Mayor Nutter was right to demand that the Philadelphia School District open its financial books to greater scrutiny if it expects to get more cash from City Hall. In fact, what took so long?

For years, the city has lacked adequate input into how the School District operates and spends taxpayer dollars even though about a third of its annual funding comes from the city.

But the School Reform Commission on Wednesday voted unanimously to accede to Nutter's wishes by approving an "educational accountability" agreement with the city.

Nutter, School Reform Commission Chairman Robert Archie, and state Education Secretary Ron Tomalis signed the agreement Thursday, laying the groundwork for a free flow of information and coordination.

Thursday's kumbaya moment came after Superintendent Arlene C. Ackerman had left the mayor with egg on his face last week. While Nutter was pleading with City Council to raise taxes to save bus transportation and full-day kindergarten, Ackerman was working out deals with the state and SEPTA to fund both programs.

There was no good excuse for having left the mayor out of the loop. His response was a nine-page letter in which he took an unusual, but needed, public step of demanding more accountability from the district.

By next week, the district must provide information on funding sources, program costs, salaries, benefits, pensions, outside labor contracts, audits, and any other data that "detail the full and complete financial condition of the School District."

Faced with a $629 million budget gap, the district had little choice but to accept Nutter's demands in exchange for additional funding to pull out of a deficit spiral.

The city will also have more say in determining the fate of threatened programs and in setting education priorities for the district.

That's good, but it again calls into question the past performance of the SRC, which, with two of its five members appointed by the mayor, should be more representative of the city's interests.

Nutter has pledged $75 million to $110 million in new funds from the city to help the schools.

Council has been reluctant to support a rescue that size without a better understanding of the district's finances and how additional funding would be spent. Nutter has proposed tax hikes as a solution to the budget deficit, but Council should look elsewhere before again going down that road.

Ackerman came up with a way to temporarily save full-day kindergarten; she should play all her cards before asking Philadelphians to take another tax hit or union employees to make more contract concessions. There should be no hidden deals. The public needs assurance that every penny spent by the School District is a penny spent wisely.