What is the best tool to use when creating a list of skills for a...

A job analysis is a foundational HR tool used to identify the essential duties, responsibilities, and skills required for a specific role. It precedes the creation of job descriptions and competency models.

Official Extract:

"Job analysis systematically collects information about the duties, responsibilities, necessary skills, outcomes, and work environment of a particular job."

(Source: HRCI PHR Content Outline 2024–2025, Talent Planning and Acquisition Section, Job Analysis and Design)