If you create a site with an assignment tool and no gradebook tool, the following RESTful feed will crash:

/direct/assignment/site/<SITE-ID>.json

Workaround is to add Gradebook tool to site.

RuntimeException:Fatal error trying to execute custom action method: site:list:getAssignmentsForSite:
java.lang.RuntimeException: Fatal error trying to execute custom action method: site:list:getAssignmentsForSite
at org.sakaiproject.entitybroker.rest.EntityActionsManager.handleCustomActionExecution(EntityActionsManager.java:231)
at org.sakaiproject.entitybroker.rest.EntityActionsManager.handleCustomActionRequest(EntityActionsManager.java:96)
at org.sakaiproject.entitybroker.rest.EntityHandlerImpl.handleEntityAccess(EntityHandlerImpl.java:403)

Caused by: org.sakaiproject.service.gradebook.shared.GradebookNotFoundException: Could not find gradebook uid=e32634cb-4132-4694-82a3-18d6df9c0411
at org.sakaiproject.component.gradebook.BaseHibernateManager.getGradebook(BaseHibernateManager.java:97)
at org.sakaiproject.component.gradebook.GradebookExternalAssessmentServiceImpl.getExternalAssignment(GradebookExternalAssessmentServiceImpl.java:290)
at org.sakaiproject.component.gradebook.GradebookExternalAssessmentServiceImpl.isExternalAssignmentDefined(GradebookExternalAssessmentServiceImpl.java:530)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)