diff --git a/docs/manual/_ext/webapidocs.py b/docs/manual/_ext/webapidocs.py
index 16905e426bd64db999083e2d9d2b7e05415b453a..0df49980c009d280f4eebc6ba7ccfb4e67592be0 100644
--- a/docs/manual/_ext/webapidocs.py
+++ b/docs/manual/_ext/webapidocs.py
@@ -73,6 +73,10 @@ class DummyRequest(HttpRequest):
         self.path = ''
         self.user = User.objects.all()[0]
 
+        # This is normally set internally by Djblets, but we don't
+        # go through the standard __call__ flow.
+        self._djblets_webapi_object_cache = {}
+
     def build_absolute_uri(self, location=None):
         if not self.path and not location:
             return '/api/'