A worker who does assigned tasks without constant supervision is said to have:

A worker who can complete tasks independently without needing constant supervision demonstrates reliability. This quality reflects not only the worker's ability to efficiently carry out responsibilities but also their trustworthiness and accountability. Employers value reliable workers because they can count on them to meet deadlines and maintain productivity without requiring ongoing oversight.

While perseverance involves persistence in the face of challenges and adaptability refers to how well a person adjusts to changes, neither directly addresses the ability to work autonomously. Poise relates more to a person's composure and confidence, which are important attributes, but they do not specifically signify the capability to perform work without supervision. Thus, reliability is the most fitting characteristic of a worker who performs their assigned tasks independently.