The breakthrough capped more than a year of negotiations begun in Norway and pressed home over the past 10 days in Dublin. Nations are expected to sign the document in December in the Norwegian capital, Oslo.
The draft treaty - obtained by The Associated Press as talks wound down with no major issues outstanding - declares that a signatory nation "undertakes never under any circumstances to use cluster munitions" nor "develop, produce, otherwise acquire, stockpile, retain or transfer to anyone, directly or indirectly, cluster munitions."
Ireland and other lead sponsors plan to unveil the treaty Friday after its translation into several languages.
The draft treaty contains two key concessions sought by the United States - a nation that shunned the talks but nonetheless cast the biggest shadow over deliberations.
The pact would allow countries that sign the treaty to keep cooperating militarily with those that do not. Earlier drafts of the treaty sought to prohibit such cooperation, an idea fought by the United States and its NATO allies on the grounds that it would complicate joint peacekeeping work.
The treaty's detailed definition of what a cluster bomb is - and isn't - also leaves the door open for signatories to develop a future generation of smaller cluster bombs that pick targets more precisely and contain self-destruct technology.
The document specifies that future designs will be permitted if each bomb, shell or rocket contains fewer than 10 "bomblets" inside. In addition, each bomblet must weigh more than 4 kilograms (8.8 pounds); contain targeting technology designed to single out a target; and have inbuilt security measures that defuse any duds.
The latter measure is designed to ensure that future cluster bombs do not kill or maim as many civilians, tens of thousands of whom have stumbled across unexploded bomblets and accidentally triggered them.
The treaty says any future cluster bomb must meet all of those requirements "to avoid indiscriminate area effects and the risks posed by unexploded submunitions."
Campaigners against the use of cluster bombs expressed joy at the treaty's commitment requiring signatories to fund projects that clear up unexploded ordnance and support families and communities victimized by cluster bombs. But they also expressed misgivings that the treaty conceded too many loopholes.
"We do feel some disappointment, because we have the feeling we missed the chance to make clear that (treaty supporters) should not assist other counties that are using cluster munitions," said Hildegarde Vansintjan, spokeswoman for Handicap International.
Her non-governmental organization was involved in the negotiations. It has spent more than a decade helping people who have lost limbs, sight or other faculties because of cluster-bomb explosions.