New York City took a crucial step earlier this year towards becoming the country's leader in public green leasing when mayor Bloomberg's Green Lease Task Force released model green lease language aimed at addressing the split incentive in most commercial office leases. The language was incorporated by Silverstein Properties into its lease with the law firm WilmerHale at the LEED Gold-certified 7 World Trade Center and adopted by the city for all of its future leases. Recently, the city of San Francisco joined the conversation by launching a Green Tenant Toolkit, created at the recommendation of the San Francisco mayor's Task Force on Existing Commercial Buildings. The free, on-line resource is being promoted as adaptable for any geographic location, though it was created for buildings in San Francisco. It was developed by a 26-member group of design, construction, real estate, and environmental professionals assembled by San Francisco's Business Council on Climate Change. The toolkit is divided into three sections: a general green leasing guide, tips on stakeholder engagement, and a checklist of items summarizing key sustainability metrics for any property. The toolkit is a good starting point for tenants and landlords that are unfamiliar with green leasing and want to learn the basics, no matter where they may find themselves in the leasing process. The N.Y.C. model language is included in the Green Tenant Toolkit's database of additional resources. San Francisco led two major urban green building indices this year: topping a list of North America's greenest cities in a study from Siemens and, for a second consecutive year, leading Cushman & Wakefield's Green Building Opportunity Index. Midtown Manhattan placed second in the latter; N.Y.C. ranked third in the Siemens study. Stephen Del Percio is a construction attorney in New York, N.Y.