City officials are wary. Union leaders are excited by promised wage boosts. Developers are enticed by extended tax breaks.

But no one knows what the return of the troubled 421a housing program, now called Affordable New York, will mean to neighborhoods that would host new projects and residents desperate for real affordable housing.

The new program provides developers with a 35-year tax break if they set aside a percentage of the units they build as “affordable” — a broad definition that covers those earning between 40 percent and 130 percent of area median income, or up to $117,780 for a family of four.

Even with new rules, the program might do little to create truly affordable housing. To evaluate its success, city and state officials need a comprehensive oversight strategy. Instead, it’s piecemeal, with no one in charge.

The city comptroller will oversee worker wages during construction. The city’s Housing Preservation & Development department has authority over eligibility and other parts of the program. The city’s Department of Finance calculates the tax breaks. And, to complete the circle, the city comptroller can audit those departments when necessary.

Although the State Legislature approved the new 421a, officials in Albany say oversight is up to the city. So, despite knowing the program was a pricey boondoggle in the past, the new version adds no accountability. It needs more to make sure developers comply with the law, maximize affordability and keep rents at required levels.

Developers are already restarting projects, like the 2,400-unit Hallets Point in Astoria, so they can take advantage of 421a. This is a perfect opportunity for state and city officials to use projects like Hallets Point as examples. Evaluate them from beginning to end and determine who benefits, what developers are giving and getting, how much the city is losing in tax dollars, and whether affordability is being achieved. Follow what happens later on to make sure affordability is maintained when renters move or projects are sold. Develop a record of success — or tell us if Affordable New York fails. Only then can we know whether the new 421a is any better than the old one.