diff --git a/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Abstractions/Contracts.cs b/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Abstractions/Contracts.cs
index 64255be..1723fd1 100644
--- a/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Abstractions/Contracts.cs
+++ b/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Abstractions/Contracts.cs
@@ -52,6 +52,10 @@ public interface ILineNumberAnnotationFormatter
     LineNumberFormattingResult Format(LineNumberAnnotationDefinition definition, IReadOnlyDictionary<string, string?> fields);
 }
 
+public sealed record DataLinksPropertyReadResult(bool Success, IReadOnlyDictionary<string, string?> Properties, string? FailureCode = null);
+public interface IDataLinksPropertyReader { DataLinksPropertyReadResult ReadProperties(long rowId); }
+public sealed record LineNumberFieldResolution(bool Success, IReadOnlyDictionary<string, string?> Values, string? FailureCode = null);
+
 public sealed record GeometrySnapshot
 {
     public Point3Dto? WorldPosition { get; init; }
diff --git a/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Core/LineNumberFieldResolver.cs b/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Core/LineNumberFieldResolver.cs
new file mode 100644
index 0000000..64d59e4
--- /dev/null
+++ b/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Core/LineNumberFieldResolver.cs
@@ -0,0 +1,23 @@
+using PRecAnnot.Abstractions;
+namespace PRecAnnot.Core;
+
+public sealed class LineNumberFieldResolver(IDataLinksPropertyReader reader)
+{
+    // Source-backed Convert_field_to_value port.  The adapter supplies a
+    // deterministic, read-only flattened key set: Table.Column and Column.
+    public LineNumberFieldResolution Resolve(long rowId, IEnumerable<string> fields)
+    {
+        var read = reader.ReadProperties(rowId);
+        if (!read.Success) return new(false, new Dictionary<string, string?>(), read.FailureCode ?? "DATALINKS_READ_FAILED");
+        var values = new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);
+        foreach (var field in fields.Distinct(StringComparer.OrdinalIgnoreCase))
+        {
+            if (string.IsNullOrWhiteSpace(field)) return new(false, values, "LINE_NUMBER_FIELD_EMPTY");
+            var dot = field.IndexOf('.', StringComparison.Ordinal);
+            if (dot <= 0 || dot == field.Length - 1) return new(false, values, "LINE_NUMBER_FIELD_INVALID:" + field);
+            if (!read.Properties.TryGetValue(field, out var value) && !read.Properties.TryGetValue(field[(dot + 1)..], out value)) return new(false, values, "LINE_NUMBER_COLUMN_MISSING:" + field);
+            values[field] = value ?? string.Empty;
+        }
+        return new(true, values);
+    }
+}
diff --git a/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Plant3D2026/PlantDataLinksPropertyReader.cs b/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Plant3D2026/PlantDataLinksPropertyReader.cs
new file mode 100644
index 0000000..e371ee5
--- /dev/null
+++ b/Plant3D2026/P_Rec_Annot/src/PRecAnnot.Plant3D2026/PlantDataLinksPropertyReader.cs
@@ -0,0 +1,20 @@
+using Autodesk.ProcessPower.DataLinks;
+using PRecAnnot.Abstractions;
+namespace PRecAnnot.Plant3D2026;
+
+internal sealed class PlantDataLinksPropertyReader(DataLinksManager dataLinks) : IDataLinksPropertyReader
+{
+    public DataLinksPropertyReadResult ReadProperties(long rowId)
+    {
+        if (rowId <= 0) return new(false, new Dictionary<string, string?>(), "DATALINKS_ROW_ID_INVALID");
+        try
+        {
+            var values = dataLinks.GetAllProperties((int)rowId, true)
+                .GroupBy(x => x.Key, StringComparer.OrdinalIgnoreCase)
+                .ToDictionary(x => x.Key, x => (string?)x.Last().Value, StringComparer.OrdinalIgnoreCase);
+            return new(true, values);
+        }
+        catch (DLException) { return new(false, new Dictionary<string, string?>(), "DATALINKS_PROPERTY_READ_FAILED"); }
+        catch (Exception) { return new(false, new Dictionary<string, string?>(), "DATALINKS_PROPERTY_READ_FAILED"); }
+    }
+}
diff --git a/Plant3D2026/P_Rec_Annot/tests/PRecAnnot.Core.Tests/LineNumberFieldResolverTests.cs b/Plant3D2026/P_Rec_Annot/tests/PRecAnnot.Core.Tests/LineNumberFieldResolverTests.cs
new file mode 100644
index 0000000..5d4b1cf
--- /dev/null
+++ b/Plant3D2026/P_Rec_Annot/tests/PRecAnnot.Core.Tests/LineNumberFieldResolverTests.cs
@@ -0,0 +1,10 @@
+using PRecAnnot.Abstractions;
+using PRecAnnot.Core;
+namespace PRecAnnot.Core.Tests;
+public sealed class LineNumberFieldResolverTests
+{
+    [Fact] public void ResolvesNullAsLegacyEmptyString() => Assert.Equal(string.Empty, new LineNumberFieldResolver(new Reader(true, new Dictionary<string,string?> { ["EngineeringItems.LineNumber"] = null })).Resolve(5, ["EngineeringItems.LineNumber"]).Values["EngineeringItems.LineNumber"]);
+    [Fact] public void RejectsInvalidField() => Assert.Equal("LINE_NUMBER_FIELD_INVALID:LineNumber", new LineNumberFieldResolver(new Reader(true, new Dictionary<string, string?>())).Resolve(5, ["LineNumber"]).FailureCode);
+    [Fact] public void PropagatesAdapterFailure() => Assert.Equal("DATALINKS_PROPERTY_READ_FAILED", new LineNumberFieldResolver(new Reader(false, new Dictionary<string, string?>())).Resolve(5, ["EngineeringItems.LineNumber"]).FailureCode);
+    private sealed record Reader(bool Ok, IReadOnlyDictionary<string,string?> Values) : IDataLinksPropertyReader { public DataLinksPropertyReadResult ReadProperties(long _) => new(Ok, Values, Ok ? null : "DATALINKS_PROPERTY_READ_FAILED"); }
+}