diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriverTelemetryNames.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriverTelemetryNames.cs
new file mode 100644
index 000000000..ec9877cbf
--- /dev/null
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/GalaxyDriverTelemetryNames.cs
@@ -0,0 +1,17 @@
+namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy;
+
+/// <summary>
+///     The Galaxy driver's OpenTelemetry instrument names, public so the host can hand them to
+///     <c>AddZbTelemetry</c>. <c>ZbTelemetryOptions.Meters</c> and <c>.ActivitySources</c> are
+///     STRICT allow-lists: a name missing there is silently never exported — the driver's
+///     <c>galaxy.*</c> spans and <c>galaxy.events.*</c> counters were dropped this way until
+///     scadaproj#13 exercised the OTLP path end to end.
+/// </summary>
+public static class GalaxyDriverTelemetryNames
+{
+    /// <summary>The meter the event pump's <c>galaxy.events.*</c> counters are created on.</summary>
+    public const string MeterName = "ZB.MOM.WW.OtOpcUa.Driver.Galaxy";
+
+    /// <summary>The activity source the traced gateway decorators open <c>galaxy.*</c> spans on.</summary>
+    public const string ActivitySourceName = "ZB.MOM.WW.OtOpcUa.Driver.Galaxy";
+}
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/EventPump.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/EventPump.cs
index 4617cb2c6..40dc34254 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/EventPump.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/EventPump.cs
@@ -34,7 +34,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
 /// </remarks>
 internal sealed class EventPump : IAsyncDisposable
 {
-    public const string MeterName = "ZB.MOM.WW.OtOpcUa.Driver.Galaxy";
+    public const string MeterName = GalaxyDriverTelemetryNames.MeterName;
     private const int DefaultChannelCapacity = 50_000;
 
     // Single static meter so a host-level MeterListener catches all pump instances.
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/GalaxyTelemetry.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/GalaxyTelemetry.cs
index d0e2dcf12..d45ebe4e0 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/GalaxyTelemetry.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy/Runtime/GalaxyTelemetry.cs
@@ -17,7 +17,7 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Runtime;
 /// </summary>
 internal static class GalaxyTelemetry
 {
-    public const string ActivitySourceName = "ZB.MOM.WW.OtOpcUa.Driver.Galaxy";
+    public const string ActivitySourceName = GalaxyDriverTelemetryNames.ActivitySourceName;
 
     public static readonly ActivitySource ActivitySource = new(ActivitySourceName);
 
diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Host/Observability/ObservabilityExtensions.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Host/Observability/ObservabilityExtensions.cs
index 171d95835..6cb3d79f8 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.Host/Observability/ObservabilityExtensions.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Host/Observability/ObservabilityExtensions.cs
@@ -1,6 +1,7 @@
 using Microsoft.Extensions.Configuration;
 using ZB.MOM.WW.LocalDb.Replication;
 using ZB.MOM.WW.OtOpcUa.Commons.Observability;
+using ZB.MOM.WW.OtOpcUa.Driver.Galaxy;
 using ZB.MOM.WW.Telemetry;
 
 namespace ZB.MOM.WW.OtOpcUa.Host.Observability;
@@ -14,6 +15,31 @@ namespace ZB.MOM.WW.OtOpcUa.Host.Observability;
 /// </summary>
 public static class ObservabilityExtensions
 {
+    /// <summary>
+    /// Every meter the host exports. <c>ZbTelemetryOptions.Meters</c> is a STRICT allowlist (no
+    /// wildcard): the LocalDb replication meter publishes its <c>localdb.sync.*</c> /
+    /// <c>localdb.oplog.depth</c> series on driver nodes, and the in-process Galaxy driver its
+    /// <c>galaxy.events.*</c> counters — each is silently absent from <c>/metrics</c> and OTLP unless
+    /// named here. Adding a meter anywhere in the product means adding it here.
+    /// </summary>
+    public static readonly string[] ObservedMeters =
+    [
+        OtOpcUaTelemetry.MeterName,
+        LocalDbMetrics.MeterName,
+        GalaxyDriverTelemetryNames.MeterName,
+    ];
+
+    /// <summary>
+    /// Every activity source the host exports over OTLP. Also a strict allowlist: the Galaxy
+    /// driver's <c>galaxy.*</c> gateway-call spans were dropped until scadaproj#13 because its source
+    /// was missing here.
+    /// </summary>
+    public static readonly string[] ObservedActivitySources =
+    [
+        OtOpcUaTelemetry.ActivitySourceName,
+        GalaxyDriverTelemetryNames.ActivitySourceName,
+    ];
+
     /// <summary>Adds OtOpcUa observability (metrics and tracing) to the service collection.</summary>
     /// <param name="services">The service collection to add observability services to.</param>
     /// <param name="configuration">
@@ -28,12 +54,9 @@ public static class ObservabilityExtensions
         return services.AddZbTelemetry(o =>
         {
             o.ServiceName = "otopcua";
-            // o.Meters is a STRICT allowlist — ZbTelemetry adds only the named meters, with no
-            // wildcard. The LocalDb replication engine publishes under its own meter name, so
-            // without this entry its localdb.sync.* / localdb.oplog.depth series are silently absent
-            // from /metrics on driver nodes (the exact omission a ScadaBridge live gate caught).
-            o.Meters = [OtOpcUaTelemetry.MeterName, LocalDbMetrics.MeterName];
-            o.ActivitySources = [OtOpcUaTelemetry.ActivitySourceName];
+            // Strict allowlists — see ObservedMeters / ObservedActivitySources.
+            o.Meters = ObservedMeters;
+            o.ActivitySources = ObservedActivitySources;
             if (Enum.TryParse<ZbExporter>(configuration["OtOpcUa:Telemetry:Exporter"], ignoreCase: true, out var exporter))
                 o.Exporter = exporter;
             var otlp = configuration["OtOpcUa:Telemetry:OtlpEndpoint"];
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ObservabilityAllowlistTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ObservabilityAllowlistTests.cs
new file mode 100644
index 000000000..c3fa072e5
--- /dev/null
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Host.IntegrationTests/ObservabilityAllowlistTests.cs
@@ -0,0 +1,87 @@
+using System.Diagnostics;
+using System.Diagnostics.Metrics;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.Extensions.DependencyInjection;
+using OpenTelemetry.Metrics;
+using OpenTelemetry.Trace;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.LocalDb.Replication;
+using ZB.MOM.WW.OtOpcUa.Commons.Observability;
+using ZB.MOM.WW.OtOpcUa.Driver.Galaxy;
+using ZB.MOM.WW.OtOpcUa.Host.Observability;
+
+namespace ZB.MOM.WW.OtOpcUa.Host.IntegrationTests;
+
+/// <summary>
+///     scadaproj#13 — <c>ZbTelemetryOptions.Meters</c> / <c>.ActivitySources</c> are strict allowlists,
+///     so a meter or activity source the host forgets to name is silently never exported (the Galaxy
+///     driver's <c>galaxy.*</c> spans and <c>galaxy.events.*</c> counters were). These tests build the
+///     real <see cref="ObservabilityExtensions.AddOtOpcUaObservability"/> container, start its
+///     providers, and assert on the listener side: a span from a named source is sampled, and an
+///     instrument on a named meter is enabled. An unregistered name is the negative control proving
+///     the assertion can fail.
+/// </summary>
+public sealed class ObservabilityAllowlistTests : IAsyncDisposable
+{
+    private readonly WebApplication _app;
+
+    public ObservabilityAllowlistTests()
+    {
+        var builder = WebApplication.CreateBuilder(new WebApplicationOptions { Args = [] });
+        builder.Services.AddOtOpcUaObservability(builder.Configuration);
+        _app = builder.Build();
+        // Resolving the providers is what attaches their ActivityListener / MeterListener.
+        _app.Services.GetRequiredService<TracerProvider>();
+        _app.Services.GetRequiredService<MeterProvider>();
+    }
+
+    [Fact]
+    public void ObservedLists_NameTheGalaxyDriverMeterAndSource()
+    {
+        ObservabilityExtensions.ObservedMeters.ShouldBe(
+            [OtOpcUaTelemetry.MeterName, LocalDbMetrics.MeterName, GalaxyDriverTelemetryNames.MeterName],
+            ignoreOrder: true);
+        ObservabilityExtensions.ObservedActivitySources.ShouldBe(
+            [OtOpcUaTelemetry.ActivitySourceName, GalaxyDriverTelemetryNames.ActivitySourceName],
+            ignoreOrder: true);
+    }
+
+    [Theory]
+    [InlineData(OtOpcUaTelemetry.ActivitySourceName)]
+    [InlineData(GalaxyDriverTelemetryNames.ActivitySourceName)]
+    public void SpanFromAnObservedSource_IsRecorded(string sourceName)
+    {
+        using var source = new ActivitySource(sourceName);
+        using var activity = source.StartActivity("allowlist-probe");
+        activity.ShouldNotBeNull();
+        activity.IsAllDataRequested.ShouldBeTrue();
+    }
+
+    [Fact]
+    public void SpanFromAnUnregisteredSource_IsDropped_NegativeControl()
+    {
+        using var source = new ActivitySource("ZB.MOM.WW.OtOpcUa.Unregistered." + Guid.NewGuid().ToString("N"));
+        source.StartActivity("allowlist-probe").ShouldBeNull();
+    }
+
+    [Theory]
+    [InlineData(OtOpcUaTelemetry.MeterName)]
+    [InlineData(LocalDbMetrics.MeterName)]
+    [InlineData(GalaxyDriverTelemetryNames.MeterName)]
+    public void InstrumentOnAnObservedMeter_IsEnabled(string meterName)
+    {
+        using var meter = new Meter(meterName);
+        var counter = meter.CreateCounter<long>("allowlist.probe." + Guid.NewGuid().ToString("N"));
+        counter.Enabled.ShouldBeTrue();
+    }
+
+    [Fact]
+    public void InstrumentOnAnUnregisteredMeter_IsNotEnabled_NegativeControl()
+    {
+        using var meter = new Meter("ZB.MOM.WW.OtOpcUa.Unregistered." + Guid.NewGuid().ToString("N"));
+        meter.CreateCounter<long>("allowlist.probe").Enabled.ShouldBeFalse();
+    }
+
+    public async ValueTask DisposeAsync() => await _app.DisposeAsync();
+}