As an administrator, it would help with field re-use to have the Custom Field description set as part of the Custom Field context.

We use a JIRA as a general issue tracker, and use over 100 custom fields. When re-using fields between projects, it would be helpful to have the Custom Field description be related to the Context (currently Global). In this manner, the description can be set for different contexts as documentation specific to that project.

Example:

I have a custom field titled "Justification". For project 1, the criteria for evaluating this field may be different than in project 2. Setting a context specific description on each project would produce more accurate submissions from the end user.