Merge main into planner

.github/workflows/release-please.yaml

@@ -14,4 +14,4 @@ jobs:
     steps:
       - uses: googleapis/release-please-action@v4
         with:
-          token: ${{ secrets.GITHUB_TOKEN }}
+          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}

a2a/src/main/java/com/google/adk/a2a/RemoteA2AAgent.java → a2a/src/main/java/com/google/adk/a2a/agent/RemoteA2AAgent.java

@@ -1,4 +1,19 @@
-package com.google.adk.a2a;
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.adk.a2a.agent;
 
 import static com.google.common.base.Strings.nullToEmpty;
 
@@ -44,26 +59,21 @@
 import org.slf4j.LoggerFactory;
 
 /**
- * Agent that communicates with a remote A2A agent via A2A client.
- *
- * <p>This agent supports multiple ways to specify the remote agent:
+ * Agent that communicates with a remote A2A agent via an A2A client.
  *
- * <ol>
- *   <li>Direct AgentCard object
- *   <li>URL to agent card JSON
- *   <li>File path to agent card JSON
- * </ol>
+ * <p>The remote agent can be specified directly by providing an {@link AgentCard} to the builder,
+ * or it can be resolved automatically using the provided A2A client.
  *
- * <p>The agent handles:
+ * <p>Key responsibilities of this agent include:
  *
  * <ul>
  *   <li>Agent card resolution and validation
- *   <li>A2A message conversion and error handling
- *   <li>Session state management across requests
+ *   <li>Converting ADK session history events into A2A requests ({@link io.a2a.spec.Message})
+ *   <li>Handling streaming and non-streaming responses from the A2A client
+ *   <li>Buffering and aggregating streamed response chunks into ADK {@link
+ *       com.google.adk.events.Event}s
+ *   <li>Converting A2A client responses back into ADK format
  * </ul>
- *
- * <p>**EXPERIMENTAL:** Subject to change, rename, or removal in any future patch release. Do not
- * use in production code.
  */
 public class RemoteA2AAgent extends BaseAgent {
 
@@ -436,7 +446,7 @@ private boolean mergeAggregatedContentIntoEvent(Event event) {
       }
       Content aggregatedContent = Content.builder().role("model").parts(parts).build();
 
-      event.setContent(Optional.of(aggregatedContent));
+      event.setContent(aggregatedContent);
 
       ImmutableList.Builder<CustomMetadata> newMetadata = ImmutableList.builder();
       event.customMetadata().ifPresent(newMetadata::addAll);

a2a/src/main/java/com/google/adk/a2a/common/A2AClientError.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.common;
 
 /** Exception thrown when the A2A client encounters an error. */

a2a/src/main/java/com/google/adk/a2a/common/A2AMetadata.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.common;
 
 /** Constants and utilities for A2A metadata keys. */

a2a/src/main/java/com/google/adk/a2a/common/GenAiFieldMissingException.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.common;
 
 /** Exception thrown when the the genai class has an empty field. */

a2a/src/main/java/com/google/adk/a2a/converters/A2ADataPartMetadataType.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.converters;
 
 /** Enum for the type of A2A DataPart metadata. */

a2a/src/main/java/com/google/adk/a2a/converters/EventConverter.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.converters;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
@@ -13,12 +28,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/**
- * Converter for ADK Events to A2A Messages.
- *
- * <p>**EXPERIMENTAL:** Subject to change, rename, or removal in any future patch release. Do not
- * use in production code.
- */
+/** Converter for ADK Events to A2A Messages. */
 public final class EventConverter {
   private static final Logger logger = LoggerFactory.getLogger(EventConverter.class);
 

a2a/src/main/java/com/google/adk/a2a/converters/PartConverter.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.converters;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
@@ -32,12 +47,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/**
- * Utility class for converting between Google GenAI Parts and A2A DataParts.
- *
- * <p>**EXPERIMENTAL:** Subject to change, rename, or removal in any future patch release. Do not
- * use in production code.
- */
+/** Utility class for converting between Google GenAI Parts and A2A DataParts. */
 public final class PartConverter {
 
   private static final Logger logger = LoggerFactory.getLogger(PartConverter.class);

a2a/src/main/java/com/google/adk/a2a/converters/ResponseConverter.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.converters;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
@@ -27,12 +42,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/**
- * Utility for converting ADK events to A2A spec messages (and back).
- *
- * <p>**EXPERIMENTAL:** Subject to change, rename, or removal in any future patch release. Do not
- * use in production code.
- */
+/** Utility for converting ADK events to A2A spec messages (and back). */
 public final class ResponseConverter {
   private static final Logger logger = LoggerFactory.getLogger(ResponseConverter.class);
   private static final ImmutableSet<TaskState> PENDING_STATES =
@@ -76,7 +86,7 @@ private static Optional<Event> handleTaskUpdate(
       boolean isLastChunk = Objects.equals(artifactEvent.isLastChunk(), true);
 
       Event eventPart = artifactToEvent(artifactEvent.getArtifact(), context);
-      eventPart.setPartial(Optional.of(isAppend || !isLastChunk));
+      eventPart.setPartial(isAppend || !isLastChunk);
       // append=true, lastChunk=false: emit as partial, update aggregation
       // append=false, lastChunk=false: emit as partial, reset aggregation
       // append=true, lastChunk=true: emit as partial, update aggregation and emit as non-partial

a2a/src/main/java/com/google/adk/a2a/executor/AgentExecutor.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.executor;
 
 import static java.util.Objects.requireNonNull;
@@ -44,12 +59,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/**
- * Implementation of the A2A AgentExecutor interface that uses ADK to execute agent tasks.
- *
- * <p>**EXPERIMENTAL:** Subject to change, rename, or removal in any future patch release. Do not
- * use in production code.
- */
+/** Implementation of the A2A AgentExecutor interface that uses ADK to execute agent tasks. */
 public class AgentExecutor implements io.a2a.server.agentexecution.AgentExecutor {
   private static final Logger logger = LoggerFactory.getLogger(AgentExecutor.class);
   private static final String USER_ID_PREFIX = "A2A_USER_";

a2a/src/main/java/com/google/adk/a2a/executor/AgentExecutorConfig.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.executor;
 
 import com.google.adk.a2a.executor.Callbacks.AfterEventCallback;

a2a/src/main/java/com/google/adk/a2a/executor/Callbacks.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.google.adk.a2a.executor;
 
 import com.google.adk.events.Event;

a2a/src/test/java/com/google/adk/a2a/RemoteA2AAgentTest.java → a2a/src/test/java/com/google/adk/a2a/agent/RemoteA2AAgentTest.java

@@ -1,4 +1,4 @@
-package com.google.adk.a2a;
+package com.google.adk.a2a.agent;
 
 import static com.google.common.truth.Truth.assertThat;
 import static java.util.concurrent.TimeUnit.SECONDS;

a2a/src/test/java/com/google/adk/a2a/executor/AgentExecutorTest.java

@@ -361,7 +361,7 @@ private RequestContext createRequestContext() {
   public void process_statefulAggregation_tracksArtifactIdAndAppendForAuthor() {
     Event partial1 =
         Event.builder()
-            .partial(Optional.of(true))
+            .partial(true)
             .author("agent_author")
             .content(
                 Content.builder()
@@ -370,7 +370,7 @@ public void process_statefulAggregation_tracksArtifactIdAndAppendForAuthor() {
             .build();
     Event partial2 =
         Event.builder()
-            .partial(Optional.of(true))
+            .partial(true)
             .author("agent_author")
             .content(
                 Content.builder()
@@ -379,7 +379,7 @@ public void process_statefulAggregation_tracksArtifactIdAndAppendForAuthor() {
             .build();
     Event finalEvent =
         Event.builder()
-            .partial(Optional.of(false))
+            .partial(false)
             .author("agent_author")
             .content(
                 Content.builder()

contrib/samples/a2a_basic/A2AAgent.java

@@ -1,6 +1,6 @@
 package com.example.a2a_basic;
 
-import com.google.adk.a2a.RemoteA2AAgent;
+import com.google.adk.a2a.agent.RemoteA2AAgent;
 import com.google.adk.agents.BaseAgent;
 import com.google.adk.agents.LlmAgent;
 import com.google.adk.tools.FunctionTool;