The centerpiece is a shift in how developers satisfy the city's inclusionary zoning requirement, which since 2000 has obligated market-rate projects to help fund income-restricted homes. Under Mayor Michelle Wu's 2022 update, which took effect in 2024, projects of seven or more units must set aside 17 to 20 percent of units as income-restricted, either on site or elsewhere in the city, up from 13 percent previously.

Some builders have blamed that increase, and the mayor, for worsening an already difficult climate. City officials counter that the policy has generated more than $200 million for income-restricted housing, translating to over 5,000 units.

The new proposal would let developers pay their affordable housing contribution in seven installments over seven years rather than two payments in a shorter window, easing the cash crunch at the front end of a project. It would also raise the inclusionary zoning threshold from seven units to 10 for a two-year trial period, exempting builders of seven-to-nine-unit projects from the requirement before the change gets a fresh review.

"Our analysis shows that these changes will meaningfully increase the feasibility of some projects without sacrificing our core goals of affordability," said Sheila Dillon, the city's housing chief.

Kairos Shen, the city's chief of planning, said the threshold change could help smaller projects grow. "We hope by rolling back the threshold to 10 units, that from one project we'll get up to about 15 units," he said. Officials estimate the shift could add 100 or more units a year.

The plan would also allow developers to build their affordable units more than half a mile from their market-rate buildings. Asked whether that could push affordable housing into communities outside Boston, Dillon was blunt: "Over my dead body."

Separately, the city wants to lower the fees condo developers pay into the affordable housing fund, hoping to spur more condo construction. And it proposes holding linkage fees — which require large commercial developers to contribute to affordable housing and job training — at current levels through 2027 instead of letting them rise automatically, while allowing those payments in seven installments rather than two.

"We're doing that to actually basically send a signal that, 'Hey, we recognize that the difficult market conditions continue, and we wanna make sure that we are sensitive to this particular linkage requirement [that] would make it even more difficult for some of these stalled projects to go forward,'" Shen said.

Few commercial projects are in the pipeline; only one under review would owe a linkage payment in 2026.

The stakes are visible in the permitting numbers. In the first nine months of this year, the city permitted 2,448 units. That puts Boston on pace for its best permitting year since 2022, but still far short of the 13,000 homes Wu set as a goal for her first term in her Boston Housing Strategy 2025.

The city has spent years trying to prod construction, creating an office-to-residential conversion program, a $110 million Housing Accelerator Fund and, most recently, time-limited tax breaks for certain residential projects.

The two linkage fee changes must clear the planning board and zoning commission. The remaining proposals need approval from the city council and then the zoning commission; the council could reject them with a two-thirds vote.

Asked whether the administration considered easing the 17-to-20 percent requirement that developers find so burdensome, Dillon declined to budge. She argued the package can jumpstart building while still protecting affordable housing.

"We have developers pay into the [inclusionary zoning] and linkage fund so we can support developments throughout Boston that right now need affordable resources to advance," she said. "So we have two goals, and we think through these policy changes, we're able to meet both."