GAE - Online admin console
You can use remote shell, that is on your app engine sdk.
For example
~/bin/google_appengine/remote_api_shell.py -s your-app-identifier.appspot.com s~your-app-identifier
When you are inside the shell, you will have the db module enabled. in order to use your models, you will have to import them.
Is there some way I can run custom python code on my google appengine app online? Is there a python console somewhere that I can use? I've seen vague references here and there, but nothing concrete.