fix: allow omitted task push config id

extras/push-notification-config-store-database-jpa/src/main/java/org/a2aproject/sdk/extras/pushnotificationconfigstore/database/jpa/JpaDatabasePushNotificationConfigStore.java

@@ -50,10 +50,8 @@ public TaskPushNotificationConfig setInfo(TaskPushNotificationConfig notificatio
     @Override
     public TaskPushNotificationConfig setInfo(TaskPushNotificationConfig notificationConfig, @Nullable String protocolVersion) {
         String taskId = Assert.checkNotNullParam("taskId", notificationConfig.taskId());
-        // Ensure config has an ID - default to taskId if not provided (mirroring InMemoryPushNotificationConfigStore behavior)
-        if (notificationConfig.id().isEmpty()) {
-            // This means the taskId and configId are same. This will not allow having multiple configs for a single Task.
-            // The configId is a required field in the spec and should not be empty
+        // Default missing config IDs to the task ID, matching the in-memory store.
+        if (notificationConfig.id() == null || notificationConfig.id().isEmpty()) {
             notificationConfig = TaskPushNotificationConfig.builder(notificationConfig).id(taskId).build();
         }
 

extras/push-notification-config-store-database-jpa/src/test/java/org/a2aproject/sdk/extras/pushnotificationconfigstore/database/jpa/JpaPushNotificationConfigStoreTest.java

@@ -161,6 +161,24 @@ public void testSetInfoWithoutConfigId() {
         assertEquals(updatedConfig.url(), configResult.configs().get(0).url());
     }
 
+    @Test
+    @Transactional
+    public void testSetInfoWithNullConfigId() {
+        String taskId = "task_null_config_id";
+        TaskPushNotificationConfig config = TaskPushNotificationConfig.builder()
+                .url("http://null-id.url/callback")
+                .taskId(taskId)
+                .build();
+
+        TaskPushNotificationConfig result = configStore.setInfo(config);
+
+        assertEquals(taskId, result.id(), "A missing config ID should default to the task ID");
+        ListTaskPushNotificationConfigsResult configResult = configStore.getInfo(
+                new ListTaskPushNotificationConfigsParams(taskId));
+        assertEquals(1, configResult.configs().size());
+        assertEquals(taskId, configResult.configs().get(0).id());
+    }
+
     @Test
     @Transactional
     public void testGetInfoExistingConfig() {

server-common/src/main/java/org/a2aproject/sdk/server/requesthandlers/DefaultRequestHandler.java

@@ -962,7 +962,8 @@ public TaskPushNotificationConfig onGetTaskPushNotificationConfig(
             throw new InternalError("No push notification config found");
         }
 
-        String configId = params.id();
+        String requestedConfigId = params.id();
+        String configId = requestedConfigId == null || requestedConfigId.isEmpty() ? params.taskId() : requestedConfigId;
         return getTaskPushNotificationConfig(listTaskPushNotificationConfigsResult, configId);
     }
 

server-common/src/main/java/org/a2aproject/sdk/server/tasks/InMemoryPushNotificationConfigStore.java

@@ -48,11 +48,13 @@ public InMemoryPushNotificationConfigStore() {
     public TaskPushNotificationConfig setInfo(TaskPushNotificationConfig notificationConfig) {
         String taskId = Assert.checkNotNullParam("taskId", notificationConfig.taskId());
         TaskPushNotificationConfig.Builder builder = TaskPushNotificationConfig.builder(notificationConfig);
-        if (notificationConfig.id().isEmpty()) {
+        String requestedConfigId = notificationConfig.id();
+        boolean configIdIsMissing = requestedConfigId == null || requestedConfigId.isEmpty();
+        String configId = configIdIsMissing ? taskId : requestedConfigId;
+        if (configIdIsMissing) {
             builder.id(taskId);
         }
         TaskPushNotificationConfig config = builder.build();
-        String configId = config.id();
         int maxPerTask = PushNotificationConfigStore.maxPushConfigsPerTask(configProvider);
 
         pushNotificationInfos.compute(taskId, (key, list) -> {

server-common/src/test/java/org/a2aproject/sdk/server/requesthandlers/DefaultRequestHandlerTest.java

@@ -43,6 +43,7 @@
 import org.a2aproject.sdk.spec.CancelTaskParams;
 import org.a2aproject.sdk.spec.Event;
 import org.a2aproject.sdk.spec.EventKind;
+import org.a2aproject.sdk.spec.GetTaskPushNotificationConfigParams;
 import org.a2aproject.sdk.spec.InvalidParamsError;
 import org.a2aproject.sdk.spec.Message;
 import org.a2aproject.sdk.spec.MessageSendConfiguration;
@@ -983,6 +984,26 @@ void testVersionStored_OnCreateTaskPushNotificationConfig() throws Exception {
             "Protocol version should be stored for the push notification config");
     }
 
+    @Test
+    void testGetTaskPushNotificationConfigDefaultsMissingIdToTaskId() throws Exception {
+        String taskId = "get-default-config-id";
+        taskStore.save(Task.builder()
+                .id(taskId)
+                .contextId("ctx-get-default-config-id")
+                .status(new TaskStatus(TaskState.TASK_STATE_WORKING))
+                .build(), false);
+        requestHandler.onCreateTaskPushNotificationConfig(TaskPushNotificationConfig.builder()
+                .taskId(taskId)
+                .url("http://example.com/get-default-config-id")
+                .build(), NULL_CONTEXT);
+
+        TaskPushNotificationConfig result = requestHandler.onGetTaskPushNotificationConfig(
+                new GetTaskPushNotificationConfigParams(taskId), NULL_CONTEXT);
+
+        assertEquals(taskId, result.id());
+        assertEquals("http://example.com/get-default-config-id", result.url());
+    }
+
     /**
      * Verify that onMessageSend stores the protocol version when the request
      * includes a push notification config (new task path).

server-common/src/test/java/org/a2aproject/sdk/server/tasks/InMemoryPushNotificationConfigStoreTest.java

@@ -149,10 +149,10 @@ public void testSetInfoAppendsToExistingConfig() {
     }
 
     @Test
-    public void testSetInfoWithoutConfigId() {
+    public void testSetInfoWithEmptyConfigId() {
         String taskId = "task1";
         TaskPushNotificationConfig initialConfig = TaskPushNotificationConfig.builder()
-                .id("") // No ID set
+                .id("")
                 .url("http://initial.url/callback")
                 .taskId(taskId)
                 .build();
@@ -165,7 +165,7 @@ public void testSetInfoWithoutConfigId() {
         assertEquals(taskId, configResult.configs().get(0).id());
 
         TaskPushNotificationConfig updatedConfig = TaskPushNotificationConfig.builder()
-                .id("") // No ID set
+                .id("")
                 .url("http://initial.url/callback_new")
                 .taskId(taskId)
                 .build();
@@ -178,6 +178,19 @@ public void testSetInfoWithoutConfigId() {
         assertEquals(updatedConfig.url(), configResult.configs().get(0).url());
     }
 
+    @Test
+    public void testSetInfoWithNullConfigId() {
+        String taskId = "task_with_null_config_id";
+        TaskPushNotificationConfig config = TaskPushNotificationConfig.builder()
+                .url("http://initial.url/callback")
+                .taskId(taskId)
+                .build();
+
+        TaskPushNotificationConfig result = configStore.setInfo(config);
+
+        assertEquals(taskId, result.id(), "Config ID should default to taskId when null");
+    }
+
     @Test
     public void testGetInfoExistingConfig() {
         String taskId = "task_get_exist";

spec/src/main/java/org/a2aproject/sdk/spec/GetTaskPushNotificationConfigParams.java

@@ -17,19 +17,27 @@
  * @see TaskPushNotificationConfig for the returned configuration structure
  * @see <a href="https://a2a-protocol.org/latest/">A2A Protocol Specification</a>
  */
-public record GetTaskPushNotificationConfigParams(String taskId, String id, @Nullable String tenant) {
+public record GetTaskPushNotificationConfigParams(String taskId, @Nullable String id, @Nullable String tenant) {
 
     /**
      * Compact constructor that validates required fields.
      *
      * @param taskId the taskId parameter (see class-level JavaDoc)
      * @param id the id parameter (see class-level JavaDoc)
      * @param tenant the tenant parameter (see class-level JavaDoc)
-     * @throws IllegalArgumentException if taskId or tenant is null
+     * @throws IllegalArgumentException if taskId is null
      */
     public GetTaskPushNotificationConfigParams {
         Assert.checkNotNullParam("taskId", taskId);
-        Assert.checkNotNullParam("id", id);
+    }
+
+    /**
+     * Convenience constructor for retrieving the configuration that uses the task ID as its default ID.
+     *
+     * @param taskId the task identifier (required)
+     */
+    public GetTaskPushNotificationConfigParams(String taskId) {
+        this(taskId, null, null);
     }
 
     /**
@@ -38,7 +46,7 @@ public record GetTaskPushNotificationConfigParams(String taskId, String id, @Nul
      * @param taskId the task identifier (required)
      * @param id optional configuration ID to retrieve
      */
-    public GetTaskPushNotificationConfigParams(String taskId, String id) {
+    public GetTaskPushNotificationConfigParams(String taskId, @Nullable String id) {
         this(taskId, id, null);
     }
 
@@ -82,7 +90,7 @@ public Builder taskId(String taskId) {
          * @param id the configuration ID
          * @return this builder for method chaining
          */
-        public Builder id(String id) {
+        public Builder id(@Nullable String id) {
             this.id = id;
             return this;
         }
@@ -106,7 +114,7 @@ public Builder tenant(@Nullable String tenant) {
         public GetTaskPushNotificationConfigParams build() {
             return new GetTaskPushNotificationConfigParams(
                     Assert.checkNotNullParam("taskId", taskId),
-                    Assert.checkNotNullParam("id", id),
+                    id,
                     tenant);
         }
     }

spec/src/main/java/org/a2aproject/sdk/spec/TaskPushNotificationConfig.java

@@ -20,7 +20,8 @@
  * Used for managing task-specific push notification settings via the push notification
  * management methods ({@code tasks/pushNotificationConfig/set}, {@code tasks/pushNotificationConfig/get}, etc.).
  *
- * @param id unique identifier (e.g. UUID) for this push notification configuration
+ * @param id optional unique identifier (e.g. UUID) for this push notification configuration.
+ *        When omitted while creating a configuration, the server assigns one.
  * @param taskId the unique identifier of the task to receive push notifications for
  * @param url the HTTP/HTTPS endpoint URL to receive push notifications (required)
  * @param token optional bearer token for simple authentication
@@ -30,22 +31,21 @@
  * @see MessageSendConfiguration for configuring push notifications on message send
  * @see <a href="https://a2a-protocol.org/latest/">A2A Protocol Specification</a>
  */
-public record TaskPushNotificationConfig(String id, @Nullable String taskId, String url, @Nullable String token,
+public record TaskPushNotificationConfig(@Nullable String id, @Nullable String taskId, String url, @Nullable String token,
         @Nullable AuthenticationInfo authentication, @Nullable String tenant) {
 
     /**
      * Compact constructor for validation.
      * Validates that required parameters are not null.
      *
-     * @param id the configuration identifier
+     * @param id the optional configuration identifier
      * @param taskId the task identifier
      * @param url the notification endpoint URL
      * @param token optional bearer token
      * @param authentication optional authentication info
      * @param tenant the tenant identifier
      */
     public TaskPushNotificationConfig {
-        Assert.checkNotNullParam("id", id);
         Assert.checkNotNullParam("url", url);
     }
 
@@ -103,10 +103,10 @@ private Builder(TaskPushNotificationConfig config) {
         /**
          * Sets the configuration identifier.
          *
-         * @param id the configuration ID
+         * @param id the optional configuration ID
          * @return this builder
          */
-        public Builder id(String id) {
+        public Builder id(@Nullable String id) {
             this.id = id;
             return this;
         }
@@ -170,11 +170,11 @@ public Builder tenant(String tenant) {
          * Builds the {@link TaskPushNotificationConfig}.
          *
          * @return a new push notification configuration
-         * @throws IllegalArgumentException if id or url is null
+         * @throws IllegalArgumentException if url is null
          */
         public TaskPushNotificationConfig build() {
             return new TaskPushNotificationConfig(
-                    Assert.checkNotNullParam("id", id),
+                    id,
                     taskId,
                     Assert.checkNotNullParam("url", url),
                     token,

spec/src/test/java/org/a2aproject/sdk/spec/GetTaskPushNotificationConfigParamsTest.java

@@ -0,0 +1,26 @@
+package org.a2aproject.sdk.spec;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class GetTaskPushNotificationConfigParamsTest {
+
+    @Test
+    void testConstructionAllowsOmittedConfigurationId() {
+        GetTaskPushNotificationConfigParams params = new GetTaskPushNotificationConfigParams("task-1");
+
+        assertEquals("task-1", params.taskId());
+        assertNull(params.id());
+    }
+
+    @Test
+    void testBuilderAllowsOmittedConfigurationId() {
+        GetTaskPushNotificationConfigParams params = GetTaskPushNotificationConfigParams.builder()
+                .taskId("task-1")
+                .build();
+
+        assertNull(params.id());
+    }
+}

spec/src/test/java/org/a2aproject/sdk/spec/TaskPushNotificationConfigTest.java

@@ -0,0 +1,20 @@
+package org.a2aproject.sdk.spec;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+class TaskPushNotificationConfigTest {
+
+    @Test
+    void builderAllowsAnOmittedConfigurationId() {
+        TaskPushNotificationConfig config = TaskPushNotificationConfig.builder()
+                .taskId("task-123")
+                .url("https://example.com/callback")
+                .build();
+
+        assertNull(config.id());
+        assertEquals("task-123", config.taskId());
+    }
+}