Detailed enough to explain the work, its practical allocation and the knowledge required, without creating artificial precision. Manager-verified estimates should agree with the project plan and any contract or staffing records.
Make each duty understandable
Replace vague phrases such as technical support with the actual decisions, systems and responsibilities involved. Explain which work follows standard instructions and which uses deeper process understanding. Include representative evidence for material specialist tasks and acknowledge routine responsibilities.
A list of percentages without supporting context is less useful than a credible picture of the proposed working role. Draft the breakdown after the manager interview, never before it. The workable order is a conversation about what the week actually contains, a written duty list returned to the manager for correction, reconciliation against the project plan and staffing records, and then the narrative a reader outside the company can follow.
Hypothetical example: a freight brokerage prepares a duty breakdown from a job posting, the operations manager later corrects half of it, and the file ends up holding two documents that describe different jobs. Where an allocation or percentage appears, it should emerge from the plan rather than be chosen first and justified afterwards, since the allocation is a finding and not a target. Date each correction so the final version stays identifiable, because a file that shows its own history is easier to explain than a suspiciously tidy one.