diff --git a/src/ZB.MOM.WW.MxGateway.Worker.Tests/DeliberateRedTests.cs b/src/ZB.MOM.WW.MxGateway.Worker.Tests/DeliberateRedTests.cs
new file mode 100644
index 0000000..e5878e2
--- /dev/null
+++ b/src/ZB.MOM.WW.MxGateway.Worker.Tests/DeliberateRedTests.cs
@@ -0,0 +1,19 @@
+using Xunit;
+
+namespace ZB.MOM.WW.MxGateway.Worker.Tests;
+
+/// <summary>
+///     TST-25 acceptance check (deliberate-red): a temporary always-failing test used to prove
+///     that a Worker.Tests failure propagates through windev-worker-ci.ps1 -> ssh ->
+///     run-windev-ci.sh -> a nonzero exit (i.e. a red CI job). This file is thrown away after the
+///     check; it must never merge to a long-lived branch.
+/// </summary>
+public sealed class DeliberateRedTests
+{
+    /// <summary>Always fails, on purpose, to exercise exit-code propagation.</summary>
+    [Fact]
+    public void DeliberateRed_AlwaysFails()
+    {
+        Assert.True(false, "TST-25 deliberate-red acceptance probe (expected failure).");
+    }
+}