Sen. Patty Murray (D-Wash.) (Elaine Thompson/Associated Press)

The Senate has agreed to require the Office of Management and Budget and the Pentagon to detail how federal agencies will implement a deep automatic budget cut set to slice domestic and defense programs in January, as Congress begins to brace for the dramatic reductions known as the “sequester.”

The chamber agreed to request the reports in an amendment to the nearly $1 trillion farm bill and the voice vote came after a compromise between Republicans — who had wanted to hear more about defense cuts — and Democrats, who asked for details about domestic reductions as well.

The Senate approved the farm bill Thursday on a 64 to 35 vote, after weeks of bipartisan work.

The goal is to require federal agencies to detail how damaging the automatic cut will be to the military and key domestic programs — a report that might spur Congressional action on a deal to avert the across-the-board budget whack.

It is the latest step taken by Congress as members of both parties warily eye a series of consequential fiscal decisions they must make by the end of the year, determining how to deal with the budget cuts, as well as the expiration of tax cuts that would raise taxes for virtually every citizen.

As part of last summer’s deal to raise the debt ceiling, Congress agreed the budget would be automatically cut by $1.2 trillion over 10 years if a special supercommittee failed to come up with a deal to achieve the same level of deficit reduction in a more targeted manner.

The cuts were to be split evenly between defense and domestic programs, so as to prove painful to both parties and compel agreement.

Republicans have been raising alarms about the possible harm to national security of allowing the defense cuts to proceed. They have been joined by defense contractors who have warned of up to a million job losses.

In the House, Republicans pressed ahead with a bill that would have replaced the defense cuts with even deeper cuts to domestic programs. Democrats believe that approach sacrifices the social safety network to spare the military and breaks last summer’s deal, and the House bill will not move ahead in the Senate.

Sen. John McCain (R-Ariz.) has vowed to amend every bill that passes the Senate in coming weeks with language requiring the Pentagon to detail impacts of the defense cuts.

“It’s absolutely necessary. The American people need to know the effects of sequestration,” he said.

But Democratic Sen. Patty Murray (D-Wash.), who chaired the supercommittee, countered with a measure that would require a report on both domestic and defense cuts. Democrats believe the sequester remains a powerful leverage to compel an agreement on deficit reduction after the election.

They have insisted the only scenario in which they would agree to put the automatic cuts aside would be if Republicans agree to a deal to cut the debt that would both raise tax revenues and cut spending.

Under the compromise, the Defense Department would report back on August 15. The Office of Management and Budget would report back 30 days after the enactment of the bill and President Obama would be required to provide a global look at the government 30 days later.

“I remain hopeful we can work together to get to the balanced and bipartisan deal required to replace the automatic cuts responsibly and fairly,” Murray told colleagues Thursday. “But as we work toward that, we should know exactly how the Administration would enact sequestration if we don’t get a deal.”