diff --git a/changelogs/client_server/newsfragments/1463.clarification b/changelogs/client_server/newsfragments/1463.clarification
new file mode 100644
index 00000000..1cf431ee
--- /dev/null
+++ b/changelogs/client_server/newsfragments/1463.clarification
@@ -0,0 +1 @@
+Clarify that servers should enforce a default `limit` on a filter if one is not specified.
diff --git a/data/api/client-server/definitions/event_filter.yaml b/data/api/client-server/definitions/event_filter.yaml
index b6888693..d03c85da 100644
--- a/data/api/client-server/definitions/event_filter.yaml
+++ b/data/api/client-server/definitions/event_filter.yaml
@@ -14,7 +14,11 @@
 title: EventFilter
 properties:
   limit:
-    description: The maximum number of events to return.
+    description: |
+      The maximum number of events to return, must be an integer greater than 0.
+
+      Servers should apply a default value, and impose a maximum value to avoid
+      resource exhaustion.
     type: integer
   not_senders:
     description: A list of sender IDs to exclude. If this list is absent then no senders