diff --git a/src/NATS.Server/NatsOptions.cs b/src/NATS.Server/NatsOptions.cs
index 0aee913..ecec1e3 100644
--- a/src/NATS.Server/NatsOptions.cs
+++ b/src/NATS.Server/NatsOptions.cs
@@ -16,6 +16,19 @@ public sealed class NatsOptions
     public TimeSpan PingInterval { get; set; } = TimeSpan.FromMinutes(2);
     public int MaxPingsOut { get; set; } = 2;
 
+    // Subscription limits
+    public int MaxSubs { get; set; }             // 0 = unlimited (per-connection)
+    public int MaxSubTokens { get; set; }        // 0 = unlimited
+
+    // Logging / diagnostics
+    public bool Debug { get; set; }
+    public bool Trace { get; set; }
+    public string? LogFile { get; set; }
+    public long LogSizeLimit { get; set; }
+
+    // Server tags (exposed via /varz)
+    public Dictionary<string, string>? Tags { get; set; }
+
     // Simple auth (single user)
     public string? Username { get; set; }
     public string? Password { get; set; }
diff --git a/tests/NATS.Server.Tests/NatsOptionsTests.cs b/tests/NATS.Server.Tests/NatsOptionsTests.cs
new file mode 100644
index 0000000..4e57769
--- /dev/null
+++ b/tests/NATS.Server.Tests/NatsOptionsTests.cs
@@ -0,0 +1,17 @@
+namespace NATS.Server.Tests;
+
+public class NatsOptionsTests
+{
+    [Fact]
+    public void Defaults_are_correct()
+    {
+        var opts = new NatsOptions();
+        opts.MaxSubs.ShouldBe(0);
+        opts.MaxSubTokens.ShouldBe(0);
+        opts.Debug.ShouldBe(false);
+        opts.Trace.ShouldBe(false);
+        opts.LogFile.ShouldBeNull();
+        opts.LogSizeLimit.ShouldBe(0L);
+        opts.Tags.ShouldBeNull();
+    }
+}