Many clients read AGENTS.md at the repo root: language, forbidden directories, test commands. It travels with the clone.
A skill is a SKILL.md in a skills directory, loaded when the task matches. It fits open-a-PR, deploy, and review checklists, and can be reused across repos.
Put stable constraints — secrets, generated folders, style — in AGENTS.md or Cursor Rules. Put reusable steps in a skill. Do not stuff a long playbook into every repo root.
Write one short AGENTS.md, then install one development skill from this directory. See Cursor Rules vs skills and how to write a SKILL.md.