diff --git a/sql/json/entity.lister_metadata.schema.json b/sql/json/entity.lister_metadata.schema.json
index d1f44046..5db15a29 100644
--- a/sql/json/entity.lister_metadata.schema.json
+++ b/sql/json/entity.lister_metadata.schema.json
@@ -1,4 +1,9 @@
 {
     "$schema": "http://json-schema.org/schema#",
-    "id": "http://softwareheritage.org/schemas/entity.lister_metadata.schema.json"
+    "id": "http://softwareheritage.org/schemas/entity.lister_metadata.schema.json",
+
+    "type": "object",
+    "properties": {
+        "lister": {"type": "string"}
+    }
 }
diff --git a/sql/json/entity_history.lister_metadata.schema.json b/sql/json/entity_history.lister_metadata.schema.json
index caec892c..5db15a29 100644
--- a/sql/json/entity_history.lister_metadata.schema.json
+++ b/sql/json/entity_history.lister_metadata.schema.json
@@ -1,4 +1,9 @@
 {
     "$schema": "http://json-schema.org/schema#",
-    "id": "http://softwareheritage.org/schemas/entity_history.lister_metadata.schema.json"
+    "id": "http://softwareheritage.org/schemas/entity.lister_metadata.schema.json",
+
+    "type": "object",
+    "properties": {
+        "lister": {"type": "string"}
+    }
 }