In a closed urban fantasy, the magical world is secret and no one knows about it. In an open urban fantasy, everyone knows about it. So with a closed fantasy, you have to figure out how the world keeps itself secret, and with an open one, you have to figure out how knowledge of magic has altered the world we know.
Cassandra ClareA very magnanimous statement, Gideon,” said Magnus. “I’m Gabriel.” Magnus waved a hand. “All Lightwoods look the same to me.
Cassandra ClareThere was no Jace Wayland more real than the one he saw in her eyes when she looked at him.
Cassandra ClareI can trust you, Jessie, but you're clearly not well enough to go. Which is unfortunate, since Aloysius always had a weakness for a pretty face." "Even more reason why I should go," said Will.
Cassandra ClareChildren of the Nephilim," Magnus said. "Well, well. I don't recall inviting you." Isabelle took out her invitation and waved it like a white flag. "I have an invitation. These"--she indicated the rest of the group with a grand wave of her arm--"are my friends." Magnus plucked the invitation out of her hand and looked at it with fastidious distaste. "I must have been drunk," he said. He threw the door open. "Come in. And try not to murder any of my guests." Jace looked at him, "Even if one of them spills something on my new shoes?" "Even then." - 219
Cassandra Clare