Your voice — learned from what you actually sent.
Edit a draft in the studio and save it. That edit becomes a brand-voice example, and future runs are written against it — tone and structure only, never the facts. A run picks up to eight of them, and it picks them for this target: the saved edits whose subject looks most like the company being pitched, with at least one example of each deliverable it has to write.
Nobody has to describe their tone of voice. You just edit, and it learns.