google · copybara-service · Jan 26, 2026 · Jan 26, 2026
diff --git a/core/src/main/java/com/google/adk/JsonBaseModel.java b/core/src/main/java/com/google/adk/JsonBaseModel.java
@@ -56,7 +56,7 @@ private static ObjectMapper createObjectMapper() {
   }
 
   /** Serializes an object to a Json string. */
-  protected static String toJsonString(Object object) {
+  public static String toJsonString(Object object) {
     try {
       return objectMapper.writeValueAsString(object);
     } catch (JsonProcessingException e) {

diff --git a/core/src/main/java/com/google/adk/agents/BaseAgent.java b/core/src/main/java/com/google/adk/agents/BaseAgent.java
@@ -18,11 +18,11 @@
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 
-import com.google.adk.Telemetry;
 import com.google.adk.agents.Callbacks.AfterAgentCallback;
 import com.google.adk.agents.Callbacks.BeforeAgentCallback;
 import com.google.adk.events.Event;
 import com.google.adk.plugins.Plugin;
+import com.google.adk.telemetry.Tracing;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.DoNotCall;
@@ -222,7 +222,7 @@ private InvocationContext createInvocationContext(InvocationContext parentContex
    * @return stream of agent-generated events.
    */
   public Flowable<Event> runAsync(InvocationContext parentContext) {
-    Tracer tracer = Telemetry.getTracer();
+    Tracer tracer = Tracing.getTracer();
     return Flowable.defer(
         () -> {
           Span span =
@@ -234,7 +234,7 @@ public Flowable<Event> runAsync(InvocationContext parentContext) {
 
           InvocationContext invocationContext = createInvocationContext(parentContext);
 
-          return Telemetry.traceFlowable(
+          return Tracing.traceFlowable(
               spanContext,
               span,
               () ->
@@ -361,7 +361,7 @@ private Single<Optional<Event>> callCallback(
    * @return stream of agent-generated events.
    */
   public Flowable<Event> runLive(InvocationContext parentContext) {
-    Tracer tracer = Telemetry.getTracer();
+    Tracer tracer = Tracing.getTracer();
     return Flowable.defer(
         () -> {
           Span span =
@@ -373,7 +373,7 @@ public Flowable<Event> runLive(InvocationContext parentContext) {
 
           InvocationContext invocationContext = createInvocationContext(parentContext);
 
-          return Telemetry.traceFlowable(spanContext, span, () -> runLiveImpl(invocationContext));
+          return Tracing.traceFlowable(spanContext, span, () -> runLiveImpl(invocationContext));
         });
   }
 

diff --git a/core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java b/core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java
@@ -16,7 +16,6 @@
 
 package com.google.adk.flows.llmflows;
 
-import com.google.adk.Telemetry;
 import com.google.adk.agents.ActiveStreamingTool;
 import com.google.adk.agents.BaseAgent;
 import com.google.adk.agents.CallbackContext;
@@ -38,6 +37,7 @@
 import com.google.adk.models.LlmRegistry;
 import com.google.adk.models.LlmRequest;
 import com.google.adk.models.LlmResponse;
+import com.google.adk.telemetry.Tracing;
 import com.google.adk.tools.ToolContext;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
@@ -178,7 +178,7 @@ private Flowable<LlmResponse> callLlm(
               return Flowable.defer(
                       () -> {
                         Span llmCallSpan =
-                            Telemetry.getTracer()
+                            Tracing.getTracer()
                                 .spanBuilder("call_llm")
                                 .setParent(Context.current())
                                 .startSpan();
@@ -199,7 +199,7 @@ private Flowable<LlmResponse> callLlm(
                               .doOnNext(
                                   llmResp -> {
                                     try (Scope innerScope = llmCallSpan.makeCurrent()) {
-                                      Telemetry.traceCallLlm(
+                                      Tracing.traceCallLlm(
                                           context,
                                           eventForCallbackUsage.id(),
                                           llmRequestBuilder.build(),
@@ -474,7 +474,7 @@ public Flowable<Event> runLive(InvocationContext invocationContext) {
                       : Completable.defer(
                           () -> {
                             Span sendDataSpan =
-                                Telemetry.getTracer()
+                                Tracing.getTracer()
                                     .spanBuilder("send_data")
                                     .setParent(Context.current())
                                     .startSpan();
@@ -484,7 +484,7 @@ public Flowable<Event> runLive(InvocationContext invocationContext) {
                                   .doOnComplete(
                                       () -> {
                                         try (Scope innerScope = sendDataSpan.makeCurrent()) {
-                                          Telemetry.traceSendData(
+                                          Tracing.traceSendData(
                                               invocationContext,
                                               eventIdForSendData,
                                               llmRequestAfterPreprocess.contents());
@@ -496,7 +496,7 @@ public Flowable<Event> runLive(InvocationContext invocationContext) {
                                             StatusCode.ERROR, error.getMessage());
                                         sendDataSpan.recordException(error);
                                         try (Scope innerScope = sendDataSpan.makeCurrent()) {
-                                          Telemetry.traceSendData(
+                                          Tracing.traceSendData(
                                               invocationContext,
                                               eventIdForSendData,
                                               llmRequestAfterPreprocess.contents());

diff --git a/core/src/main/java/com/google/adk/flows/llmflows/Functions.java b/core/src/main/java/com/google/adk/flows/llmflows/Functions.java
@@ -20,7 +20,6 @@
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
 
-import com.google.adk.Telemetry;
 import com.google.adk.agents.ActiveStreamingTool;
 import com.google.adk.agents.Callbacks.AfterToolCallback;
 import com.google.adk.agents.Callbacks.BeforeToolCallback;
@@ -31,6 +30,7 @@
 import com.google.adk.events.Event;
 import com.google.adk.events.EventActions;
 import com.google.adk.events.ToolConfirmation;
+import com.google.adk.telemetry.Tracing;
 import com.google.adk.tools.BaseTool;
 import com.google.adk.tools.FunctionTool;
 import com.google.adk.tools.ToolContext;
@@ -178,11 +178,11 @@ public static Maybe<Event> handleFunctionCalls(
               var mergedEvent = maybeMergedEvent.get();
 
               if (events.size() > 1) {
-                Tracer tracer = Telemetry.getTracer();
+                Tracer tracer = Tracing.getTracer();
                 Span mergedSpan =
                     tracer.spanBuilder("tool_response").setParent(Context.current()).startSpan();
                 try (Scope scope = mergedSpan.makeCurrent()) {
-                  Telemetry.traceToolResponse(invocationContext, mergedEvent.id(), mergedEvent);
+                  Tracing.traceToolResponse(invocationContext, mergedEvent.id(), mergedEvent);
                 } finally {
                   mergedSpan.end();
                 }
@@ -552,7 +552,7 @@ private static Maybe<Map<String, Object>> maybeInvokeAfterToolCall(
 
   private static Maybe<Map<String, Object>> callTool(
       BaseTool tool, Map<String, Object> args, ToolContext toolContext) {
-    Tracer tracer = Telemetry.getTracer();
+    Tracer tracer = Tracing.getTracer();
     return Maybe.defer(
         () -> {
           Span span =
@@ -561,7 +561,7 @@ private static Maybe<Map<String, Object>> callTool(
                   .setParent(Context.current())
                   .startSpan();
           try (Scope scope = span.makeCurrent()) {
-            Telemetry.traceToolCall(args);
+            Tracing.traceToolCall(args);
             return tool.runAsync(args, toolContext)
                 .toMaybe()
                 .doOnError(span::recordException)
@@ -579,7 +579,7 @@ private static Event buildResponseEvent(
       Map<String, Object> response,
       ToolContext toolContext,
       InvocationContext invocationContext) {
-    Tracer tracer = Telemetry.getTracer();
+    Tracer tracer = Tracing.getTracer();
     Span span =
         tracer
             .spanBuilder("tool_response [" + tool.name() + "]")
@@ -615,7 +615,7 @@ private static Event buildResponseEvent(
                           .build()))
               .actions(toolContext.eventActions())
               .build();
-      Telemetry.traceToolResponse(invocationContext, event.id(), event);
+      Tracing.traceToolResponse(invocationContext, event.id(), event);
       return event;
     } finally {
       span.end();

diff --git a/core/src/main/java/com/google/adk/runner/Runner.java b/core/src/main/java/com/google/adk/runner/Runner.java
@@ -16,7 +16,6 @@
 
 package com.google.adk.runner;
 
-import com.google.adk.Telemetry;
 import com.google.adk.agents.ActiveStreamingTool;
 import com.google.adk.agents.BaseAgent;
 import com.google.adk.agents.InvocationContext;
@@ -39,6 +38,7 @@
 import com.google.adk.summarizer.EventsCompactionConfig;
 import com.google.adk.summarizer.LlmEventSummarizer;
 import com.google.adk.summarizer.SlidingWindowEventCompactor;
+import com.google.adk.telemetry.Tracing;
 import com.google.adk.tools.BaseTool;
 import com.google.adk.tools.FunctionTool;
 import com.google.adk.utils.CollectionUtils;
@@ -450,7 +450,7 @@ public Flowable<Event> runAsync(
       RunConfig runConfig,
       @Nullable Map<String, Object> stateDelta) {
     Span span =
-        Telemetry.getTracer().spanBuilder("invocation").setParent(Context.current()).startSpan();
+        Tracing.getTracer().spanBuilder("invocation").setParent(Context.current()).startSpan();
     Context spanContext = Context.current().with(span);
 
     try {
@@ -465,7 +465,7 @@ public Flowable<Event> runAsync(
               .userContent(newMessage)
               .build();
 
-      return Telemetry.traceFlowable(
+      return Tracing.traceFlowable(
           spanContext,
           span,
           () ->
@@ -645,7 +645,7 @@ private InvocationContext.Builder newInvocationContextBuilder(Session session) {
   public Flowable<Event> runLive(
       Session session, LiveRequestQueue liveRequestQueue, RunConfig runConfig) {
     Span span =
-        Telemetry.getTracer().spanBuilder("invocation").setParent(Context.current()).startSpan();
+        Tracing.getTracer().spanBuilder("invocation").setParent(Context.current()).startSpan();
     Context spanContext = Context.current().with(span);
 
     try {
@@ -668,7 +668,7 @@ public Flowable<Event> runLive(
 
       return invocationContextSingle.flatMapPublisher(
           updatedInvocationContext ->
-              Telemetry.traceFlowable(
+              Tracing.traceFlowable(
                   spanContext,
                   span,
                   () ->

diff --git a/...c/main/java/com/google/adk/Telemetry.java → ...ava/com/google/adk/telemetry/Tracing.java b/...c/main/java/com/google/adk/Telemetry.java → ...ava/com/google/adk/telemetry/Tracing.java
@@ -14,12 +14,13 @@
  * limitations under the License.
  */
 
-package com.google.adk;
+package com.google.adk.telemetry;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.core.type.TypeReference;
+import com.google.adk.JsonBaseModel;
 import com.google.adk.agents.InvocationContext;
 import com.google.adk.events.Event;
 import com.google.adk.models.LlmRequest;
@@ -47,18 +48,22 @@
  * LLM interactions, and data handling. It leverages OpenTelemetry for tracing and logging for
  * detailed information. These traces can then be exported through the ADK Dev Server UI.
  */
-public class Telemetry {
+public class Tracing {
 
-  private static final Logger log = LoggerFactory.getLogger(Telemetry.class);
+  private static final Logger log = LoggerFactory.getLogger(Tracing.class);
 
   @SuppressWarnings("NonFinalStaticField")
-  private static Tracer tracer = GlobalOpenTelemetry.getTracer("gcp.vertex.agent");
+  private static Tracer tracer = GlobalOpenTelemetry.getTracer("com.google.adk");
 
-  private Telemetry() {}
+  private static final boolean CAPTURE_MESSAGE_CONTENT_IN_SPANS =
+      Boolean.parseBoolean(
+          System.getenv().getOrDefault("ADK_CAPTURE_MESSAGE_CONTENT_IN_SPANS", "true"));
+
+  private Tracing() {}
 
   /** Sets the OpenTelemetry instance to be used for tracing. This is for testing purposes only. */
   public static void setTracerForTesting(Tracer tracer) {
-    Telemetry.tracer = tracer;
+    Tracing.tracer = tracer;
   }
 
   /**
@@ -73,10 +78,9 @@ public static void traceToolCall(Map<String, Object> args) {
       return;
     }
 
-    span.setAttribute("gen_ai.system", "gcp.vertex.agent");
+    span.setAttribute("gen_ai.system", "com.google.adk");
     try {
-      span.setAttribute(
-          "gcp.vertex.agent.tool_call_args", JsonBaseModel.getMapper().writeValueAsString(args));
+      span.setAttribute("adk.tool_call_args", JsonBaseModel.getMapper().writeValueAsString(args));
     } catch (JsonProcessingException e) {
       log.warn("traceToolCall: Failed to serialize tool call args to JSON", e);
     }
@@ -97,16 +101,16 @@ public static void traceToolResponse(
       return;
     }
 
-    span.setAttribute("gen_ai.system", "gcp.vertex.agent");
-    span.setAttribute("gcp.vertex.agent.invocation_id", invocationContext.invocationId());
-    span.setAttribute("gcp.vertex.agent.event_id", eventId);
-    span.setAttribute("gcp.vertex.agent.tool_response", functionResponseEvent.toJson());
+    span.setAttribute("gen_ai.system", "com.google.adk");
+    span.setAttribute("adk.invocation_id", invocationContext.invocationId());
+    span.setAttribute("adk.event_id", eventId);
+    span.setAttribute("adk.tool_response", functionResponseEvent.toJson());
 
     // Setting empty llm request and response (as the AdkDevServer UI expects these)
-    span.setAttribute("gcp.vertex.agent.llm_request", "{}");
-    span.setAttribute("gcp.vertex.agent.llm_response", "{}");
+    span.setAttribute("adk.llm_request", "{}");
+    span.setAttribute("adk.llm_response", "{}");
     if (invocationContext.session() != null && invocationContext.session().id() != null) {
-      span.setAttribute("gcp.vertex.agent.session_id", invocationContext.session().id());
+      span.setAttribute("adk.session_id", invocationContext.session().id());
     }
   }
 
@@ -158,26 +162,31 @@ public static void traceCallLlm(
       return;
     }
 
-    span.setAttribute("gen_ai.system", "gcp.vertex.agent");
+    span.setAttribute("gen_ai.system", "com.google.adk");
     llmRequest.model().ifPresent(modelName -> span.setAttribute("gen_ai.request.model", modelName));
-    span.setAttribute("gcp.vertex.agent.invocation_id", invocationContext.invocationId());
-    span.setAttribute("gcp.vertex.agent.event_id", eventId);
+    span.setAttribute("adk.invocation_id", invocationContext.invocationId());
+    span.setAttribute("adk.event_id", eventId);
 
     if (invocationContext.session() != null && invocationContext.session().id() != null) {
-      span.setAttribute("gcp.vertex.agent.session_id", invocationContext.session().id());
+      span.setAttribute("adk.session_id", invocationContext.session().id());
     } else {
       log.trace(
           "traceCallLlm: InvocationContext session or session ID is null, cannot set"
-              + " gcp.vertex.agent.session_id");
+              + " adk.session_id");
     }
 
-    try {
-      span.setAttribute(
-          "gcp.vertex.agent.llm_request",
-          JsonBaseModel.getMapper().writeValueAsString(buildLlmRequestForTrace(llmRequest)));
-      span.setAttribute("gcp.vertex.agent.llm_response", llmResponse.toJson());
-    } catch (JsonProcessingException e) {
-      log.warn("traceCallLlm: Failed to serialize LlmRequest or LlmResponse to JSON", e);
+    if (CAPTURE_MESSAGE_CONTENT_IN_SPANS) {
+      try {
+        span.setAttribute(
+            "adk.llm_request",
+            JsonBaseModel.getMapper().writeValueAsString(buildLlmRequestForTrace(llmRequest)));
+        span.setAttribute("adk.llm_response", llmResponse.toJson());
+      } catch (JsonProcessingException e) {
+        log.warn("traceCallLlm: Failed to serialize LlmRequest or LlmResponse to JSON", e);
+      }
+    } else {
+      span.setAttribute("adk.llm_request", "{}");
+      span.setAttribute("adk.llm_response", "{}");
     }
   }
 
@@ -196,13 +205,13 @@ public static void traceSendData(
       return;
     }
 
-    span.setAttribute("gcp.vertex.agent.invocation_id", invocationContext.invocationId());
+    span.setAttribute("adk.invocation_id", invocationContext.invocationId());
     if (eventId != null && !eventId.isEmpty()) {
-      span.setAttribute("gcp.vertex.agent.event_id", eventId);
+      span.setAttribute("adk.event_id", eventId);
     }
 
     if (invocationContext.session() != null && invocationContext.session().id() != null) {
-      span.setAttribute("gcp.vertex.agent.session_id", invocationContext.session().id());
+      span.setAttribute("adk.session_id", invocationContext.session().id());
     }
 
     try {
@@ -216,7 +225,7 @@ public static void traceSendData(
           }
         }
       }
-      span.setAttribute("gcp.vertex.agent.data", JsonBaseModel.toJsonString(dataList));
+      span.setAttribute("adk.data", JsonBaseModel.toJsonString(dataList));
     } catch (IllegalStateException e) {
       log.warn("traceSendData: Failed to serialize data to JSON", e);
     }