diff --git a/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs b/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs
index 4157e644a23..df1717b4faa 100644
--- a/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs
+++ b/src/Libraries/Microsoft.Extensions.AI/ChatCompletion/OpenTelemetryChatClient.cs
@@ -302,7 +302,8 @@ public override async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseA
 
                     if (_system is not null)
                     {
-                        if (options.AdditionalProperties is { } props)
+                        // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data
+                        if (EnableSensitiveData && options.AdditionalProperties is { } props)
                         {
                             // Log all additional request options as per-provider tags. This is non-normative, but it covers cases where
                             // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.request.service_tier),
@@ -404,11 +405,12 @@ private void TraceResponse(
 
                 if (_system is not null)
                 {
-                    // Log all additional response properties as per-provider tags. This is non-normative, but it covers cases where
-                    // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.response.system_fingerprint),
-                    // and more generally cases where there's additional useful information to be logged.
-                    if (response.AdditionalProperties is { } props)
+                    // Since AdditionalProperties has undefined meaning, we treat it as potentially sensitive data
+                    if (EnableSensitiveData && response.AdditionalProperties is { } props)
                     {
+                        // Log all additional response properties as per-provider tags. This is non-normative, but it covers cases where
+                        // there's a per-provider specification in a best-effort manner (e.g. gen_ai.openai.response.system_fingerprint),
+                        // and more generally cases where there's additional useful information to be logged.
                         foreach (KeyValuePair<string, object?> prop in props)
                         {
                             _ = activity.AddTag(
diff --git a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs
index 37ae545c04c..4d0122c7c92 100644
--- a/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs
+++ b/test/Libraries/Microsoft.Extensions.AI.Tests/ChatCompletion/OpenTelemetryChatClientTests.cs
@@ -165,16 +165,16 @@ async static IAsyncEnumerable<ChatResponseUpdate> CallbackAsync(
         Assert.Equal(7, activity.GetTagItem("gen_ai.request.top_k"));
         Assert.Equal(123, activity.GetTagItem("gen_ai.request.max_tokens"));
         Assert.Equal("""["hello", "world"]""", activity.GetTagItem("gen_ai.request.stop_sequences"));
-        Assert.Equal("value1", activity.GetTagItem("gen_ai.testservice.request.service_tier"));
-        Assert.Equal("value2", activity.GetTagItem("gen_ai.testservice.request.something_else"));
+        Assert.Equal(enableSensitiveData ? "value1" : null, activity.GetTagItem("gen_ai.testservice.request.service_tier"));
+        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("gen_ai.testservice.request.something_else"));
         Assert.Equal(42L, activity.GetTagItem("gen_ai.request.seed"));
 
         Assert.Equal("id123", activity.GetTagItem("gen_ai.response.id"));
         Assert.Equal("""["stop"]""", activity.GetTagItem("gen_ai.response.finish_reasons"));
         Assert.Equal(10, activity.GetTagItem("gen_ai.response.input_tokens"));
         Assert.Equal(20, activity.GetTagItem("gen_ai.response.output_tokens"));
-        Assert.Equal("abcdefgh", activity.GetTagItem("gen_ai.testservice.response.system_fingerprint"));
-        Assert.Equal("value2", activity.GetTagItem("gen_ai.testservice.response.and_something_else"));
+        Assert.Equal(enableSensitiveData ? "abcdefgh" : null, activity.GetTagItem("gen_ai.testservice.response.system_fingerprint"));
+        Assert.Equal(enableSensitiveData ? "value2" : null, activity.GetTagItem("gen_ai.testservice.response.and_something_else"));
 
         Assert.True(activity.Duration.TotalMilliseconds > 0);