From 2c46514527c00b53194a955ae397e951b698775f Mon Sep 17 00:00:00 2001
From: Daria Wieliczko <wieliczko@google.com>
Date: Fri, 17 Apr 2026 18:16:50 +0000
Subject: [PATCH] fix(tck): resolve capability test failures for extensions and
 push notifications

- Default `extensions` to an empty list in `AgentCapabilities` to ensure it serializes as an array, fixing `test_capabilities_structure`.
- Save `pushNotificationConfig` in `onMessageSend` for non-streaming messages, fixing `test_send_message_with_push_notification_config`
---
 .../server/requesthandlers/DefaultRequestHandler.java    | 9 +++++++--
 spec/src/main/java/io/a2a/spec/AgentCapabilities.java    | 4 ++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/server-common/src/main/java/io/a2a/server/requesthandlers/DefaultRequestHandler.java b/server-common/src/main/java/io/a2a/server/requesthandlers/DefaultRequestHandler.java
index 577e571c9..67c474a9c 100644
--- a/server-common/src/main/java/io/a2a/server/requesthandlers/DefaultRequestHandler.java
+++ b/server-common/src/main/java/io/a2a/server/requesthandlers/DefaultRequestHandler.java
@@ -326,8 +326,13 @@ public EventKind onMessageSend(MessageSendParams params, ServerCallContext conte
                     }
                 }
             }
-            if (kind instanceof Task taskResult && !taskId.equals(taskResult.getId())) {
-                throw new InternalError("Task ID mismatch in agent response");
+            if (kind instanceof Task taskResult) {
+                if (shouldAddPushInfo(params)) {
+                    pushConfigStore.setInfo(taskResult.getId(), params.configuration().pushNotificationConfig());
+                }
+                if (taskId != null && !taskId.equals(taskResult.getId())) {
+                    throw new InternalError("Task ID mismatch in agent response");
+                }
             }
 
             // Send push notification after initial return (for both blocking and non-blocking)
diff --git a/spec/src/main/java/io/a2a/spec/AgentCapabilities.java b/spec/src/main/java/io/a2a/spec/AgentCapabilities.java
index 2b4fbcee5..3abacf733 100644
--- a/spec/src/main/java/io/a2a/spec/AgentCapabilities.java
+++ b/spec/src/main/java/io/a2a/spec/AgentCapabilities.java
@@ -13,6 +13,10 @@
 public record AgentCapabilities(boolean streaming, boolean pushNotifications, boolean stateTransitionHistory,
                                 List<AgentExtension> extensions) {
 
+    public AgentCapabilities {
+        extensions = extensions == null ? List.of() : extensions;
+    }
+
     public static class Builder {
 
         private boolean streaming;