Why I still need to unlock ssh key

I'm very confused. Every manual I read the last 15 minutes tells me this should work but it does not:

$ ssh-agent -s
SSH_AUTH_SOCK=/tmp/ssh-syXn9Tk09V9P/agent.16332; export SSH_AUTH_SOCK;
SSH_AGENT_PID=16333; export SSH_AGENT_PID;
echo Agent pid 16333;
$ eval `ssh-agent -s`
Agent pid 16362
$ ssh-add -l
The agent has no identities.
$ ssh-add .ssh/user@server.de.key
Enter passphrase for .ssh/user@server.de.key: 
Identity added: .ssh/user@server.de.key (.ssh/user@server.de.key)
$ ssh user@server.de
Enter passphrase for key '/home/iras/.ssh/user@server.de.key':

In the ssh config there is an entry for server.de with another identity.