CLAUDE.md

@@ -319,11 +319,12 @@ When the section is disabled the applier binds the no-op `NullHistorianProvision
 run. Every dispatch logs a tally (`dispatched/requested/ensured/skipped/failed`); `dispatched=N` with
 `requested=0` flags the dormant no-op. The API key must carry `historian:tags:write` for `EnsureTags`. (PR
 #423 shipped `GatewayTagProvisioner` but left this wiring out, so provisioning was dormant; restored 2026-06-27.)
-**0.2.0 DataType delta (archreview 06/U-7):** `EnsureTags` is an **upsert** (create-or-update, not
-skip-if-exists), and the 0.2.0 `HistorianTagDefinition.DataType` proto3-optional change means Boolean tags now
-provision as **Int1** (0.1.0 silently defaulted them to Float). A pre-bump Float Boolean is asked to retype
-on its next deploy; the AVEVA-side retype policy is pinned by the live retype probe — see the "0.2.0 DataType
-provisioning delta" section in `docs/Historian.md`.
+**DataType mapping (issue #441):** `EnsureTags` is an **upsert** (create-or-update, not skip-if-exists).
+`HistorianTypeMapper` maps **`Boolean → Int2`** (Boolean historizes as a small 0/1 integer) because the
+historian's `Int1` analog-tag creation path is **server-degenerate** — `EnsureTags(Int1)` stores an unusable
+stub (live-probed; gateway-side resolution in HistorianGateway #11 / PR #16). Both Float and Int2 are
+supported analog types, so a pre-existing Float Boolean tag retypes cleanly to Int2 on its next deploy — see
+the "Boolean historization maps to Int2" section in `docs/Historian.md`.
 
 ### Gateway-side prerequisites
 
@@ -358,7 +359,7 @@ export HISTGW_GATEWAY_ENDPOINT=https://wonder-sql-vd03:5222   # absolute gateway
 export HISTGW_GATEWAY_APIKEY=histgw_<id>_<secret>             # must carry historian:read + historian:write (+ tags:write) scopes
 export HISTGW_TEST_TAG=<existing-tag>                         # read round-trip
 export HISTGW_WRITE_SANDBOX_TAG=<writable-float-tag>          # e.g. HistGW.LiveTest.Sandbox — write round-trip (EnsureTags + write)
-export HISTGW_BOOL_SANDBOX_TAG=<writable-bool-tag>            # e.g. HistGW.LiveTest.BoolSandbox — 0.2.0 Boolean EnsureTags leg + retype probe (06/U-7)
+export HISTGW_BOOL_SANDBOX_TAG=<writable-bool-tag>            # e.g. HistGW.LiveTest.BoolSandbox — Boolean→Int2 EnsureTags leg + retype probe (issue #441)
 export HISTGW_ALARM_SOURCE=<source-name>                      # alarm SendEvent → ReadEvents round-trip
 dotnet test --filter "Category=LiveIntegration"
 ```

archreview/plans/STATUS.md

@@ -327,24 +327,31 @@ convention) + a regression unit test + `StorageRateMs` on the live-suite inline
 - ✅ `Write_then_read_on_sandbox_tag` — `EnsureTags(Float)` + `WriteLiveValues` (SQL) + read-back.
 - ✅ `Alarm_SendEvent_is_acked` + ✅ `Alarm_SendEvent_then_ReadEvents` — alarm `SendEvent` + SQL `ReadEvents`.
 - ✅ `EnsureTags_type_change_outcome_is_observable` — now observes a **real** retype outcome (not a storage-rate error).
-- ❌ `EnsureTags_boolean_sandbox_provisions_as_Int1` — **Int1 (Boolean) tag creation is not supported by the
-  gateway's histsdk on this historian**: `EnsureTags(Int1)` returns `ProtocolEvidenceMissingException` (the vendored
-  client's "no capture evidence for this type" guard → gRPC `Unimplemented`), both fresh and as a retype target.
-  A **type sweep** confirmed it is Int1-specific: **Int2/UInt2/Int4/UInt4/Float/Double all provision `success=True`;
-  only Int1 fails.** Root cause: `histsdk` `HistorianTagWriteProtocol.GetAnalogDataTypeCode` has no captured
-  CTagMetadata wire code for Int1. This is a **gateway/histsdk type-support gap**, not an OtOpcUa defect — **filed as
-  [historiangw#11](https://gitea.dohertylan.com/dohertj2/historiangw/issues/11)**.
+- ⚠️ `EnsureTags_boolean_sandbox_provisions_as_Int1` (as originally written) — **Int1 (Boolean) tag creation is not
+  supported by the gateway's histsdk on this historian**: `EnsureTags(Int1)` returns `ProtocolEvidenceMissingException`
+  (the vendored client's "no capture evidence for this type" guard → gRPC `Unimplemented`), both fresh and as a retype
+  target. A **type sweep** confirmed it is Int1-specific: **Int2/UInt2/Int4/UInt4/Float/Double all provision
+  `success=True`; only Int1 fails.** Root cause: `histsdk` `HistorianTagWriteProtocol.GetAnalogDataTypeCode` has no
+  captured CTagMetadata wire code for Int1 — a **gateway/histsdk type-support gap**, not an OtOpcUa defect
+  (**filed as [historiangw#11](https://gitea.dohertylan.com/dohertj2/historiangw/issues/11)**, which routed the
+  decision back as **[issue #441](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/441)**).
+
+  **✅ RESOLVED (issue #441, 2026-07-14):** `HistorianTypeMapper` now maps **`Boolean → Int2`** (0/1 integer) instead
+  of the degenerate `Int1`. Int2 is a proven-creatable analog type on this historian, and the value-write path already
+  sends every value as a `double` on `WriteLiveValues` regardless of tag type, so Boolean `0.0/1.0` round-trips
+  cleanly. The live gate test is renamed `EnsureTags_boolean_sandbox_provisions_as_Int2` and now passes → **6/6**. Unit
+  pins updated (`HistorianTypeMapperTests`, `GatewayTagProvisionerTests.Boolean_definition_carries_explicit_Int2_presence`);
+  gateway driver unit `103/103`.
 
 **✅ U-7 retype policy — ANSWERED (via `grpcurl` against the real historian):**
 - `EnsureTags` is a **real create-or-update upsert** — re-`EnsureTags` of an existing tag at the same type → `success`.
 - An **in-place retype between SUPPORTED types is ACCEPTED** — `Float→Double` on an existing tag returns `success`
   (of the three 06/U-7 hypotheses: **accepted-retyped**, not rejected).
-- **But the specific 0.2.0 Boolean case (Float→Int1) can't retype** — Int1 isn't a creatable type here, so a
-  pre-0.2.0 **Float Boolean tag asked to become Int1 fails the provision** with `ProtocolEvidenceMissingException`
-  — it is **neither silently retyped nor data-lost**; the provision just fails (and is metered `failed=N`). That is
-  the practically-relevant U-7 answer for Boolean tags on this deployment.
+- **The specific `Int1` case can't retype** — Int1 isn't a creatable type here. Rather than accept a broken Boolean
+  path, OtOpcUa **remapped `Boolean → Int2`** (issue #441, above), which retypes cleanly from a pre-existing Float
+  Boolean tag (both are supported analog types) and never hits the Int1 gap.
 
-The R2-06 **code** deliverables (S-11 fail-fast + `ServerHistorianOptionsValidator`; U-7 Boolean→Int1 mapping +
+The R2-06 **code** deliverables (S-11 fail-fast + `ServerHistorianOptionsValidator`; Boolean provisioning mapping +
 upsert; C-7 doc) were already unit-covered + merged; this live gate additionally **found + fixed the StorageRateMs
-provisioning bug** and **answered the U-7 retype policy**. The one remaining red test is a documented gateway
-histsdk Int1-support gap.
+provisioning bug**, **answered the U-7 retype policy**, and surfaced the Int1 histsdk gap that drove the
+**Boolean→Int2 remap (issue #441)** — closing the last red test to reach **6/6**.

docs/Historian.md

@@ -141,48 +141,44 @@ for this node), which is the signal to check that `ServerHistorian:Enabled=true`
 > so a HistoryRead on it runs to the full `CallTimeout` (~30 s) before erroring. Auto-provisioning on deploy
 > keeps freshly-historized tags from hitting that slow path. See the `CallTimeout` row above.
 
-### 0.2.0 DataType provisioning delta (archreview 06/U-7)
+### Boolean historization maps to Int2 (issue #441)
 
-`EnsureTags` is contract-documented (HistorianGateway 0.2.0) as an **upsert** — *"creates or updates
+`EnsureTags` is contract-documented (HistorianGateway 0.2.0+) as an **upsert** — *"creates or updates
 historian tags according to the given definitions"* — that maps per-tag onto AVEVA's
 `HistorianClient.EnsureTagAsync(definition) -> bool`. It is **not idempotent** (not routed through the
 idempotent retry pipeline) and **not skip-if-exists**.
 
-The 0.1.0→0.2.0 client bump made `HistorianTagDefinition.DataType` **proto3-optional** (explicit presence).
-Under 0.1.0, the provisioner's `Boolean → Int1` mapping sent wire value `0`, indistinguishable from unset, so
-the gateway defaulted such tags to the SDK-default **Float**. Under 0.2.0 the same call carries explicit
-presence, so Boolean tags now provision as **Int1** (the pre-existing intent of `HistorianTypeMapper` — no
-mapper code change is needed or wanted). Consequences:
+`HistorianTypeMapper` maps **`DriverDataType.Boolean → HistorianDataType.Int2`** and Boolean values
+historize as a small **0/1 integer**. Int2 is used rather than the semantically-exact `Int1` because the
+historian's **`Int1` analog-tag creation path is server-degenerate** — `EnsureTags(Int1)` stores an
+unusable stub, so a Boolean tag mapped to `Int1` never becomes historizable. This is an evidence-based
+decision from a live probe against the deployed 2023 R2 historian; the root cause and gateway-side
+resolution are tracked in [issue #441](https://gitea.dohertylan.com/dohertj2/lmxopcua/issues/441) and
+HistorianGateway [#11](https://gitea.dohertylan.com/dohertj2/historiangw/issues/11) / PR #16 (which
+documents `Int1` as an explicit, evidence-based exclusion). The value-write path is unaffected: the
+recorder sends every value as a `double` on `WriteLiveValues` regardless of tag type, so a Boolean
+`0.0/1.0` round-trips cleanly into the Int2 tag.
 
-1. **New Boolean tags provision correctly as Int1.** This is the fix arriving as a silent, zero-diff
-   semantic change from the bump.
-2. **Pre-bump Boolean tags exist historian-side as Float.** On the next deploy that dispatches provisioning
-   for such a tag, the gateway is asked (via the upsert) to update it to Int1.
+**Observed live (2026-07-13, real 0.2.0 gateway → real AVEVA historian on `wonder-sql-vd03`, probed via
+`grpcurl` — archreview R2-06 T12):**
+- `EnsureTags` is a **real create-or-update upsert** — re-`EnsureTags` of an existing tag at the same type
+  returns `Success=true`.
+- An **in-place retype between SUPPORTED types is ACCEPTED** — `Float→Double` on an existing tag returns
+  `Success=true`.
+- A type sweep confirmed **`Int2/UInt2/Int4/UInt4/Float/Double` all provision `Success=true`; only `Int1`
+  fails** (`Success=false, Error="ProtocolEvidenceMissingException"` — the vendored client's "no capture
+  evidence for this type" guard → gRPC `Unimplemented`), both for a fresh tag and as a retype target. Mapping
+  Boolean to `Int2` sidesteps that gap entirely.
 
-   **Observed live (2026-07-13, real 0.2.0 gateway → real AVEVA historian on `wonder-sql-vd03`, probed via
-   `grpcurl` — archreview R2-06 T12):**
-   - `EnsureTags` is a **real create-or-update upsert** — re-`EnsureTags` of an existing tag at the same type
-     returns `Success=true`.
-   - An **in-place retype between SUPPORTED types is ACCEPTED** — `Float→Double` on an existing tag returns
-     `Success=true` (hypothesis **(ii) accepted as a plain retype**, not rejected).
-   - **BUT `Int1` — the 0.2.0 Boolean target — is *not a creatable type* on this historian's histsdk:**
-     `EnsureTags(Int1)` returns `Success=false, Error="ProtocolEvidenceMissingException"` (the vendored client's
-     "no capture evidence for this type" guard → gRPC `Unimplemented`), both for a fresh tag and as a retype
-     target. A type sweep confirmed it is **Int1-specific**: `Int2/UInt2/Int4/UInt4/Float/Double` all provision
-     `Success=true`; only `Int1` fails.
-   - **Net for a pre-bump Float Boolean tag asked to become Int1:** the provision **fails** (per-tag
-     `Success=false` → `failed=N` tally). It is **neither silently retyped nor data-lost** — the tag stays Float
-     and remains readable; the Int1 provision simply doesn't land until the gateway's histsdk gains `Int1`
-     create-evidence — filed as
-     [historiangw#11](https://gitea.dohertylan.com/dohertj2/historiangw/issues/11). (Prerequisite for reaching this
-     outcome at all: the provisioner must stamp a **positive
-     `StorageRateMs`** — a `0` made `EnsureTags` throw `ArgumentOutOfRangeException` and fail *every* provision;
-     fixed in `GatewayTagProvisioner`, PR #439.)
-3. **The failure mode is bounded and observable either way.** Provisioning is fire-and-forget and never
-   blocks/fails a deploy; a per-tag rejection surfaces only as the tally's `failed` count. Values written to
-   a still-Float tag by the recorder remain readable (Float supersets Int1's 0/1 range); nothing is lost
-   pending a reconcile. A bulk retype sweep is **not** done in code — assess via the probe first, then decide
-   whether reconciliation is a one-time operator action.
+> **Prerequisite for provisioning to land at all:** the provisioner must stamp a **positive `StorageRateMs`**
+> — a `0` made `EnsureTags` throw `ArgumentOutOfRangeException` and fail *every* provision (fixed in
+> `GatewayTagProvisioner`, PR #439).
+
+**Migration note for pre-existing Boolean tags.** A Boolean tag historian-side as Float (e.g. from the
+0.1.0-era default) is asked, on its next deploy, to upsert to Int2. Both are supported analog types, so the
+retype is accepted. Provisioning is fire-and-forget and never blocks/fails a deploy; a per-tag rejection (if
+any) surfaces only as the tally's `failed` count, and values written to a still-Float tag remain readable
+(Float supersets the 0/1 range) pending reconcile. A bulk retype sweep is **not** done in code.
 
 ---
 
@@ -407,11 +403,11 @@ The gateway-backed driver also ships an env-gated live suite (`Category=LiveInte
 `HISTGW_GATEWAY_ENDPOINT` / `HISTGW_GATEWAY_APIKEY` / `HISTGW_TEST_TAG` / `HISTGW_WRITE_SANDBOX_TAG` /
 `HISTGW_BOOL_SANDBOX_TAG` / `HISTGW_ALARM_SOURCE` env vars (it skips cleanly when they are absent).
 `HISTGW_BOOL_SANDBOX_TAG` (e.g. `HistGW.LiveTest.BoolSandbox`, a **dedicated** writable Boolean tag —
-never the shared Float write sandbox) drives the 0.2.0 Boolean `EnsureTags` leg
-(`EnsureTags_boolean_sandbox_provisions_as_Int1`) and the retype probe
-(`EnsureTags_type_change_outcome_is_observable`) that resolve the
-[0.2.0 DataType provisioning delta](#020-datatype-provisioning-delta-archreview-06u-7) open question. Running
-the full suite against a **0.2.0** gateway (all six tests, none skipped) also discharges 06/U-2's
+never the shared Float write sandbox) drives the Boolean historization leg
+(`EnsureTags_boolean_sandbox_provisions_as_Int2`) and the retype probe
+(`EnsureTags_type_change_outcome_is_observable`) that back the
+[Boolean historization maps to Int2](#boolean-historization-maps-to-int2-issue-441) decision. Running
+the full suite against the gateway (all six tests, none skipped) also discharges 06/U-2's
 "full documented run" for the historian suite.
 
 See [AlarmHistorian.md](AlarmHistorian.md) for the alarm write path and

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway/Mapping/HistorianTypeMapper.cs

@@ -9,11 +9,14 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Mapping;
 /// </summary>
 /// <remarks>
 /// Only the nine numeric types are historizable on the gateway's analog write path. Two of them
-/// fall back to a wider historian type because the narrower one's write path is deferred upstream:
-/// <see cref="DriverDataType.UInt16"/> maps to <see cref="HistorianDataType.Uint4"/> (the historian's
-/// <c>UInt2</c> write path is not proven). String / DateTime / Reference are not historized in v1
-/// and throw <see cref="NotSupportedException"/>; callers that want to skip them without catching an
-/// exception should consult <see cref="IsHistorizable(DriverDataType)"/> first.
+/// fall back to a wider/adjacent historian type because the exact one's write path is not usable
+/// upstream: <see cref="DriverDataType.UInt16"/> maps to <see cref="HistorianDataType.Uint4"/> (the
+/// historian's <c>UInt2</c> write path is not proven), and <see cref="DriverDataType.Boolean"/> maps
+/// to <see cref="HistorianDataType.Int2"/> — the historian's <c>Int1</c> analog-tag creation path is
+/// server-degenerate (issue #441 / HistorianGateway #11: <c>EnsureTags(Int1)</c> stores an unusable
+/// stub), so Boolean historizes as a small 0/1 integer instead. String / DateTime / Reference are not
+/// historized in v1 and throw <see cref="NotSupportedException"/>; callers that want to skip them
+/// without catching an exception should consult <see cref="IsHistorizable(DriverDataType)"/> first.
 /// </remarks>
 internal static class HistorianTypeMapper
 {
@@ -25,7 +28,8 @@ internal static class HistorianTypeMapper
     /// </exception>
     public static HistorianDataType ToHistorianDataType(DriverDataType dataType) => dataType switch
     {
-        DriverDataType.Boolean => HistorianDataType.Int1,
+        DriverDataType.Boolean => HistorianDataType.Int2, // Int1 analog-tag creation is server-degenerate (issue #441) → store 0/1
+
         DriverDataType.Int16 => HistorianDataType.Int2,
         DriverDataType.Int32 => HistorianDataType.Int4,
         DriverDataType.Int64 => HistorianDataType.Int8,

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests/GatewayTagProvisionerTests.cs

@@ -26,24 +26,23 @@ public sealed class GatewayTagProvisionerTests
         Assert.NotNull(fake.LastEnsureDefinitions);
         Assert.Equal(2, fake.LastEnsureDefinitions!.Count);
         Assert.Equal(HistorianDataType.Float, fake.LastEnsureDefinitions[0].DataType);
-        Assert.Equal(HistorianDataType.Int1, fake.LastEnsureDefinitions[1].DataType);
+        Assert.Equal(HistorianDataType.Int2, fake.LastEnsureDefinitions[1].DataType);
         Assert.Equal(2, result.Requested);
         Assert.Equal(0, result.Skipped);
     }
 
     /// <summary>
-    /// archreview 06/U-7 — pins the 0.2.0 Boolean→Int1 provisioning semantics at TWO levels. The
-    /// 0.1.0→0.2.0 client bump made <c>HistorianTagDefinition.DataType</c> proto3-optional (explicit
-    /// presence): under 0.1.0 the provisioner's <c>Int1</c> (wire 0) was indistinguishable from unset,
-    /// so the gateway defaulted Boolean tags to Float; under 0.2.0 the same call carries explicit
-    /// presence and provisions Int1 (the intended behavior). Asserting BOTH the mapped type AND
-    /// <c>HasDataType</c> compile-pins the package floor (the <c>HasDataType</c>/<c>ClearDataType</c>
-    /// members exist only on the 0.2.0 proto3-optional contract — a downgrade breaks the build) and
-    /// assert-pins that the provisioner always sends explicit presence (a future contract change that
-    /// stopped sending it would break the assert). This is a pin, not a fix — it passes on current code.
+    /// Pins the Boolean→Int2 provisioning semantics at TWO levels. Boolean maps to <c>Int2</c> because
+    /// the historian's <c>Int1</c> analog-tag creation path is server-degenerate — <c>EnsureTags(Int1)</c>
+    /// stores an unusable stub (issue #441 / HistorianGateway #11) — so Boolean historizes as a small 0/1
+    /// integer. Asserting BOTH the mapped type AND <c>HasDataType</c> compile-pins the package floor (the
+    /// <c>HasDataType</c>/<c>ClearDataType</c> members exist only on the 0.2.0+ proto3-optional contract —
+    /// a downgrade breaks the build) and assert-pins that the provisioner always sends explicit presence
+    /// (a future contract change that stopped sending it would default the tag to the SDK's Float and
+    /// break this assert). This is a pin, not a fix — it passes on current code.
     /// </summary>
     [Fact]
-    public async Task Boolean_definition_carries_explicit_Int1_presence()
+    public async Task Boolean_definition_carries_explicit_Int2_presence()
     {
         var fake = new FakeHistorianGatewayClient { EnsureTagsResult = new TagOperationResults() };
         var p = Provisioner(fake);
@@ -54,9 +53,9 @@ public sealed class GatewayTagProvisionerTests
 
         var defs = fake.LastEnsureDefinitions!;
         Assert.Single(defs);
-        Assert.Equal(HistorianDataType.Int1, defs[0].DataType);
-        // 0.2.0 proto3-optional presence witness — explicit presence is what flips the gateway from its
-        // SDK-default Float to the requested Int1. Without this, a Boolean tag would provision as Float.
+        Assert.Equal(HistorianDataType.Int2, defs[0].DataType);
+        // proto3-optional presence witness — explicit presence is what flips the gateway from its
+        // SDK-default Float to the requested Int2. Without this, a Boolean tag would provision as Float.
         Assert.True(defs[0].HasDataType);
     }
 

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests/Live/GatewayLiveIntegrationTests.cs

@@ -255,25 +255,26 @@ public sealed class GatewayLiveIntegrationTests(GatewayLiveFixture fixture) : IC
     }
 
     /// <summary>
-    ///     archreview 06/U-7 — Boolean provisioning leg on the 0.2.0 contract. Through the <b>real</b>
+    ///     issue #441 — Boolean historization leg. Through the <b>real</b>
     ///     <see cref="GatewayTagProvisioner"/>, <c>EnsureTags</c> a <see cref="DriverDataType.Boolean"/>
-    ///     request for the dedicated Boolean sandbox tag (mapped to <c>Int1</c> with explicit proto3
-    ///     presence), assert it is ensured (not failed), then <c>WriteLiveValues</c> a <c>1.0</c> and read
-    ///     it back over a wide window. This retires "the live EnsureTags leg has never run on 0.2.0" for
-    ///     the Boolean path. The ±12h read window + timezone caveat mirror <see cref="Write_then_read_on_sandbox_tag"/>.
+    ///     request for the dedicated Boolean sandbox tag (mapped to <c>Int2</c> — the historian's
+    ///     <c>Int1</c> analog-tag creation path is server-degenerate, see issue #441 / HistorianGateway
+    ///     #11, so Boolean historizes as a small 0/1 integer), assert it is ensured (not failed), then
+    ///     <c>WriteLiveValues</c> a <c>1.0</c> and read it back over a wide window. The ±12h read window
+    ///     + timezone caveat mirror <see cref="Write_then_read_on_sandbox_tag"/>.
     /// </summary>
     [Fact]
     [Trait("Category", "LiveIntegration")]
-    public async Task EnsureTags_boolean_sandbox_provisions_as_Int1()
+    public async Task EnsureTags_boolean_sandbox_provisions_as_Int2()
     {
         if (_fx.NotConfigured) Assert.Skip(_fx.SkipReason!);
         if (_fx.BoolSandboxTag is null)
-            Assert.Skip("Skipped: set HISTGW_BOOL_SANDBOX_TAG to a writable Boolean sandbox tag (e.g. HistGW.LiveTest.BoolSandbox) to run the 0.2.0 Boolean EnsureTags leg.");
+            Assert.Skip("Skipped: set HISTGW_BOOL_SANDBOX_TAG to a writable Boolean sandbox tag (e.g. HistGW.LiveTest.BoolSandbox) to run the Boolean historization leg.");
 
         var ct = TestContext.Current.CancellationToken;
         var tag = _fx.BoolSandboxTag;
 
-        // EnsureTags (Boolean → Int1) through the REAL provisioner seam (the same code path deploys use).
+        // EnsureTags (Boolean → Int2) through the REAL provisioner seam (the same code path deploys use).
         await using var writeClient = _fx.CreateClient();
         var provisioner = new GatewayTagProvisioner(writeClient, NullLogger<GatewayTagProvisioner>.Instance);
         var provision = await provisioner.EnsureTagsAsync(
@@ -281,7 +282,7 @@ public sealed class GatewayLiveIntegrationTests(GatewayLiveFixture fixture) : IC
             ct);
 
         provision.Ensured.ShouldBe(1,
-            "the Boolean sandbox tag must be ensured (needs the gateway on 0.2.0 contracts + an API key carrying historian:tags:write).");
+            "the Boolean sandbox tag must be ensured as Int2 (needs the gateway on 0.2.0+ contracts + an API key carrying historian:tags:write).");
         provision.Failed.ShouldBe(0);
 
         // WriteLiveValues a Boolean-as-1.0 and read it back (SQL live path can lag a flush cadence → poll).
@@ -308,14 +309,16 @@ public sealed class GatewayLiveIntegrationTests(GatewayLiveFixture fixture) : IC
 
         hit.ShouldNotBeNull($"the written Boolean sample ({written}) should read back from '{tag}'.");
         TestContext.Current.SendDiagnosticMessage(
-            $"Boolean round-trip: EnsureTags(Int1) + WriteLiveValues '{tag}'={written} → read back at {hit!.SourceTimestampUtc:O}.");
+            $"Boolean round-trip: EnsureTags(Int2) + WriteLiveValues '{tag}'={written} → read back at {hit!.SourceTimestampUtc:O}.");
     }
 
     /// <summary>
     ///     archreview 06/U-7 retype probe — answers the assessment note's open question: what does the
     ///     deployed AVEVA Historian do when <c>EnsureTags</c> (an <b>upsert</b>) is asked to change an
     ///     existing tag's type? Against the <b>dedicated Boolean sandbox tag only</b> (never the shared
-    ///     Float write sandbox), EnsureTags first as <c>Float</c> then as <c>Int1</c> and assert the second
+    ///     Float write sandbox), EnsureTags first as <c>Float</c> then as <c>Int2</c> (both supported
+    ///     analog types — <c>Int2</c> is the type Boolean now historizes as; the previously-probed
+    ///     <c>Int1</c> is a documented server-degenerate exclusion, issue #441) and assert the second
     ///     call's per-tag outcome is <em>deterministic and observable</em> — either <c>Success=true</c>
     ///     (retype / tag-versioning accepted) or <c>Success=false</c> with a non-empty <c>Error</c> (mapped
     ///     to the provisioner's <c>failed</c> tally). The assertion accepts both because the contract
@@ -336,7 +339,7 @@ public sealed class GatewayLiveIntegrationTests(GatewayLiveFixture fixture) : IC
 
         await using var client = _fx.CreateClient();
 
-        // First establish the tag as Float, then ask EnsureTags to retype it to Int1 (Boolean).
+        // First establish the tag as Float, then ask EnsureTags to retype it to Int2.
         await client.EnsureTagsAsync(
             new[]
             {
@@ -357,9 +360,9 @@ public sealed class GatewayLiveIntegrationTests(GatewayLiveFixture fixture) : IC
                 new HistorianTagDefinition
                 {
                     TagName = tag,
-                    DataType = HistorianDataType.Int1,
+                    DataType = HistorianDataType.Int2,
                     EngineeringUnit = string.Empty,
-                    Description = "OtOpcUa live validation retype probe (stage 2: Int1)",
+                    Description = "OtOpcUa live validation retype probe (stage 2: Int2)",
                     StorageRateMs = 1000, // 0 makes the gateway's EnsureTags throw (storageRateMs must be > 0).
                 },
             },
@@ -372,7 +375,7 @@ public sealed class GatewayLiveIntegrationTests(GatewayLiveFixture fixture) : IC
             "or Success=false with a non-empty Error (mapped to the provisioner's failed tally).");
 
         TestContext.Current.SendDiagnosticMessage(
-            $"retype probe '{tag}' Float→Int1: Success={outcome.Success}, Error='{outcome.Error}'. " +
+            $"retype probe '{tag}' Float→Int2: Success={outcome.Success}, Error='{outcome.Error}'. " +
             "(records the deployed historian's in-place analog-retype policy — feed this back into docs/Historian.md).");
     }
 }

tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests/Mapping/HistorianTypeMapperTests.cs

@@ -8,7 +8,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Historian.Gateway.Tests.Mapping;
 public sealed class HistorianTypeMapperTests
 {
     [Theory]
-    [InlineData(DriverDataType.Boolean, HistorianDataType.Int1)]
+    [InlineData(DriverDataType.Boolean, HistorianDataType.Int2)]  // Int1 analog-tag creation is server-degenerate (issue #441) → store 0/1
     [InlineData(DriverDataType.Int16,   HistorianDataType.Int2)]
     [InlineData(DriverDataType.Int32,   HistorianDataType.Int4)]
     [InlineData(DriverDataType.Int64,   HistorianDataType.Int8)]