When military and civilian experts on peacekeeping started meeting in Geneva in the spring of 2022, they insisted on discretion. Their topic was sensitive: how to implement a future cease-fire in Ukraine.

Last week, that group of experts went public for the first time, publishing a 31-page paper that delves into the technical details of how a cease-fire along a more than 700-mile front line could be monitored and enforced. The paper was shared last month via another confidential channel: a recurring meeting in Geneva between American, Russian and Ukrainian foreign-policy experts who are close to their governments.

The paper, one of the most detailed templates for a Ukraine cease-fire to have been published, is a sign of how quickly the topic of planning for a cease-fire has gone from a controversial and theoretical exercise to an urgent and practical issue.

France and Britain have raised the prospect of sending thousands of their own troops to Ukraine after the fighting stops, though there is little clarity about what that force’s responsibility would be. Russia has shown no sign of agreeing to such a force, while President Trump has offered few assurances of any American backup to it.

“One of the biggest cease-fire monitoring operations ever will be coming at us very quickly, with no planning thus far of what that would look like,” said Walter Kemp, a specialist on European security who drafted the Geneva group’s document.

Mr. Trump has said he wants a quick settlement and in the last week has taken steps aimed at forcing Ukraine to the negotiating table: Suspending military aid and the sharing of intelligence to Ukraine, while repeatedly saying, with no evidence, that he thinks President Vladimir V. Putin of Russia wants to make a deal.