Job descriptions have a habit of drifting. Someone capable takes on extra work, the description is updated to match, and over a few years the role has been quietly rewritten around one individual.
The moment that person leaves, the organization discovers it is trying to recruit for a job that only ever existed once.
Accountabilities, not activities
A useful profile states what the role is answerable for, not the list of tasks the current holder happens to perform. Activities change with tools and workload; accountabilities are far more stable.
Document the KSAOs
Knowledge, skills, abilities and other attributes should be recorded explicitly. They are what turn a profile into something recruitment, evaluation and development can all use.
One source, many uses
Done properly, a role library serves recruitment, performance evaluation, job evaluation, pay banding and development planning from a single document. Done badly, each of those functions maintains its own version and none of them agree.