diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/LibplctagConfinementGuardTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/LibplctagConfinementGuardTests.cs
new file mode 100644
index 00000000..dae8c0b0
--- /dev/null
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests/LibplctagConfinementGuardTests.cs
@@ -0,0 +1,46 @@
+using System.Text.RegularExpressions;
+using Shouldly;
+using Xunit;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.Ab.Transport.Tests;
+
+public sealed class LibplctagConfinementGuardTests
+{
+    private static readonly Regex Reference = new(
+        @"\busing\s+libplctag\b|\blibplctag\.(Tag|Status|PlcType|Protocol|LibPlcTagException|NativeImport)\b",
+        RegexOptions.Compiled);
+
+    [Fact]
+    public void Only_the_libplctag_adapters_reference_libplctag()
+    {
+        var root = new DirectoryInfo(AppContext.BaseDirectory);
+        while (root is not null && !File.Exists(Path.Combine(root.FullName, "ZB.MOM.WW.OtOpcUa.slnx"))) root = root.Parent;
+        root.ShouldNotBeNull("could not find the repo root");
+
+        var offenders = new List<string>();
+        foreach (var file in Directory.EnumerateFiles(Path.Combine(root.FullName, "src"), "*.cs", SearchOption.AllDirectories))
+        {
+            if (file.Contains($"{Path.DirectorySeparatorChar}bin{Path.DirectorySeparatorChar}") ||
+                file.Contains($"{Path.DirectorySeparatorChar}obj{Path.DirectorySeparatorChar}")) continue;
+            var name = Path.GetFileName(file);
+            var dir = Path.GetFileName(Path.GetDirectoryName(file)!);
+            var allowed = name.StartsWith("Libplctag", StringComparison.Ordinal)
+                && dir is "ZB.MOM.WW.OtOpcUa.Driver.AbCip" or "ZB.MOM.WW.OtOpcUa.Driver.AbLegacy";
+            if (allowed) continue;
+            var lines = File.ReadAllLines(file);
+            for (var i = 0; i < lines.Length; i++)
+            {
+                var code = lines[i].Split("//")[0];
+                if (Reference.IsMatch(code)) offenders.Add($"{Path.GetRelativePath(root.FullName, file)}:{i + 1}: {lines[i].Trim()}");
+            }
+        }
+        offenders.ShouldBeEmpty(string.Join(Environment.NewLine, offenders));
+    }
+
+    [Fact]
+    public void Prose_mentions_of_libplctag_do_not_trip_the_guard()
+    {
+        var prose = "via libplctag. Second of six driver CLIs";
+        Reference.IsMatch(prose).ShouldBeFalse();
+    }
+}