Activists intend to file an environmental appeal on a project that would build 75 units of housing at 2918 Mission St., and that plan has the developer ready to do battle.

“Please consider this email to be the equivalent to a fencer’s salute before beginning a duel,” wrote Robert Tillman, the property owner and developer of 2918 Mission. “We intend to have fun creating a legal precedent that will shut down forever the shakedown racket of MEDA, of Calle 24, and of the other Mission Activists.”

The appeal in this case is being brought by Scott Weaver on behalf of the Calle 24 Latino Cultural Corridor group. MEDA, the Mission Economic Development Agency, is not involved in the appeal — the nonprofit made an offer to purchase the property, but the offer was rejected as insufficient.

The project was approved after two tense hearings before the Planning Commission, where commissioners argued that the project provided little affordable housing but couldn’t argue with a state law that demands projects be approved if they reach a certain threshold of affordability — a threshold lower than what local laws prescribe.

Once filed, the Board of Supervisors first considers the appeal. If they uphold it, Tillman would file suit against the city for violating the state’s housing laws, thereby setting a precedent, if he were successful.

Weaver, for his part, said it would be irresponsible not to appeal the project to secure additional environmental mitigation, and pushed back on the characterization of activist objections to development as a “shakedown,” saying the groups he represents do not ask for benefits that would go to their own coffers, but rather push for increased below-market-rate housing onsite and other concessions, such as hosting temporary shelters on the site before construction begins or finding muralists in the neighborhood to decorate blank walls.

“We do not intend to request any concessions from you. We have met with you several times and you have been clear that you have no intention to even minimally provide community benefits that other developers have been willing to provide,” he responded to Tillman.

Weaver, who volunteers as legal representation for groups like Calle 24, said development in the Mission has not stopped it from becoming an area of “advanced gentrification,” according to a UC Berkeley study. He also argues that the number of market-rate units developed in the neighborhood has far exceeded the number anticipated by the 2008 city plan for the area, called the Eastern Neighborhoods Plan.

“Seeking equity from developers is hardly a shakedown — it’s a desperate attempt to keep the community intact. But, then again, your interest is only to maximize the bottom line,” Weaver wrote to Tillman. “I hope you see the irony of your planned attempt to ‘shut down’ those very activists and organizations that are trying to keep the Mission’s Latino Community alive.”

The escalating confrontation is a tonally more aggressive version of a disagreement that has played out between developers and activists repeatedly in the neighborhood: Those who advocate for more development say any and all housing added to San Francisco’s starved market will help alleviate displacement pressures, and tenant advocates who insist only an influx of affordable housing will help working class families stay in place.

On previous occasions where a resolution didn’t crystallize between the parties left to their own devices, Supervisor Hillary Ronen and her staff have stepped in to mediate — most recently, for 40 units of housing at 1726 Mission, and a nonprofit space planned at 1850 Bryant Street.

Amy Beinart, an aide to Ronen, said the office hasn’t yet reached out to Tillman and Weaver, but would be willing to lend assistance. Otherwise, she said, Ronen will remain neutral before reviewing the case and subsequently casting a vote to uphold or dismiss the appeal at the Board of Supervisors.