diff --git a/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonMessages.java b/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonMessages.java
index e71e6b3b4..f73e9d8ed 100644
--- a/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonMessages.java
+++ b/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonMessages.java
@@ -216,7 +216,7 @@ public class JsonMessages {
              "error": {
                 "code": -32702,
                 "message": "Invalid parameters",
-                "details": {"info": "Hello world"}
+                "data": {"info": "Hello world"}
              }
             }""";
 
diff --git a/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonStreamingMessages.java b/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonStreamingMessages.java
index 7b36552b9..f9c006b2c 100644
--- a/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonStreamingMessages.java
+++ b/client/transport/jsonrpc/src/test/java/org/a2aproject/sdk/client/transport/jsonrpc/JsonStreamingMessages.java
@@ -99,7 +99,7 @@ public class JsonStreamingMessages {
                   "error": {
                     "code": -32602,
                     "message": "Invalid parameters",
-                    "details": {"info": "Missing required field"}
+                    "data": {"info": "Missing required field"}
                   }
              }""";
 
diff --git a/spec-grpc/src/main/java/org/a2aproject/sdk/grpc/utils/JSONRPCUtils.java b/spec-grpc/src/main/java/org/a2aproject/sdk/grpc/utils/JSONRPCUtils.java
index 270fde3a7..db43d92a9 100644
--- a/spec-grpc/src/main/java/org/a2aproject/sdk/grpc/utils/JSONRPCUtils.java
+++ b/spec-grpc/src/main/java/org/a2aproject/sdk/grpc/utils/JSONRPCUtils.java
@@ -392,8 +392,8 @@ private static A2AError processError(JsonObject error) {
         String message = error.has("message") ? error.get("message").getAsString() : null;
         Integer code = error.has("code") ? error.get("code").getAsInt() : null;
         Map<String, Object> details = null;
-        if (error.has("details") && error.get("details").isJsonObject()) {
-            details =GSON.fromJson(error.get("details"), Map.class);
+        if (error.has("data") && error.get("data").isJsonObject()) {
+            details =GSON.fromJson(error.get("data"), Map.class);
         }
         if (code != null) {
             A2AErrorCodes errorCode = A2AErrorCodes.fromCode(code);
@@ -606,7 +606,7 @@ public static String toJsonRPCErrorResponse(Object requestId, A2AError error) {
             output.name("code").value(error.getCode());
             output.name("message").value(error.getMessage());
             if (!error.getDetails().isEmpty()) {
-                output.name("details");
+                output.name("data");
                 GSON.toJson(error.getDetails(), Map.class, output);
             }
             output.endObject();