The city’s principals and assistant principals will receive raises, retroactive pay and new incentives to work in low-performing schools under a tentative contract agreement between the city and Council of School Supervisors and Administrators, that will also offer bonuses to principals for short-term takeovers of struggling schools.

A nine-year, $891 million deal would increase pay by 18 percent by 2019 through raises paid out in seven increments, city officials said. It also includes an agreement to find nearly $150 million in savings on health care plans. CSA members would see an immediate 2 percent raise, but most would not come until 2017 and 2018, a cost-saving measure to which other municipal unions, including the United Federation of Teachers, have also agreed.

In addition, more than 2,000 CSA members who had been promoted from teachers to administrators since 2009 will receive $120 million in backpay and raises that the city originally argued they were not eligible for.  The issue became a sticking point in negotiations and both sides entered mediation to settle the dispute two weeks ago.

In the resulting agreement, the city and the union will split the $120 million cost of those payments. The city will pay $72 million, and the rest will come in savings by delaying when CSA members will receive some of their raises.

(See the scheduled dates for when principals and APs will see each raise and retroactive payments)

“I don’t recall anything like this,” said Robert Linn, the city’s chief labor negotiator, of the cost-sharing maneuver.

Members would also receive a $1,000 cash bonus once the deal is ratified.

Like the United Federation of Teachers deal struck earlier this year, the contract also creates new positions that provide additional pay for assistant principals and principals who take on additional responsibilities.

Mayor Bill de Blasio said that he intended to use the positions to incentivize administrators with proven experience in improving low-performing schools to work in struggling schools, including ones that are part of his Renewal Schools program. Those “ambassador” principals and assistant principals, brought in to fill vacancies or take struggling schools, will receive $15,000 and $10,000 and have the option to return to their original schools after one year.

That arrangement mirrors the one offered to Michael Wiltshire, the new principal of Boys and Girls High School, earlier this year.  It is also similar to the executive principal program introduced in 2008 as a way to draw seasoned principals to ailing schools, though that strategy had largely been abandoned just by 2010. (The executive principal role also required a longer commitment from school leaders.)

The new contract agreement also creates the roles of “master” and “model” principals and assistant principals, who will get raises in return for mentoring other school leaders.

“It’s a pretty common-sense idea,” de Blasio said at the union’s leadership conference on Saturday, where the deal was first announced.