DataDog · dougqh · May 30, 2026
@@ -2,6 +2,7 @@
 
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.activeSpan;
 
+import datadog.context.Context;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import java.util.function.Function;
 import reactor.core.publisher.Mono;
@@ -11,14 +12,15 @@ public class CaptureConnectSpan
     implements Function<Mono<? extends Connection>, Mono<? extends Connection>> {
 
   static final String CONNECT_SPAN = "datadog.connect.span";
+  static final String CONNECT_CONTEXT = "datadog.connect.context";
 
   @Override
   public Mono<? extends Connection> apply(Mono<? extends Connection> mono) {
     return mono.contextWrite(
         context -> {
           final AgentSpan span = activeSpan();
           if (null != span) {
-            return context.put(CONNECT_SPAN, span);
+            return context.put(CONNECT_SPAN, span).put(CONNECT_CONTEXT, Context.current());
           } else {
             return context;
           }

@@ -2,8 +2,10 @@
 
 import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.captureSpan;
 import static datadog.trace.instrumentation.netty41.AttributeKeys.CONNECT_PARENT_CONTINUATION_ATTRIBUTE_KEY;
+import static datadog.trace.instrumentation.reactor.netty.CaptureConnectSpan.CONNECT_CONTEXT;
 import static datadog.trace.instrumentation.reactor.netty.CaptureConnectSpan.CONNECT_SPAN;
 
+import datadog.context.Context;
 import datadog.trace.bootstrap.instrumentation.api.AgentScope.Continuation;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import java.util.function.BiConsumer;
@@ -14,7 +16,13 @@ public class TransferConnectSpan implements BiConsumer<HttpClientRequest, Connec
   @Override
   public void accept(HttpClientRequest httpClientRequest, Connection connection) {
     final AgentSpan span = httpClientRequest.currentContextView().getOrDefault(CONNECT_SPAN, null);
-    final Continuation continuation = null == span ? null : captureSpan(span);
+    if (null == span) {
+      return;
+    }
+    final Context capturedContext =
+        httpClientRequest.currentContextView().getOrDefault(CONNECT_CONTEXT, null);
+    final Continuation continuation =
+        capturedContext != null ? captureSpan(span, capturedContext) : captureSpan(span);
     if (null != continuation) {
       Continuation current =
           connection

@@ -22,6 +22,7 @@
 import datadog.communication.ddagent.DDAgentFeaturesDiscovery;
 import datadog.communication.ddagent.ExternalAgentLauncher;
 import datadog.communication.ddagent.SharedCommunicationObjects;
+import datadog.context.Context;
 import datadog.context.propagation.Propagators;
 import datadog.environment.ThreadSupport;
 import datadog.logging.RatelimitedLogger;
@@ -1163,6 +1164,11 @@ public AgentScope.Continuation captureSpan(final AgentSpan span) {
     return scopeManager.captureSpan(span);
   }
 
+  @Override
+  public AgentScope.Continuation captureSpan(final AgentSpan span, final Context capturedContext) {
+    return scopeManager.captureSpan(span, capturedContext);
+  }
+
   @Override
   public boolean isAsyncPropagationEnabled() {
     return scopeManager.isAsyncPropagationEnabled();

@@ -121,6 +121,13 @@ public AgentScope.Continuation captureSpan(final AgentSpan span) {
     return captureSpan(context, INSTRUMENTATION, span);
   }
 
+  public AgentScope.Continuation captureSpan(final AgentSpan span, final Context capturedContext) {
+    if (span == null) {
+      return AgentTracer.noopContinuation();
+    }
+    return captureSpan(capturedContext.with(span), INSTRUMENTATION, span);
+  }
+
   private AgentScope.Continuation captureSpan(Context context, byte source, AgentSpan span) {
     AgentTraceCollector traceCollector = span.context().getTraceCollector();
     return new ScopeContinuation(this, context, source, traceCollector).register();

@@ -1,5 +1,6 @@
 package datadog.trace.bootstrap.instrumentation.api;
 
+import datadog.context.Context;
 import datadog.trace.api.ConfigDefaults;
 import datadog.trace.api.DDTraceId;
 import datadog.trace.api.EndpointCheckpointer;
@@ -104,6 +105,23 @@ public static AgentScope.Continuation captureSpan(final AgentSpan span) {
     return get().captureSpan(span);
   }
 
+  /**
+   * Like {@link #captureSpan(AgentSpan)} but uses an explicitly supplied context instead of the
+   * current thread's scope-stack context. Use this when the context with baggage was captured on a
+   * different thread (e.g. a Reactor subscription thread) and needs to be carried into the
+   * continuation created on an I/O thread that has no active scope.
+   *
+   * @param span the span to include in the continuation
+   * @param capturedContext the context (e.g. containing baggage) captured from the originating
+   *     thread
+   * @return Continuation with the supplied context, no-op continuation if the span is null.
+   */
+  @Nonnull
+  public static AgentScope.Continuation captureSpan(
+      final AgentSpan span, final Context capturedContext) {
+    return get().captureSpan(span, capturedContext);
+  }
+
   /**
    * Checkpoints the active scope. A subsequent call to {@link #rollbackActiveToCheckpoint()} closes
    * outstanding scopes up to but not including the most recent checkpointed scope.
@@ -329,6 +347,8 @@ AgentSpan startSpan(
 
     AgentScope.Continuation captureSpan(AgentSpan span);
 
+    AgentScope.Continuation captureSpan(AgentSpan span, Context capturedContext);
+
     void checkpointActiveForRollback();
 
     void rollbackActiveToCheckpoint();
@@ -488,6 +508,12 @@ public AgentScope.Continuation captureSpan(final AgentSpan span) {
       return NoopContinuation.INSTANCE;
     }
 
+    @Override
+    public AgentScope.Continuation captureSpan(
+        final AgentSpan span, final Context capturedContext) {
+      return NoopContinuation.INSTANCE;
+    }
+
     @Override
     public boolean isAsyncPropagationEnabled() {
       return false;