A vague letter may fail to explain why the actual work fits a listed profession. A matching title alone does not establish the nature of the duties. Ask for enough factual detail to assess the role before treating the letter as evidence that all professional requirements are satisfied.
Clarify the work rather than embellish the wording
Identify which statements could describe almost any employee, then ask the hiring manager for the underlying activity and required knowledge. Check whether the resulting description supports the category and your credentials. Do not promise that adding detail will produce approval; it may instead reveal a mismatch that was previously hidden.
Citizenship, prearranged employment and a temporary purpose also remain necessary. The letter is part of the evidence, not a replacement for reviewing the complete eligibility picture. The distinction worth holding onto is between describing the job better and describing a different job.
Clarification means obtaining information that already exists inside the organization and was simply left out; embellishment means adding responsibilities in order to reach a category. The first strengthens a file, the second creates a document the applicant will have to defend under questioning about work they may not actually do. Test each proposed addition against a simple question: could the person who supervises this role confirm it from their own knowledge, and does anything in the company's records contradict it?
Where a duty is genuinely performed but was omitted, add it and identify who can verify it. Where it is being added because the category seems to require it, that is a signal that the position and the category may not fit, and the fit is what needs examining.