diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/BrowseRoundTripTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/BrowseRoundTripTests.cs
index f1e1b8ab..100b9945 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/BrowseRoundTripTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/BrowseRoundTripTests.cs
@@ -16,8 +16,8 @@ public class BrowseRoundTripTests
     [Fact]
     public async Task Three_level_expand_round_trips_resolve_back()
     {
-        var endpoint = Environment.GetEnvironmentVariable("OPCUA_SIM_ENDPOINT")
-                       ?? "opc.tcp://10.100.0.35:50000";
+        OpcPlcProbe.SkipUnlessReachable();
+        var endpoint = OpcPlcProbe.Endpoint;
         // Numeric ordinals because the production browser uses default System.Text.Json
         // without a JsonStringEnumConverter (SecurityPolicy.None=0, SecurityMode.None=0,
         // AuthType.Anonymous=0).
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/OpcPlcProbe.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/OpcPlcProbe.cs
new file mode 100644
index 00000000..183bcd37
--- /dev/null
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/OpcPlcProbe.cs
@@ -0,0 +1,53 @@
+using System.Net;
+using System.Net.Sockets;
+
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests;
+
+/// <summary>
+///     Reachability gate for the shared opc-plc fixture (<c>OPCUA_SIM_ENDPOINT</c>, default
+///     <c>opc.tcp://10.100.0.35:50000</c>). A small copy of the probe in
+///     <c>Driver.OpcUaClient.IntegrationTests/OpcPlcFixture</c> rather than a cross-project reference —
+///     that project drags the whole driver in. Tests call <see cref="SkipUnlessReachable"/> first, so a
+///     machine without the simulator reports Skipped instead of a connect failure.
+/// </summary>
+internal static class OpcPlcProbe
+{
+    private const string EndpointEnvVar = "OPCUA_SIM_ENDPOINT";
+    private const string DefaultEndpoint = "opc.tcp://10.100.0.35:50000";
+
+    /// <summary>The simulator endpoint the tests should connect to.</summary>
+    public static string Endpoint =>
+        Environment.GetEnvironmentVariable(EndpointEnvVar) is { Length: > 0 } e ? e : DefaultEndpoint;
+
+    private static readonly Lazy<string?> Reason = new(Probe);
+
+    /// <summary>Skips the calling test when opc-plc does not accept a TCP connection (probed once per run).</summary>
+    public static void SkipUnlessReachable()
+    {
+        if (Reason.Value is { } reason) Xunit.Assert.Skip(reason);
+    }
+
+    private static string? Probe()
+    {
+        var body = Endpoint.StartsWith("opc.tcp://", StringComparison.OrdinalIgnoreCase)
+            ? Endpoint["opc.tcp://".Length..]
+            : Endpoint;
+        var slash = body.IndexOf('/');
+        if (slash >= 0) body = body[..slash];
+        var colon = body.LastIndexOf(':');
+        var host = colon >= 0 ? body[..colon] : body;
+        var port = colon >= 0 && int.TryParse(body[(colon + 1)..], out var p) ? p : 4840;
+        try
+        {
+            using var client = new TcpClient(AddressFamily.InterNetwork);
+            var addr = Dns.GetHostAddresses(host).FirstOrDefault(a => a.AddressFamily == AddressFamily.InterNetwork)
+                       ?? IPAddress.Loopback;
+            if (client.ConnectAsync(addr, port).Wait(TimeSpan.FromSeconds(2)) && client.Connected) return null;
+            return $"opc-plc simulator at {host}:{port} did not accept a TCP connection within 2s. Start it or override {EndpointEnvVar}.";
+        }
+        catch (Exception ex)
+        {
+            return $"opc-plc simulator at {host}:{port} unreachable: {ex.GetType().Name}: {ex.Message}. Start it or override {EndpointEnvVar}.";
+        }
+    }
+}
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests/OpcUaClientBrowseSessionTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/OpcUaClientBrowseSessionTests.cs
similarity index 85%
rename from tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests/OpcUaClientBrowseSessionTests.cs
rename to tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/OpcUaClientBrowseSessionTests.cs
index 7ea07a5e..d84794b6 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests/OpcUaClientBrowseSessionTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests/OpcUaClientBrowseSessionTests.cs
@@ -3,21 +3,20 @@ using Xunit;
 using ZB.MOM.WW.OtOpcUa.Commons.Browsing;
 using ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser;
 
-namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.Tests;
+namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.Browser.IntegrationTests;
 
 /// <summary>
 ///     Live-server tests against the opc-plc Docker fixture. Bring up with
 ///     `lmxopcua-fix up opcuaclient` from PowerShell before running. These tests
 ///     drive the internal <c>OpcUaClientBrowseSession</c> through its public factory
 ///     <see cref="OpcUaClientDriverBrowser"/> so no InternalsVisibleTo is needed.
-///     Filter out with <c>--filter "Category!=RequiresOpcPlc"</c> when the fixture
-///     is unreachable.
+///     Each test skips (<see cref="OpcPlcProbe"/>) when the fixture is unreachable. Moved here from the
+///     unit project, which must hold no live-server tests (#594).
 /// </summary>
-[Trait("Category", "RequiresOpcPlc")]
+[Trait("Category", "Integration"), Trait("Fixture", "opc-plc")]
 public sealed class OpcUaClientBrowseSessionTests
 {
-    private static string Endpoint =>
-        Environment.GetEnvironmentVariable("OPCUA_SIM_ENDPOINT") ?? "opc.tcp://10.100.0.35:50000";
+    private static string Endpoint => OpcPlcProbe.Endpoint;
 
     // SecurityPolicy.None, SecurityMode.None, OpcUaAuthType.Anonymous are all
     // index 0 and can also be written as string names now that the browser carries
@@ -40,6 +39,7 @@ public sealed class OpcUaClientBrowseSessionTests
     [Fact]
     public async Task RootAsync_returns_at_least_one_node()
     {
+        OpcPlcProbe.SkipUnlessReachable();
         var ct = TestContext.Current.CancellationToken;
         var browser = new OpcUaClientDriverBrowser();
         await using var session = await browser.OpenAsync(ConfigJson, ct);
@@ -52,6 +52,7 @@ public sealed class OpcUaClientBrowseSessionTests
     [Fact]
     public async Task ExpandAsync_round_trips_stable_NodeId()
     {
+        OpcPlcProbe.SkipUnlessReachable();
         var ct = TestContext.Current.CancellationToken;
         var browser = new OpcUaClientDriverBrowser();
         await using var session = await browser.OpenAsync(ConfigJson, ct);
@@ -67,6 +68,7 @@ public sealed class OpcUaClientBrowseSessionTests
     [Fact]
     public async Task AttributesAsync_is_empty_for_opcuaclient()
     {
+        OpcPlcProbe.SkipUnlessReachable();
         var ct = TestContext.Current.CancellationToken;
         var browser = new OpcUaClientDriverBrowser();
         await using var session = await browser.OpenAsync(ConfigJson, ct);