        repoint.Current.BackingRawPath.ShouldBe("Plant/Modbus1/PLC-A/Velocity");
+
+        // The raw container topology (Folder/Driver/Device) is untouched by a tag rename.
+        plan.AddedRawContainers.ShouldBeEmpty();
+        plan.RemovedRawContainers.ShouldBeEmpty();
+        plan.ChangedRawContainers.ShouldBeEmpty();
+    }
+
+    /// <summary>A display-name-override change is a UNS-only change (no raw delta): same reference row id,
+    /// the effective name + UNS NodeId move, the backing RawPath is unchanged.</summary>
+    [Fact]
+    public void Display_name_override_change_is_uns_only_no_raw_change()
+    {
+        var prev = Compose("Speed", displayOverride: "Spd");
+        var next = Compose("Speed", displayOverride: "Speedy"); // only the override changed
+
+        var plan = AddressSpacePlanner.Compute(prev, next);
+
+        // No raw-side change whatsoever.
+        plan.AddedRawTags.ShouldBeEmpty();
+        plan.RemovedRawTags.ShouldBeEmpty();
+        plan.ChangedRawTags.ShouldBeEmpty();
+        plan.AddedRawContainers.ShouldBeEmpty();
+        plan.RemovedRawContainers.ShouldBeEmpty();
+        plan.ChangedRawContainers.ShouldBeEmpty();
+
+        // UNS: same reference row id, effective name + NodeId changed, backing RawPath unchanged.
+        var delta = plan.ChangedUnsReferenceVariables.ShouldHaveSingleItem();
+        delta.Previous.UnsTagReferenceId.ShouldBe("ref-1");
+        delta.Previous.EffectiveName.ShouldBe("Spd");
+        delta.Current.EffectiveName.ShouldBe("Speedy");
+        delta.Previous.NodeId.ShouldNotBe(delta.Current.NodeId);
+        delta.Previous.BackingRawPath.ShouldBe(delta.Current.BackingRawPath);
+        plan.AddedUnsReferenceVariables.ShouldBeEmpty();
+        plan.RemovedUnsReferenceVariables.ShouldBeEmpty();
+    }
+
+    /// <summary>An attribute-only raw-tag edit (historize toggle) keeps the same RawPath ⇒ a
+    /// ChangedRawTags delta (not remove+add).</summary>
+    [Fact]
+    public void Raw_tag_attribute_edit_keeps_nodeid_and_routes_to_ChangedRawTags()
+    {
+        var prev = Compose("Speed", displayOverride: null);
+        // next: same identity + name, but toggle historize on the raw tag.
+        var folder = new RawFolder { RawFolderId = "raw-plant", ClusterId = "c1", Name = RawFolderName };
+        var driver = new DriverInstance
+        {
+            DriverInstanceId = "drv-modbus", ClusterId = "c1", RawFolderId = "raw-plant",
+            Name = DriverName, DriverType = "Modbus", DriverConfig = "{}",
+        };
+        var device = new Device { DeviceId = "dev-1", DriverInstanceId = "drv-modbus", Name = DeviceName, DeviceConfig = "{}" };
+        var tag = new Tag
+        {
+            TagId = "t-speed", DeviceId = "dev-1", Name = "Speed",
+            DataType = "Float", AccessLevel = TagAccessLevel.ReadWrite, TagConfig = "{\"isHistorized\":true}",
+        };
+        var next = AddressSpaceComposer.Compose(
+            Array.Empty<UnsArea>(), Array.Empty<UnsLine>(), Array.Empty<Equipment>(),
+            new[] { driver }, Array.Empty<ScriptedAlarm>(),
+            tags: new[] { tag }, rawFolders: new[] { folder }, devices: new[] { device });
+
+        var prevRawOnly = AddressSpaceComposer.Compose(
+            Array.Empty<UnsArea>(), Array.Empty<UnsLine>(), Array.Empty<Equipment>(),
+            new[] { driver }, Array.Empty<ScriptedAlarm>(),
+            tags: new[] { new Tag { TagId = "t-speed", DeviceId = "dev-1", Name = "Speed", DataType = "Float", AccessLevel = TagAccessLevel.ReadWrite, TagConfig = "{}" } },
+            rawFolders: new[] { folder }, devices: new[] { device });
+
+        var plan = AddressSpacePlanner.Compute(prevRawOnly, next);
+
+        plan.AddedRawTags.ShouldBeEmpty();
+        plan.RemovedRawTags.ShouldBeEmpty();
+        var changed = plan.ChangedRawTags.ShouldHaveSingleItem();
+        changed.Previous.NodeId.ShouldBe(changed.Current.NodeId);
+        changed.Previous.IsHistorized.ShouldBeFalse();
+        changed.Current.IsHistorized.ShouldBeTrue();
+        _ = prev;
+    }
+
+    /// <summary>Identical compositions diff to an empty plan across both realms (fresh list instances must
+    /// not spuriously flag RawTags/UnsReferenceVariables as changed).</summary>
+    [Fact]
+    public void Identical_dual_namespace_compositions_diff_to_empty()
+    {
+        var prev = Compose("Speed", displayOverride: "Spd");
+        var next = Compose("Speed", displayOverride: "Spd");
+
+        var plan = AddressSpacePlanner.Compute(prev, next);
+
+        plan.IsEmpty.ShouldBeTrue();
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/AlarmCommandRouterTests.cs

@@ -34,8 +34,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-1");
         condition.ShouldNotBeNull();
         condition!.OnAcknowledge.ShouldNotBeNull();
@@ -66,8 +66,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-2", parentNodeId: null, displayName: "Equipment 2");
+        nm.EnsureFolder("eq-2", parentNodeId: null, displayName: "Equipment 2", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-2", "eq-2", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-2", "eq-2", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-2");
         condition.ShouldNotBeNull();
 
@@ -91,8 +91,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-3", parentNodeId: null, displayName: "Equipment 3");
+        nm.EnsureFolder("eq-3", parentNodeId: null, displayName: "Equipment 3", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-3", "eq-3", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-3", "eq-3", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-3");
         condition.ShouldNotBeNull();
 
@@ -115,8 +115,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-c", parentNodeId: null, displayName: "Equipment C");
+        nm.EnsureFolder("eq-c", parentNodeId: null, displayName: "Equipment C", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-c", "eq-c", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-c", "eq-c", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-c");
         condition.ShouldNotBeNull();
         condition!.OnConfirm.ShouldNotBeNull();
@@ -142,8 +142,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-ac", parentNodeId: null, displayName: "Equipment AC");
+        nm.EnsureFolder("eq-ac", parentNodeId: null, displayName: "Equipment AC", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-ac", "eq-ac", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-ac", "eq-ac", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-ac");
         condition.ShouldNotBeNull();
         condition!.OnAddComment.ShouldNotBeNull();
@@ -168,8 +168,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-s1", parentNodeId: null, displayName: "Equipment S1");
+        nm.EnsureFolder("eq-s1", parentNodeId: null, displayName: "Equipment S1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-s1", "eq-s1", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-s1", "eq-s1", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-s1");
         condition.ShouldNotBeNull();
         condition!.OnShelve.ShouldNotBeNull();
@@ -196,8 +196,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-s2", parentNodeId: null, displayName: "Equipment S2");
+        nm.EnsureFolder("eq-s2", parentNodeId: null, displayName: "Equipment S2", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-s2", "eq-s2", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-s2", "eq-s2", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-s2");
         condition.ShouldNotBeNull();
 
@@ -228,8 +228,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-s3", parentNodeId: null, displayName: "Equipment S3");
+        nm.EnsureFolder("eq-s3", parentNodeId: null, displayName: "Equipment S3", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-s3", "eq-s3", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-s3", "eq-s3", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-s3");
         condition.ShouldNotBeNull();
 
@@ -254,8 +254,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-s4", parentNodeId: null, displayName: "Equipment S4");
+        nm.EnsureFolder("eq-s4", parentNodeId: null, displayName: "Equipment S4", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-s4", "eq-s4", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-s4", "eq-s4", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-s4");
         condition.ShouldNotBeNull();
 
@@ -287,8 +287,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-tu", parentNodeId: null, displayName: "Equipment TU");
+        nm.EnsureFolder("eq-tu", parentNodeId: null, displayName: "Equipment TU", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-tu", "eq-tu", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-tu", "eq-tu", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-tu");
         condition.ShouldNotBeNull();
         condition!.OnTimedUnshelve.ShouldNotBeNull();
@@ -322,8 +322,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-ed1", parentNodeId: null, displayName: "Equipment ED1");
+        nm.EnsureFolder("eq-ed1", parentNodeId: null, displayName: "Equipment ED1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-ed1", "eq-ed1", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-ed1", "eq-ed1", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-ed1");
         condition.ShouldNotBeNull();
         condition!.OnEnableDisable.ShouldNotBeNull();
@@ -351,8 +351,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-ed2", parentNodeId: null, displayName: "Equipment ED2");
+        nm.EnsureFolder("eq-ed2", parentNodeId: null, displayName: "Equipment ED2", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-ed2", "eq-ed2", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-ed2", "eq-ed2", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-ed2");
         condition.ShouldNotBeNull();
         condition!.OnEnableDisable.ShouldNotBeNull();
@@ -379,8 +379,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-ed3", parentNodeId: null, displayName: "Equipment ED3");
+        nm.EnsureFolder("eq-ed3", parentNodeId: null, displayName: "Equipment ED3", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-ed3", "eq-ed3", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-ed3", "eq-ed3", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-ed3");
         condition.ShouldNotBeNull();
 
@@ -405,8 +405,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var captured = new List<AlarmCommand>();
         nm.AlarmCommandRouter = captured.Add;
 
-        nm.EnsureFolder("eq-ed4", parentNodeId: null, displayName: "Equipment ED4");
+        nm.EnsureFolder("eq-ed4", parentNodeId: null, displayName: "Equipment ED4", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-ed4", "eq-ed4", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true);
+        nm.MaterialiseAlarmCondition("alm-ed4", "eq-ed4", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-ed4");
         condition.ShouldNotBeNull();
         condition!.OnEnableDisable.ShouldNotBeNull();
@@ -436,8 +436,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         nm.AlarmCommandRouter = scripted.Add;
         nm.NativeAlarmAckRouter = native.Add;
 
-        nm.EnsureFolder("eq-nak1", parentNodeId: null, displayName: "Equipment NAK1");
+        nm.EnsureFolder("eq-nak1", parentNodeId: null, displayName: "Equipment NAK1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-nak1", "eq-nak1", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true);
+        nm.MaterialiseAlarmCondition("alm-nak1", "eq-nak1", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-nak1");
         condition.ShouldNotBeNull();
         condition!.OnAcknowledge.ShouldNotBeNull();
@@ -469,8 +469,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         nm.AlarmCommandRouter = scripted.Add;
         nm.NativeAlarmAckRouter = native.Add;
 
-        nm.EnsureFolder("eq-nak2", parentNodeId: null, displayName: "Equipment NAK2");
+        nm.EnsureFolder("eq-nak2", parentNodeId: null, displayName: "Equipment NAK2", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-nak2", "eq-nak2", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-nak2", "eq-nak2", "HighTemp", "OffNormalAlarm", severity: 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-nak2");
         condition.ShouldNotBeNull();
         condition!.OnAcknowledge.ShouldNotBeNull();
@@ -503,8 +503,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         nm.AlarmCommandRouter = scripted.Add;
         nm.NativeAlarmAckRouter = native.Add;
 
-        nm.EnsureFolder("eq-nak4", parentNodeId: null, displayName: "Equipment NAK4");
+        nm.EnsureFolder("eq-nak4", parentNodeId: null, displayName: "Equipment NAK4", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-nak4", "eq-nak4", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true);
+        nm.MaterialiseAlarmCondition("alm-nak4", "eq-nak4", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-nak4");
         condition.ShouldNotBeNull();
 
@@ -531,8 +531,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         nm.AlarmCommandRouter = scripted.Add;
         nm.NativeAlarmAckRouter = native.Add;
 
-        nm.EnsureFolder("eq-nak3", parentNodeId: null, displayName: "Equipment NAK3");
+        nm.EnsureFolder("eq-nak3", parentNodeId: null, displayName: "Equipment NAK3", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-nak3", "eq-nak3", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true);
+        nm.MaterialiseAlarmCondition("alm-nak3", "eq-nak3", "HighTemp", "OffNormalAlarm", severity: 700, isNative: true, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-nak3");
         condition.ShouldNotBeNull();
 
@@ -555,8 +555,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var nm = server.NodeManager!;
         // No router set (default null).
 
-        nm.EnsureFolder("eq-nr", parentNodeId: null, displayName: "Equipment NR");
+        nm.EnsureFolder("eq-nr", parentNodeId: null, displayName: "Equipment NR", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-nr", "eq-nr", "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alm-nr", "eq-nr", "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var condition = nm.TryGetAlarmCondition("alm-nr");
         condition.ShouldNotBeNull();
 
@@ -576,8 +576,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: true);
+        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Uns);
 
         nm.IsNativeAlarmNode("a1").ShouldBeTrue();
 
@@ -591,8 +591,8 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("a2", "eq", "d", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("a2", "eq", "d", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
 
         nm.IsNativeAlarmNode("a2").ShouldBeFalse();
 
@@ -611,15 +611,15 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: true);
+        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Uns);
         nm.IsNativeAlarmNode("a1").ShouldBeTrue();
 
         // RebuildAddressSpace clears the folder set too, so the equipment folder must be re-ensured
         // before the same id can be re-materialised (ResolveParentFolder needs the parent back).
         nm.RebuildAddressSpace();
-        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
 
         nm.IsNativeAlarmNode("a1").ShouldBeFalse();
 
@@ -636,13 +636,13 @@ public sealed class AlarmCommandRouterTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
         nm.IsNativeAlarmNode("a1").ShouldBeFalse();
 
         nm.RebuildAddressSpace();
-        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder("eq", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: true);
+        nm.MaterialiseAlarmCondition("a1", "eq", "d", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Uns);
 
         nm.IsNativeAlarmNode("a1").ShouldBeTrue();
 

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/DeferredAddressSpaceSinkTests.cs

@@ -14,8 +14,8 @@ public sealed class DeferredAddressSpaceSinkTests
         var deferred = new DeferredAddressSpaceSink();
 
         // No throw, no observable side effect.
-        deferred.WriteValue("x", 1, OpcUaQuality.Good, DateTime.UtcNow);
+        deferred.WriteValue("x", 1, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
-        deferred.WriteAlarmCondition("a", Snapshot(active: true), DateTime.UtcNow);
+        deferred.WriteAlarmCondition("a", Snapshot(active: true), DateTime.UtcNow, AddressSpaceRealm.Uns);
         deferred.RebuildAddressSpace();
     }
 
@@ -27,10 +27,10 @@ public sealed class DeferredAddressSpaceSinkTests
         var inner = new RecordingSink();
         deferred.SetSink(inner);
 
-        deferred.WriteValue("x", 42, OpcUaQuality.Good, DateTime.UtcNow);
+        deferred.WriteValue("x", 42, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
-        deferred.WriteAlarmCondition("a-1", Snapshot(active: true), DateTime.UtcNow);
+        deferred.WriteAlarmCondition("a-1", Snapshot(active: true), DateTime.UtcNow, AddressSpaceRealm.Uns);
         deferred.RebuildAddressSpace();
-        deferred.RaiseNodesAddedModelChange("eq-1");
+        deferred.RaiseNodesAddedModelChange("eq-1", AddressSpaceRealm.Uns);
 
         inner.Calls.ShouldBe(new[] { "WV:x", "WA:a-1", "RB", "NA:eq-1" });
     }
@@ -42,11 +42,11 @@ public sealed class DeferredAddressSpaceSinkTests
         var deferred = new DeferredAddressSpaceSink();
         var inner = new RecordingSink();
         deferred.SetSink(inner);
-        deferred.WriteValue("x", 1, OpcUaQuality.Good, DateTime.UtcNow);
+        deferred.WriteValue("x", 1, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
         inner.Calls.Count.ShouldBe(1);
 
         deferred.SetSink(null);
-        deferred.WriteValue("y", 2, OpcUaQuality.Good, DateTime.UtcNow); // dropped
+        deferred.WriteValue("y", 2, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns); // dropped
         inner.Calls.Count.ShouldBe(1);
     }
 
@@ -59,10 +59,10 @@ public sealed class DeferredAddressSpaceSinkTests
         var second = new RecordingSink();
 
         deferred.SetSink(first);
-        deferred.WriteValue("a", 1, OpcUaQuality.Good, DateTime.UtcNow);
+        deferred.WriteValue("a", 1, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
         deferred.SetSink(second);
-        deferred.WriteValue("b", 2, OpcUaQuality.Good, DateTime.UtcNow);
+        deferred.WriteValue("b", 2, OpcUaQuality.Good, DateTime.UtcNow, AddressSpaceRealm.Uns);
 
         first.Calls.Single().ShouldBe("WV:a");
         second.Calls.Single().ShouldBe("WV:b");
@@ -77,7 +77,7 @@ public sealed class DeferredAddressSpaceSinkTests
         var inner = new RecordingSink();
         deferred.SetSink(inner);
 
-        deferred.EnsureVariable("v-1", null, "MyVar", "Float", writable: false, historianTagname: "MyTag.PV");
+        deferred.EnsureVariable("v-1", null, "MyVar", "Float", writable: false, historianTagname: "MyTag.PV", realm: AddressSpaceRealm.Uns);
 
         var call = inner.HistorianCalls.ShouldHaveSingleItem();
         call.NodeId.ShouldBe("v-1");
@@ -96,7 +96,7 @@ public sealed class DeferredAddressSpaceSinkTests
         deferred.SetSink(inner);
 
         ((ISurgicalAddressSpaceSink)deferred).UpdateTagAttributes("v-1", writable: true, historianTagname: "MyTag.PV",
-            dataType: "Int32", isArray: true, arrayLength: 8u)
+            dataType: "Int32", isArray: true, arrayLength: 8u, AddressSpaceRealm.Uns)
             .ShouldBeTrue();
 
         var call = inner.SurgicalCalls.ShouldHaveSingleItem();
@@ -119,7 +119,7 @@ public sealed class DeferredAddressSpaceSinkTests
         deferred.SetSink(new SurgicalRecordingSink { Result = false });
 
         ((ISurgicalAddressSpaceSink)deferred).UpdateTagAttributes("v-1", writable: false, historianTagname: null,
-            dataType: "Float", isArray: false, arrayLength: null)
+            dataType: "Float", isArray: false, arrayLength: null, AddressSpaceRealm.Uns)
             .ShouldBeFalse();
     }
 
@@ -131,12 +131,12 @@ public sealed class DeferredAddressSpaceSinkTests
     {
         var deferred = new DeferredAddressSpaceSink();   // default inner = null sink (not surgical)
         ((ISurgicalAddressSpaceSink)deferred).UpdateTagAttributes("v-1", writable: true, historianTagname: null,
-            dataType: "Float", isArray: false, arrayLength: null)
+            dataType: "Float", isArray: false, arrayLength: null, AddressSpaceRealm.Uns)
             .ShouldBeFalse();
 
         deferred.SetSink(new RecordingSink());           // a non-surgical inner
         ((ISurgicalAddressSpaceSink)deferred).UpdateTagAttributes("v-1", writable: true, historianTagname: null,
-            dataType: "Float", isArray: false, arrayLength: null)
+            dataType: "Float", isArray: false, arrayLength: null, AddressSpaceRealm.Uns)
             .ShouldBeFalse();
     }
 
@@ -151,7 +151,7 @@ public sealed class DeferredAddressSpaceSinkTests
         var inner = new SurgicalRecordingSink { Result = true };
         deferred.SetSink(inner);
 
-        ((ISurgicalAddressSpaceSink)deferred).UpdateFolderDisplayName("area-1", "Plant South")
+        ((ISurgicalAddressSpaceSink)deferred).UpdateFolderDisplayName("area-1", "Plant South", AddressSpaceRealm.Uns)
             .ShouldBeTrue();
 
         var call = inner.FolderRenameCalls.ShouldHaveSingleItem();
@@ -167,11 +167,11 @@ public sealed class DeferredAddressSpaceSinkTests
         var deferred = new DeferredAddressSpaceSink();
         // Inner reports the folder missing ⇒ forward returns false.
         deferred.SetSink(new SurgicalRecordingSink { Result = false });
-        ((ISurgicalAddressSpaceSink)deferred).UpdateFolderDisplayName("area-1", "X").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).UpdateFolderDisplayName("area-1", "X", AddressSpaceRealm.Uns).ShouldBeFalse();
 
         // Non-surgical inner (the null sink before swap-in) ⇒ false.
         deferred.SetSink(null);
-        ((ISurgicalAddressSpaceSink)deferred).UpdateFolderDisplayName("area-1", "X").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).UpdateFolderDisplayName("area-1", "X", AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     /// <summary>R2-07 Phase 2 — the three surgical remove members forward to a surgical inner with
@@ -184,9 +184,9 @@ public sealed class DeferredAddressSpaceSinkTests
         var inner = new SurgicalRecordingSink { Result = true };
         deferred.SetSink(inner);
 
-        ((ISurgicalAddressSpaceSink)deferred).RemoveVariableNode("eq-1/A").ShouldBeTrue();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveVariableNode("eq-1/A", AddressSpaceRealm.Uns).ShouldBeTrue();
-        ((ISurgicalAddressSpaceSink)deferred).RemoveAlarmConditionNode("alm-1").ShouldBeTrue();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveAlarmConditionNode("alm-1", AddressSpaceRealm.Uns).ShouldBeTrue();
-        ((ISurgicalAddressSpaceSink)deferred).RemoveEquipmentSubtree("eq-1").ShouldBeTrue();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveEquipmentSubtree("eq-1", AddressSpaceRealm.Uns).ShouldBeTrue();
 
         inner.RemoveCalls.ShouldBe(new[] { ("var", "eq-1/A"), ("alarm", "alm-1"), ("equipment", "eq-1") });
     }
@@ -198,14 +198,14 @@ public sealed class DeferredAddressSpaceSinkTests
     {
         var deferred = new DeferredAddressSpaceSink();
         deferred.SetSink(new SurgicalRecordingSink { Result = false });
-        ((ISurgicalAddressSpaceSink)deferred).RemoveVariableNode("v-1").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveVariableNode("v-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        ((ISurgicalAddressSpaceSink)deferred).RemoveAlarmConditionNode("a-1").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveAlarmConditionNode("a-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        ((ISurgicalAddressSpaceSink)deferred).RemoveEquipmentSubtree("eq-1").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveEquipmentSubtree("eq-1", AddressSpaceRealm.Uns).ShouldBeFalse();
 
         deferred.SetSink(null);
-        ((ISurgicalAddressSpaceSink)deferred).RemoveVariableNode("v-1").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveVariableNode("v-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        ((ISurgicalAddressSpaceSink)deferred).RemoveAlarmConditionNode("a-1").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveAlarmConditionNode("a-1", AddressSpaceRealm.Uns).ShouldBeFalse();
-        ((ISurgicalAddressSpaceSink)deferred).RemoveEquipmentSubtree("eq-1").ShouldBeFalse();
+        ((ISurgicalAddressSpaceSink)deferred).RemoveEquipmentSubtree("eq-1", AddressSpaceRealm.Uns).ShouldBeFalse();
     }
 
     /// <summary>Builds a minimal <see cref="AlarmConditionSnapshot"/> for the forwarding tests (the
@@ -228,19 +228,19 @@ public sealed class DeferredAddressSpaceSinkTests
         public List<(string NodeId, string? HistorianTagname)> HistorianCalls => HistorianQueue.ToList();
 
         /// <inheritdoc />
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc)
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => CallQueue.Enqueue($"WV:{nodeId}");
         /// <inheritdoc />
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc)
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => CallQueue.Enqueue($"WA:{alarmNodeId}");
         /// <inheritdoc />
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false)
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false)
             => CallQueue.Enqueue($"MA:{alarmNodeId}");
         /// <inheritdoc />
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName)
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
             => CallQueue.Enqueue($"EF:{folderNodeId}");
         /// <inheritdoc />
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null)
         {
             CallQueue.Enqueue($"EV:{variableNodeId}");
             HistorianQueue.Enqueue((variableNodeId, historianTagname));
@@ -248,7 +248,9 @@ public sealed class DeferredAddressSpaceSinkTests
         /// <inheritdoc />
         public void RebuildAddressSpace() => CallQueue.Enqueue("RB");
         /// <inheritdoc />
-        public void RaiseNodesAddedModelChange(string affectedNodeId) => CallQueue.Enqueue($"NA:{affectedNodeId}");
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) => CallQueue.Enqueue($"NA:{affectedNodeId}");
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 
     private sealed class SurgicalRecordingSink : IOpcUaAddressSpaceSink, ISurgicalAddressSpaceSink
@@ -261,14 +263,14 @@ public sealed class DeferredAddressSpaceSinkTests
         public List<(string FolderNodeId, string DisplayName)> FolderRenameCalls { get; } = new();
 
         /// <inheritdoc />
-        public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength)
+        public bool UpdateTagAttributes(string variableNodeId, bool writable, string? historianTagname, string dataType, bool isArray, uint? arrayLength, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             SurgicalCalls.Add((variableNodeId, writable, historianTagname, dataType, isArray, arrayLength));
             return Result;
         }
 
         /// <inheritdoc />
-        public bool UpdateFolderDisplayName(string folderNodeId, string displayName)
+        public bool UpdateFolderDisplayName(string folderNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns)
         {
             FolderRenameCalls.Add((folderNodeId, displayName));
             return Result;
@@ -278,25 +280,27 @@ public sealed class DeferredAddressSpaceSinkTests
         public List<(string Kind, string NodeId)> RemoveCalls { get; } = new();
 
         /// <inheritdoc />
-        public bool RemoveVariableNode(string variableNodeId) { RemoveCalls.Add(("var", variableNodeId)); return Result; }
+        public bool RemoveVariableNode(string variableNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { RemoveCalls.Add(("var", variableNodeId)); return Result; }
         /// <inheritdoc />
-        public bool RemoveAlarmConditionNode(string alarmNodeId) { RemoveCalls.Add(("alarm", alarmNodeId)); return Result; }
+        public bool RemoveAlarmConditionNode(string alarmNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { RemoveCalls.Add(("alarm", alarmNodeId)); return Result; }
         /// <inheritdoc />
-        public bool RemoveEquipmentSubtree(string equipmentNodeId) { RemoveCalls.Add(("equipment", equipmentNodeId)); return Result; }
+        public bool RemoveEquipmentSubtree(string equipmentNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { RemoveCalls.Add(("equipment", equipmentNodeId)); return Result; }
 
         /// <inheritdoc />
-        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc) { }
+        public void WriteValue(string nodeId, object? value, OpcUaQuality quality, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <inheritdoc />
-        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc) { }
+        public void WriteAlarmCondition(string alarmNodeId, AlarmConditionSnapshot state, DateTime sourceTimestampUtc, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <inheritdoc />
-        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, bool isNative = false) { }
+        public void MaterialiseAlarmCondition(string alarmNodeId, string equipmentNodeId, string displayName, string alarmType, int severity, AddressSpaceRealm realm, bool isNative = false) { }
         /// <inheritdoc />
-        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName) { }
+        public void EnsureFolder(string folderNodeId, string? parentNodeId, string displayName, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
         /// <inheritdoc />
-        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
+        public void EnsureVariable(string variableNodeId, string? parentFolderNodeId, string displayName, string dataType, bool writable, AddressSpaceRealm realm, string? historianTagname = null, bool isArray = false, uint? arrayLength = null) { }
         /// <inheritdoc />
         public void RebuildAddressSpace() { }
         /// <inheritdoc />
-        public void RaiseNodesAddedModelChange(string affectedNodeId) { }
+        public void RaiseNodesAddedModelChange(string affectedNodeId, AddressSpaceRealm realm = AddressSpaceRealm.Uns) { }
+        public void WireAlarmNotifiers(string alarmNodeId, AddressSpaceRealm alarmRealm, IReadOnlyList<string> notifierFolderNodeIds, AddressSpaceRealm notifierFolderRealm) { }
+        public void AddReference(string sourceNodeId, AddressSpaceRealm sourceRealm, string targetNodeId, AddressSpaceRealm targetRealm, string referenceType = "Organizes") { }
     }
 }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerAlarmIdempotentMaterialiseTests.cs

@@ -1,4 +1,5 @@
 using Shouldly;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Xunit;
 
 namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
@@ -27,14 +28,14 @@ public sealed class NodeManagerAlarmIdempotentMaterialiseTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
 
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var first = nm.TryGetAlarmCondition("alm-1");
         first.ShouldNotBeNull();
 
         // Same id + same kind ⇒ skip-if-present: the existing instance is kept.
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var second = nm.TryGetAlarmCondition("alm-1");
 
         second.ShouldBeSameAs(first);
@@ -50,14 +51,14 @@ public sealed class NodeManagerAlarmIdempotentMaterialiseTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
 
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var scripted = nm.TryGetAlarmCondition("alm-1");
         nm.IsNativeAlarmNode("alm-1").ShouldBeFalse();
 
         // Same id but the OTHER kind ⇒ recreate (a different instance) and the native flag is now set.
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: true);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Uns);
         var native = nm.TryGetAlarmCondition("alm-1");
 
         native.ShouldNotBeSameAs(scripted);
@@ -75,16 +76,16 @@ public sealed class NodeManagerAlarmIdempotentMaterialiseTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
 
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var before = nm.TryGetAlarmCondition("alm-1");
 
         nm.RebuildAddressSpace();
         nm.TryGetAlarmCondition("alm-1").ShouldBeNull();
 
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 700, isNative: false, realm: AddressSpaceRealm.Uns);
         var after = nm.TryGetAlarmCondition("alm-1");
 
         after.ShouldNotBeNull();

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerAlarmSourceFieldsTests.cs

@@ -0,0 +1,188 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Opc.Ua;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     Issue #473 — every materialised Part 9 condition must carry the mandatory <c>BaseEventType</c>
+///     identity fields <c>EventType</c> / <c>SourceNode</c> / <c>SourceName</c>. The SDK does NOT synthesise
+///     them on this path: <see cref="NodeState.Create"/> initialises from the type's embedded definition,
+///     which declares all three as mandatory children with NO default value, and the auto-filling
+///     <see cref="BaseEventState.Initialize(ISystemContext, NodeState, EventSeverity, LocalizedText)"/>
+///     overload (which would set SourceNode/SourceName from a source node) is only used for transient
+///     events. <c>ReportEvent</c> and <c>InstanceStateSnapshot</c> copy the children verbatim and synthesise
+///     nothing — so a field left null at materialise arrives null on the wire on EVERY condition event.
+///     <para>
+///         The contract locked in here (see <c>docs/AlarmTracking.md</c>): the condition node IS the source
+///         node — a native-alarm raw tag materialises ONLY a condition (no separate value variable), so
+///         <c>SourceNode</c> self-references the condition's own NodeId and <c>SourceName</c> carries the
+///         same identifying id string (<c>alarmNodeId</c>: the RawPath for native, the ScriptedAlarmId for
+///         scripted), matching <c>ConditionId</c>. The leaf/display name stays on <c>ConditionName</c>, so
+///         no information is lost by SourceName carrying the unique id rather than the ambiguous leaf.
+///     </para>
+/// </summary>
+public sealed class NodeManagerAlarmSourceFieldsTests : IDisposable
+{
+    private static CancellationToken Ct => TestContext.Current.CancellationToken;
+
+    private const string RawDeviceFolder = "Plant/Modbus/dev1";
+    private const string RawAlarmPath = "Plant/Modbus/dev1/HR200";
+
+    private readonly string _pkiRoot = Path.Combine(
+        Path.GetTempPath(),
+        $"otopcua-alarm-src-fields-{Guid.NewGuid():N}");
+
+    /// <summary>A NATIVE condition (Raw realm, ConditionId = RawPath) carries all three identity fields:
+    /// EventType = its type definition, SourceNode = its own NodeId, SourceName = the RawPath. The leaf name
+    /// remains on ConditionName so the short name is still available to clients.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task Native_condition_carries_EventType_SourceNode_and_SourceName()
+    {
+        await using var host = await BootAsync();
+        var nm = host.Nm;
+        var rawNs = nm.NamespaceIndexForRealm(AddressSpaceRealm.Raw);
+
+        nm.EnsureFolder(RawDeviceFolder, parentNodeId: null, displayName: "dev1", realm: AddressSpaceRealm.Raw);
+        nm.MaterialiseAlarmCondition(RawAlarmPath, RawDeviceFolder, "HR200", "OffNormalAlarm", 700,
+            realm: AddressSpaceRealm.Raw, isNative: true);
+
+        var condition = nm.TryGetAlarmCondition(RawAlarmPath, AddressSpaceRealm.Raw);
+        condition.ShouldNotBeNull();
+
+        // EventType — the concrete condition type, so a client reading the FIELD (not just an OfType
+        // where-clause) can resolve the type.
+        condition.EventType.ShouldNotBeNull();
+        condition.EventType.Value.ShouldBe(ObjectTypeIds.OffNormalAlarmType);
+
+        // SourceNode — the condition's own NodeId (it IS the source: no separate value variable exists
+        // for an alarm-bearing raw tag). Equal to ConditionId.
+        condition.SourceNode.ShouldNotBeNull();
+        condition.SourceNode.Value.ShouldBe(new NodeId(RawAlarmPath, rawNs));
+
+        // SourceName — the RawPath: unique across devices, matching ConditionId/SourceNode.
+        condition.SourceName.ShouldNotBeNull();
+        condition.SourceName.Value.ShouldBe(RawAlarmPath);
+
+        // The leaf name is NOT lost — it stays on ConditionName.
+        condition.ConditionName!.Value.ShouldBe("HR200");
+
+    }
+
+    /// <summary>A SCRIPTED condition (UNS realm, ConditionId = ScriptedAlarmId) follows the SAME uniform rule:
+    /// SourceNode = its own NodeId, SourceName = the ScriptedAlarmId. Scripted and native conditions share the
+    /// materialise path, so neither may regress independently.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task Scripted_condition_carries_EventType_SourceNode_and_SourceName()
+    {
+        await using var host = await BootAsync();
+        var nm = host.Nm;
+        var unsNs = nm.NamespaceIndexForRealm(AddressSpaceRealm.Uns);
+
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Station 1", realm: AddressSpaceRealm.Uns);
+        nm.MaterialiseAlarmCondition("tank-overflow", "eq-1", "Tank Overflow", "OffNormalAlarm", 700,
+            realm: AddressSpaceRealm.Uns, isNative: false);
+
+        var condition = nm.TryGetAlarmCondition("tank-overflow", AddressSpaceRealm.Uns);
+        condition.ShouldNotBeNull();
+
+        condition.EventType!.Value.ShouldBe(ObjectTypeIds.OffNormalAlarmType);
+        condition.SourceNode!.Value.ShouldBe(new NodeId("tank-overflow", unsNs));
+        condition.SourceName!.Value.ShouldBe("tank-overflow");
+        // The human-readable name stays on ConditionName.
+        condition.ConditionName!.Value.ShouldBe("Tank Overflow");
+
+    }
+
+    /// <summary>EventType tracks the ACTUAL materialised type, not a hardcoded constant: an unknown alarm type
+    /// falls back to the base <see cref="AlarmConditionState"/> and its EventType must report that base type
+    /// rather than a subtype the node does not have.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task EventType_reflects_the_fallback_base_type_for_an_unknown_alarm_type()
+    {
+        await using var host = await BootAsync();
+        var nm = host.Nm;
+
+        nm.EnsureFolder("eq-2", parentNodeId: null, displayName: "Station 2", realm: AddressSpaceRealm.Uns);
+        nm.MaterialiseAlarmCondition("alm-x", "eq-2", "Generic", "LimitAlarm", 500,
+            realm: AddressSpaceRealm.Uns, isNative: false);
+
+        var condition = nm.TryGetAlarmCondition("alm-x", AddressSpaceRealm.Uns);
+        condition.ShouldNotBeNull();
+        condition.GetType().ShouldBe(typeof(AlarmConditionState)); // base-type fallback
+        condition.EventType!.Value.ShouldBe(ObjectTypeIds.AlarmConditionType);
+
+    }
+
+    /// <summary>The identity fields survive a re-materialise that DROPS and re-creates the node (the native↔scripted
+    /// kind-swap path), so a redeploy can never leave a condition emitting null identity.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task Identity_fields_survive_a_kind_swap_rematerialise()
+    {
+        await using var host = await BootAsync();
+        var nm = host.Nm;
+        var unsNs = nm.NamespaceIndexForRealm(AddressSpaceRealm.Uns);
+
+        nm.EnsureFolder("eq-3", parentNodeId: null, displayName: "Station 3", realm: AddressSpaceRealm.Uns);
+        nm.MaterialiseAlarmCondition("alm-swap", "eq-3", "Swap", "OffNormalAlarm", 700,
+            realm: AddressSpaceRealm.Uns, isNative: false);
+        // Kind swap (scripted → native) drops the prior instance and re-creates it.
+        nm.MaterialiseAlarmCondition("alm-swap", "eq-3", "Swap", "OffNormalAlarm", 700,
+            realm: AddressSpaceRealm.Uns, isNative: true);
+
+        var condition = nm.TryGetAlarmCondition("alm-swap", AddressSpaceRealm.Uns);
+        condition.ShouldNotBeNull();
+        condition.EventType!.Value.ShouldBe(ObjectTypeIds.OffNormalAlarmType);
+        condition.SourceNode!.Value.ShouldBe(new NodeId("alm-swap", unsNs));
+        condition.SourceName!.Value.ShouldBe("alm-swap");
+
+    }
+
+    /// <summary>A booted server + its node manager, disposed via <c>await using</c> so an assertion failure
+    /// cannot leak a live server (and its bound port) into the rest of the test run.</summary>
+    private sealed class BootedServer(OpcUaApplicationHost host, OtOpcUaNodeManager nm) : IAsyncDisposable
+    {
+        public OtOpcUaNodeManager Nm { get; } = nm;
+        public ValueTask DisposeAsync() => host.DisposeAsync();
+    }
+
+    private async Task<BootedServer> BootAsync()
+    {
+        var host = new OpcUaApplicationHost(
+            new OpcUaApplicationHostOptions
+            {
+                ApplicationName = "OtOpcUa.AlarmSourceFieldsTest",
+                ApplicationUri = $"urn:OtOpcUa.AlarmSourceFieldsTest:{Guid.NewGuid():N}",
+                OpcUaPort = AllocateFreePort(),
+                PublicHostname = "localhost",
+                PkiStoreRoot = _pkiRoot,
+            },
+            NullLogger<OpcUaApplicationHost>.Instance);
+
+        var server = new OtOpcUaSdkServer();
+        await host.StartAsync(server, Ct);
+        return new BootedServer(host, server.NodeManager!);
+    }
+
+    private static int AllocateFreePort()
+    {
+        using var listener = new System.Net.Sockets.TcpListener(System.Net.IPAddress.Loopback, 0);
+        listener.Start();
+        return ((System.Net.IPEndPoint)listener.LocalEndpoint).Port;
+    }
+
+    public void Dispose()
+    {
+        if (Directory.Exists(_pkiRoot))
+        {
+            try { Directory.Delete(_pkiRoot, recursive: true); }
+            catch { /* best-effort */ }
+        }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerArrayTests.cs

@@ -32,7 +32,7 @@ public sealed class NodeManagerArrayTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/arr", parentFolderNodeId: null, displayName: "arr", dataType: "Int32",
-            writable: false, historianTagname: null, isArray: true, arrayLength: 8);
+            writable: false, historianTagname: null, isArray: true, arrayLength: 8, realm: AddressSpaceRealm.Uns);
 
         var variable = nm.TryGetVariable("eq-1/arr");
         variable.ShouldNotBeNull();
@@ -52,7 +52,7 @@ public sealed class NodeManagerArrayTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/arr-unfixed", parentFolderNodeId: null, displayName: "arr-unfixed", dataType: "Int32",
-            writable: false, historianTagname: null, isArray: true, arrayLength: null);
+            writable: false, historianTagname: null, isArray: true, arrayLength: null, realm: AddressSpaceRealm.Uns);
 
         var variable = nm.TryGetVariable("eq-1/arr-unfixed");
         variable.ShouldNotBeNull();
@@ -72,7 +72,7 @@ public sealed class NodeManagerArrayTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/scalar", parentFolderNodeId: null, displayName: "scalar", dataType: "Int32",
-            writable: false);
+            writable: false, realm: AddressSpaceRealm.Uns);
 
         var variable = nm.TryGetVariable("eq-1/scalar");
         variable.ShouldNotBeNull();
@@ -91,10 +91,10 @@ public sealed class NodeManagerArrayTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/arrwrite", parentFolderNodeId: null, displayName: "arrwrite", dataType: "Int32",
-            writable: false, historianTagname: null, isArray: true, arrayLength: 3);
+            writable: false, historianTagname: null, isArray: true, arrayLength: 3, realm: AddressSpaceRealm.Uns);
 
         var payload = new[] { 1, 2, 3 };
-        nm.WriteValue("eq-1/arrwrite", payload, OpcUaQuality.Good, DateTime.UtcNow);
+        nm.WriteValue("eq-1/arrwrite", payload, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
 
         var variable = nm.TryGetVariable("eq-1/arrwrite");
         variable.ShouldNotBeNull();

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistorizeTests.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.Logging.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Opc.Ua;
 using Shouldly;
 using Xunit;
@@ -29,7 +30,7 @@ public sealed class NodeManagerHistorizeTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp", dataType: "Float",
-            writable: false, historianTagname: "WW.Tag");
+            writable: false, historianTagname: "WW.Tag", realm: AddressSpaceRealm.Uns);
 
         var variable = nm.TryGetVariable("eq-1/temp");
         variable.ShouldNotBeNull();
@@ -56,9 +57,9 @@ public sealed class NodeManagerHistorizeTests : IDisposable
 
         // Explicit null and the defaulted-param form both mean "not historized".
         nm.EnsureVariable("eq-1/plain", parentFolderNodeId: null, displayName: "Plain", dataType: "Int32",
-            writable: false, historianTagname: null);
+            writable: false, historianTagname: null, realm: AddressSpaceRealm.Uns);
         nm.EnsureVariable("eq-1/plain2", parentFolderNodeId: null, displayName: "Plain2", dataType: "Int32",
-            writable: false);
+            writable: false, realm: AddressSpaceRealm.Uns);
 
         foreach (var nodeId in new[] { "eq-1/plain", "eq-1/plain2" })
         {
@@ -83,7 +84,7 @@ public sealed class NodeManagerHistorizeTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/setpoint", parentFolderNodeId: null, displayName: "Setpoint", dataType: "Float",
-            writable: true, historianTagname: "WW.Setpoint");
+            writable: true, historianTagname: "WW.Setpoint", realm: AddressSpaceRealm.Uns);
 
         var variable = nm.TryGetVariable("eq-1/setpoint");
         variable.ShouldNotBeNull();
@@ -109,7 +110,7 @@ public sealed class NodeManagerHistorizeTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp", dataType: "Float",
-            writable: false, historianTagname: "WW.Tag");
+            writable: false, historianTagname: "WW.Tag", realm: AddressSpaceRealm.Uns);
         nm.TryGetHistorizedTagname("eq-1/temp", out _).ShouldBeTrue();
 
         nm.RebuildAddressSpace();

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadConcurrencyTests.cs

@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Microsoft.Extensions.Logging.Abstractions;
 using Opc.Ua;
 using Opc.Ua.Server;
@@ -228,7 +229,7 @@ public sealed class NodeManagerHistoryReadConcurrencyTests : IDisposable
         {
             var key = $"eq/tag{i}";
             nm.EnsureVariable(key, parentFolderNodeId: null, displayName: $"Tag{i}", dataType: "Float",
-                writable: false, historianTagname: $"WW.Tag{i}");
+                writable: false, historianTagname: $"WW.Tag{i}", realm: AddressSpaceRealm.Uns);
             ids[i] = nm.TryGetVariable(key)!.NodeId;
         }
 

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadEventsTests.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.Logging.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Opc.Ua;
 using Opc.Ua.Server;
 using Shouldly;
@@ -42,8 +43,8 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         nm.HistorianDataSource = fake;
 
         const string equipmentId = "eq-evt";
-        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alarm-1", equipmentId, "HighTemp", "OffNormalAlarm", severity: 700);
+        nm.MaterialiseAlarmCondition("alarm-1", equipmentId, "HighTemp", "OffNormalAlarm", severity: 700, realm: AddressSpaceRealm.Uns);
         var notifierNodeId = nm.TryGetFolder(equipmentId)!.NodeId;
 
         var evtTime = new DateTime(2026, 6, 14, 10, 0, 0, DateTimeKind.Utc);
@@ -107,8 +108,8 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         nm.HistorianDataSource = fake;
 
         const string equipmentId = "eq-unbounded";
-        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alarm-0", equipmentId, "Cond", "OffNormalAlarm", severity: 600);
+        nm.MaterialiseAlarmCondition("alarm-0", equipmentId, "Cond", "OffNormalAlarm", severity: 600, realm: AddressSpaceRealm.Uns);
         var notifierNodeId = nm.TryGetFolder(equipmentId)!.NodeId;
 
         fake.EventsResult = new HistoricalEventsResult(
@@ -143,8 +144,8 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         nm.HistorianDataSource = fake;
 
         const string equipmentId = "eq-unsupported";
-        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alarm-2", equipmentId, "Cond", "OffNormalAlarm", severity: 500);
+        nm.MaterialiseAlarmCondition("alarm-2", equipmentId, "Cond", "OffNormalAlarm", severity: 500, realm: AddressSpaceRealm.Uns);
         var notifierNodeId = nm.TryGetFolder(equipmentId)!.NodeId;
 
         fake.EventsResult = new HistoricalEventsResult(
@@ -187,8 +188,8 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         nm.HistorianDataSource = fake;
 
         const string equipmentId = "eq-empty";
-        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alarm-3", equipmentId, "Cond", "OffNormalAlarm", severity: 300);
+        nm.MaterialiseAlarmCondition("alarm-3", equipmentId, "Cond", "OffNormalAlarm", severity: 300, realm: AddressSpaceRealm.Uns);
         var notifierNodeId = nm.TryGetFolder(equipmentId)!.NodeId;
 
         var details = new ReadEventDetails
@@ -221,8 +222,8 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         // Materialise the alarm while the source is still the Null default — the folder is promoted to
         // SubscribeToEvents but DOES NOT get the HistoryRead bit / source registration.
         const string equipmentId = "eq-nosrc";
-        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alarm-4", equipmentId, "Cond", "OffNormalAlarm", severity: 200);
+        nm.MaterialiseAlarmCondition("alarm-4", equipmentId, "Cond", "OffNormalAlarm", severity: 200, realm: AddressSpaceRealm.Uns);
         var notifierNodeId = nm.TryGetFolder(equipmentId)!.NodeId;
 
         // Wire a real source AFTER promotion — it must NOT retroactively make the folder a source.
@@ -271,7 +272,7 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         // A historized variable node — has AccessLevel.HistoryRead (variable-history reads) but
         // EventNotifier=None (no event-notifier bit). The SDK base rejects it before our override runs.
         nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp", dataType: "Float",
-            writable: false, historianTagname: "WW.Temp");
+            writable: false, historianTagname: "WW.Temp", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/temp")!.NodeId;
 
         var details = new ReadEventDetails
@@ -303,8 +304,8 @@ public sealed class NodeManagerHistoryReadEventsTests : IDisposable
         nm.HistorianDataSource = fake;
 
         const string equipmentId = "eq-boom";
-        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment");
+        nm.EnsureFolder(equipmentId, parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alarm-5", equipmentId, "Cond", "OffNormalAlarm", severity: 900);
+        nm.MaterialiseAlarmCondition("alarm-5", equipmentId, "Cond", "OffNormalAlarm", severity: 900, realm: AddressSpaceRealm.Uns);
         var notifierNodeId = nm.TryGetFolder(equipmentId)!.NodeId;
 
         var details = new ReadEventDetails

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadPagingTests.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.Logging.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Opc.Ua;
 using Opc.Ua.Server;
 using Shouldly;
@@ -42,7 +43,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = new SeriesHistorianDataSource(series);
 
         nm.EnsureVariable("eq-1/pv", parentFolderNodeId: null, displayName: "PV", dataType: "Double",
-            writable: false, historianTagname: "WW.PV");
+            writable: false, historianTagname: "WW.PV", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/pv")!.NodeId;
 
         var collected = new List<double>();
@@ -84,7 +85,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = new SeriesHistorianDataSource(MakeSeries(count: 100, stepSeconds: 1));
 
         nm.EnsureVariable("eq-1/exact", parentFolderNodeId: null, displayName: "Exact", dataType: "Double",
-            writable: false, historianTagname: "WW.Exact");
+            writable: false, historianTagname: "WW.Exact", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/exact")!.NodeId;
 
         var (r1, _, cp1) = ReadRaw(nm, nodeId, Epoch, Epoch.AddHours(1), max: 100, inboundCp: null);
@@ -123,7 +124,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = new SeriesHistorianDataSource(series);
 
         nm.EnsureVariable("eq-1/tie", parentFolderNodeId: null, displayName: "Tie", dataType: "Double",
-            writable: false, historianTagname: "WW.Tie");
+            writable: false, historianTagname: "WW.Tie", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/tie")!.NodeId;
 
         var collected = new List<double>();
@@ -167,7 +168,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = new SeriesHistorianDataSource(series);
 
         nm.EnsureVariable("eq-1/burst", parentFolderNodeId: null, displayName: "Burst", dataType: "Double",
-            writable: false, historianTagname: "WW.Burst");
+            writable: false, historianTagname: "WW.Burst", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/burst")!.NodeId;
 
         var collected = new List<double>();
@@ -211,7 +212,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = new SeriesHistorianDataSource(series);
 
         nm.EnsureVariable("eq-1/absurd", parentFolderNodeId: null, displayName: "Absurd", dataType: "Double",
-            writable: false, historianTagname: "WW.Absurd");
+            writable: false, historianTagname: "WW.Absurd", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/absurd")!.NodeId;
 
         // Page 1: a full page of the first 2 ties, with a continuation point.
@@ -241,7 +242,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = new SeriesHistorianDataSource(MakeSeries(count: 250, stepSeconds: 1));
 
         nm.EnsureVariable("eq-1/all", parentFolderNodeId: null, displayName: "All", dataType: "Double",
-            writable: false, historianTagname: "WW.All");
+            writable: false, historianTagname: "WW.All", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/all")!.NodeId;
 
         var (r, e, cp) = ReadRaw(nm, nodeId, Epoch, Epoch.AddHours(1), max: 0, inboundCp: null);
@@ -265,7 +266,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/bad-cp", parentFolderNodeId: null, displayName: "BadCp", dataType: "Double",
-            writable: false, historianTagname: "WW.BadCp");
+            writable: false, historianTagname: "WW.BadCp", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/bad-cp")!.NodeId;
 
         fake.ResetReadCount();
@@ -291,7 +292,7 @@ public sealed class NodeManagerHistoryReadPagingTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/rel", parentFolderNodeId: null, displayName: "Rel", dataType: "Double",
-            writable: false, historianTagname: "WW.Rel");
+            writable: false, historianTagname: "WW.Rel", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/rel")!.NodeId;
 
         // Page 1 — get a CP.

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerHistoryReadTests.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.Logging.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Opc.Ua;
 using Opc.Ua.Server;
 using Shouldly;
@@ -39,7 +40,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp", dataType: "Float",
-            writable: false, historianTagname: "WW.Temp");
+            writable: false, historianTagname: "WW.Temp", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/temp")!.NodeId;
 
         var src = DateTime.UtcNow.AddSeconds(-5);
@@ -91,7 +92,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
 
         // Node id "eq-9/flow" but a DISTINCT historian tagname "Plant.Flow.PV".
         nm.EnsureVariable("eq-9/flow", parentFolderNodeId: null, displayName: "Flow", dataType: "Double",
-            writable: false, historianTagname: "Plant.Flow.PV");
+            writable: false, historianTagname: "Plant.Flow.PV", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-9/flow")!.NodeId;
 
         var details = new ReadRawModifiedDetails
@@ -123,7 +124,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/empty", parentFolderNodeId: null, displayName: "Empty", dataType: "Float",
-            writable: false, historianTagname: "WW.Empty");
+            writable: false, historianTagname: "WW.Empty", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/empty")!.NodeId;
 
         var details = new ReadRawModifiedDetails
@@ -156,7 +157,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
 
         // Plain (non-historized) variable — no HistoryRead access bit.
         nm.EnsureVariable("eq-1/plain", parentFolderNodeId: null, displayName: "Plain", dataType: "Int32",
-            writable: false, historianTagname: null);
+            writable: false, historianTagname: null, realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/plain")!.NodeId;
 
         var details = new ReadRawModifiedDetails
@@ -185,7 +186,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/mod", parentFolderNodeId: null, displayName: "Mod", dataType: "Float",
-            writable: false, historianTagname: "WW.Mod");
+            writable: false, historianTagname: "WW.Mod", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/mod")!.NodeId;
 
         var details = new ReadRawModifiedDetails
@@ -215,7 +216,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/avg", parentFolderNodeId: null, displayName: "Avg", dataType: "Float",
-            writable: false, historianTagname: "WW.Avg");
+            writable: false, historianTagname: "WW.Avg", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/avg")!.NodeId;
 
         var details = new ReadProcessedDetails
@@ -247,7 +248,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/sd", parentFolderNodeId: null, displayName: "Sd", dataType: "Float",
-            writable: false, historianTagname: "WW.Sd");
+            writable: false, historianTagname: "WW.Sd", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/sd")!.NodeId;
 
         var details = new ReadProcessedDetails
@@ -277,7 +278,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/at", parentFolderNodeId: null, displayName: "At", dataType: "Float",
-            writable: false, historianTagname: "WW.At");
+            writable: false, historianTagname: "WW.At", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/at")!.NodeId;
 
         var t1 = DateTime.UtcNow.AddMinutes(-2);
@@ -309,9 +310,9 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
 
         // Materialise two distinct historized variables under separate equipment folders.
         nm.EnsureVariable("eqA/good", parentFolderNodeId: null, displayName: "Good", dataType: "Float",
-            writable: false, historianTagname: "A.PV");
+            writable: false, historianTagname: "A.PV", realm: AddressSpaceRealm.Uns);
         nm.EnsureVariable("eqB/bad", parentFolderNodeId: null, displayName: "Bad", dataType: "Float",
-            writable: false, historianTagname: "B.PV");
+            writable: false, historianTagname: "B.PV", realm: AddressSpaceRealm.Uns);
 
         var goodNodeId = nm.TryGetVariable("eqA/good")!.NodeId;
         var badNodeId  = nm.TryGetVariable("eqB/bad")!.NodeId;
@@ -368,7 +369,7 @@ public sealed class NodeManagerHistoryReadTests : IDisposable
         nm.HistorianDataSource = fake;
 
         nm.EnsureVariable("eq-1/boom", parentFolderNodeId: null, displayName: "Boom", dataType: "Float",
-            writable: false, historianTagname: "WW.Boom");
+            writable: false, historianTagname: "WW.Boom", realm: AddressSpaceRealm.Uns);
         var nodeId = nm.TryGetVariable("eq-1/boom")!.NodeId;
 
         var details = new ReadRawModifiedDetails

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerModelChangeOnAddTests.cs

@@ -43,8 +43,8 @@ public sealed class NodeManagerModelChangeOnAddTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureFolder("eq-7", parentNodeId: null, displayName: "Equipment 7");
+        nm.EnsureFolder("eq-7", parentNodeId: null, displayName: "Equipment 7", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-7/speed", parentFolderNodeId: "eq-7", displayName: "Speed", dataType: "Float", writable: false);
+        nm.EnsureVariable("eq-7/speed", parentFolderNodeId: "eq-7", displayName: "Speed", dataType: "Float", writable: false, realm: AddressSpaceRealm.Uns);
         var parent = nm.TryGetFolder("eq-7")!;
 
         var e = nm.BuildNodesAddedModelChange("eq-7");
@@ -95,13 +95,13 @@ public sealed class NodeManagerModelChangeOnAddTests : IDisposable
         var nm = server.NodeManager!;
 
         // Before any nodes exist under the parent — must not throw.
-        Should.NotThrow(() => nm.RaiseNodesAddedModelChange("eq-9"));
+        Should.NotThrow(() => nm.RaiseNodesAddedModelChange("eq-9", realm: AddressSpaceRealm.Uns));
 
-        nm.EnsureFolder("eq-9", parentNodeId: null, displayName: "Equipment 9");
+        nm.EnsureFolder("eq-9", parentNodeId: null, displayName: "Equipment 9", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-9/temp", parentFolderNodeId: "eq-9", displayName: "Temp", dataType: "Float", writable: false);
+        nm.EnsureVariable("eq-9/temp", parentFolderNodeId: "eq-9", displayName: "Temp", dataType: "Float", writable: false, realm: AddressSpaceRealm.Uns);
 
         // After the nodes are materialised — still must not throw.
-        Should.NotThrow(() => nm.RaiseNodesAddedModelChange("eq-9"));
+        Should.NotThrow(() => nm.RaiseNodesAddedModelChange("eq-9", realm: AddressSpaceRealm.Uns));
 
         await host.DisposeAsync();
     }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerMultiNotifierAlarmTests.cs

@@ -0,0 +1,238 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+
+namespace ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests;
+
+/// <summary>
+///     v3 Batch 4 (B4-WP4) — the native-alarm <b>multi-notifier</b> wiring +
+///     <b>teardown symmetry</b> on <see cref="OtOpcUaNodeManager"/>. A native alarm is a SINGLE Part 9
+///     condition materialised once at its raw tag (ConditionId = RawPath, Raw realm);
+///     <see cref="OtOpcUaNodeManager.WireAlarmNotifiers"/> wires that one condition as an event notifier of
+///     EACH referencing equipment's UNS folder so one <c>ReportEvent</c> fans one event to every referencing
+///     equipment (never re-reported per root). The obligation these tests lock in: the wiring is idempotent,
+///     a missing folder is a safe skip, and every teardown path (condition-removal / equipment-subtree-removal
+///     / full rebuild + re-wire) removes the notifier pair BIDIRECTIONALLY so no inverse-notifier entry leaks
+///     across redeploys (exactly N notifiers after a re-trip, not 2N).
+/// </summary>
+public sealed class NodeManagerMultiNotifierAlarmTests : IDisposable
+{
+    private static CancellationToken Ct => TestContext.Current.CancellationToken;
+
+    private const string RawAlarm = "Plant/Modbus/dev1/temp_hi";
+    private const string RawDeviceFolder = "Plant/Modbus/dev1";
+    private const string Equip1 = "EQ-filling-line1-station1";
+    private const string Equip2 = "EQ-filling-line2-station2";
+
+    private readonly string _pkiRoot = Path.Combine(
+        Path.GetTempPath(),
+        $"otopcua-multi-notifier-{Guid.NewGuid():N}");
+
+    /// <summary>Materialise the raw device folder + the single native condition + two equipment folders, then
+    /// wire the condition as a notifier of both. Returns the node manager.</summary>
+    private async Task<(OpcUaApplicationHost Host, OtOpcUaNodeManager Nm)> BootWithTwoEquipmentAsync()
+    {
+        var (host, server) = await BootAsync();
+        var nm = server.NodeManager!;
+        // Raw device folder (the condition's HasComponent parent) + the single native condition at the RawPath.
+        nm.EnsureFolder(RawDeviceFolder, parentNodeId: null, displayName: "dev1", realm: AddressSpaceRealm.Raw);
+        nm.MaterialiseAlarmCondition(RawAlarm, RawDeviceFolder, "temp_hi", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Raw);
+        // Two referencing equipment folders (UNS realm).
+        nm.EnsureFolder(Equip1, parentNodeId: null, displayName: "station1", realm: AddressSpaceRealm.Uns);
+        nm.EnsureFolder(Equip2, parentNodeId: null, displayName: "station2", realm: AddressSpaceRealm.Uns);
+        return (host, nm);
+    }
+
+    /// <summary>The single condition is wired as a notifier of EACH referencing equipment folder: the condition
+    /// carries one inverse-notifier entry per folder, each folder carries the inverse back to the condition, and
+    /// each folder becomes a root (Server-object) event notifier.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task WireAlarmNotifiers_wires_the_single_condition_to_each_equipment_folder()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+
+        // One inverse-notifier entry per equipment folder on the single condition.
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(2);
+        // Each equipment folder holds the inverse entry back to the condition + is a root notifier.
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(1);
+        nm.FolderNotifierCount(Equip2, AddressSpaceRealm.Uns).ShouldBe(1);
+        nm.IsRootNotifier(Equip1, AddressSpaceRealm.Uns).ShouldBeTrue();
+        nm.IsRootNotifier(Equip2, AddressSpaceRealm.Uns).ShouldBeTrue();
+
+        await host.DisposeAsync();
+    }
+
+    /// <summary>Re-wiring the SAME pairs (an idempotent re-apply of the raw subtree pass) does not duplicate the
+    /// notifier entries — the SDK dedups by node reference and the tracking dedups its list.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task WireAlarmNotifiers_is_idempotent_no_duplicate_on_re_wire()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(2);
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(1);
+        nm.FolderNotifierCount(Equip2, AddressSpaceRealm.Uns).ShouldBe(1);
+
+        await host.DisposeAsync();
+    }
+
+    /// <summary>A referencing equipment folder that is not (yet) materialised is skipped (no throw); the present
+    /// folders are still wired. A missing condition is likewise a no-op.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task WireAlarmNotifiers_missing_folder_or_condition_is_a_safe_skip()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+
+        // "EQ-missing" was never materialised — it is skipped; Equip1 is still wired.
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, "EQ-missing" }, AddressSpaceRealm.Uns);
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(1);
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(1);
+
+        // An unmaterialised condition id is a no-op (never throws).
+        Should.NotThrow(() =>
+            nm.WireAlarmNotifiers("Plant/Modbus/dev1/does_not_exist", AddressSpaceRealm.Raw, new[] { Equip1 }, AddressSpaceRealm.Uns));
+
+        await host.DisposeAsync();
+    }
+
+    /// <summary>Removing the condition in place (surgical raw-alarm-tag removal) tears the notifier pairs down
+    /// BIDIRECTIONALLY: the surviving equipment folders lose their inverse-notifier entry back to the removed
+    /// condition (no dangling reference).</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task RemoveAlarmConditionNode_unwires_notifiers_from_surviving_folders()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(1);
+
+        nm.RemoveAlarmConditionNode(RawAlarm, AddressSpaceRealm.Raw).ShouldBeTrue();
+
+        // Condition gone; the surviving equipment folders no longer reference it (bidirectional teardown).
+        nm.TryGetAlarmCondition(RawAlarm, AddressSpaceRealm.Raw).ShouldBeNull();
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(0);
+        nm.FolderNotifierCount(Equip2, AddressSpaceRealm.Uns).ShouldBe(0);
+
+        await host.DisposeAsync();
+    }
+
+    /// <summary>Removing one referencing equipment's subtree unwires ONLY that folder from the surviving raw
+    /// condition (which lives in the Raw realm and is untouched by a UNS subtree removal): the condition drops
+    /// exactly one notifier and keeps the other.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task RemoveEquipmentSubtree_unwires_only_that_folder_from_surviving_condition()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(2);
+
+        nm.RemoveEquipmentSubtree(Equip1, AddressSpaceRealm.Uns).ShouldBeTrue();
+
+        // The raw condition SURVIVES (Raw realm) and now notifies only the remaining equipment folder.
+        nm.TryGetAlarmCondition(RawAlarm, AddressSpaceRealm.Raw).ShouldNotBeNull();
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(1);
+        nm.FolderNotifierCount(Equip2, AddressSpaceRealm.Uns).ShouldBe(1);
+        nm.IsRootNotifier(Equip2, AddressSpaceRealm.Uns).ShouldBeTrue();
+
+        await host.DisposeAsync();
+    }
+
+    /// <summary>Teardown-symmetry / "exactly one copy after a re-trip": a full rebuild + re-materialise +
+    /// re-wire leaves EXACTLY the same notifier count (2), not a doubled/leaked set — the rebuild unwired the
+    /// prior notifier pairs bidirectionally before dropping the nodes.</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task Rebuild_then_rewire_has_no_leaked_notifier_duplicates()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(2);
+
+        // Redeploy (the full-rebuild path).
+        nm.RebuildAddressSpace();
+        nm.TryGetAlarmCondition(RawAlarm, AddressSpaceRealm.Raw).ShouldBeNull();
+
+        // Re-materialise the whole thing + re-wire (what the applier does every apply).
+        nm.EnsureFolder(RawDeviceFolder, parentNodeId: null, displayName: "dev1", realm: AddressSpaceRealm.Raw);
+        nm.MaterialiseAlarmCondition(RawAlarm, RawDeviceFolder, "temp_hi", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Raw);
+        nm.EnsureFolder(Equip1, parentNodeId: null, displayName: "station1", realm: AddressSpaceRealm.Uns);
+        nm.EnsureFolder(Equip2, parentNodeId: null, displayName: "station2", realm: AddressSpaceRealm.Uns);
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+
+        // Exactly 2 again — no leaked inverse-notifier entries carried across the rebuild.
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(2);
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(1);
+        nm.FolderNotifierCount(Equip2, AddressSpaceRealm.Uns).ShouldBe(1);
+
+        await host.DisposeAsync();
+    }
+
+    /// <summary>Wave C review M3 — <see cref="OtOpcUaNodeManager.WireAlarmNotifiers"/> is a RECONCILE: re-wiring
+    /// with a SHRUNK folder set unwires (bidirectionally) the dropped equipment folder, so a de-referenced
+    /// equipment stops receiving the alarm. (Guards a future surgical ChangedRawTags path; today the shrink
+    /// arrives as a full rebuild.)</summary>
+    [Trait("Category", "Unit")]
+    [Fact]
+    public async Task WireAlarmNotifiers_reconciles_a_dropped_folder_out_of_the_notifier_set()
+    {
+        var (host, nm) = await BootWithTwoEquipmentAsync();
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1, Equip2 }, AddressSpaceRealm.Uns);
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(2);
+
+        // Re-wire with only Equip1 (Equip2 de-referenced) — reconcile unwires Equip2 bidirectionally.
+        nm.WireAlarmNotifiers(RawAlarm, AddressSpaceRealm.Raw, new[] { Equip1 }, AddressSpaceRealm.Uns);
+
+        nm.AlarmNotifierCount(RawAlarm, AddressSpaceRealm.Raw).ShouldBe(1);
+        nm.FolderNotifierCount(Equip1, AddressSpaceRealm.Uns).ShouldBe(1);
+        nm.FolderNotifierCount(Equip2, AddressSpaceRealm.Uns).ShouldBe(0); // no dangling inverse to the condition
+
+        await host.DisposeAsync();
+    }
+
+    private async Task<(OpcUaApplicationHost Host, OtOpcUaSdkServer Server)> BootAsync()
+    {
+        var host = new OpcUaApplicationHost(
+            new OpcUaApplicationHostOptions
+            {
+                ApplicationName = "OtOpcUa.MultiNotifierTest",
+                ApplicationUri = $"urn:OtOpcUa.MultiNotifierTest:{Guid.NewGuid():N}",
+                OpcUaPort = AllocateFreePort(),
+                PublicHostname = "localhost",
+                PkiStoreRoot = _pkiRoot,
+            },
+            Microsoft.Extensions.Logging.Abstractions.NullLogger<OpcUaApplicationHost>.Instance);
+
+        var server = new OtOpcUaSdkServer();
+        await host.StartAsync(server, Ct);
+        return (host, server);
+    }
+
+    private static int AllocateFreePort()
+    {
+        using var listener = new System.Net.Sockets.TcpListener(System.Net.IPAddress.Loopback, 0);
+        listener.Start();
+        var port = ((System.Net.IPEndPoint)listener.LocalEndpoint).Port;
+        listener.Stop();
+        return port;
+    }
+
+    /// <summary>Cleans up the PKI root directory.</summary>
+    public void Dispose()
+    {
+        if (Directory.Exists(_pkiRoot))
+        {
+            try { Directory.Delete(_pkiRoot, recursive: true); }
+            catch { /* best-effort cleanup */ }
+        }
+    }
+}

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerPreStartGuardTests.cs

@@ -38,7 +38,7 @@ public sealed class NodeManagerPreStartGuardTests : IDisposable
         try
         {
             var ex = Should.Throw<InvalidOperationException>(() =>
-                nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment"));
+                nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment", realm: AddressSpaceRealm.Uns));
             ex.Message.ShouldContain("address space has not been created");
         }
         finally
@@ -55,7 +55,7 @@ public sealed class NodeManagerPreStartGuardTests : IDisposable
         {
             Should.Throw<InvalidOperationException>(() =>
                 nm.EnsureVariable("eq-1/temp", parentFolderNodeId: null, displayName: "Temp",
-                    dataType: "Float", writable: false));
+                    dataType: "Float", writable: false, realm: AddressSpaceRealm.Uns));
         }
         finally
         {
@@ -70,7 +70,7 @@ public sealed class NodeManagerPreStartGuardTests : IDisposable
         try
         {
             Should.Throw<InvalidOperationException>(() =>
-                nm.WriteValue("eq-1/temp", 1.0, OpcUaQuality.Good, DateTime.UtcNow));
+                nm.WriteValue("eq-1/temp", 1.0, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns));
         }
         finally
         {
@@ -85,7 +85,7 @@ public sealed class NodeManagerPreStartGuardTests : IDisposable
         try
         {
             Should.Throw<InvalidOperationException>(() =>
-                nm.MaterialiseAlarmCondition("alarm-1", "eq-1", "Cond", "OffNormalAlarm", severity: 500));
+                nm.MaterialiseAlarmCondition("alarm-1", "eq-1", "Cond", "OffNormalAlarm", severity: 500, realm: AddressSpaceRealm.Uns));
         }
         finally
         {

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerSurgicalRemoveTests.cs

@@ -1,4 +1,5 @@
 using Opc.Ua;
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
 using Shouldly;
 using Xunit;
 
@@ -31,13 +32,13 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-1/A", "eq-1", "A", "Float", writable: false, historianTagname: "Hist.A");
+        nm.EnsureVariable("eq-1/A", "eq-1", "A", "Float", writable: false, historianTagname: "Hist.A", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-1/B", "eq-1", "B", "Float", writable: false);
+        nm.EnsureVariable("eq-1/B", "eq-1", "B", "Float", writable: false, realm: AddressSpaceRealm.Uns);
         var countBefore = nm.VariableCount;
         nm.TryGetHistorizedTagname("eq-1/A", out _).ShouldBeTrue();
 
-        nm.RemoveVariableNode("eq-1/A").ShouldBeTrue();
+        nm.RemoveVariableNode("eq-1/A", realm: AddressSpaceRealm.Uns).ShouldBeTrue();
 
         nm.TryGetVariable("eq-1/A").ShouldBeNull();
         nm.VariableCount.ShouldBe(countBefore - 1);
@@ -56,7 +57,7 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.RemoveVariableNode("eq-1/nope").ShouldBeFalse();
+        nm.RemoveVariableNode("eq-1/nope", realm: AddressSpaceRealm.Uns).ShouldBeFalse();
 
         await host.DisposeAsync();
     }
@@ -68,8 +69,8 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-1/A", "eq-1", "A", "Float", writable: false);
+        nm.EnsureVariable("eq-1/A", "eq-1", "A", "Float", writable: false, realm: AddressSpaceRealm.Uns);
 
         var e = nm.BuildNodesRemovedModelChange("eq-1/A");
 
@@ -92,17 +93,17 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("eq-1/OverTemp", "eq-1", "OverTemp", "OffNormalAlarm", 700, isNative: true);
+        nm.MaterialiseAlarmCondition("eq-1/OverTemp", "eq-1", "OverTemp", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Uns);
         nm.TryGetAlarmCondition("eq-1/OverTemp").ShouldNotBeNull();
         nm.IsNativeAlarmNode("eq-1/OverTemp").ShouldBeTrue();
 
-        nm.RemoveAlarmConditionNode("eq-1/OverTemp").ShouldBeTrue();
+        nm.RemoveAlarmConditionNode("eq-1/OverTemp", realm: AddressSpaceRealm.Uns).ShouldBeTrue();
 
         nm.TryGetAlarmCondition("eq-1/OverTemp").ShouldBeNull();
         nm.IsNativeAlarmNode("eq-1/OverTemp").ShouldBeFalse();
 
-        nm.RemoveAlarmConditionNode("eq-1/OverTemp").ShouldBeFalse(); // already gone ⇒ false
+        nm.RemoveAlarmConditionNode("eq-1/OverTemp", realm: AddressSpaceRealm.Uns).ShouldBeFalse(); // already gone ⇒ false
 
         await host.DisposeAsync();
     }
@@ -114,10 +115,10 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
     {
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 500, isNative: false);
+        nm.MaterialiseAlarmCondition("alm-1", "eq-1", "HighTemp", "OffNormalAlarm", 500, isNative: false, realm: AddressSpaceRealm.Uns);
 
-        nm.RemoveAlarmConditionNode("alm-1").ShouldBeTrue();
+        nm.RemoveAlarmConditionNode("alm-1", realm: AddressSpaceRealm.Uns).ShouldBeTrue();
         nm.TryGetAlarmCondition("alm-1").ShouldBeNull();
 
         await host.DisposeAsync();
@@ -136,17 +137,17 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
         var nm = server.NodeManager!;
 
         // Target equipment eq-1 with a sub-folder, two variables (one historized), and a native condition.
-        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1");
+        nm.EnsureFolder("eq-1", parentNodeId: null, displayName: "Equipment 1", realm: AddressSpaceRealm.Uns);
-        nm.EnsureFolder("eq-1/Diag", parentNodeId: "eq-1", displayName: "Diag");
+        nm.EnsureFolder("eq-1/Diag", parentNodeId: "eq-1", displayName: "Diag", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-1/A", "eq-1", "A", "Float", writable: false, historianTagname: "Hist.A");
+        nm.EnsureVariable("eq-1/A", "eq-1", "A", "Float", writable: false, historianTagname: "Hist.A", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-1/Diag/T", "eq-1/Diag", "T", "Float", writable: false);
+        nm.EnsureVariable("eq-1/Diag/T", "eq-1/Diag", "T", "Float", writable: false, realm: AddressSpaceRealm.Uns);
-        nm.MaterialiseAlarmCondition("eq-1/OverTemp", "eq-1", "OverTemp", "OffNormalAlarm", 700, isNative: true);
+        nm.MaterialiseAlarmCondition("eq-1/OverTemp", "eq-1", "OverTemp", "OffNormalAlarm", 700, isNative: true, realm: AddressSpaceRealm.Uns);
 
         // Sibling equipment eq-2 that must survive untouched.
-        nm.EnsureFolder("eq-2", parentNodeId: null, displayName: "Equipment 2");
+        nm.EnsureFolder("eq-2", parentNodeId: null, displayName: "Equipment 2", realm: AddressSpaceRealm.Uns);
-        nm.EnsureVariable("eq-2/S", "eq-2", "S", "Float", writable: false);
+        nm.EnsureVariable("eq-2/S", "eq-2", "S", "Float", writable: false, realm: AddressSpaceRealm.Uns);
 
-        nm.RemoveEquipmentSubtree("eq-1").ShouldBeTrue();
+        nm.RemoveEquipmentSubtree("eq-1", realm: AddressSpaceRealm.Uns).ShouldBeTrue();
 
         // Every eq-1 descendant is gone from every map.
         nm.TryGetFolder("eq-1").ShouldBeNull();
@@ -163,7 +164,7 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
 
         // Re-materialising an alarm under eq-2 still works (the notifier machinery was not corrupted by the
         // eq-1 demotion) — proves no orphaned root-notifier ref broke the event path.
-        Should.NotThrow(() => nm.MaterialiseAlarmCondition("eq-2/Alm", "eq-2", "Alm", "OffNormalAlarm", 300, isNative: false));
+        Should.NotThrow(() => nm.MaterialiseAlarmCondition("eq-2/Alm", "eq-2", "Alm", "OffNormalAlarm", 300, isNative: false, realm: AddressSpaceRealm.Uns));
 
         await host.DisposeAsync();
     }
@@ -176,7 +177,7 @@ public sealed class NodeManagerSurgicalRemoveTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.RemoveEquipmentSubtree("eq-nope").ShouldBeFalse();
+        nm.RemoveEquipmentSubtree("eq-nope", realm: AddressSpaceRealm.Uns).ShouldBeFalse();
 
         await host.DisposeAsync();
     }

tests/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer.Tests/NodeManagerSurgicalShapeUpdateTests.cs

@@ -44,13 +44,13 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Float", writable: false);
+        nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Float", writable: false, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/sp", 3.5f, OpcUaQuality.Good, DateTime.UtcNow);
+        nm.WriteValue("eq-1/sp", 3.5f, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
         node.DataType.ShouldBe(DataTypeIds.Float); // arrange guard
 
         var applied = nm.UpdateTagAttributes("eq-1/sp", writable: false, historianTagname: null,
-            dataType: "Int32", isArray: false, arrayLength: null);
+            dataType: "Int32", isArray: false, arrayLength: null, realm: AddressSpaceRealm.Uns);
 
         applied.ShouldBeTrue();
         node.DataType.ShouldBe(DataTypeIds.Int32);                      // swapped in place
@@ -69,13 +69,13 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureVariable("eq-1/buf", parentFolderNodeId: null, displayName: "Buf", dataType: "Int16", writable: false);
+        nm.EnsureVariable("eq-1/buf", parentFolderNodeId: null, displayName: "Buf", dataType: "Int16", writable: false, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/buf", (short)42, OpcUaQuality.Good, DateTime.UtcNow);
+        nm.WriteValue("eq-1/buf", (short)42, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/buf")!;
         node.ValueRank.ShouldBe(ValueRanks.Scalar); // arrange guard
 
         var applied = nm.UpdateTagAttributes("eq-1/buf", writable: false, historianTagname: null,
-            dataType: "Int16", isArray: true, arrayLength: 8u);
+            dataType: "Int16", isArray: true, arrayLength: 8u, realm: AddressSpaceRealm.Uns);
 
         applied.ShouldBeTrue();
         node.ValueRank.ShouldBe(ValueRanks.OneDimension);
@@ -96,13 +96,13 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/buf", parentFolderNodeId: null, displayName: "Buf", dataType: "Int16",
-            writable: false, historianTagname: null, isArray: true, arrayLength: 4u);
+            writable: false, historianTagname: null, isArray: true, arrayLength: 4u, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/buf", new short[] { 1, 2, 3, 4 }, OpcUaQuality.Good, DateTime.UtcNow);
+        nm.WriteValue("eq-1/buf", new short[] { 1, 2, 3, 4 }, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/buf")!;
         node.ArrayDimensions![0].ShouldBe(4u); // arrange guard
 
         var applied = nm.UpdateTagAttributes("eq-1/buf", writable: false, historianTagname: null,
-            dataType: "Int16", isArray: true, arrayLength: 8u);
+            dataType: "Int16", isArray: true, arrayLength: 8u, realm: AddressSpaceRealm.Uns);
 
         applied.ShouldBeTrue();
         node.ArrayDimensions[0].ShouldBe(8u);
@@ -121,13 +121,13 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var nm = server.NodeManager!;
 
         nm.EnsureVariable("eq-1/buf", parentFolderNodeId: null, displayName: "Buf", dataType: "Int16",
-            writable: false, historianTagname: null, isArray: true, arrayLength: 4u);
+            writable: false, historianTagname: null, isArray: true, arrayLength: 4u, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/buf", new short[] { 1, 2, 3, 4 }, OpcUaQuality.Good, DateTime.UtcNow);
+        nm.WriteValue("eq-1/buf", new short[] { 1, 2, 3, 4 }, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/buf")!;
         node.ValueRank.ShouldBe(ValueRanks.OneDimension); // arrange guard
 
         var applied = nm.UpdateTagAttributes("eq-1/buf", writable: false, historianTagname: null,
-            dataType: "Int16", isArray: false, arrayLength: null);
+            dataType: "Int16", isArray: false, arrayLength: null, realm: AddressSpaceRealm.Uns);
 
         applied.ShouldBeTrue();
         node.ValueRank.ShouldBe(ValueRanks.Scalar);
@@ -146,11 +146,11 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureVariable("eq-1/buf", parentFolderNodeId: null, displayName: "Buf", dataType: "Int16", writable: false);
+        nm.EnsureVariable("eq-1/buf", parentFolderNodeId: null, displayName: "Buf", dataType: "Int16", writable: false, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/buf")!;
 
         var applied = nm.UpdateTagAttributes("eq-1/buf", writable: false, historianTagname: null,
-            dataType: "Int16", isArray: true, arrayLength: null);
+            dataType: "Int16", isArray: true, arrayLength: null, realm: AddressSpaceRealm.Uns);
 
         applied.ShouldBeTrue();
         node.ValueRank.ShouldBe(ValueRanks.OneDimension);
@@ -171,13 +171,13 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Float", writable: false);
+        nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Float", writable: false, realm: AddressSpaceRealm.Uns);
-        nm.WriteValue("eq-1/sp", 7.0f, OpcUaQuality.Good, DateTime.UtcNow);
+        nm.WriteValue("eq-1/sp", 7.0f, OpcUaQuality.Good, DateTime.UtcNow, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
 
         // Same DataType ("Float") + same scalar shape — only Writable flips false → true.
         var applied = nm.UpdateTagAttributes("eq-1/sp", writable: true, historianTagname: null,
-            dataType: "Float", isArray: false, arrayLength: null);
+            dataType: "Float", isArray: false, arrayLength: null, realm: AddressSpaceRealm.Uns);
 
         applied.ShouldBeTrue();
         node.Value.ShouldBe(7.0f);                                    // value preserved (NOT reset)
@@ -199,7 +199,7 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
 
         bool result = true;
         Should.NotThrow(() => result = nm.UpdateTagAttributes("eq-1/gone", writable: false, historianTagname: null,
-            dataType: "Int32", isArray: false, arrayLength: null));
+            dataType: "Int32", isArray: false, arrayLength: null, realm: AddressSpaceRealm.Uns));
         result.ShouldBeFalse();
 
         await host.DisposeAsync();
@@ -215,7 +215,7 @@ public sealed class NodeManagerSurgicalShapeUpdateTests : IDisposable
         var (host, server) = await BootAsync();
         var nm = server.NodeManager!;
 
-        nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Float", writable: false);
+        nm.EnsureVariable("eq-1/sp", parentFolderNodeId: null, displayName: "Sp", dataType: "Float", writable: false, realm: AddressSpaceRealm.Uns);
         var node = nm.TryGetVariable("eq-1/sp")!;
 
         var e = nm.BuildNodeShapeChangedEvent(node);