diff --git a/AGENTS.md b/AGENTS.md
index 693b48a8d971..dbf89a033dff 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -213,6 +213,7 @@ tracer/src/Datadog.Trace
 - Add missing `using` directives instead of fully-qualified type names
 - Use modern C# syntax, but avoid features requiring types unavailable in older runtimes (e.g., no `ValueTuple` syntax for .NET Framework 4.6.1)
 - Prefer modern collection expressions (`[]`)
+- Use `StringUtil.IsNullOrEmpty()` instead of `string.IsNullOrEmpty()` for compatibility across all supported runtimes
 - StyleCop: see `tracer/stylecop.json`; address warnings before pushing
 
 **C/C++ style:**
diff --git a/tracer/src/Datadog.Trace/Logging/DirectSubmission/Formatting/LogFormatter.cs b/tracer/src/Datadog.Trace/Logging/DirectSubmission/Formatting/LogFormatter.cs
index 11dc23e826b3..d44d43ff3e6e 100644
--- a/tracer/src/Datadog.Trace/Logging/DirectSubmission/Formatting/LogFormatter.cs
+++ b/tracer/src/Datadog.Trace/Logging/DirectSubmission/Formatting/LogFormatter.cs
@@ -12,7 +12,6 @@
 using Datadog.Trace.Ci.Tags;
 using Datadog.Trace.ClrProfiler.AutoInstrumentation.Logging;
 using Datadog.Trace.Configuration;
-using Datadog.Trace.ExtensionMethods;
 using Datadog.Trace.Util;
 using Datadog.Trace.Vendors.Newtonsoft.Json;
 
@@ -20,8 +19,8 @@ namespace Datadog.Trace.Logging.DirectSubmission.Formatting
 {
     internal class LogFormatter
     {
-        private const string KeyValueTagSeparator = ":";
-        private const string TagSeparator = ",";
+        private const char KeyValueTagSeparator = ':';
+        private const char TagSeparator = ',';
         private const string SourcePropertyName = "ddsource";
         private const string ServicePropertyName = "service";
         private const string HostPropertyName = "host";
@@ -76,9 +75,9 @@ private static string StringifyGlobalTags(IReadOnlyDictionary<string, string> gl
             foreach (var tagPair in globalTags)
             {
                 sb.Append(tagPair.Key)
-                  .Append(':')
+                  .Append(KeyValueTagSeparator)
                   .Append(tagPair.Value)
-                  .Append(',');
+                  .Append(TagSeparator);
             }
 
             // remove final joiner
@@ -86,16 +85,63 @@ private static string StringifyGlobalTags(IReadOnlyDictionary<string, string> gl
             return StringBuilderCache.GetStringAndRelease(sb);
         }
 
-        private string? EnrichTagsWithAasMetadata(string globalTags, ImmutableAzureAppServiceSettings? aasSettings)
+        private static string RemoveScheme(string url)
+        {
+            if (url.StartsWith("https://", StringComparison.OrdinalIgnoreCase))
+            {
+                return url.Substring("https://".Length);
+            }
+
+            if (url.StartsWith("http://", StringComparison.OrdinalIgnoreCase))
+            {
+                return url.Substring("http://".Length);
+            }
+
+            return url;
+        }
+
+        private static string EnrichTagsWithAasMetadata(string globalTags, ImmutableAzureAppServiceSettings? aasSettings)
         {
             if (aasSettings is null)
             {
-                return string.IsNullOrEmpty(globalTags) ? null : globalTags;
+                return globalTags;
+            }
+
+            var hasResourceId = !string.IsNullOrEmpty(aasSettings.ResourceId);
+            var hasSiteKind = !string.IsNullOrEmpty(aasSettings.SiteKind);
+
+            if (!hasResourceId && !hasSiteKind)
+            {
+                return globalTags;
+            }
+
+            var sb = StringBuilderCache.Acquire();
+
+            if (hasResourceId)
+            {
+                sb.Append(Trace.Tags.AzureAppServicesResourceId)
+                  .Append(KeyValueTagSeparator)
+                  .Append(aasSettings.ResourceId)
+                  .Append(TagSeparator);
             }
 
-            var aasTags = $"{Trace.Tags.AzureAppServicesResourceId}{KeyValueTagSeparator}{aasSettings.ResourceId}";
+            if (hasSiteKind)
+            {
+                sb.Append(Trace.Tags.AzureAppServicesSiteKind)
+                  .Append(KeyValueTagSeparator)
+                  .Append(aasSettings.SiteKind)
+                  .Append(TagSeparator);
+            }
 
-            return string.IsNullOrEmpty(globalTags) ? aasTags : aasTags + TagSeparator + globalTags;
+            // remove final joiner
+            sb.Remove(sb.Length - 1, length: 1);
+            if (!string.IsNullOrEmpty(globalTags))
+            {
+                sb.Append(TagSeparator)
+                  .Append(globalTags);
+            }
+
+            return StringBuilderCache.GetStringAndRelease(sb);
         }
 
         private void EnrichTagsStringWithGitMetadata()
@@ -120,16 +166,6 @@ private void EnrichTagsStringWithGitMetadata()
             _gitMetadataAdded = true;
         }
 
-        private string? RemoveScheme(string url)
-        {
-            return url switch
-            {
-                { } when url.StartsWith("https://", StringComparison.OrdinalIgnoreCase) => url.Substring("https://".Length),
-                { } when url.StartsWith("http://", StringComparison.OrdinalIgnoreCase) => url.Substring("http://".Length),
-                _ => url
-            };
-        }
-
         internal static bool IsSourceProperty(string? propertyName) =>
             string.Equals(propertyName, SourcePropertyName, StringComparison.OrdinalIgnoreCase);
 
@@ -317,7 +353,7 @@ internal void FormatLog<T>(
 
             EnrichTagsStringWithGitMetadata();
 
-            if (Tags is not null && !renderingDetails.HasRenderedTags)
+            if (!StringUtil.IsNullOrEmpty(Tags) && !renderingDetails.HasRenderedTags)
             {
                 writer.WritePropertyName(TagsPropertyName, escape: false);
                 writer.WriteValue(Tags);
diff --git a/tracer/test/Datadog.Trace.Tests/Logging/DirectSubmission/Formatting/LogFormatterTests.cs b/tracer/test/Datadog.Trace.Tests/Logging/DirectSubmission/Formatting/LogFormatterTests.cs
index d7a2871bd64b..5aeb241e1309 100644
--- a/tracer/test/Datadog.Trace.Tests/Logging/DirectSubmission/Formatting/LogFormatterTests.cs
+++ b/tracer/test/Datadog.Trace.Tests/Logging/DirectSubmission/Formatting/LogFormatterTests.cs
@@ -182,7 +182,7 @@ public void WritesLogFormatCorrectly(
             (string Key, string Value)[] expectedTags = (isInAas, hasRenderedTags) switch
             {
                 (_, true) => null, // if the log itself adds this, we don't add the global tags currently
-                (true, false) => [("aas.resource.id", aasSettings!.ResourceId), ("Key1", "Value1"), ("Key2", "Value2")],
+                (true, false) => [("aas.resource.id", aasSettings!.ResourceId), ("aas.site.kind", aasSettings.SiteKind), ("Key1", "Value1"), ("Key2", "Value2")],
                 (false, false) => [("Key1", "Value1"), ("Key2", "Value2")],
             };