The agreement is exactly what has been in the air since Rohani's charm offensive in New York. There is no reason why it could not have been formalized in the first round of the Geneva talks. The only explanation for the delay is that it was made to wait until the Saudis and the Iranians resolved their differences.
U.S. deploys more Patriot missiles in South Korea (AP)
from the article: Arab media reactions to Iran deal reflect regional divisions