diff --git a/archreview/plans/R2-11-tagconfig-consolidation-plan.md.tasks.json b/archreview/plans/R2-11-tagconfig-consolidation-plan.md.tasks.json
index 19647b38..6bbe0462 100644
--- a/archreview/plans/R2-11-tagconfig-consolidation-plan.md.tasks.json
+++ b/archreview/plans/R2-11-tagconfig-consolidation-plan.md.tasks.json
@@ -4,7 +4,7 @@
   "tasks": [
     { "id": "T1",  "subject": "Golden TagConfig corpus + compose→encode→decode parity characterization test (Runtime.Tests, green on unmodified tree)", "status": "completed", "blockedBy": [] },
     { "id": "T2",  "subject": "FullName-semantics characterization for EquipmentNodeWalker (Core.Tests) + DraftValidator Galaxy rule (Configuration.Tests)", "status": "completed", "blockedBy": [] },
-    { "id": "T3",  "subject": "TagConfigIntent + TagAlarmIntent in Commons/Types (TDD; port composer semantics verbatim + OpcUaServer ExtractTag* test tables)", "status": "pending", "blockedBy": [] },
+    { "id": "T3",  "subject": "TagConfigIntent + TagAlarmIntent in Commons/Types (TDD; port composer semantics verbatim + OpcUaServer ExtractTag* test tables)", "status": "completed", "blockedBy": [] },
     { "id": "T4",  "subject": "DeviceConfigIntent (TryExtractHost/NormalizeHost) in Commons/Types (TDD)", "status": "pending", "blockedBy": [] },
     { "id": "T5",  "subject": "AddressSpaceComposer swap: single TagConfigIntent.Parse per tag, delete 4 Extract* statics (P-1 parse-once)", "status": "pending", "blockedBy": ["T1", "T3"] },
     { "id": "T6",  "subject": "Device-host re-home: composer TryExtractDeviceHost/NormalizeDeviceHost → DeviceConfigIntent; update DriverHostActor + DeploymentArtifact callers", "status": "pending", "blockedBy": ["T4", "T5"] },
diff --git a/src/Core/ZB.MOM.WW.OtOpcUa.Commons/Types/TagConfigIntent.cs b/src/Core/ZB.MOM.WW.OtOpcUa.Commons/Types/TagConfigIntent.cs
new file mode 100644
index 00000000..ba81fcf2
--- /dev/null
+++ b/src/Core/ZB.MOM.WW.OtOpcUa.Commons/Types/TagConfigIntent.cs
@@ -0,0 +1,129 @@
+using System.Text.Json;
+
+namespace ZB.MOM.WW.OtOpcUa.Commons.Types;
+
+/// <summary>
+///     The cross-driver platform intents parsed from a Tag's schemaless <c>TagConfig</c> JSON.
+///     SINGLE SOURCE OF TRUTH for the byte-parity contract shared by the live-compose seam
+///     (<c>AddressSpaceComposer</c>), the artifact-decode seam (<c>DeploymentArtifact</c>), the draft
+///     gate (<c>DraftValidator</c>), and the walker (<c>EquipmentNodeWalker</c>). One
+///     <see cref="JsonDocument.Parse(string)"/> per blob. Never throws.
+///     <para>Two deliberate variations are carried on the record so every seam can be served from one
+///     parse:</para>
+///     <list type="bullet">
+///         <item><description><see cref="FullName"/> is the driver-side wire reference: the top-level
+///         <c>FullName</c> string when present, else the RAW blob (an equipment tag's TagConfig JSON
+///         <em>is</em> its wire reference for the six protocol drivers). <c>Parse(null)</c> ⇒
+///         <c>FullName == ""</c>.</description></item>
+///         <item><description><see cref="ExplicitFullName"/> is the <c>FullName</c> property ONLY when
+///         present-and-string, else <see langword="null"/> — the DraftValidator Galaxy-rule semantics
+///         (it wants the explicit reference, not the raw-blob fallback).</description></item>
+///     </list>
+/// </summary>
+/// <param name="FullName">Top-level <c>FullName</c> string, else the raw blob (wire-reference fallback).</param>
+/// <param name="ExplicitFullName">The <c>FullName</c> property when present-and-string, else <see langword="null"/>.</param>
+/// <param name="Alarm">The optional native-alarm intent parsed from the <c>alarm</c> object; <see langword="null"/> ⇒ plain value variable.</param>
+/// <param name="IsHistorized"><c>isHistorized</c> — true only when the value is a bool <c>true</c>.</param>
+/// <param name="HistorianTagname">Non-whitespace <c>historianTagname</c> string override, else <see langword="null"/> (not trimmed).</param>
+/// <param name="IsArray"><c>isArray</c> bool.</param>
+/// <param name="ArrayLength"><c>arrayLength</c> honoured ONLY when <see cref="IsArray"/> and a JSON number fitting <see cref="uint"/>; else <see langword="null"/>.</param>
+public sealed record TagConfigIntent(
+    string FullName,
+    string? ExplicitFullName,
+    TagAlarmIntent? Alarm,
+    bool IsHistorized,
+    string? HistorianTagname,
+    bool IsArray,
+    uint? ArrayLength)
+{
+    /// <summary>
+    ///     Parse a Tag's schemaless <c>TagConfig</c> JSON into the cross-driver platform intents.
+    ///     Never throws: malformed JSON / non-object root / blank / null ⇒ all intents default with
+    ///     <see cref="FullName"/> = the raw blob (or "" for null). Semantics are ported verbatim from the
+    ///     historical <c>AddressSpaceComposer.Extract*</c> statics (the canonical copy).
+    /// </summary>
+    /// <param name="tagConfig">The tag's raw <c>TagConfig</c> JSON (nullable/blank tolerated).</param>
+    /// <returns>The parsed intents; never <see langword="null"/>.</returns>
+    public static TagConfigIntent Parse(string? tagConfig)
+    {
+        if (string.IsNullOrWhiteSpace(tagConfig))
+            return new TagConfigIntent(tagConfig ?? string.Empty, null, null, false, null, false, null);
+
+        try
+        {
+            using var doc = JsonDocument.Parse(tagConfig);
+            var root = doc.RootElement;
+            if (root.ValueKind != JsonValueKind.Object)
+                return new TagConfigIntent(tagConfig, null, null, false, null, false, null);
+
+            var explicitFullName =
+                root.TryGetProperty("FullName", out var fn) && fn.ValueKind == JsonValueKind.String
+                    ? fn.GetString()
+                    : null;
+            var fullName = explicitFullName ?? tagConfig;
+
+            var (isHistorized, historianTagname) = ParseHistorize(root);
+            var (isArray, arrayLength) = ParseArray(root);
+
+            return new TagConfigIntent(
+                fullName, explicitFullName, ParseAlarm(root),
+                isHistorized, historianTagname, isArray, arrayLength);
+        }
+        catch (JsonException)
+        {
+            return new TagConfigIntent(tagConfig, null, null, false, null, false, null);
+        }
+    }
+
+    private static TagAlarmIntent? ParseAlarm(JsonElement root)
+    {
+        if (!root.TryGetProperty("alarm", out var a) || a.ValueKind != JsonValueKind.Object) return null;
+        var type = a.TryGetProperty("alarmType", out var tEl) && tEl.ValueKind == JsonValueKind.String
+            ? (tEl.GetString() ?? "AlarmCondition") : "AlarmCondition";
+        var sev = a.TryGetProperty("severity", out var sEl) && sEl.ValueKind == JsonValueKind.Number
+            && sEl.TryGetInt32(out var sv) ? sv : 500;
+        // historizeToAveva (bool?, absent ⇒ null ⇒ historize): only an explicit false suppresses the
+        // durable AVEVA write at the HistorianAdapterActor gate; a non-bool node ⇒ null (default-on).
+        bool? historize = a.TryGetProperty("historizeToAveva", out var hEl)
+                && hEl.ValueKind is JsonValueKind.True or JsonValueKind.False
+            ? hEl.GetBoolean()
+            : null;
+        return new TagAlarmIntent(type, sev, historize);
+    }
+
+    private static (bool IsHistorized, string? HistorianTagname) ParseHistorize(JsonElement root)
+    {
+        var isHistorized = root.TryGetProperty("isHistorized", out var hEl)
+            && (hEl.ValueKind == JsonValueKind.True || hEl.ValueKind == JsonValueKind.False)
+            && hEl.GetBoolean();
+        string? tagname = null;
+        if (root.TryGetProperty("historianTagname", out var nEl) && nEl.ValueKind == JsonValueKind.String)
+        {
+            var raw = nEl.GetString();
+            if (!string.IsNullOrWhiteSpace(raw)) tagname = raw; // not trimmed
+        }
+        return (isHistorized, tagname);
+    }
+
+    private static (bool IsArray, uint? ArrayLength) ParseArray(JsonElement root)
+    {
+        var isArray = root.TryGetProperty("isArray", out var aEl)
+            && (aEl.ValueKind == JsonValueKind.True || aEl.ValueKind == JsonValueKind.False)
+            && aEl.GetBoolean();
+        uint? arrayLength = null;
+        if (isArray
+            && root.TryGetProperty("arrayLength", out var lEl)
+            && lEl.ValueKind == JsonValueKind.Number
+            && lEl.TryGetUInt32(out var len))
+        {
+            arrayLength = len;
+        }
+        return (isArray, arrayLength);
+    }
+}
+
+/// <summary>The optional native-alarm intent parsed from a tag's <c>TagConfig.alarm</c> object.</summary>
+/// <param name="AlarmType">OPC UA Part 9 subtype string; default <c>"AlarmCondition"</c>.</param>
+/// <param name="Severity">1..1000 severity; default <c>500</c>.</param>
+/// <param name="HistorizeToAveva">Per-condition durable-write opt-out (<c>bool?</c>; absent ⇒ <see langword="null"/> ⇒ historize).</param>
+public sealed record TagAlarmIntent(string AlarmType, int Severity, bool? HistorizeToAveva);
diff --git a/tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/TagConfigIntentTests.cs b/tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/TagConfigIntentTests.cs
new file mode 100644
index 00000000..b19f46fb
--- /dev/null
+++ b/tests/Core/ZB.MOM.WW.OtOpcUa.Commons.Tests/TagConfigIntentTests.cs
@@ -0,0 +1,128 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+
+namespace ZB.MOM.WW.OtOpcUa.Commons.Tests;
+
+/// <summary>
+///     The single byte-parity authority for the cross-driver TagConfig platform intents (R2-11, 01/C-1).
+///     Ports the three retired <c>OpcUaServer.Tests/ExtractTag{Alarm,Historize,Array}Tests</c> tables and
+///     adds the <see cref="TagConfigIntent.FullName"/> / <see cref="TagConfigIntent.ExplicitFullName"/>
+///     distinction plus the never-throws property.
+/// </summary>
+public sealed class TagConfigIntentTests
+{
+    // ---- FullName / ExplicitFullName ----
+
+    [Theory]
+    [InlineData("{\"FullName\":\"X.Y\"}", "X.Y", "X.Y")]
+    [InlineData("{\"FullName\":\"   \"}", "   ", "   ")]        // whitespace string returned verbatim (not trimmed)
+    [InlineData("{\"FullName\":\"A.B\",\"region\":\"Coils\"}", "A.B", "A.B")]
+    // fallbacks: FullName = raw blob, ExplicitFullName = null
+    [InlineData("{\"region\":\"HoldingRegisters\"}", "{\"region\":\"HoldingRegisters\"}", null)]
+    [InlineData("{\"FullName\":123}", "{\"FullName\":123}", null)]
+    [InlineData("[1,2]", "[1,2]", null)]
+    [InlineData("not json {", "not json {", null)]
+    [InlineData("   ", "   ", null)]
+    public void FullName_and_ExplicitFullName(string cfg, string expectedFullName, string? expectedExplicit)
+    {
+        var intent = TagConfigIntent.Parse(cfg);
+        intent.FullName.ShouldBe(expectedFullName);
+        intent.ExplicitFullName.ShouldBe(expectedExplicit);
+    }
+
+    [Fact]
+    public void Parse_null_yields_empty_FullName_and_null_explicit()
+    {
+        var intent = TagConfigIntent.Parse(null);
+        intent.FullName.ShouldBe(string.Empty);
+        intent.ExplicitFullName.ShouldBeNull();
+        intent.Alarm.ShouldBeNull();
+        intent.IsHistorized.ShouldBeFalse();
+        intent.IsArray.ShouldBeFalse();
+    }
+
+    // ---- Alarm (ported from ExtractTagAlarmTests) ----
+
+    [Theory]
+    [InlineData("{\"FullName\":\"X.Y\"}", false, null, 0)]
+    [InlineData("{\"FullName\":\"X.Y\",\"alarm\":{}}", true, "AlarmCondition", 500)]
+    [InlineData("{\"FullName\":\"X.Y\",\"alarm\":{\"alarmType\":\"OffNormalAlarm\",\"severity\":700}}", true, "OffNormalAlarm", 700)]
+    [InlineData("not json", false, null, 0)]
+    [InlineData("{\"FullName\":\"X.Y\",\"alarm\":\"oops\"}", false, null, 0)]
+    [InlineData("{\"alarm\":{\"severity\":\"high\"}}", true, "AlarmCondition", 500)]  // non-number severity → 500
+    [InlineData("{\"alarm\":{\"alarmType\":123}}", true, "AlarmCondition", 500)]      // non-string type → default
+    public void Alarm_parses_or_null(string cfg, bool present, string? type, int sev)
+    {
+        var alarm = TagConfigIntent.Parse(cfg).Alarm;
+        if (!present) { alarm.ShouldBeNull(); return; }
+        alarm!.AlarmType.ShouldBe(type);
+        alarm.Severity.ShouldBe(sev);
+    }
+
+    [Theory]
+    [InlineData("{\"alarm\":{\"alarmType\":\"LimitAlarm\",\"severity\":500}}", null)]
+    [InlineData("{\"alarm\":{\"alarmType\":\"LimitAlarm\",\"severity\":500,\"historizeToAveva\":true}}", true)]
+    [InlineData("{\"alarm\":{\"alarmType\":\"LimitAlarm\",\"severity\":500,\"historizeToAveva\":false}}", false)]
+    [InlineData("{\"alarm\":{\"alarmType\":\"LimitAlarm\",\"severity\":500,\"historizeToAveva\":\"oops\"}}", null)]
+    public void Alarm_historizeToAveva(string cfg, bool? expected)
+    {
+        TagConfigIntent.Parse(cfg).Alarm!.HistorizeToAveva.ShouldBe(expected);
+    }
+
+    // ---- Historize ----
+
+    [Theory]
+    [InlineData("{\"FullName\":\"A\",\"isHistorized\":true}", true, null)]
+    [InlineData("{\"FullName\":\"A\",\"isHistorized\":true,\"historianTagname\":\"P.L.X\"}", true, "P.L.X")]
+    [InlineData("{\"FullName\":\"A\",\"isHistorized\":false,\"historianTagname\":null}", false, null)]
+    [InlineData("{\"FullName\":\"A\",\"isHistorized\":true,\"historianTagname\":\"   \"}", true, null)]  // whitespace → null
+    [InlineData("{\"FullName\":\"A\",\"isHistorized\":\"yes\"}", false, null)]                          // non-bool → false
+    [InlineData("{\"FullName\":\"A\"}", false, null)]
+    public void Historize(string cfg, bool expectedHistorized, string? expectedTagname)
+    {
+        var intent = TagConfigIntent.Parse(cfg);
+        intent.IsHistorized.ShouldBe(expectedHistorized);
+        intent.HistorianTagname.ShouldBe(expectedTagname);
+    }
+
+    // ---- Array (ported from ExtractTagArrayTests) ----
+
+    [Theory]
+    [InlineData("{\"FullName\":\"T.A\",\"isArray\":true,\"arrayLength\":16}", true, (uint)16)]
+    [InlineData("{\"FullName\":\"T.A\",\"isArray\":true}", true, null)]
+    [InlineData("{\"FullName\":\"T.A\"}", false, null)]
+    [InlineData("{\"FullName\":\"T.A\",\"isArray\":false,\"arrayLength\":16}", false, null)]
+    [InlineData("{\"FullName\":\"T.A\",\"isArray\":true,\"arrayLength\":0}", true, (uint)0)]
+    [InlineData(null, false, null)]
+    [InlineData("", false, null)]
+    [InlineData("not json {", false, null)]
+    [InlineData("[1,2]", false, null)]
+    [InlineData("{\"isArray\":\"yes\"}", false, null)]
+    [InlineData("{\"isArray\":true,\"arrayLength\":\"16\"}", true, null)]
+    [InlineData("{\"isArray\":true,\"arrayLength\":-1}", true, null)]
+    [InlineData("{\"isArray\":true,\"arrayLength\":16.5}", true, null)]
+    [InlineData("{\"isArray\":true,\"arrayLength\":4294967296}", true, null)]
+    public void Array_parses_or_defaults(string? cfg, bool expectedIsArray, uint? expectedLength)
+    {
+        var intent = TagConfigIntent.Parse(cfg);
+        intent.IsArray.ShouldBe(expectedIsArray);
+        intent.ArrayLength.ShouldBe(expectedLength);
+    }
+
+    // ---- never-throws property over an adversarial set ----
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("not json {")]
+    [InlineData("[1,2,3]")]
+    [InlineData("42")]
+    [InlineData("\"just a string\"")]
+    [InlineData("{\"alarm\":42,\"isArray\":\"x\",\"arrayLength\":true,\"isHistorized\":123}")]
+    public void Parse_never_throws(string? cfg)
+    {
+        Should.NotThrow(() => TagConfigIntent.Parse(cfg));
+    }
+}