A type of improvement required under the provisions of a lease agreement is known as:

The concept of a mandatory improvement in the context of a lease agreement refers to specific improvements or modifications that a tenant is required to make to the leased property. These improvements are often stipulated in the lease to ensure that the property meets certain standards or usage requirements laid out by the landlord.

Mandatory improvements are essential for maintaining the functionality, safety, and value of the property. For instance, a lease may require a tenant to install certain fixtures, comply with safety regulations, or ensure the property meets building codes. The rationale behind this requirement is typically to protect the investment of the landlord and optimize the property's utility for both parties.

In contrast, optional improvements refer to enhancements that the tenant can choose to undertake but are not required by the lease. Tenant enhancements could also include upgrades the tenant makes for their benefit, which might be optional depending on the terms of the lease. Structural changes usually involve significant modifications to the property’s infrastructure and may not be stipulated in the same manner as mandatory improvements.

Therefore, the designation of mandatory improvements signifies an obligation set forth within the lease that aims to maintain the integrity and usability of the property during the tenant's occupancy. This understanding is crucial for both landlords and tenants during negotiations and compliance with lease terms.