title: Google App Engine Cloud Endpoints OAuth 2.0 Scopes
body: <p>I'm trying to follow the following guide:
  <a href="https://developers.google.com/appengine/docs/java/endpoints/auth" rel="nofollow">https://developers.google.com/appengine/docs/java/endpoints/auth</a></p>
  
  <p>I've followed the steps and added the client id and the User parameter which when null I throw an OAuthRequestException exception.</p>
  
  <p>When I deploy to Google and access the API using the API Explorer I get the expected unauthorised exception when accessing the API without OAuth. Great everything works so far! </p>
  
  <p>It suggests to switch the OAuth 2.0 toggle. I do this and I get a message saying:</p>
  
  <p><em>*</em> API does not declare any scopes. You can manually add scopes using the box below</p>
  
  <p>the message also directs me to:
  <a href="http://code.google.com/apis/accounts/docs/OAuth2.html" rel="nofollow">http://code.google.com/apis/accounts/docs/OAuth2.html</a>
  to learn more about Scopes.</p>
  
  <p>But there is very limited information about scopes on that suggested page. I'm new to OAuth and despite searching Google and StackOverflow 
  I'm not sure what a scope is?
  How do I declare on in the API?
  When I manually add something to the API explorer prompt I get an error message saying it is an invalid_scope. So what is a valid scope?</p>