diff --git a/CHANGES b/CHANGES
index 8f523e6927..dd0e70e345 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,16 @@
+8.0.0-dev.447 | 2025-06-22 15:49:11 +0200
+
+  * GH-4594: Align WebSocket error in cluster with one in Broker (Benjamin Bannier, Corelight)
+
+    The schema of cluster WebSocket error messages deviated from the
+    existing one in Broker which breaks seamless migration from the Broker
+    WebSocket bindings.
+
+    This patch aligns the serialization in cluster with the one in Broker.
+    This is technically a breaking change of the cluster schema, but since
+    it never worked like documented and is still experimental this is
+    probably fine.
+
 8.0.0-dev.445 | 2025-06-22 15:48:21 +0200
 
   * GH-4571: broker: Handle Broker::publish() with non Broker::Event (Arne Welzel, Corelight)
diff --git a/VERSION b/VERSION
index 54d53db5dd..67aaef6c49 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.0.0-dev.445
+8.0.0-dev.447
diff --git a/src/cluster/websocket/WebSocket.cc b/src/cluster/websocket/WebSocket.cc
index d9797aa0ed..e66f0854b2 100644
--- a/src/cluster/websocket/WebSocket.cc
+++ b/src/cluster/websocket/WebSocket.cc
@@ -144,7 +144,7 @@ WebSocketClient::SendInfo WebSocketClient::SendError(std::string_view tag, std::
     *out++ = ',';
     broker::format::json::v1::append_field("code", tag, out);
     *out++ = ',';
-    broker::format::json::v1::append_field("message", message, out);
+    broker::format::json::v1::append_field("context", message, out);
     *out++ = '}';
     return SendText(buf);
 }
diff --git a/testing/btest/Baseline/cluster.websocket.bad-event-args/..client.out b/testing/btest/Baseline/cluster.websocket.bad-event-args/..client.out
index f9e01b1fea..a325fb3fae 100644
--- a/testing/btest/Baseline/cluster.websocket.bad-event-args/..client.out
+++ b/testing/btest/Baseline/cluster.websocket.bad-event-args/..client.out
@@ -1,7 +1,7 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 Connected!
-err1 {'type': 'error', 'code': 'deserialization_failed', 'message': 'failed to decode JSON object'}
-err2 {'type': 'error', 'code': 'deserialization_failed', 'message': 'failed to create Zeek event'}
-err3 {'type': 'error', 'code': 'deserialization_failed', 'message': 'failed to create Zeek event'}
+err1 {'type': 'error', 'code': 'deserialization_failed', 'context': 'failed to decode JSON object'}
+err2 {'type': 'error', 'code': 'deserialization_failed', 'context': 'failed to create Zeek event'}
+err3 {'type': 'error', 'code': 'deserialization_failed', 'context': 'failed to create Zeek event'}
 pong {'@data-type': 'string', 'data': 'pong'} {'@data-type': 'vector', 'data': [{'@data-type': 'string', 'data': 'Hello'}, {'@data-type': 'count', 'data': 42}]}
-err4 {'type': 'error', 'code': 'deserialization_failed', 'message': 'failed to decode JSON object'}
+err4 {'type': 'error', 'code': 'deserialization_failed', 'context': 'failed to decode JSON object'}
diff --git a/testing/btest/Baseline/cluster.websocket.bad-subscriptions/..client.out b/testing/btest/Baseline/cluster.websocket.bad-subscriptions/..client.out
index 228c6687c9..223dec6314 100644
--- a/testing/btest/Baseline/cluster.websocket.bad-subscriptions/..client.out
+++ b/testing/btest/Baseline/cluster.websocket.bad-subscriptions/..client.out
@@ -1,5 +1,5 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-broken array response {'type': 'error', 'code': 'deserialization_failed', 'message': 'subscriptions not an array'}
-non string error {'type': 'error', 'code': 'deserialization_failed', 'message': 'individual subscription not a string'}
-mix error {'type': 'error', 'code': 'deserialization_failed', 'message': 'individual subscription not a string'}
+broken array response {'type': 'error', 'code': 'deserialization_failed', 'context': 'subscriptions not an array'}
+non string error {'type': 'error', 'code': 'deserialization_failed', 'context': 'individual subscription not a string'}
+mix error {'type': 'error', 'code': 'deserialization_failed', 'context': 'individual subscription not a string'}
 ack True
diff --git a/testing/btest/Baseline/cluster.websocket.bad-url/..client.out b/testing/btest/Baseline/cluster.websocket.bad-url/..client.out
index 360a9982a2..a168cba450 100644
--- a/testing/btest/Baseline/cluster.websocket.bad-url/..client.out
+++ b/testing/btest/Baseline/cluster.websocket.bad-url/..client.out
@@ -1,4 +1,4 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 Connected ws_good!
 Connected ws_bad!
-Error for ws_bad {'type': 'error', 'code': 'invalid_uri', 'message': 'Invalid URI - use /v1/messages/json'}
+Error for ws_bad {'type': 'error', 'code': 'invalid_uri', 'context': 'Invalid URI - use /v1/messages/json'}