diff --git a/src/locations/building.jsonnet b/src/locations/building.jsonnet
index e04962e..6c82228 100644
--- a/src/locations/building.jsonnet
+++ b/src/locations/building.jsonnet
@@ -6,7 +6,9 @@ entity
   '$id': 'https://picc.app/schemata/v0.1-dev/locations/building',
   title: 'Building',
   description: |||
-    A building
+    A building.
+
+    Rooms are optionally defined in-place.
   |||,
 
   properties+: {
@@ -15,14 +17,10 @@ entity
     rooms: {
       type: 'array',
       description: 'Rooms contained in this building.',
-      items: {
-        oneOf: [
-          {
-            '$ref': 'https://picc.app/schemata/v0.1-dev/room',
-          },
-          $.properties.id,
-        ],
-      },
+      items:
+        {
+          '$ref': 'https://picc.app/schemata/v0.1-dev/locations/room',
+        },
     },
   },
 }
diff --git a/src/locations/site.jsonnet b/src/locations/site.jsonnet
index da18780..8552e9f 100644
--- a/src/locations/site.jsonnet
+++ b/src/locations/site.jsonnet
@@ -5,21 +5,19 @@ entity
   '$id': 'https://picc.app/schemata/v0.1-dev/locations/site',
   title: 'Site',
   description: |||
-    A site
+    A site.
+
+    Buildings are optionally defined in-place.
   |||,
 
   properties+: {
     buildings: {
       type: 'array',
       description: 'Buildings at this site.',
-      items: {
-        oneOf: [
-          {
-            '$ref': 'https://picc.app/schemata/v0.1-dev/building',
-          },
-          $.properties.id,
-        ],
-      },
+      items:
+        {
+          '$ref': 'https://picc.app/schemata/v0.1-dev/building',
+        },
     },
   },
 }