feat: Add an optional tenant parameter to the getExtendedAgentCard operation

client/base/src/main/java/io/a2a/client/AbstractClient.java

@@ -390,17 +390,41 @@ public abstract void resubscribe(@NonNull TaskIdParams request,
      * @throws A2AClientException if retrieving the extended agent card fails for any reason
      */
     public AgentCard getExtendedAgentCard() throws A2AClientException {
-        return getExtendedAgentCard(null);
+        return getExtendedAgentCard(null, null);
     }
 
     /**
      * Retrieve the extended AgentCard.
      *
+     * @param tenant Optional tenant
+     * @return the extended AgentCard
+     * @throws A2AClientException if retrieving the extended agent card fails for any reason
+     */
+    public AgentCard getExtendedAgentCard(@Nullable String tenant) throws A2AClientException {
+        return getExtendedAgentCard(tenant, null);
+    }
+
+    /**
+     * Retrieve the extended AgentCard.
+     *
+     * @param context optional client call context for the request (may be {@code null})
+     * @return the extended AgentCard
+     * @throws A2AClientException if retrieving the extended agent card fails for any reason
+     */
+    public AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException {
+        return getExtendedAgentCard(null, context);
+    }
+
+    /**
+     * Retrieve the extended AgentCard.
+     *
+     * @param tenant Optional tenant
      * @param context optional client call context for the request (may be {@code null})
      * @return the extended AgentCard
      * @throws A2AClientException if retrieving the extended agent card fails for any reason
      */
-    public abstract AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException;
+    public abstract AgentCard getExtendedAgentCard(@Nullable String tenant,
+                                                   @Nullable ClientCallContext context) throws A2AClientException;
 
     /**
      * Close the transport and release any associated resources.

client/base/src/main/java/io/a2a/client/Client.java

@@ -17,6 +17,7 @@
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.DeleteTaskPushNotificationConfigParams;
 import io.a2a.spec.EventKind;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigResult;
@@ -601,19 +602,21 @@ public void resubscribe(@NonNull TaskIdParams request,
      * <p>
      * Example:
      * <pre>{@code
-     * AgentCard updatedCard = client.getExtendedAgentCard(null);
+     * AgentCard updatedCard = client.getExtendedAgentCard();
      * System.out.println("Agent version: " + updatedCard.version());
      * System.out.println("Skills: " + updatedCard.skills().size());
      * }</pre>
      *
+     * @param tenant Optional tenant
      * @param context custom call context for request interceptors (optional)
      * @return the agent's extended agent card
      * @throws A2AClientException if the extended agent card cannot be retrieved
      * @see AgentCard
      */
     @Override
-    public AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException {
-        agentCard = clientTransport.getExtendedAgentCard(context);
+    public AgentCard getExtendedAgentCard(@Nullable String tenant, @Nullable ClientCallContext context) throws A2AClientException {
+        GetExtendedAgentCardParams params = new GetExtendedAgentCardParams(tenant);
+        agentCard = clientTransport.getExtendedAgentCard(params, context);
         return agentCard;
     }
 

client/transport/grpc/src/main/java/io/a2a/client/transport/grpc/GrpcTransport.java

@@ -35,6 +35,7 @@
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.DeleteTaskPushNotificationConfigParams;
 import io.a2a.spec.EventKind;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigResult;
@@ -350,9 +351,12 @@ private MessageSendParams createRequestWithTenant(MessageSendParams request) {
     }
 
     @Override
-    public AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException {
-        GetExtendedAgentCardRequest request = GetExtendedAgentCardRequest.newBuilder()
-                .build();
+    public AgentCard getExtendedAgentCard(GetExtendedAgentCardParams params, @Nullable ClientCallContext context) throws A2AClientException {
+        GetExtendedAgentCardRequest.Builder builder = GetExtendedAgentCardRequest.newBuilder();
+        if (params.tenant() != null) {
+            builder.setTenant(params.tenant());
+        }
+        GetExtendedAgentCardRequest request = builder.build();
         PayloadAndHeaders payloadAndHeaders = applyInterceptors(GET_EXTENDED_AGENT_CARD_METHOD, request, agentCard, context);
 
         try {

client/transport/jsonrpc/src/main/java/io/a2a/client/transport/jsonrpc/JSONRPCTransport.java

@@ -51,6 +51,7 @@
 import io.a2a.spec.AgentInterface;
 import io.a2a.spec.DeleteTaskPushNotificationConfigParams;
 import io.a2a.spec.EventKind;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigResult;
@@ -284,13 +285,13 @@ public void resubscribe(TaskIdParams request, Consumer<StreamingEventKind> event
     }
 
     @Override
-    public AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException {
+    public AgentCard getExtendedAgentCard(GetExtendedAgentCardParams params, @Nullable ClientCallContext context) throws A2AClientException {
         try {
             PayloadAndHeaders payloadAndHeaders = applyInterceptors(GET_EXTENDED_AGENT_CARD_METHOD,
-                    ProtoUtils.ToProto.extendedAgentCard(), agentCard, context);
+                    ProtoUtils.ToProto.extendedAgentCard(params), agentCard, context);
 
             try {
-                String httpResponseBody = sendPostRequest(Utils.buildBaseUrl(agentInterface, ""), payloadAndHeaders, GET_EXTENDED_AGENT_CARD_METHOD);
+                String httpResponseBody = sendPostRequest(Utils.buildBaseUrl(agentInterface, params.tenant()), payloadAndHeaders, GET_EXTENDED_AGENT_CARD_METHOD);
                 GetExtendedAgentCardResponse response = unmarshalResponse(httpResponseBody, GET_EXTENDED_AGENT_CARD_METHOD);
                 return response.getResult();
             } catch (IOException | InterruptedException | JsonProcessingException e) {

client/transport/jsonrpc/src/test/java/io/a2a/client/transport/jsonrpc/JSONRPCTransportTest.java

@@ -1,7 +1,5 @@
 package io.a2a.client.transport.jsonrpc;
 
-import static io.a2a.client.transport.jsonrpc.JsonMessages.AGENT_CARD;
-import static io.a2a.client.transport.jsonrpc.JsonMessages.AGENT_CARD_SUPPORTS_EXTENDED;
 import static io.a2a.client.transport.jsonrpc.JsonMessages.CANCEL_TASK_TEST_REQUEST;
 import static io.a2a.client.transport.jsonrpc.JsonMessages.CANCEL_TASK_TEST_RESPONSE;
 import static io.a2a.client.transport.jsonrpc.JsonMessages.GET_AUTHENTICATED_EXTENDED_AGENT_CARD_REQUEST;
@@ -43,7 +41,6 @@
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.ExtensionSupportRequiredError;
 import io.a2a.spec.VersionNotSupportedError;
-import io.a2a.spec.AgentInterface;
 import io.a2a.spec.AgentSkill;
 import io.a2a.spec.Artifact;
 import io.a2a.spec.AuthenticationInfo;
@@ -53,6 +50,7 @@
 import io.a2a.spec.FilePart;
 import io.a2a.spec.FileWithBytes;
 import io.a2a.spec.FileWithUri;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.Message;
 import io.a2a.spec.MessageSendConfiguration;
@@ -67,7 +65,6 @@
 import io.a2a.spec.TaskQueryParams;
 import io.a2a.spec.TaskState;
 import io.a2a.spec.TextPart;
-import io.a2a.spec.TransportProtocol;
 import io.a2a.util.Utils;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
@@ -368,7 +365,8 @@ public void testA2AClientGetExtendedAgentCard() throws Exception {
                 );
 
         JSONRPCTransport client = new JSONRPCTransport("http://localhost:4001");
-        AgentCard agentCard = client.getExtendedAgentCard(null);
+        GetExtendedAgentCardParams params = new GetExtendedAgentCardParams(null);
+        AgentCard agentCard = client.getExtendedAgentCard(params, null);
         assertEquals("GeoSpatial Route Planner Agent Extended", agentCard.name());
         assertEquals("Extended description", agentCard.description());
         assertEquals("https://georoute-agent.example.com/a2a/v1", Utils.getFavoriteInterface(agentCard).url());

client/transport/rest/src/main/java/io/a2a/client/transport/rest/RestTransport.java

@@ -27,7 +27,7 @@
 import com.google.protobuf.InvalidProtocolBufferException;
 import com.google.protobuf.MessageOrBuilder;
 import com.google.protobuf.util.JsonFormat;
-import io.a2a.client.http.A2ACardResolver;
+
 import io.a2a.client.http.A2AHttpClient;
 import io.a2a.client.http.A2AHttpClientFactory;
 import io.a2a.client.http.A2AHttpResponse;
@@ -46,6 +46,7 @@
 import io.a2a.spec.AgentInterface;
 import io.a2a.spec.DeleteTaskPushNotificationConfigParams;
 import io.a2a.spec.EventKind;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigResult;
@@ -415,15 +416,13 @@ public void resubscribe(TaskIdParams request, Consumer<StreamingEventKind> event
     }
 
     @Override
-    public AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException {
+    public AgentCard getExtendedAgentCard(GetExtendedAgentCardParams params, @Nullable ClientCallContext context) throws A2AClientException {
         try {
             PayloadAndHeaders payloadAndHeaders = applyInterceptors(GET_EXTENDED_AGENT_CARD_METHOD, null, agentCard, context);
-            String url = Utils.buildBaseUrl(agentInterface, "") + "/extendedAgentCard";
+            String url = Utils.buildBaseUrl(agentInterface, params.tenant()) + "/extendedAgentCard";
             A2AHttpClient.GetBuilder getBuilder = httpClient.createGet().url(url);
-            if (payloadAndHeaders.getHeaders() != null) {
-                for (Map.Entry<String, String> entry : payloadAndHeaders.getHeaders().entrySet()) {
+            for (Map.Entry<String, String> entry : payloadAndHeaders.getHeaders().entrySet()) {
                     getBuilder.addHeader(entry.getKey(), entry.getValue());
-                }
             }
             A2AHttpResponse response = getBuilder.get();
             if (!response.success()) {

client/transport/spi/src/main/java/io/a2a/client/transport/spi/ClientTransport.java

@@ -8,6 +8,7 @@
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.DeleteTaskPushNotificationConfigParams;
 import io.a2a.spec.EventKind;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigParams;
 import io.a2a.spec.ListTaskPushNotificationConfigResult;
@@ -139,11 +140,12 @@ void resubscribe(TaskIdParams request, Consumer<StreamingEventKind> eventConsume
     /**
      * Retrieve the extended AgentCard.
      *
+     * @param params the parameters to get the extended agent card.
      * @param context optional client call context for the request (may be {@code null})
      * @return the extended agent card
      * @throws A2AClientException if retrieving the agent card fails for any reason
      */
-    AgentCard getExtendedAgentCard(@Nullable ClientCallContext context) throws A2AClientException;
+    AgentCard getExtendedAgentCard(GetExtendedAgentCardParams params, @Nullable ClientCallContext context) throws A2AClientException;
 
     /**
      * Close the transport and release any associated resources.

spec-grpc/src/main/java/io/a2a/grpc/utils/ProtoUtils.java

@@ -27,6 +27,7 @@
 import io.a2a.spec.AgentCard;
 import io.a2a.spec.DeleteTaskPushNotificationConfigParams;
 import io.a2a.spec.EventKind;
+import io.a2a.spec.GetExtendedAgentCardParams;
 import io.a2a.spec.GetTaskPushNotificationConfigParams;
 import io.a2a.spec.InvalidParamsError;
 import io.a2a.spec.ListTaskPushNotificationConfigParams;
@@ -55,8 +56,12 @@ public static io.a2a.grpc.AgentCard agentCard(AgentCard agentCard) {
             return AgentCardMapper.INSTANCE.toProto(agentCard);
         }
 
-        public static io.a2a.grpc.GetExtendedAgentCardRequest extendedAgentCard() {
-            return GetExtendedAgentCardRequest.newBuilder().build();
+        public static io.a2a.grpc.GetExtendedAgentCardRequest extendedAgentCard(GetExtendedAgentCardParams params) {
+            GetExtendedAgentCardRequest.Builder builder = GetExtendedAgentCardRequest.newBuilder();
+            if (params.tenant() != null) {
+                builder.setTenant(params.tenant());
+            }
+            return builder.build();
         }
 
         public static io.a2a.grpc.GetTaskRequest getTaskRequest(TaskQueryParams params) {

spec/src/main/java/io/a2a/spec/GetExtendedAgentCardParams.java

@@ -0,0 +1,12 @@
+package io.a2a.spec;
+
+import org.jspecify.annotations.Nullable;
+
+/**
+ * Parameters to get the extended agent card.
+ *
+ * @param tenant optional tenant, provided as a path parameter.
+ * @see <a href="https://a2a-protocol.org/latest/">A2A Protocol Specification</a>
+ */
+public record GetExtendedAgentCardParams(@Nullable String tenant) {
+}