VATICAN CITY — The Vatican on Tuesday released the first details of Pope Francis’ upcoming high-stakes sex-abuse prevention summit, making clear that bishops attending the gathering must reach out to victims before they get to Rome and that accountability is very much on the agenda.

Organizers of the Feb. 21-24 summit warned participants in a letter that failure to address the scandal now threatens the very credibility of the Catholic Church around the world.

As a first step, they urged the 130 presidents of national bishops’ conferences attending the summit to meet with survivors in their home countries “to learn firsthand the suffering that they have endured.”

Francis invited the church leaders to the meeting to develop a comprehensive response to what has become the gravest threat to his papacy, as the abuse and cover-up scandal erupted anew in the U.S., Chile and elsewhere this year.

Survivors have been dubious about what the meeting can accomplish, given the limited time, the varied experiences and needs of national churches and the fact that the problem has already been known for years.

“They’re just now getting around to this? Good Lord, where’ve you been?” marveled Barbara Dorris, a survivor of abuse who has been a longtime outspoken advocate for victims.