fix: propagate A2A request metadata into the run config in AgentExecutor

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

@@ -20,6 +20,7 @@
 import com.google.adk.a2a.converters.EventConverter;
 import com.google.adk.a2a.converters.PartConverter;
 import com.google.adk.agents.BaseAgent;
+import com.google.adk.agents.RunConfig;
 import com.google.adk.apps.App;
 import com.google.adk.artifacts.BaseArtifactService;
 import com.google.adk.events.Event;
@@ -38,6 +39,7 @@
 import io.a2a.spec.Artifact;
 import io.a2a.spec.InvalidAgentResponseError;
 import io.a2a.spec.Message;
+import io.a2a.spec.MessageSendParams;
 import io.a2a.spec.Part;
 import io.a2a.spec.TaskArtifactUpdateEvent;
 import io.a2a.spec.TaskState;
@@ -63,6 +65,7 @@
 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_";
+  private static final String A2A_METADATA_KEY = "a2a_metadata";
   private final Map<String, Disposable> activeTasks = new ConcurrentHashMap<>();
   private final Runner.Builder runnerBuilder;
   private final AgentExecutorConfig agentExecutorConfig;
@@ -217,7 +220,7 @@ public void execute(RequestContext ctx, EventQueue eventQueue) {
                                 getUserId(ctx),
                                 session.id(),
                                 content,
-                                agentExecutorConfig.runConfig());
+                                runConfigWithA2aMetadata(ctx));
                           });
                 })
             .concatMap(
@@ -273,6 +276,23 @@ private String getUserId(RequestContext ctx) {
     return USER_ID_PREFIX + ctx.getContextId();
   }
 
+  /**
+   * Returns the configured run config enriched with the caller's incoming A2A request metadata
+   * under the {@code a2a_metadata} key, so downstream processing can read it via {@link
+   * RunConfig#customMetadata()}.
+   */
+  private RunConfig runConfigWithA2aMetadata(RequestContext ctx) {
+    RunConfig runConfig = agentExecutorConfig.runConfig();
+    MessageSendParams params = ctx.getParams();
+    Map<String, Object> requestMetadata = params == null ? null : params.metadata();
+    if (requestMetadata == null || requestMetadata.isEmpty()) {
+      return runConfig;
+    }
+    Map<String, Object> customMetadata = new HashMap<>(runConfig.customMetadata());
+    customMetadata.put(A2A_METADATA_KEY, requestMetadata);
+    return runConfig.toBuilder().customMetadata(customMetadata).build();
+  }
+
   private Maybe<Session> prepareSession(
       RequestContext ctx, String appName, BaseSessionService service) {
     return service

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

@@ -12,6 +12,7 @@
 
 import com.google.adk.agents.BaseAgent;
 import com.google.adk.agents.InvocationContext;
+import com.google.adk.agents.RunConfig;
 import com.google.adk.apps.App;
 import com.google.adk.artifacts.InMemoryArtifactService;
 import com.google.adk.events.Event;
@@ -24,6 +25,7 @@
 import io.a2a.server.agentexecution.RequestContext;
 import io.a2a.server.events.EventQueue;
 import io.a2a.spec.Message;
+import io.a2a.spec.MessageSendParams;
 import io.a2a.spec.TaskArtifactUpdateEvent;
 import io.a2a.spec.TaskState;
 import io.a2a.spec.TaskStatus;
@@ -342,6 +344,62 @@ public void execute_runnerSucceeds_registerCompletedTaskFails_noFailedTaskRegist
     assertThat(statusEvents).isEmpty();
   }
 
+  @Test
+  public void execute_propagatesRequestMetadataIntoRunConfig() {
+    testAgent.setEventsToEmit(Flowable.empty());
+    AgentExecutor executor =
+        new AgentExecutor.Builder()
+            .agentExecutorConfig(AgentExecutorConfig.builder().build())
+            .app(App.builder().name("test_app").rootAgent(testAgent).build())
+            .sessionService(new InMemorySessionService())
+            .artifactService(new InMemoryArtifactService())
+            .build();
+
+    Message message =
+        new Message.Builder()
+            .messageId("msg-1")
+            .role(Message.Role.USER)
+            .parts(ImmutableList.of(new TextPart("trigger")))
+            .build();
+    MessageSendParams params =
+        new MessageSendParams.Builder()
+            .message(message)
+            .metadata(ImmutableMap.of("key", "value"))
+            .build();
+    RequestContext ctx = mock(RequestContext.class);
+    when(ctx.getMessage()).thenReturn(message);
+    when(ctx.getTaskId()).thenReturn("task-1");
+    when(ctx.getContextId()).thenReturn("ctx-1");
+    when(ctx.getParams()).thenReturn(params);
+
+    executor.execute(ctx, eventQueue);
+
+    // The runner passes the enriched run config down to the agent's invocation context.
+    RunConfig runConfig = testAgent.lastInvocationContext.runConfig();
+    assertThat(runConfig.customMetadata())
+        .containsEntry("a2a_metadata", ImmutableMap.of("key", "value"));
+  }
+
+  @Test
+  public void execute_withoutRequestMetadata_leavesRunConfigCustomMetadataEmpty() {
+    testAgent.setEventsToEmit(Flowable.empty());
+    AgentExecutor executor =
+        new AgentExecutor.Builder()
+            .agentExecutorConfig(AgentExecutorConfig.builder().build())
+            .app(App.builder().name("test_app").rootAgent(testAgent).build())
+            .sessionService(new InMemorySessionService())
+            .artifactService(new InMemoryArtifactService())
+            .build();
+
+    // createRequestContext() does not stub getParams(), mirroring a request with no metadata.
+    RequestContext ctx = createRequestContext();
+
+    executor.execute(ctx, eventQueue);
+
+    RunConfig runConfig = testAgent.lastInvocationContext.runConfig();
+    assertThat(runConfig.customMetadata()).doesNotContainKey("a2a_metadata");
+  }
+
   private RequestContext createRequestContext() {
     Message message =
         new Message.Builder()
@@ -507,6 +565,7 @@ public void execute_withDefaultArtifactPerRun_emitsMessageAndLastChunk() {
 
   private static final class TestAgent extends BaseAgent {
     private Flowable<Event> eventsToEmit;
+    private volatile InvocationContext lastInvocationContext;
 
     TestAgent() {
       this(Flowable.empty());
@@ -524,6 +583,7 @@ void setEventsToEmit(Flowable<Event> events) {
 
     @Override
     protected Flowable<Event> runAsyncImpl(InvocationContext invocationContext) {
+      this.lastInvocationContext = invocationContext;
       return eventsToEmit;
     }