From 12c8524f4ab22f44a28328dac20647f3238cb366 Mon Sep 17 00:00:00 2001
From: Andrew Glaude <andrew.glaude@datadoghq.com>
Date: Fri, 10 Oct 2025 16:32:42 -0400
Subject: [PATCH 1/2] Add top_level to span debug output

---
 .../src/main/java/datadog/trace/core/DDSpanContext.java        | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
index 4c404ae0a38..30d6cf8c55f 100644
--- a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
+++ b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanContext.java
@@ -1018,6 +1018,9 @@ public String toString() {
     if (measured) {
       s.append(" *measured*");
     }
+    if (topLevel) {
+      s.append(" *top_level*");
+    }
 
     synchronized (unsafeTags) {
       s.append(" tags=").append(new TreeMap<>(getTags()));

From 922ebe32121f5200e8bd6c09f4fdde32209d27f4 Mon Sep 17 00:00:00 2001
From: Andrew Glaude <andrew.glaude@datadoghq.com>
Date: Fri, 10 Oct 2025 16:46:41 -0400
Subject: [PATCH 2/2] add test for top_level in output

---
 .../trace/core/DDSpanContextTest.groovy       | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/dd-trace-core/src/test/groovy/datadog/trace/core/DDSpanContextTest.groovy b/dd-trace-core/src/test/groovy/datadog/trace/core/DDSpanContextTest.groovy
index 1cdaa33d668..22bc295d9b6 100644
--- a/dd-trace-core/src/test/groovy/datadog/trace/core/DDSpanContextTest.groovy
+++ b/dd-trace-core/src/test/groovy/datadog/trace/core/DDSpanContextTest.groovy
@@ -312,6 +312,37 @@ class DDSpanContextTest extends DDCoreSpecification {
     context.toString().contains("id=-") == false
   }
 
+  def "toString includes top_level flag"() {
+    setup:
+    def parent = tracer.buildSpan("parentOperation")
+      .withServiceName("parentService")
+      .withResourceName("parentResource")
+      .start()
+
+    // Child span with different service name should be top-level
+    def topLevelSpan = tracer.buildSpan("childOperation")
+      .withServiceName("childService")
+      .withResourceName("childResource")
+      .asChildOf(parent.context())
+      .start()
+
+    // Child span with same service name should not be top-level
+    def nonTopLevelSpan = tracer.buildSpan("childOperation2")
+      .withServiceName("parentService")
+      .withResourceName("childResource2")
+      .asChildOf(parent.context())
+      .start()
+
+    def topLevelContext = topLevelSpan.context() as DDSpanContext
+    def nonTopLevelContext = nonTopLevelSpan.context() as DDSpanContext
+
+    expect:
+    topLevelContext.isTopLevel() == true
+    topLevelContext.toString().contains("*top_level*") == true
+    nonTopLevelContext.isTopLevel() == false
+    nonTopLevelContext.toString().contains("*top_level*") == false
+  }
+
   static void assertTagmap(Map source, Map comparison, boolean removeThread = false) {
     def sourceWithoutCommonTags = new HashMap(source)
     sourceWithoutCommonTags.remove("runtime-id")