OLYMPIA — Shortly before dawn Wednesday, lawmakers reached an “agreement in principle” on a new state budget they say will satisfy a Supreme Court mandate on education funding and avert an unprecedented government shutdown.

They reportedly reached consensus around 4 a.m. and notified Gov. Jay Inslee a couple of hours later. His office announced the deal first in a press release noting the agreement covers “spending and resource levels.”

But the content of the two-year spending plan remained largely a mystery throughout the day as House and Senate leaders refused to reveal details until they are shared with lawmakers Thursday morning.

That could happen as early as 10 a.m., when the Democratic and Republican caucuses in each chamber are slated to meet, legislative leaders said.

If it does, then around noon they expect the public to get a look at some of the blueprint of how the state will spend an amount in the neighborhood of $44 billion. The single biggest chunk will be for the public school system.

The actual budget might not be completely written until Friday. That won’t leave much time for legislators to digest details before voting on it. Lawmakers must make sure it is delivered to Inslee for signing before midnight to assure no interruption of government services.

“This is not an ideal situation,” said House Majority Leader Pat Sullivan, D-Covington, who said they negotiated until 6:30 a.m. Wednesday. “We also want to be sure the budget we put together is right.”

First-year Sen. Guy Palumbo, D-Maltby, called the process “very disheartening” and expressed deep concern about not having enough time to vet components with civic leaders and educators he represents in parts of Snohomish County and King County.

Sen. Marko Liias, D-Mukilteo, didn’t express the same degree of worry.

“If we can avoid a government shutdown and give every kid a chance at a great education, I would call that a win,” he said, adding “it sounds like” the deal accomplishes both.

Wednesday’s announcement came on the eighth day of a third special session, the 173rd day of what’s been a legislative marathon.

It is about a day and a half later than in 2015, when the Legislature also reached the brink of a shutdown, said House Minority Leader Dan Kristiansen, R-Snohomish.

Nonetheless, he never fretted about a shuttering of state agencies.

“This is the closest we’ve ever come to one,” he said. It would be “irresponsible for us to allow that to happen.”

When the agreement becomes public, many will look to see how the Democrat-controlled House and Republican-led Senate agreed to amply fund public schools by the court’s Sept. 1, 2018, deadline.

In the regular session, the House passed a $44.6 billion spending plan and the Senate approved a $43.3 billion blueprint. Negotiators for the House met with their counterparts in the Senate, where a coalition of 24 Republicans and one Democrat comprise the majority. They spent the past two months trying to reconcile differences.

The major sticking point has been how the state complies with McCleary. Lawmakers have said they might need to put an additional $2 billion into schools in this budget and another $5 billion in the next to satisfy the court. Most of the money in the next two years is to cover the state’s share of salaries of teachers, staff and administrators, which school districts now pay with their local levies.

An increase in the statewide property tax will be one source of money, Kristiansen said. There will be some alterations to local levies, too, though he declined to say how much. The result will be some people will see their net property taxes go up and others will see theirs go down, Kristiansen said.

On Thursday, lawmakers will receive information for each school district they represent showing how the changes affect property tax rates within those districts, as well as how much more state money will flow to the schools, he said.

“Everybody will see a net increase in terms of how much state money is going to districts,” Kristiansen said. “We believe we’re really going to solve the problem.”

Sullivan provided one other key detail Wednesday: The property tax increase will not be subject to voter approval as Senate Republicans proposed.

Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com. Twitter: @dospueblos.